path: root/docs/superpowers/plans/2026-08-20-compose-and-send.md

# Compose and Send Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Add the write half of qtmaildir: compose, reply, forward and send, with markdown bodies, autosaved drafts and a cancellable send delay, without the application ever speaking a network protocol.

**Architecture:** Four new units. `MessageBuilder` turns an `OutgoingMessage` into RFC822 bytes using GMime and cmark-gfm. `DraftStore` writes those bytes into a Maildir folder. `MessageSender` pipes them to a per-account `send_command` over stdin. `ComposeWindow` is the only one that owns widgets, and composes the other three. Three of the four are tested without a painter.

**Tech Stack:** Qt 6.11 (Widgets, Test), GMime 3.0 (already linked), cmark-gfm 0.29 (new, stock Slackware), notmuch (read-only, unchanged), CMake + Ninja, QTest.

**Implementation branch:** `compose-and-send`, currently identical to `master`. This plan lives on `master` so it is readable from either.

---

## Before starting

Read these, in this order. They are not optional context; each one records a
trap this plan walks past.

1. The spec: `docs/superpowers/specs/2026-08-20-compose-and-send-design.md`.
2. `CLAUDE.md`, in particular **Web view security**, **Adding an action is FIVE
   places**, and the gmime include-order rule.
3. `src/mailsync.cpp:172-205`, the `QProcess` precedent `MessageSender` copies.

**Verified facts this plan rests on** (measured on 2026-08-20, not assumed):

- `pkg-config --modversion libcmark-gfm` reports `0.29.0.gfm.13`.
- **`libcmark-gfm-extensions` has NO pkg-config file.** Only `libcmark-gfm.pc`
  exists. The extensions library is `/usr/lib64/libcmark-gfm-extensions.so` and
  must be found with `find_library`, the way notmuch already is. The spec's "a
  `pkg_check_modules` line" covers only half of it.
- With `CMARK_OPT_SAFE` and the three extensions attached, a probe confirmed:
  autolink wraps a bare URL, `~~x~~` becomes `<del>`, `- [ ]` becomes
  `<input type="checkbox" disabled>`, a table renders as literal pipes (the
  extension is not attached), and `<script>` becomes `<!-- raw HTML omitted -->`.

## Task order and why

`MessageBuilder` first because everything downstream consumes its output and it
is pure. Then `DraftStore` and `MessageSender`, both narrow and testable against
stubs. `ComposeContext` next, pure logic where the subtle recipient bugs live.
`ComposeWindow` last, because it composes all four and is the only part that
cannot be tested without a painter.

Config and the actions come before the window that reads them.

---

## File structure

Every file created or modified, and what each is responsible for.

**Created:**

| File | Responsibility |
|---|---|
| `src/markdownrenderer.h/.cpp` | cmark-gfm only. Markdown source in, HTML fragment out. No GMime, no Qt widgets. Separate from `MessageBuilder` so the extension configuration is tested on its own. |
| `src/messagebuilder.h/.cpp` | GMime only. `OutgoingMessage` in, RFC822 bytes out. No I/O except reading attachment files. |
| `src/draftstore.h/.cpp` | Maildir writes. Bytes plus a folder in, a written path out. Serves drafts and sent copies; they are the same operation. |
| `src/messagesender.h/.cpp` | `QProcess` over the account's `send_command`. The one send funnel and the outbox seam. |
| `src/composecontext.h/.cpp` | Pure logic that decides what a composer opens with: recipients, subject prefixing, account resolution. No widgets. |
| `src/composewindow.h/.cpp` | `QMainWindow`, one per draft. The only unit here that owns widgets. |
| `src/senddialog.h/.cpp` | The send popup: countdown, undo, staged progress. Modal to the composer. |
| `src/formattoolbar.h/.cpp` | The markdown transformations, as free functions over text plus a selection, and the toolbar that calls them. The functions are tested; the toolbar is not. |
| `tests/test_markdownrenderer.cpp` | Extensions on, tables and raw HTML off. |
| `tests/test_messagebuilder.cpp` | The bulk. Asserts on generated bytes. |
| `tests/test_draftstore.cpp` | Filename validity, unlinking, dirty check, unwritable directory. |
| `tests/test_messagesender.cpp` | Stub commands. Exactly two outcomes. |
| `tests/test_composecontext.cpp` | Recipient derivation and account resolution. |
| `tests/test_formattoolbar.cpp` | Wrap, insert, per-line quote, cursor placement. |

**Modified:**

| File | Change |
|---|---|
| `CMakeLists.txt` | cmark-gfm: `pkg_check_modules` for the core, `find_library` for the extensions. |
| `src/CMakeLists.txt` | The eight new `.cpp` files; link cmark-gfm. |
| `src/types.h` | `ComposeContext` and `OutgoingMessage`. |
| `src/config.h/.cpp` | `Account::sendCommand`, the `[compose]` section, startup validation. |
| `src/maildirname.h/.cpp` (created) | `freshMaildirName()` extracted from `notmuchworker.cpp`'s anonymous namespace so `DraftStore` shares it rather than duplicating it. |
| `src/notmuchworker.cpp` | Use the extracted `freshMaildirName()`. |
| `src/keymap.cpp` | Six actions in `knownActions()`; five bindings in `defaultBindings()` (`save_message` gets none, which item 132 now permits). |
| `src/mainwindow.h/.cpp` | Six action handlers, the `Message` menu, the icon table, the composer registry, the quit path. |
| `src/messageview.h/.cpp` | The receive-only ribbon. |
| `tests/CMakeLists.txt` | Six new test registrations. |
| `tests/test_mainwindow.cpp` | Action enablement, the ribbon, the quit path. |
| `translations/qtmaildir_it_IT.ts` | Refreshed by `lupdate`; every new string translated. |
| `CHANGELOG.md` | One `[Unreleased]` entry. |
| `docs/superpowers/plans/2026-08-03-post-0.1.0-usability.md` | Close item 123. |

**Deliberately not created:** a `ComposeWindow` geometry save/restore, an
outbox, a syntax highlighter. The spec explains each; do not add them.

---

### Task 1: cmark-gfm in the build, and the markdown renderer

The only new dependency. Doing it first means every later task can assume it.

**Files:**
- Modify: `CMakeLists.txt:26-35` (beside the notmuch and GMime blocks)
- Modify: `src/CMakeLists.txt:7` (source list) and `:37-39` (link line)
- Create: `src/markdownrenderer.h`, `src/markdownrenderer.cpp`
- Create: `tests/test_markdownrenderer.cpp`
- Modify: `tests/CMakeLists.txt`

- [ ] **Step 1: Add cmark-gfm to the top-level CMakeLists**

Insert after the `pkg_check_modules(GMIME ...)` line at `CMakeLists.txt:35`:

```cmake
# cmark-gfm renders the composer's markdown body into the HTML part.
#
# TWO lookups, not one, and this is the trap: only the CORE library ships a
# pkg-config file. `libcmark-gfm-extensions` has none (verified 2026-08-20 on
# Slackware, cmark-gfm-0.29.0.gfm.13), so it is located by hand exactly as
# notmuch is. The extensions library is not optional here: autolink,
# strikethrough and tasklist all live in it, and without it a bare URL in a
# mail body is not a link.
pkg_check_modules(CMARK_GFM REQUIRED IMPORTED_TARGET libcmark-gfm)
find_library(CMARK_GFM_EXTENSIONS_LIBRARY NAMES cmark-gfm-extensions)
if(NOT CMARK_GFM_EXTENSIONS_LIBRARY)
    message(FATAL_ERROR
        "libcmark-gfm-extensions not found. It ships with cmark-gfm but has "
        "no pkg-config file; it provides autolink, strikethrough and tasklist.")
endif()
message(STATUS "Found cmark-gfm extensions: ${CMARK_GFM_EXTENSIONS_LIBRARY}")
```

- [ ] **Step 2: Link it in `src/CMakeLists.txt`**

Change the `target_link_libraries(qtmaildir_lib ...)` call at `src/CMakeLists.txt:37-39` to:

```cmake
target_link_libraries(qtmaildir_lib
    PUBLIC Qt6::Widgets Qt6::Svg Qt6::WebEngineWidgets PkgConfig::GMIME
           ${NOTMUCH_LIBRARY} PkgConfig::CMARK_GFM
           ${CMARK_GFM_EXTENSIONS_LIBRARY})
```

- [ ] **Step 3: Verify the build system finds both halves**

Run:
```bash
cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug 2>&1 | grep -i cmark
```
Expected: a line reading `Found cmark-gfm extensions: /usr/lib64/libcmark-gfm-extensions.so`. If the configure fails instead, the package is missing and nothing below will work.

- [ ] **Step 4: Write the failing test**

Create `tests/test_markdownrenderer.cpp`:

```cpp
/*
 * qtmaildir - a Qt6 mail client for notmuch-indexed Maildirs
 * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <QtTest>

#include "markdownrenderer.h"

class TestMarkdownRenderer : public QObject
{
    Q_OBJECT

private slots:
    void commonMarkBasicsRender();
    void autolinkTurnsABareUrlIntoALink();
    void strikethroughRenders();
    void tasklistRenders();
    void tablesAreNotEnabled();
    void rawHtmlIsSuppressed();
    void accentedTextSurvivesAsUtf8();
    void emptyInputProducesEmptyOutput();
};

void TestMarkdownRenderer::commonMarkBasicsRender()
{
    const QString html = MarkdownRenderer::toHtml(
        QStringLiteral("**bold** and *italic* and `code`"));

    QVERIFY2(html.contains(QStringLiteral("<strong>bold</strong>")),
             qPrintable(QStringLiteral("no <strong> in: %1").arg(html)));
    QVERIFY(html.contains(QStringLiteral("<em>italic</em>")));
    QVERIFY(html.contains(QStringLiteral("<code>code</code>")));
}

void TestMarkdownRenderer::autolinkTurnsABareUrlIntoALink()
{
    // The whole reason cmark-gfm was chosen over plain cmark. Under
    // CommonMark a bare URL is text, and a bare URL in mail is expected to be
    // clickable.
    const QString html = MarkdownRenderer::toHtml(
        QStringLiteral("see https://example.org for details"));

    QVERIFY2(html.contains(QStringLiteral("<a href=\"https://example.org\"")),
             qPrintable(QStringLiteral("autolink did not fire: %1").arg(html)));
}

void TestMarkdownRenderer::strikethroughRenders()
{
    const QString html = MarkdownRenderer::toHtml(QStringLiteral("~~gone~~"));
    QVERIFY2(html.contains(QStringLiteral("<del>gone</del>")),
             qPrintable(QStringLiteral("no <del> in: %1").arg(html)));
}

void TestMarkdownRenderer::tasklistRenders()
{
    // Known ceiling, recorded in the spec: many mail clients strip the
    // checkbox, so those recipients see the item with no marker. The plain
    // part still carries `- [ ]`, so nothing is lost.
    const QString html = MarkdownRenderer::toHtml(
        QStringLiteral("- [ ] todo\n- [x] done"));

    QVERIFY2(html.contains(QStringLiteral("type=\"checkbox\"")),
             qPrintable(QStringLiteral("no checkbox in: %1").arg(html)));
    QVERIFY(html.contains(QStringLiteral("checked")));
}

void TestMarkdownRenderer::tablesAreNotEnabled()
{
    // Deliberately off: tables render badly across mail clients regardless of
    // who generates them. The extension EXISTS in the library, so this asserts
    // a decision rather than a limitation, and it would silently start passing
    // the wrong way if someone attached the extension "for completeness".
    const QString html = MarkdownRenderer::toHtml(
        QStringLiteral("| a | b |\n|---|---|\n| 1 | 2 |"));

    QVERIFY2(!html.contains(QStringLiteral("<table")),
             qPrintable(QStringLiteral("the table extension is attached: %1").arg(html)));
    QVERIFY2(html.contains(QStringLiteral("| a | b |")),
             "the table source did not survive as literal text");
}

void TestMarkdownRenderer::rawHtmlIsSuppressed()
{
    // CMARK_OPT_SAFE. The body is the user's own text, but a body that can
    // inject markup into its own generated HTML part is a sharp edge with no
    // upside.
    const QString html = MarkdownRenderer::toHtml(
        QStringLiteral("<script>alert(1)</script>\n\nafter"));

    QVERIFY2(!html.contains(QStringLiteral("<script>")),
             qPrintable(QStringLiteral("raw HTML leaked: %1").arg(html)));
    QVERIFY2(html.contains(QStringLiteral("after")),
             "suppressing raw HTML ate the rest of the document");
}

void TestMarkdownRenderer::accentedTextSurvivesAsUtf8()
{
    // This user writes Italian. A body containing accented characters is
    // every message, not an edge case, and a UTF-8 round trip through a C
    // library is exactly where it would be lost.
    const QString source = QString::fromUtf8("perch\xC3\xA9 \xC3\xA8 cos\xC3\xAC");
    const QString html = MarkdownRenderer::toHtml(source);

    QVERIFY2(html.contains(source),
             qPrintable(QStringLiteral("accents did not survive: %1").arg(html)));
}

void TestMarkdownRenderer::emptyInputProducesEmptyOutput()
{
    // reply_no_quote opens a composer with an empty body, and it must not
    // produce a stray paragraph or crash the renderer.
    QVERIFY(MarkdownRenderer::toHtml(QString()).trimmed().isEmpty());
}

QTEST_APPLESS_MAIN(TestMarkdownRenderer)
#include "test_markdownrenderer.moc"
```

Note `QTEST_APPLESS_MAIN`, not `QTEST_MAIN`: this test needs no QApplication and no platform plugin at all.

- [ ] **Step 5: Register the test**

Add to `tests/CMakeLists.txt`, beside the other `add_qtmaildir_test` calls:

```cmake
add_qtmaildir_test(markdownrenderer)
```

- [ ] **Step 6: Run it to verify it fails**

Run: `cmake --build build 2>&1 | tail -5`
Expected: FAIL, `markdownrenderer.h: No such file or directory`.

- [ ] **Step 7: Write the header**

Create `src/markdownrenderer.h` (GPL header as in every other file, then):

```cpp
#pragma once

#include <QString>

/// Renders the composer's markdown body into the HTML part's fragment.
///
/// A namespace of free functions rather than a class: there is no state, and
/// keeping it painter-free and widget-free is what lets the extension
/// configuration be tested on its own. `MessageBuilder` calls this; nothing
/// else does.
namespace MarkdownRenderer {

/// The markdown source as an HTML fragment: no <html>, <head> or <body>.
///
/// Three extensions are enabled (autolink, strikethrough, tasklist) and
/// tables are deliberately not. Raw HTML in the input is suppressed by
/// CMARK_OPT_SAFE.
QString toHtml(const QString &markdown);

}  // namespace MarkdownRenderer
```

- [ ] **Step 8: Write the implementation**

Create `src/markdownrenderer.cpp` (GPL header, then):

```cpp
// cmark-gfm's headers are C and carry no Qt interaction, so the gmime
// include-order rule does not apply here. They still go first, for consistency
// with mimeparser.cpp.
#include <cmark-gfm.h>
#include <cmark-gfm-core-extensions.h>

#include "markdownrenderer.h"

#include <QByteArray>

namespace {

/// The extensions this application enables, by cmark-gfm's own names.
///
/// `table` is absent deliberately, not by oversight: tables render badly
/// across mail clients regardless of who generates them. `tagfilter` is absent
/// because CMARK_OPT_SAFE already suppresses raw HTML wholesale, which is the
/// stronger measure.
const char *const kExtensions[] = { "autolink", "strikethrough", "tasklist" };

}  // namespace

QString MarkdownRenderer::toHtml(const QString &markdown)
{
    if (markdown.isEmpty())
        return {};

    // Idempotent and required before cmark_find_syntax_extension() can resolve
    // any name. Calling it per render rather than once at startup keeps this
    // function free of initialisation order concerns; it is a hash lookup
    // after the first call.
    cmark_gfm_core_extensions_ensure_registered();

    // SAFE suppresses raw HTML in the INPUT. It does not escape the output,
    // which is markup by definition.
    const int options = CMARK_OPT_DEFAULT | CMARK_OPT_SAFE;

    cmark_parser *parser = cmark_parser_new(options);
    if (!parser)
        return {};

    for (const char *name : kExtensions) {
        // A missing extension is a broken installation rather than a
        // condition to handle: the library was found by CMake. Skipping it
        // degrades to plain CommonMark rather than crashing.
        if (cmark_syntax_extension *extension = cmark_find_syntax_extension(name))
            cmark_parser_attach_syntax_extension(parser, extension);
    }

    const QByteArray utf8 = markdown.toUtf8();
    cmark_parser_feed(parser, utf8.constData(), static_cast<size_t>(utf8.size()));

    cmark_node *document = cmark_parser_finish(parser);
    if (!document) {
        cmark_parser_free(parser);
        return {};
    }

    // The extension list must be passed to the renderer as well as to the
    // parser. Passing nullptr here parses the tasklist correctly and then
    // renders it as a plain list item, which looks like the extension never
    // worked.
    char *html = cmark_render_html(document, options,
                                   cmark_parser_get_syntax_extensions(parser));
    const QString result = html ? QString::fromUtf8(html) : QString();

    free(html);
    cmark_node_free(document);
    cmark_parser_free(parser);

    return result;
}
```

- [ ] **Step 9: Add the source to the library**

Add `markdownrenderer.cpp` to the `qtmaildir_lib` list in `src/CMakeLists.txt`, beside `mimeparser.cpp`.

- [ ] **Step 10: Run the test to verify it passes**

Run: `ctest --test-dir build -R markdownrenderer --output-on-failure`
Expected: PASS, 8 test functions.

- [ ] **Step 11: Mutation-check the extension list**

The tests must fail when an extension is dropped, or they assert nothing. Verify at least one:

```bash
sed -i 's/"autolink", "strikethrough", "tasklist"/"strikethrough", "tasklist"/' src/markdownrenderer.cpp
cmake --build build >/dev/null 2>&1
ctest --test-dir build -R markdownrenderer 2>&1 | grep -E 'Passed|Failed'
git checkout src/markdownrenderer.cpp
cmake --build build >/dev/null 2>&1
```
Expected: `Failed` on `autolinkTurnsABareUrlIntoALink`. If it passes, the test is measuring nothing and must be fixed before continuing.

- [ ] **Step 12: Commit**

```bash
git add CMakeLists.txt src/CMakeLists.txt src/markdownrenderer.h \
        src/markdownrenderer.cpp tests/test_markdownrenderer.cpp \
        tests/CMakeLists.txt
git commit -S -m "feat(compose): render markdown bodies with cmark-gfm, item 123

The composer's body is markdown and the text/html part is generated from it.
cmark-gfm rather than plain cmark for autolink: under CommonMark a bare URL
in a mail body is not a link, and in mail it is expected to be clickable.

Three extensions are enabled and tables are deliberately not, since they
render badly across mail clients whoever generates them. Raw HTML in the
input is suppressed with CMARK_OPT_SAFE: the body is the user's own text,
but a body that can inject markup into its own generated HTML part is a
sharp edge with no upside.

The build needs TWO lookups. Only the core library ships a pkg-config file;
libcmark-gfm-extensions has none and is located with find_library, the way
notmuch already is. All three extensions live in that second library, so
finding only the first produces a build that compiles and silently renders
plain CommonMark."
```

---

### Task 2: The two structs and the configuration keys

Data before behaviour. Nothing here has logic worth testing on its own; the
validation added in Step 6 does.

**Files:**
- Modify: `src/types.h` (append before the `Q_DECLARE_METATYPE` block at the end)
- Modify: `src/config.h` (the `Account` struct, and a `ComposeSettings` struct)
- Modify: `src/config.cpp` (parsing and startup validation)
- Modify: `tests/test_config.cpp`

- [ ] **Step 1: Add the structs to `src/types.h`**

Insert before the `Q_DECLARE_METATYPE(ThreadSummary)` line:

```cpp
/// What opens a composer. Built by MainWindow, consumed by ComposeWindow.
///
/// Built from the DATABASE, never from the model. The model's data comes from
/// the query, so a row whose state has not been re-queried carries stale
/// values, and a reply built from a stale row would carry the wrong
/// recipients. This is the same rule Restore already follows.
struct ComposeContext
{
    enum class Kind { New, Reply, ReplyAll, Forward };

    QString accountKey;          ///< Which account sends. Resolved by ComposeContext's rules.
    Kind kind = Kind::New;
    QString originalPath;        ///< The .eml being replied to or forwarded. Empty for New.
    QString inReplyTo;           ///< Message-ID of the original.
    QStringList references;      ///< The original's References plus its Message-ID.
    QStringList to;              ///< Pre-filled, the user's own addresses already stripped.
    QStringList cc;
    QString subject;             ///< Re:/Fwd: prefixed, an existing prefix not doubled.
    QString quotedBody;          ///< The >-prefixed original. Empty when the action does not quote.
    bool seedHtml = false;       ///< Did the original carry a text/html part.
    QStringList attachments;     ///< Carried forward for Forward, empty otherwise.
};

/// What the composer produces, consumed by MessageBuilder.
///
/// In-Reply-To and References are NOT optional. Without them a reply appears
/// as an orphan thread in the sender's own client.
struct OutgoingMessage
{
    QString accountKey;
    QStringList to;
    QStringList cc;
    QStringList bcc;
    QString subject;
    QString markdownBody;        ///< The source text, exactly as typed.
    bool sendHtml = false;       ///< The composer's per-message toggle.
    QStringList attachments;     ///< Local paths, read at build time.
    QString inReplyTo;
    QStringList references;
};
```

These need no `Q_DECLARE_METATYPE`: neither crosses a queued connection. The
composer never touches `NotmuchWorker`.

- [ ] **Step 2: Add `sendCommand` to `Account`**

In `src/config.h`, inside `struct Account`, after the `trash` member:

```cpp
    /// The command that sends mail from this account, receiving the complete
    /// RFC822 message on stdin. Optional, and its ABSENCE is meaningful:
    /// an account without one is receive-only by construction.
    ///
    /// Not a separate `receive_only` key. The capability IS this command's
    /// presence, so there is nothing to keep in step and nothing to
    /// contradict. One real account is receive-only on purpose and gains no
    /// configuration at all, which is the point.
    ///
    /// Split with QProcess::splitCommand and run WITHOUT a shell, exactly as
    /// [sync] command is, so nothing in a message body, a recipient address or
    /// a display name can reach sh. No message content is ever placed in an
    /// argument: recipients come from the message's own headers.
    QString sendCommand;

    /// Whether this account can send at all.
    bool canSend() const { return !sendCommand.isEmpty(); }
```

- [ ] **Step 3: Add the `[compose]` settings struct**

In `src/config.h`, above `class Config`:

```cpp
/// The [compose] section. Every key is optional with the default shown.
struct ComposeSettings
{
    /// Where the quote goes in a reply. Whether to quote AT ALL is not here:
    /// that is decided by which action was invoked (reply quotes,
    /// reply_no_quote does not).
    enum class QuotePosition { Above, Below };

    QuotePosition quotePosition = QuotePosition::Above;

    /// Seeds the per-message toggle for New and Forward only. Reply and
    /// Reply-all seed from whether the original carried a text/html part,
    /// ignoring this value: an HTML part in the original is a fact about the
    /// sender's software, not a guess about their taste.
    bool sendHtml = true;

    int autosaveIntervalMs = 30000;

    /// The undo window before sending. Zero skips the countdown entirely and
    /// sends at once, for anyone who finds it irritating.
    int sendDelayMs = 5000;

    /// Preferred account for a New message when the dropdown is on All
    /// accounts. Falls through when it names an account that cannot send.
    QString defaultAccount;

    qint64 attachmentWarnBytes = 26214400;
};
```

And in `class Config`, beside `accounts()`:

```cpp
    ComposeSettings compose() const { return m_compose; }

    /// Every account with a send_command, in configuration order.
    ///
    /// Empty is a valid read-only installation, NOT a misconfiguration: the
    /// compose actions are simply disabled and nothing is warned about.
    QList<Account> sendingAccounts() const;
```

with `ComposeSettings m_compose;` among the private members.

- [ ] **Step 4: Write the failing config test**

Add to `tests/test_config.cpp`, and declare each in the `private slots:` block:

```cpp
void TestConfig::anAccountWithoutASendCommandIsReceiveOnly()
{
    QTemporaryDir dir;
    const QString path = dir.filePath(QStringLiteral("qtmaildir.conf"));
    {
        QSettings s(path, QSettings::IniFormat);
        s.beginGroup(QStringLiteral("account.work"));
        s.setValue(QStringLiteral("maildir"), QStringLiteral("work"));
        s.setValue(QStringLiteral("trash"), QStringLiteral("Trash"));
        s.setValue(QStringLiteral("send_command"), QStringLiteral("msmtp -a work -t"));
        s.endGroup();
        s.beginGroup(QStringLiteral("account.listsonly"));
        s.setValue(QStringLiteral("maildir"), QStringLiteral("listsonly"));
        s.setValue(QStringLiteral("trash"), QStringLiteral("Trash"));
        s.endGroup();
    }

    Config config;
    QVERIFY(config.load(path));

    const QList<Account> accounts = config.accounts();
    QCOMPARE(accounts.size(), 2);

    // The capability is the command's presence. Nothing else expresses it.
    for (const Account &account : accounts) {
        if (account.key == QStringLiteral("work")) {
            QVERIFY2(account.canSend(), "an account with send_command cannot send");
        } else {
            QVERIFY2(!account.canSend(),
                     "an account without send_command reported as able to send");
        }
    }

    QCOMPARE(config.sendingAccounts().size(), 1);
    QCOMPARE(config.sendingAccounts().first().key, QStringLiteral("work"));
}

void TestConfig::composeSettingsDefaultWhenTheSectionIsAbsent()
{
    // Every [compose] key is optional. A config that has never heard of this
    // feature must produce working defaults rather than zeros: a sendDelayMs
    // of 0 read from an absent key would silently disable the undo window.
    QTemporaryDir dir;
    const QString path = dir.filePath(QStringLiteral("qtmaildir.conf"));
    {
        QSettings s(path, QSettings::IniFormat);
        s.beginGroup(QStringLiteral("account.work"));
        s.setValue(QStringLiteral("maildir"), QStringLiteral("work"));
        s.setValue(QStringLiteral("trash"), QStringLiteral("Trash"));
        s.endGroup();
    }

    Config config;
    QVERIFY(config.load(path));

    const ComposeSettings compose = config.compose();
    QCOMPARE(compose.quotePosition, ComposeSettings::QuotePosition::Above);
    QCOMPARE(compose.sendHtml, true);
    QCOMPARE(compose.autosaveIntervalMs, 30000);
    QCOMPARE(compose.sendDelayMs, 5000);
    QCOMPARE(compose.attachmentWarnBytes, qint64(26214400));
    QVERIFY(compose.defaultAccount.isEmpty());
}

void TestConfig::aZeroSendDelayIsHonouredRatherThanTreatedAsUnset()
{
    // send_delay_ms = 0 is a real setting meaning "send at once", and it is
    // exactly the value an absent key would produce if the default were
    // applied by testing for zero. Reading it back as 5000 would silently
    // ignore what the user asked for.
    QTemporaryDir dir;
    const QString path = dir.filePath(QStringLiteral("qtmaildir.conf"));
    {
        QSettings s(path, QSettings::IniFormat);
        s.beginGroup(QStringLiteral("compose"));
        s.setValue(QStringLiteral("send_delay_ms"), 0);
        s.endGroup();
    }

    Config config;
    QVERIFY(config.load(path));
    QCOMPARE(config.compose().sendDelayMs, 0);
}

void TestConfig::aDefaultAccountThatCannotSendIsWarnedAbout()
{
    // Following the pattern that already warns about an unresolvable
    // startup_query. The setting is not silently corrected: it falls through
    // to the next rule AND says so, because a user who named an account
    // expects mail to come from it.
    QTemporaryDir dir;
    const QString path = dir.filePath(QStringLiteral("qtmaildir.conf"));
    {
        QSettings s(path, QSettings::IniFormat);
        s.beginGroup(QStringLiteral("account.listsonly"));
        s.setValue(QStringLiteral("maildir"), QStringLiteral("listsonly"));
        s.setValue(QStringLiteral("trash"), QStringLiteral("Trash"));
        s.endGroup();
        s.beginGroup(QStringLiteral("compose"));
        s.setValue(QStringLiteral("default_account"), QStringLiteral("listsonly"));
        s.endGroup();
    }

    Config config;
    QVERIFY(config.load(path));

    const QStringList warnings = config.warnings();
    QVERIFY2(std::any_of(warnings.cbegin(), warnings.cend(),
                         [](const QString &w) {
                             return w.contains(QStringLiteral("listsonly"));
                         }),
             qPrintable(QStringLiteral("no warning named the account: %1")
                            .arg(warnings.join(QStringLiteral(" | ")))));
}

void TestConfig::anInstallationWhereNoAccountCanSendIsNotWarnedAbout()
{
    // A read-only installation is VALID. The compose actions are disabled and
    // that is the whole response; warning about it would train the user to
    // ignore warnings, which is the lesson TagRules already records.
    QTemporaryDir dir;
    const QString path = dir.filePath(QStringLiteral("qtmaildir.conf"));
    {
        QSettings s(path, QSettings::IniFormat);
        s.beginGroup(QStringLiteral("account.listsonly"));
        s.setValue(QStringLiteral("maildir"), QStringLiteral("listsonly"));
        s.setValue(QStringLiteral("trash"), QStringLiteral("Trash"));
        s.endGroup();
    }

    Config config;
    QVERIFY(config.load(path));
    QVERIFY(config.sendingAccounts().isEmpty());

    const QStringList warnings = config.warnings();
    QVERIFY2(std::none_of(warnings.cbegin(), warnings.cend(),
                          [](const QString &w) {
                              return w.contains(QStringLiteral("send"),
                                                Qt::CaseInsensitive);
                          }),
             qPrintable(QStringLiteral("a read-only installation was warned about: %1")
                            .arg(warnings.join(QStringLiteral(" | ")))));
}
```

Add `#include <algorithm>` to the test file's includes if it is not already there.

- [ ] **Step 5: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -5`
Expected: FAIL, `'canSend' is not a member of 'Account'`.

- [ ] **Step 6: Implement the parsing**

In `src/config.cpp`, inside the per-account loop where `trash` and `inbox` are read, add:

```cpp
        account.sendCommand = settings.value(QStringLiteral("send_command")).toString().trimmed();
```

Then add the `[compose]` reader. Note the group name: `compose` is an ordinary
section, unlike `[general]`, which QSettings strips.

```cpp
    settings.beginGroup(QStringLiteral("compose"));
    // value(key, default) throughout rather than testing contains(): an
    // absent key and a key set to its default must behave identically, and
    // send_delay_ms = 0 is a REAL setting meaning "send at once" that a
    // zero-test would mistake for unset.
    m_compose.quotePosition =
        settings.value(QStringLiteral("quote_position"), QStringLiteral("above"))
                    .toString().compare(QStringLiteral("below"), Qt::CaseInsensitive) == 0
            ? ComposeSettings::QuotePosition::Below
            : ComposeSettings::QuotePosition::Above;
    m_compose.sendHtml =
        settings.value(QStringLiteral("send_html"), true).toBool();
    m_compose.autosaveIntervalMs =
        settings.value(QStringLiteral("autosave_interval_ms"), 30000).toInt();
    m_compose.sendDelayMs =
        settings.value(QStringLiteral("send_delay_ms"), 5000).toInt();
    m_compose.defaultAccount =
        settings.value(QStringLiteral("default_account")).toString().trimmed();
    m_compose.attachmentWarnBytes =
        settings.value(QStringLiteral("attachment_warn_bytes"), qint64(26214400))
            .toLongLong();
    settings.endGroup();
```

And the accessor plus validation, after the accounts are loaded:

```cpp
QList<Account> Config::sendingAccounts() const
{
    QList<Account> sending;
    for (const Account &account : m_accounts) {
        if (account.canSend())
            sending.append(account);
    }
    return sending;
}
```

```cpp
    // Startup validation. Note what is NOT warned about: an installation where
    // no account can send at all. That is a valid read-only installation and
    // the compose actions simply disable themselves.
    if (!m_compose.defaultAccount.isEmpty()) {
        const auto named = std::find_if(
            m_accounts.cbegin(), m_accounts.cend(),
            [this](const Account &a) { return a.key == m_compose.defaultAccount; });

        if (named == m_accounts.cend()) {
            m_warnings.append(
                tr("[compose] default_account names '%1', which is not a "
                   "configured account. A new message will pick a sending "
                   "account by the usual rules.")
                    .arg(m_compose.defaultAccount));
        } else if (!named->canSend()) {
            m_warnings.append(
                tr("[compose] default_account names '%1', which has no "
                   "send_command and cannot send. A new message will pick a "
                   "sending account by the usual rules.")
                    .arg(m_compose.defaultAccount));
        }
    }

    for (const Account &account : m_accounts) {
        if (!account.canSend())
            continue;
        if (account.sent.isEmpty()) {
            m_warnings.append(
                tr("Account '%1' can send but configures no `sent` folder, so "
                   "no local copy of sent mail is filed.")
                    .arg(account.key));
        }
        if (account.drafts.isEmpty()) {
            m_warnings.append(
                tr("Account '%1' can send but configures no `drafts` folder, "
                   "so the composer runs without draft protection.")
                    .arg(account.key));
        }
    }
```

- [ ] **Step 7: Run the tests**

Run: `ctest --test-dir build -R config --output-on-failure`
Expected: PASS, including the five new functions.

- [ ] **Step 8: Commit**

```bash
git add src/types.h src/config.h src/config.cpp tests/test_config.cpp
git commit -S -m "feat(config): send_command and the [compose] section, item 123

An account's ability to send IS its send_command's presence. Not a separate
receive_only key: with one key there is nothing to keep in step and nothing
to contradict, and a receive-only account is expressed by omission, which is
how one real account here is meant to work.

Startup validation follows the startup_query pattern, and is deliberately
asymmetric. A default_account that cannot send is warned about, because the
user named an account and expects mail to come from it. An installation
where NO account can send is not: that is a valid read-only installation,
and warning about it would train the user to ignore warnings.

Every [compose] key reads through value(key, default) rather than testing
contains(), because send_delay_ms = 0 is a real setting meaning 'send at
once' that a zero-test would mistake for unset."
```

---

### Task 3: Extract `freshMaildirName()` so DraftStore can share it

`notmuchworker.cpp` holds this in an anonymous namespace. `DraftStore` needs
exactly the same logic, and duplicating it would duplicate a correctness
property: the comment there records that carrying the `,U=` infix across a
folder boundary produced `Maildir error: duplicate UID` on real mail.

A pure move, no behaviour change. Doing it as its own commit means any later
bisect can tell a move from a new feature.

**Files:**
- Create: `src/maildirname.h`, `src/maildirname.cpp`
- Modify: `src/notmuchworker.cpp:713-743` (delete the local copy, include the header)
- Modify: `src/CMakeLists.txt`
- Create: `tests/test_maildirname.cpp`
- Modify: `tests/CMakeLists.txt`

- [ ] **Step 1: Write the failing test**

Create `tests/test_maildirname.cpp` (GPL header, then):

```cpp
#include <QtTest>

#include "maildirname.h"

class TestMaildirName : public QObject
{
    Q_OBJECT

private slots:
    void aFreshNameIsUniquePerCall();
    void theFlagSuffixIsPreserved();
    void anEmptyFlagSuffixIsPreserved();
    void aNameWithNoSuffixGetsNone();
    void theUidInfixIsNotCarriedAcross();
};

void TestMaildirName::aFreshNameIsUniquePerCall()
{
    // Two messages written in the same second must not collide. A timestamp
    // alone does not guarantee that, which is what the counter is for.
    QSet<QString> seen;
    for (int i = 0; i < 100; ++i)
        seen.insert(MaildirName::fresh(QStringLiteral("1234.M1P1Q1.host")));

    QCOMPARE(seen.size(), 100);
}

void TestMaildirName::theFlagSuffixIsPreserved()
{
    // The flags say whether a message is read, flagged or draft. Losing them
    // on a move silently marks mail unread again.
    const QString fresh = MaildirName::fresh(QStringLiteral("1234.M1P1Q1.host:2,FS"));
    QVERIFY2(fresh.endsWith(QStringLiteral(":2,FS")),
             qPrintable(QStringLiteral("flags lost: %1").arg(fresh)));
}

void TestMaildirName::anEmptyFlagSuffixIsPreserved()
{
    // `:2,` with no flags is not the same as no suffix at all: it says the
    // flags are known and empty. Preserved as faithfully as `:2,FS`.
    const QString fresh = MaildirName::fresh(QStringLiteral("1234.M1P1Q1.host:2,"));
    QVERIFY2(fresh.endsWith(QStringLiteral(":2,")),
             qPrintable(QStringLiteral("empty flag suffix lost: %1").arg(fresh)));
}

void TestMaildirName::aNameWithNoSuffixGetsNone()
{
    const QString fresh = MaildirName::fresh(QStringLiteral("1234.M1P1Q1.host"));
    QVERIFY2(!fresh.contains(QStringLiteral(":2,")),
             qPrintable(QStringLiteral("a suffix was invented: %1").arg(fresh)));
}

void TestMaildirName::theUidInfixIsNotCarriedAcross()
{
    // The reason this function exists rather than reusing the old name.
    // mbsync writes a `,U=<n>` infix that is meaningful only within one
    // folder; carrying it across a folder boundary produced
    // "Maildir error: duplicate UID" on the user's real mail.
    const QString fresh =
        MaildirName::fresh(QStringLiteral("1234.M1P1Q1.host,U=42:2,S"));
    QVERIFY2(!fresh.contains(QStringLiteral("U=42")),
             qPrintable(QStringLiteral("the UID infix was carried across: %1").arg(fresh)));
    QVERIFY2(fresh.endsWith(QStringLiteral(":2,S")),
             qPrintable(QStringLiteral("flags lost while dropping the UID: %1").arg(fresh)));
}

QTEST_MAIN(TestMaildirName)
#include "test_maildirname.moc"
```

`QTEST_MAIN` rather than `QTEST_APPLESS_MAIN`: the implementation calls
`QCoreApplication::applicationPid()`.

- [ ] **Step 2: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `maildirname.h: No such file or directory`.

- [ ] **Step 3: Create the header**

`src/maildirname.h` (GPL header, then):

```cpp
#pragma once

#include <QString>

/// Maildir filename generation, shared by every path that writes a message
/// file: NotmuchWorker::moveMessages() and DraftStore.
///
/// A namespace rather than a class; there is no state beyond a counter.
namespace MaildirName {

/// A fresh, unique Maildir filename, preserving \p oldName's flag suffix.
///
/// A FRESH name, never a reuse. mbsync writes a `,U=<n>` infix that is
/// meaningful only within one folder, and carrying it across a folder
/// boundary produced "Maildir error: duplicate UID" on real mail. Only the
/// `:2,` flag suffix is carried, because the flags describe the message
/// rather than its position.
///
/// Pass an empty string for a message that has no previous name, which is
/// what a newly composed draft is.
QString fresh(const QString &oldName);

}  // namespace MaildirName
```

- [ ] **Step 4: Move the implementation**

Create `src/maildirname.cpp` with the body currently at
`src/notmuchworker.cpp:713-743`, unchanged except for the name and the
includes. Copy it verbatim, including its comments, and add:

```cpp
#include "maildirname.h"

#include <QCoreApplication>
#include <QDateTime>
#include <QHostInfo>
```

Rename `freshMaildirName` to `MaildirName::fresh`.

- [ ] **Step 5: Delete the original and include the header**

In `src/notmuchworker.cpp`, delete the whole `freshMaildirName` function from
the anonymous namespace, add `#include "maildirname.h"` with the other project
includes, and change the one call site (near `:829`) from
`freshMaildirName(...)` to `MaildirName::fresh(...)`.

- [ ] **Step 6: Register the source and the test**

Add `maildirname.cpp` to `src/CMakeLists.txt` and
`add_qtmaildir_test(maildirname)` to `tests/CMakeLists.txt`.

- [ ] **Step 7: Run the full suite**

Run: `ctest --test-dir build --output-on-failure 2>&1 | tail -5`
Expected: every test passes. `test_notmuchworker` is the one that matters here: it exercises the moved function through `moveMessages`, so a botched move fails there rather than in the new test.

- [ ] **Step 8: Commit**

```bash
git add src/maildirname.h src/maildirname.cpp src/notmuchworker.cpp \
        src/CMakeLists.txt tests/test_maildirname.cpp tests/CMakeLists.txt
git commit -S -m "refactor(maildir): extract freshMaildirName for reuse, item 123

DraftStore needs the same filename generation moveMessages() already has,
and duplicating it would duplicate a correctness property rather than a
convenience: the comment records that carrying mbsync's ,U= infix across a
folder boundary produced 'Maildir error: duplicate UID' on real mail.

A pure move with no behaviour change, committed on its own so a bisect can
tell it apart from the feature that needed it. The function gains its own
tests, including the UID-infix case that previously had none."
```

---

### Task 4: MessageBuilder

The heart of the feature and the largest task. Pure: an `OutgoingMessage` in,
RFC822 bytes out, no I/O except reading attachment files.

**Read before starting.** The GMime calls below were verified empirically on
2026-08-20 against GMime 3.2 on this machine, because the obvious ones are
wrong in a way that only shows on accented text:

- **GMime defaults to iso-8859-1, not UTF-8.** A subject set without an
  explicit charset argument came out `=?iso-8859-1?B?...?=`. This user writes
  Italian, so this is every message rather than an edge case.
- **`g_mime_text_part_set_text()` encodes using the charset set at the moment
  it is called.** Setting the charset afterwards relabels the part without
  re-encoding it, producing a part labelled `charset=utf-8` whose bytes are
  latin-1: mojibake that looks correct in the headers. The plan below builds
  the content stream directly instead, so the bytes are exactly the UTF-8
  supplied.
- **`g_mime_format_options_set_allow_international()` is commented out** in
  this build's headers and cannot be used.
- No `Date` or `Message-ID` header is generated unless asked for.

**Files:**
- Create: `src/messagebuilder.h`, `src/messagebuilder.cpp`
- Create: `tests/test_messagebuilder.cpp`
- Modify: `src/CMakeLists.txt`, `tests/CMakeLists.txt`

- [ ] **Step 1: Write the header**

`src/messagebuilder.h` (GPL header, then):

```cpp
#pragma once

#include <QByteArray>
#include <QString>

#include "types.h"

class Account;

/// Turns an OutgoingMessage into the RFC822 bytes that get sent.
///
/// ONE built message serves three consumers: the autosaved draft, the bytes on
/// the send command's stdin, and the sent copy. A draft is therefore
/// byte-identical to what would be sent.
///
/// GMime rather than assembling RFC822 by string. The alternative means
/// reimplementing RFC 2047 header encoding, quoted-printable for accented
/// bodies, boundary uniqueness and line-length limits. This user writes
/// Italian; a body containing an accented character is every message, and a
/// bug there produces mail that looks correct locally and arrives as mojibake.
namespace MessageBuilder {

struct Result
{
    QByteArray bytes;    ///< The complete message. Empty on failure.
    QString error;       ///< Empty on success.
    QString messageId;   ///< The generated Message-ID, for the caller's records.

    bool ok() const { return error.isEmpty(); }
};

/// Builds \p message as sent from \p account.
///
/// Fails, rather than sending a partial message, when an attachment named in
/// the message no longer exists. That is checked HERE, at build time, rather
/// than when the file was attached: a file can vanish in between, and the
/// failure must stop the send rather than produce a message missing the thing
/// it was written to carry.
Result build(const OutgoingMessage &message, const Account &account);

}  // namespace MessageBuilder
```

- [ ] **Step 2: Write the failing test**

Create `tests/test_messagebuilder.cpp`. This asserts on the **generated bytes**
rather than round-tripping through `MimeParser`, since a builder and a parser
that agree can be wrong together.

```cpp
#include <QtTest>
#include <QTemporaryDir>

#include "config.h"
#include "messagebuilder.h"
#include "types.h"

class TestMessageBuilder : public QObject
{
    Q_OBJECT

private slots:
    void initTestCase();

    void plainOnlyWhenSendHtmlIsOff();
    void multipartAlternativeWhenSendHtmlIsOn();
    void thePlainPartCarriesTheMarkdownSourceUnmodified();
    void theHtmlPartIsRenderedFromTheSameSource();
    void anAccentedBodyIsUtf8QuotedPrintable();
    void anAccentedSubjectIsRfc2047Utf8();
    void inReplyToAndReferencesAreCarried();
    void attachmentsProduceMultipartMixed();
    void aMissingAttachmentFailsTheBuild();
    void everyMessageCarriesADateAndMessageId();
    void recipientsAppearInTheirOwnHeaders();

private:
    Account m_account;
};

void TestMessageBuilder::initTestCase()
{
    m_account.key = QStringLiteral("work");
    m_account.name = QStringLiteral("Danilo M.");
    m_account.address = QStringLiteral("user@example.org");
    m_account.maildir = QStringLiteral("work");
    m_account.sendCommand = QStringLiteral("/bin/true");
}

void TestMessageBuilder::plainOnlyWhenSendHtmlIsOff()
{
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.subject = QStringLiteral("Subject");
    message.markdownBody = QStringLiteral("**bold**");
    message.sendHtml = false;

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY2(text.contains(QStringLiteral("Content-Type: text/plain")),
             qPrintable(QStringLiteral("no text/plain part:\n%1").arg(text)));
    QVERIFY2(!text.contains(QStringLiteral("multipart/alternative")),
             "sendHtml was off and an alternative part was built anyway");
    QVERIFY2(!text.contains(QStringLiteral("text/html")),
             "sendHtml was off and an HTML part was built anyway");
}

void TestMessageBuilder::multipartAlternativeWhenSendHtmlIsOn()
{
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.subject = QStringLiteral("Subject");
    message.markdownBody = QStringLiteral("**bold**");
    message.sendHtml = true;

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY(text.contains(QStringLiteral("multipart/alternative")));
    QVERIFY(text.contains(QStringLiteral("text/plain")));
    QVERIFY(text.contains(QStringLiteral("text/html")));

    // Order matters in multipart/alternative: least-rich first, so a client
    // that renders the LAST part it understands picks the HTML.
    const int plainAt = text.indexOf(QStringLiteral("text/plain"));
    const int htmlAt = text.indexOf(QStringLiteral("text/html"));
    QVERIFY2(plainAt < htmlAt,
             "text/html came before text/plain, so clients pick the plain part");
}

void TestMessageBuilder::thePlainPartCarriesTheMarkdownSourceUnmodified()
{
    // The markdown source IS the plain part. Not a stripped-of-syntax version
    // of it: `**bold**` is readable as emphasis and rewriting it would mean
    // inventing a second renderer.
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QStringLiteral("**bold** and - [ ] a task");
    message.sendHtml = true;

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    QVERIFY2(QString::fromUtf8(result.bytes).contains(QStringLiteral("**bold**")),
             "the markdown source did not survive into the plain part");
}

void TestMessageBuilder::theHtmlPartIsRenderedFromTheSameSource()
{
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QStringLiteral("**bold**");
    message.sendHtml = true;

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    QVERIFY2(QString::fromUtf8(result.bytes).contains(QStringLiteral("<strong>bold</strong>")),
             "the HTML part was not rendered from the markdown");
}

void TestMessageBuilder::anAccentedBodyIsUtf8QuotedPrintable()
{
    // The trap this test exists for. GMime defaults to iso-8859-1, and
    // set_text() encodes with whatever charset is set at the moment it runs,
    // so a part can be LABELLED utf-8 while carrying latin-1 bytes. That
    // arrives as mojibake and looks correct locally.
    //
    // Asserting on the bytes: `=C3=A9` is UTF-8 quoted-printable for e-acute.
    // `=E9` is the latin-1 encoding of the same character and is the failure.
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QString::fromUtf8("perch\xC3\xA9 \xC3\xA8 cos\xC3\xAC");
    message.sendHtml = false;

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY2(text.contains(QStringLiteral("charset=utf-8"), Qt::CaseInsensitive),
             qPrintable(QStringLiteral("the part is not labelled utf-8:\n%1").arg(text)));
    QVERIFY2(text.contains(QStringLiteral("=C3=A9")),
             qPrintable(QStringLiteral("the body is not UTF-8 quoted-printable:\n%1").arg(text)));
    QVERIFY2(!text.contains(QStringLiteral("=E9")),
             "the body carries latin-1 bytes under a utf-8 label: mojibake");
}

void TestMessageBuilder::anAccentedSubjectIsRfc2047Utf8()
{
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.subject = QString::fromUtf8("Perch\xC3\xA9 \xC3\xA8 importante");
    message.markdownBody = QStringLiteral("body");

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY2(text.contains(QStringLiteral("=?UTF-8?"), Qt::CaseInsensitive),
             qPrintable(QStringLiteral("the subject is not RFC2047 UTF-8:\n%1").arg(text)));
    QVERIFY2(!text.contains(QStringLiteral("=?iso-8859-1?"), Qt::CaseInsensitive),
             "the subject fell back to iso-8859-1, GMime's default");
}

void TestMessageBuilder::inReplyToAndReferencesAreCarried()
{
    // Not optional. Without them a reply appears as an orphan thread in the
    // sender's own client.
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QStringLiteral("body");
    message.inReplyTo = QStringLiteral("<orig@example.org>");
    message.references = { QStringLiteral("<older@example.org>"),
                           QStringLiteral("<orig@example.org>") };

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY2(text.contains(QStringLiteral("In-Reply-To: <orig@example.org>")),
             qPrintable(QStringLiteral("no In-Reply-To:\n%1").arg(text)));
    QVERIFY2(text.contains(QStringLiteral("References:")),
             "no References header");
    QVERIFY2(text.contains(QStringLiteral("<older@example.org>")),
             "References dropped the older entry");
}

void TestMessageBuilder::attachmentsProduceMultipartMixed()
{
    QTemporaryDir dir;
    const QString path = dir.filePath(QStringLiteral("note.txt"));
    {
        QFile file(path);
        QVERIFY(file.open(QIODevice::WriteOnly));
        file.write("attached content\n");
    }

    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QStringLiteral("see attached");
    message.sendHtml = true;
    message.attachments = { path };

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY2(text.contains(QStringLiteral("multipart/mixed")),
             qPrintable(QStringLiteral("no multipart/mixed:\n%1").arg(text)));
    // The alternative nests INSIDE the mixed part, not beside it.
    QVERIFY(text.contains(QStringLiteral("multipart/alternative")));
    QVERIFY2(text.indexOf(QStringLiteral("multipart/mixed"))
                 < text.indexOf(QStringLiteral("multipart/alternative")),
             "the alternative part is not nested inside the mixed part");
    QVERIFY2(text.contains(QStringLiteral("note.txt")),
             "the attachment filename is not in the message");
    QVERIFY(text.contains(QStringLiteral("Content-Disposition: attachment")));
}

void TestMessageBuilder::aMissingAttachmentFailsTheBuild()
{
    // Checked at BUILD time, not at attach time: a file can vanish in
    // between, and the failure must stop the send rather than produce a
    // message missing the thing it was written to carry.
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QStringLiteral("see attached");
    message.attachments = { QStringLiteral("/nonexistent/vanished.pdf") };

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(!result.ok(), "a build with a missing attachment reported success");
    QVERIFY2(result.bytes.isEmpty(),
             "a failed build still produced bytes, which could be sent");
    QVERIFY2(result.error.contains(QStringLiteral("vanished.pdf")),
             qPrintable(QStringLiteral("the error does not name the file: %1").arg(result.error)));
}

void TestMessageBuilder::everyMessageCarriesADateAndMessageId()
{
    // GMime generates neither unless asked. A message without a Message-ID
    // cannot be threaded by anything that receives it.
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.markdownBody = QStringLiteral("body");

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY2(text.contains(QStringLiteral("Date:")), "no Date header");
    QVERIFY2(text.contains(QStringLiteral("Message-Id:"), Qt::CaseInsensitive),
             "no Message-ID header");
    QVERIFY2(!result.messageId.isEmpty(),
             "the built message-id was not reported back to the caller");
}

void TestMessageBuilder::recipientsAppearInTheirOwnHeaders()
{
    // Bcc must NOT appear in the built bytes: the whole point is that other
    // recipients cannot see it. The send command gets recipients from the
    // envelope, which is what `-t` reads, so a Bcc header here would leak.
    OutgoingMessage message;
    message.to = { QStringLiteral("to@example.org") };
    message.cc = { QStringLiteral("cc@example.org") };
    message.bcc = { QStringLiteral("bcc@example.org") };
    message.markdownBody = QStringLiteral("body");

    const MessageBuilder::Result result = MessageBuilder::build(message, m_account);
    QVERIFY2(result.ok(), qPrintable(result.error));

    const QString text = QString::fromUtf8(result.bytes);
    QVERIFY(text.contains(QStringLiteral("To: to@example.org")));
    QVERIFY(text.contains(QStringLiteral("Cc: cc@example.org")));
    QVERIFY(text.contains(QStringLiteral("From: ")));
    QVERIFY2(text.contains(QStringLiteral("bcc@example.org")),
             "the Bcc recipient is absent entirely, so -t cannot deliver to them");
}

QTEST_MAIN(TestMessageBuilder)
#include "test_messagebuilder.moc"
```

**A decision the last test encodes.** `Bcc` is kept in the built message
because the example `send_command` is `msmtp -t`, which reads recipients from
the headers and *strips* `Bcc` itself before transmission. Removing it here
would mean blind recipients never receive the message at all. If a later change
switches to passing recipients as arguments, this test must change with it, and
the spec's rule that no message content reaches an argument makes that
unlikely.

- [ ] **Step 3: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `messagebuilder.h: No such file or directory`.

- [ ] **Step 4: Write the implementation**

Create `src/messagebuilder.cpp`:

```cpp
// gmime BEFORE any Qt header. glib declares a struct field named `signals`,
// which Qt defines as a macro. This is the rule CLAUDE.md records and it
// applies to every translation unit that touches GMime.
#include <gmime/gmime.h>

#include "messagebuilder.h"

#include "config.h"
#include "markdownrenderer.h"

#include <QDateTime>
#include <QFileInfo>
#include <QMimeDatabase>
#include <QMimeType>

namespace {

/// Initialises GMime exactly once per process.
///
/// g_mime_init() is not reentrant and the library is also initialised by
/// MimeParser. Calling it twice is harmless but this keeps the ordering
/// obvious from either entry point.
void ensureGMimeInitialised()
{
    static bool done = false;
    if (!done) {
        g_mime_init();
        done = true;
    }
}

/// A text part carrying exactly the UTF-8 bytes supplied.
///
/// Built from an explicit stream rather than with g_mime_text_part_set_text().
/// That function encodes using the charset set at the moment it is CALLED, so
/// setting the charset afterwards relabels the part without re-encoding it and
/// produces a part marked `charset=utf-8` whose bytes are latin-1. Verified on
/// 2026-08-20: it arrives as mojibake and looks correct in the headers.
GMimePart *makeTextPart(const QString &subtype, const QString &text)
{
    const QByteArray utf8 = text.toUtf8();

    GMimePart *part = g_mime_part_new_with_type(
        "text", subtype.toUtf8().constData());
    g_mime_object_set_content_type_parameter(GMIME_OBJECT(part), "charset", "utf-8");

    GMimeStream *stream =
        g_mime_stream_mem_new_with_buffer(utf8.constData(), utf8.size());
    GMimeDataWrapper *wrapper =
        g_mime_data_wrapper_new_with_stream(stream, GMIME_CONTENT_ENCODING_DEFAULT);
    g_mime_part_set_content(part, wrapper);

    // Quoted-printable rather than 8bit: some servers still refuse 8-bit
    // bodies, and an accented Italian body is every message here.
    g_mime_part_set_content_encoding(part, GMIME_CONTENT_ENCODING_QUOTEDPRINTABLE);

    g_object_unref(wrapper);
    g_object_unref(stream);
    return part;
}

/// Sets an address header with explicit UTF-8 encoding of display names.
void setAddressHeader(GMimeMessage *message, const char *header,
                      const QStringList &addresses, GMimeFormatOptions *format)
{
    if (addresses.isEmpty())
        return;

    InternetAddressList *list = internet_address_list_new();
    for (const QString &address : addresses) {
        const QByteArray utf8 = address.trimmed().toUtf8();
        if (utf8.isEmpty())
            continue;
        // parse() rather than mailbox_new(): the field may hold
        // "Name <addr>" as typed, and re-parsing is what splits it correctly.
        InternetAddressList *parsed =
            internet_address_list_parse(nullptr, utf8.constData());
        if (parsed) {
            internet_address_list_append(list, parsed);
            g_object_unref(parsed);
        }
    }

    char *rendered = internet_address_list_to_string(list, format, TRUE);
    if (rendered) {
        g_mime_object_set_header(GMIME_OBJECT(message), header, rendered, "utf-8");
        g_free(rendered);
    }
    g_object_unref(list);
}

}  // namespace

MessageBuilder::Result MessageBuilder::build(const OutgoingMessage &message,
                                             const Account &account)
{
    Result result;
    ensureGMimeInitialised();

    // Every attachment is checked BEFORE anything is built. A partial message
    // that is missing the file it was written to carry must never reach the
    // send command.
    for (const QString &path : message.attachments) {
        const QFileInfo info(path);
        if (!info.exists() || !info.isReadable()) {
            result.error =
                QObject::tr("The attachment '%1' no longer exists or cannot be read.")
                    .arg(info.fileName().isEmpty() ? path : info.fileName());
            return result;
        }
    }

    GMimeFormatOptions *format = g_mime_format_options_get_default();
    GMimeMessage *mime = g_mime_message_new(TRUE);

    // From: the account's own identity.
    g_mime_message_add_mailbox(mime, GMIME_ADDRESS_TYPE_FROM,
                               account.name.toUtf8().constData(),
                               account.address.toUtf8().constData());

    setAddressHeader(mime, "To", message.to, format);
    setAddressHeader(mime, "Cc", message.cc, format);
    // Bcc is kept in the built bytes deliberately: `msmtp -t` reads its
    // recipients from the headers and strips Bcc itself before transmission,
    // so removing it here would mean blind recipients never receive the
    // message at all.
    setAddressHeader(mime, "Bcc", message.bcc, format);

    // The explicit "utf-8" argument is required. Without it GMime encodes the
    // subject as iso-8859-1, which is its default rather than an inference
    // from the content.
    g_mime_message_set_subject(mime, message.subject.toUtf8().constData(), "utf-8");

    // Threading. Not optional: without these a reply appears as an orphan
    // thread in the sender's own client.
    if (!message.inReplyTo.isEmpty()) {
        g_mime_object_set_header(GMIME_OBJECT(mime), "In-Reply-To",
                                 message.inReplyTo.toUtf8().constData(), "utf-8");
    }
    if (!message.references.isEmpty()) {
        const QString joined = message.references.join(QLatin1Char(' '));
        g_mime_object_set_header(GMIME_OBJECT(mime), "References",
                                 joined.toUtf8().constData(), "utf-8");
    }

    // GMime generates neither of these on its own.
    GDateTime *now = g_date_time_new_now_local();
    g_mime_message_set_date(mime, now);
    g_date_time_unref(now);

    const QString domain = account.address.section(QLatin1Char('@'), 1);
    char *generatedId = g_mime_utils_generate_message_id(
        domain.isEmpty() ? "localhost" : domain.toUtf8().constData());
    if (generatedId) {
        g_mime_message_set_message_id(mime, generatedId);
        result.messageId = QStringLiteral("<%1>").arg(QString::fromUtf8(generatedId));
        g_free(generatedId);
    }

    // The body. The markdown source IS the plain part, unmodified.
    GMimeObject *body = nullptr;
    GMimePart *plain = makeTextPart(QStringLiteral("plain"), message.markdownBody);

    if (message.sendHtml) {
        const QString html = MarkdownRenderer::toHtml(message.markdownBody);
        GMimePart *htmlPart = makeTextPart(QStringLiteral("html"), html);

        GMimeMultipart *alternative =
            GMIME_MULTIPART(g_mime_multipart_new_with_subtype("alternative"));
        // Least-rich FIRST. A client renders the last part it understands, so
        // this order is what makes the HTML win where it is supported.
        g_mime_multipart_add(alternative, GMIME_OBJECT(plain));
        g_mime_multipart_add(alternative, GMIME_OBJECT(htmlPart));
        g_object_unref(plain);
        g_object_unref(htmlPart);
        body = GMIME_OBJECT(alternative);
    } else {
        body = GMIME_OBJECT(plain);
    }

    if (!message.attachments.isEmpty()) {
        // multipart/mixed WRAPPING the body, so the alternative nests inside
        // rather than sitting beside the attachments.
        GMimeMultipart *mixed =
            GMIME_MULTIPART(g_mime_multipart_new_with_subtype("mixed"));
        g_mime_multipart_add(mixed, body);
        g_object_unref(body);

        QMimeDatabase mimeDatabase;
        for (const QString &path : message.attachments) {
            const QFileInfo info(path);
            const QMimeType type = mimeDatabase.mimeTypeForFile(info);
            const QString typeName =
                type.isValid() ? type.name() : QStringLiteral("application/octet-stream");

            GMimePart *part = g_mime_part_new_with_type(
                typeName.section(QLatin1Char('/'), 0, 0).toUtf8().constData(),
                typeName.section(QLatin1Char('/'), 1).toUtf8().constData());

            GMimeStream *stream = g_mime_stream_file_open(
                path.toUtf8().constData(), "r", nullptr);
            if (!stream) {
                g_object_unref(part);
                g_object_unref(mixed);
                g_object_unref(mime);
                result.error = QObject::tr("The attachment '%1' could not be opened.")
                                   .arg(info.fileName());
                return result;
            }

            GMimeDataWrapper *wrapper = g_mime_data_wrapper_new_with_stream(
                stream, GMIME_CONTENT_ENCODING_DEFAULT);
            g_mime_part_set_content(part, wrapper);
            g_mime_part_set_content_encoding(part, GMIME_CONTENT_ENCODING_BASE64);
            g_mime_part_set_filename(part, info.fileName().toUtf8().constData());
            g_mime_object_set_disposition(GMIME_OBJECT(part), "attachment");

            g_mime_multipart_add(mixed, GMIME_OBJECT(part));
            g_object_unref(wrapper);
            g_object_unref(stream);
            g_object_unref(part);
        }
        body = GMIME_OBJECT(mixed);
    }

    g_mime_message_set_mime_part(mime, body);
    g_object_unref(body);

    char *rendered = g_mime_object_to_string(GMIME_OBJECT(mime), format);
    if (rendered) {
        result.bytes = QByteArray(rendered);
        g_free(rendered);
    } else {
        result.error = QObject::tr("The message could not be assembled.");
    }

    g_object_unref(mime);
    return result;
}
```

Add `#include <QObject>` if `tr()` does not resolve.

- [ ] **Step 5: Register the source and the test**

`messagebuilder.cpp` in `src/CMakeLists.txt`, `add_qtmaildir_test(messagebuilder)` in `tests/CMakeLists.txt`.

- [ ] **Step 6: Run the tests**

Run: `ctest --test-dir build -R messagebuilder --output-on-failure`
Expected: PASS, 11 functions.

- [ ] **Step 7: Mutation-check the encoding tests**

These are the ones that matter and the ones most likely to be vacuous. Verify the accented-body test can fail:

```bash
sed -i 's/"charset", "utf-8"/"charset", "iso-8859-1"/' src/messagebuilder.cpp
cmake --build build >/dev/null 2>&1
ctest --test-dir build -R messagebuilder 2>&1 | grep -E 'Passed|Failed'
git checkout src/messagebuilder.cpp
cmake --build build >/dev/null 2>&1
```
Expected: `Failed`. If it passes, the test is not looking at what it claims to.

- [ ] **Step 8: Commit**

```bash
git add src/messagebuilder.h src/messagebuilder.cpp src/CMakeLists.txt \
        tests/test_messagebuilder.cpp tests/CMakeLists.txt
git commit -S -m "feat(compose): build outgoing messages with GMime, item 123

One built message serves three consumers: the autosaved draft, the bytes on
the send command's stdin, and the sent copy. A draft is therefore
byte-identical to what would be sent.

Three GMime defaults are wrong for this application and each is corrected
explicitly, because all three fail only on accented text and this user
writes Italian:

GMime encodes as iso-8859-1 unless told otherwise, so the subject carries an
explicit utf-8 argument. g_mime_text_part_set_text() encodes with whatever
charset is set when it is CALLED, so setting the charset afterwards produces
a part labelled utf-8 carrying latin-1 bytes; the content stream is built
directly instead. And neither Date nor Message-ID is generated unless asked
for, and a message without a Message-ID cannot be threaded by anything that
receives it.

Attachments are checked at build time rather than at attach time: a file can
vanish in between, and a message missing the thing it was written to carry
must never reach the send command."
```

---

### Task 5: DraftStore

Maildir writes. Drafts and sent copies are the same operation into two folders,
which is why this is one unit rather than two.

**Files:**
- Create: `src/draftstore.h`, `src/draftstore.cpp`
- Create: `tests/test_draftstore.cpp`
- Modify: `src/CMakeLists.txt`, `tests/CMakeLists.txt`

- [ ] **Step 1: Write the header**

`src/draftstore.h` (GPL header, then):

```cpp
#pragma once

#include <QByteArray>
#include <QString>

/// Writes message bytes into a Maildir folder.
///
/// Drafts and sent copies are the same operation into different folders with
/// different flags, so they are one unit. Nothing here calls notmuch: the
/// files become visible on the next sync, which keeps the read-only-by-default
/// rule intact and needs no write lock.
class DraftStore
{
public:
    struct Result
    {
        QString path;   ///< The file written. Empty on failure.
        QString error;  ///< Empty on success.

        bool ok() const { return error.isEmpty(); }
    };

    /// Writes \p bytes into \p folderPath, an absolute Maildir folder.
    ///
    /// \p flags is the Maildir flag string without the `:2,` prefix: "D" for a
    /// draft, "S" for a sent copy.
    ///
    /// \p previousPath, when not empty, is unlinked AFTER the new file is
    /// safely in place. Maildir has no in-place edit, so a draft rewritten
    /// every thirty seconds would otherwise accumulate one file per pause.
    /// The order matters: unlinking first would lose the draft entirely if the
    /// write then failed.
    static Result write(const QString &folderPath, const QByteArray &bytes,
                        const QString &flags, const QString &previousPath = {});
};
```

- [ ] **Step 2: Write the failing test**

Create `tests/test_draftstore.cpp`:

```cpp
#include <QtTest>
#include <QTemporaryDir>

#include "draftstore.h"

class TestDraftStore : public QObject
{
    Q_OBJECT

private slots:
    void aWriteLandsInCurWithTheGivenFlags();
    void twoWritesProduceDistinctFiles();
    void thePreviousRevisionIsUnlinked();
    void theNewFileExistsBeforeTheOldOneGoes();
    void anUnwritableDirectoryReportsRatherThanThrows();
    void theFolderIsCreatedWhenAbsent();
    void theBytesAreWrittenVerbatim();
};

void TestDraftStore::aWriteLandsInCurWithTheGivenFlags()
{
    // cur/, never new/. A file dropped in new/ is re-announced as fresh mail
    // by every reader of the Maildir, so a draft would arrive as a new
    // message every time it autosaved.
    QTemporaryDir dir;
    const DraftStore::Result result = DraftStore::write(
        dir.path(), QByteArray("From: a@example.org\r\n\r\nbody\r\n"),
        QStringLiteral("D"));

    QVERIFY2(result.ok(), qPrintable(result.error));
    QVERIFY2(result.path.contains(QStringLiteral("/cur/")),
             qPrintable(QStringLiteral("not written to cur/: %1").arg(result.path)));
    QVERIFY2(result.path.endsWith(QStringLiteral(":2,D")),
             qPrintable(QStringLiteral("flags missing: %1").arg(result.path)));
    QVERIFY(QFile::exists(result.path));
}

void TestDraftStore::twoWritesProduceDistinctFiles()
{
    QTemporaryDir dir;
    const DraftStore::Result first = DraftStore::write(
        dir.path(), QByteArray("one"), QStringLiteral("D"));
    const DraftStore::Result second = DraftStore::write(
        dir.path(), QByteArray("two"), QStringLiteral("D"));

    QVERIFY(first.ok() && second.ok());
    QVERIFY2(first.path != second.path,
             "two writes in the same second produced the same filename");
}

void TestDraftStore::thePreviousRevisionIsUnlinked()
{
    // Otherwise a draft autosaved every thirty seconds accumulates one file
    // per pause, and every one of them syncs to the server.
    QTemporaryDir dir;
    const DraftStore::Result first = DraftStore::write(
        dir.path(), QByteArray("revision one"), QStringLiteral("D"));
    QVERIFY(first.ok());

    const DraftStore::Result second = DraftStore::write(
        dir.path(), QByteArray("revision two"), QStringLiteral("D"), first.path);
    QVERIFY(second.ok());

    QVERIFY2(!QFile::exists(first.path),
             "the previous draft revision was left behind");
    QVERIFY(QFile::exists(second.path));
}

void TestDraftStore::theNewFileExistsBeforeTheOldOneGoes()
{
    // The ordering that matters: unlinking first would lose the draft
    // entirely if the write then failed. Asserted by pointing the write at an
    // unwritable destination and checking the old revision SURVIVED.
    QTemporaryDir good;
    const DraftStore::Result first = DraftStore::write(
        good.path(), QByteArray("precious"), QStringLiteral("D"));
    QVERIFY(first.ok());

    const DraftStore::Result failed = DraftStore::write(
        QStringLiteral("/proc/nonexistent-and-unwritable"),
        QByteArray("replacement"), QStringLiteral("D"), first.path);

    QVERIFY2(!failed.ok(), "a write to an unwritable path reported success");
    QVERIFY2(QFile::exists(first.path),
             "the previous revision was unlinked even though the new write failed");
}

void TestDraftStore::anUnwritableDirectoryReportsRatherThanThrows()
{
    const DraftStore::Result result = DraftStore::write(
        QStringLiteral("/proc/nonexistent-and-unwritable"),
        QByteArray("body"), QStringLiteral("D"));

    QVERIFY2(!result.ok(), "an unwritable directory reported success");
    QVERIFY2(!result.error.isEmpty(), "a failure carried no message to show");
    QVERIFY(result.path.isEmpty());
}

void TestDraftStore::theFolderIsCreatedWhenAbsent()
{
    // A configured drafts folder that does not exist yet is ordinary on a
    // fresh account. Note the asymmetry with the trash folder: creating a
    // folder here is safe because the NAME came from configuration and is
    // validated at load, not composed from a tag.
    QTemporaryDir dir;
    const QString nested = dir.filePath(QStringLiteral("Drafts"));
    const DraftStore::Result result = DraftStore::write(
        nested, QByteArray("body"), QStringLiteral("D"));

    QVERIFY2(result.ok(), qPrintable(result.error));
    QVERIFY(QDir(nested + QStringLiteral("/cur")).exists());
}

void TestDraftStore::theBytesAreWrittenVerbatim()
{
    // A draft must be byte-identical to what would be sent, so nothing here
    // may re-encode, add a trailing newline, or translate line endings.
    QTemporaryDir dir;
    const QByteArray bytes("From: a@example.org\r\nSubject: x\r\n\r\nbody\r\n");
    const DraftStore::Result result =
        DraftStore::write(dir.path(), bytes, QStringLiteral("D"));
    QVERIFY(result.ok());

    QFile file(result.path);
    QVERIFY(file.open(QIODevice::ReadOnly));
    QCOMPARE(file.readAll(), bytes);
}

QTEST_MAIN(TestDraftStore)
#include "test_draftstore.moc"
```

- [ ] **Step 3: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `draftstore.h: No such file or directory`.

- [ ] **Step 4: Write the implementation**

`src/draftstore.cpp` (GPL header, then):

```cpp
#include "draftstore.h"

#include "maildirname.h"

#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QSaveFile>

DraftStore::Result DraftStore::write(const QString &folderPath,
                                     const QByteArray &bytes,
                                     const QString &flags,
                                     const QString &previousPath)
{
    Result result;

    if (folderPath.isEmpty()) {
        result.error = QObject::tr("No folder was configured to write to.");
        return result;
    }

    // cur/, never new/. A file in new/ is re-announced as fresh mail by every
    // reader of the Maildir, so an autosaved draft would arrive as a new
    // message on every revision.
    const QString curPath = folderPath + QStringLiteral("/cur");
    if (!QDir().mkpath(curPath)) {
        result.error = QObject::tr("Cannot create the folder %1.").arg(curPath);
        return result;
    }

    const QString name = MaildirName::fresh(QString())
                         + QStringLiteral(":2,") + flags;
    const QString target = curPath + QLatin1Char('/') + name;

    // QSaveFile: writes to a temporary and renames into place, so a reader
    // never sees a half-written message. mbsync and notmuch both watch this
    // directory.
    QSaveFile file(target);
    if (!file.open(QIODevice::WriteOnly)) {
        result.error = QObject::tr("Cannot write to %1: %2")
                           .arg(target, file.errorString());
        return result;
    }

    if (file.write(bytes) != bytes.size() || !file.commit()) {
        result.error = QObject::tr("Cannot write to %1: %2")
                           .arg(target, file.errorString());
        return result;
    }

    result.path = target;

    // AFTER the new file is safely in place, never before: unlinking first
    // would lose the draft entirely if the write then failed. A failure to
    // remove the old revision is not reported as a failure of the write,
    // because the new revision IS on disk; the cost is one stale file.
    if (!previousPath.isEmpty() && previousPath != target)
        QFile::remove(previousPath);

    return result;
}
```

Add `#include <QObject>` for `tr()`.

- [ ] **Step 5: Register and run**

Add the source and `add_qtmaildir_test(draftstore)`, then:

Run: `ctest --test-dir build -R draftstore --output-on-failure`
Expected: PASS, 7 functions.

- [ ] **Step 6: Commit**

```bash
git add src/draftstore.h src/draftstore.cpp src/CMakeLists.txt \
        tests/test_draftstore.cpp tests/CMakeLists.txt
git commit -S -m "feat(compose): write drafts and sent copies to the Maildir, item 123

Drafts and sent copies are the same operation into two folders with two flag
sets, so they are one unit rather than two.

Two orderings are load-bearing. The file goes to cur/ and never new/, since
a file in new/ is re-announced as fresh mail by every reader of the Maildir
and an autosaved draft would arrive as a new message on each revision. And
the previous revision is unlinked only AFTER the new one is safely in place:
the reverse order loses the draft entirely if the write then fails, which is
the case a test now covers by pointing a write at an unwritable path and
asserting the old revision survived.

QSaveFile rather than QFile so a reader never sees a half-written message;
mbsync and notmuch both watch this directory. Nothing here calls notmuch:
the files become visible on the next sync, so no write lock is needed and
the read-only-by-default rule is untouched."
```

---

### Task 6: MessageSender

The one send funnel, and the seam an outbox would later be built around. It
knows nothing about composers, which is the whole reason it is a separate unit
rather than a method on the window.

**Files:**
- Create: `src/messagesender.h`, `src/messagesender.cpp`
- Create: `tests/test_messagesender.cpp`
- Modify: `src/CMakeLists.txt`, `tests/CMakeLists.txt`

- [ ] **Step 1: Write the header**

`src/messagesender.h` (GPL header, then):

```cpp
#pragma once

#include <QObject>
#include <QProcess>

/// Runs an account's send_command with the message on stdin.
///
/// EXACTLY TWO OUTCOMES: sent, or not sent with a reason. Exit code 75 has no
/// special meaning here, unlike in the sync path. Item 125 is open precisely
/// because mailsync.sh treats 75 as neither success nor failure and hangs on
/// it; that exists because the script contends for a lock and there is no lock
/// here. Recorded so the two paths are not later "harmonised".
///
/// This is the outbox seam. An outbox is built by calling this from a drain
/// loop; nothing in the composer would need to change.
class MessageSender : public QObject
{
    Q_OBJECT

public:
    explicit MessageSender(QObject *parent = nullptr);

    /// Starts \p command with \p bytes on stdin.
    ///
    /// Returns false without emitting anything when the command is empty or a
    /// send is already running. A true return means the process was handed to
    /// the event loop, NOT that it launched: a missing binary surfaces
    /// asynchronously through finished(false, ...), exactly as MailSync
    /// documents.
    bool send(const QString &command, const QByteArray &bytes);

    bool isRunning() const;

signals:
    /// \p error is empty on success and carries the command's stderr, or a
    /// description of why it could not start, on failure.
    void finished(bool sent, const QString &error);

private:
    void handleFinished(int exitCode, QProcess::ExitStatus status);
    void handleError(QProcess::ProcessError error);

    QProcess m_process;
    QString m_command;
    bool m_reported = false;
};
```

- [ ] **Step 2: Write the failing test**

Create `tests/test_messagesender.cpp`. Stub commands, never a real MTA: there
is none on this machine and there will not be one in CI.

```cpp
#include <QtTest>
#include <QTemporaryDir>

#include "messagesender.h"

class TestMessageSender : public QObject
{
    Q_OBJECT

private slots:
    void aSuccessfulCommandReportsSent();
    void theMessageArrivesOnStdinIntact();
    void aFailingCommandReportsItsStderr();
    void aCommandThatDoesNotExistReportsAFailure();
    void anEmptyCommandIsRefusedWithoutRunning();
    void exitCode75IsAnOrdinaryFailure();

private:
    QString writeStub(const QString &name, const QString &body);

    QTemporaryDir m_dir;
};

QString TestMessageSender::writeStub(const QString &name, const QString &body)
{
    const QString path = m_dir.filePath(name);
    QFile file(path);
    if (!file.open(QIODevice::WriteOnly))
        return {};
    file.write(QStringLiteral("#!/bin/sh\n%1\n").arg(body).toUtf8());
    file.close();
    file.setPermissions(QFile::ReadOwner | QFile::WriteOwner | QFile::ExeOwner);
    return path;
}

void TestMessageSender::aSuccessfulCommandReportsSent()
{
    const QString stub = writeStub(QStringLiteral("ok.sh"), QStringLiteral("cat >/dev/null"));
    QVERIFY(!stub.isEmpty());

    MessageSender sender;
    QSignalSpy spy(&sender, &MessageSender::finished);
    QVERIFY(sender.send(stub, QByteArray("From: a@example.org\r\n\r\nbody\r\n")));

    QVERIFY(spy.wait(5000));
    QCOMPARE(spy.count(), 1);
    QCOMPARE(spy.at(0).at(0).toBool(), true);
    QVERIFY2(spy.at(0).at(1).toString().isEmpty(),
             "a successful send carried an error message");
}

void TestMessageSender::theMessageArrivesOnStdinIntact()
{
    // The property that matters most: the bytes the builder produced are the
    // bytes the command receives. A stub that writes stdin to a file is the
    // only way to see it, since there is no MTA to ask.
    const QString captured = m_dir.filePath(QStringLiteral("captured.eml"));
    const QString stub = writeStub(QStringLiteral("capture.sh"),
                                   QStringLiteral("cat > '%1'").arg(captured));
    QVERIFY(!stub.isEmpty());

    const QByteArray bytes(
        "From: a@example.org\r\n"
        "Subject: =?UTF-8?B?UGVyY2jDqQ==?=\r\n"
        "\r\n"
        "Perch=C3=A9 accented body.\r\n");

    MessageSender sender;
    QSignalSpy spy(&sender, &MessageSender::finished);
    QVERIFY(sender.send(stub, bytes));
    QVERIFY(spy.wait(5000));
    QCOMPARE(spy.at(0).at(0).toBool(), true);

    QFile file(captured);
    QVERIFY2(file.open(QIODevice::ReadOnly), "the stub captured no stdin at all");
    QCOMPARE(file.readAll(), bytes);
}

void TestMessageSender::aFailingCommandReportsItsStderr()
{
    // stderr is shown verbatim: network errors, authentication failures and
    // server rejections all belong to send_command, and this application
    // deliberately does not interpret them.
    const QString stub = writeStub(
        QStringLiteral("fail.sh"),
        QStringLiteral("cat >/dev/null; echo 'auth failed: bad password' >&2; exit 1"));
    QVERIFY(!stub.isEmpty());

    MessageSender sender;
    QSignalSpy spy(&sender, &MessageSender::finished);
    QVERIFY(sender.send(stub, QByteArray("body")));

    QVERIFY(spy.wait(5000));
    QCOMPARE(spy.at(0).at(0).toBool(), false);
    QVERIFY2(spy.at(0).at(1).toString().contains(QStringLiteral("auth failed")),
             qPrintable(QStringLiteral("stderr was not reported: '%1'")
                            .arg(spy.at(0).at(1).toString())));
}

void TestMessageSender::aCommandThatDoesNotExistReportsAFailure()
{
    // A typo'd path is the likely cause, so the message names the command.
    // QProcess emits errorOccurred(FailedToStart) INSTEAD OF finished(), which
    // is the trap MailSync already documents: without handling it the signal
    // never arrives and the popup waits forever.
    MessageSender sender;
    QSignalSpy spy(&sender, &MessageSender::finished);
    QVERIFY(sender.send(QStringLiteral("/nonexistent/msmtp"), QByteArray("body")));

    QVERIFY2(spy.wait(5000), "no result was ever reported for a missing command");
    QCOMPARE(spy.at(0).at(0).toBool(), false);
    QVERIFY2(spy.at(0).at(1).toString().contains(QStringLiteral("msmtp")),
             qPrintable(QStringLiteral("the error does not name the command: '%1'")
                            .arg(spy.at(0).at(1).toString())));
}

void TestMessageSender::anEmptyCommandIsRefusedWithoutRunning()
{
    // A receive-only account. The compose actions are disabled on its mail, so
    // this should be unreachable; refusing here rather than asserting means a
    // future caller cannot accidentally send from an account that cannot.
    MessageSender sender;
    QSignalSpy spy(&sender, &MessageSender::finished);
    QVERIFY2(!sender.send(QString(), QByteArray("body")),
             "an empty command was accepted");
    QCOMPARE(spy.count(), 0);
}

void TestMessageSender::exitCode75IsAnOrdinaryFailure()
{
    // Explicitly asserted so the sync path's special handling of 75 is never
    // copied here. There is no lock to contend for, so 75 means only what the
    // command chose it to mean: not sent.
    const QString stub = writeStub(QStringLiteral("busy.sh"),
                                   QStringLiteral("cat >/dev/null; exit 75"));
    QVERIFY(!stub.isEmpty());

    MessageSender sender;
    QSignalSpy spy(&sender, &MessageSender::finished);
    QVERIFY(sender.send(stub, QByteArray("body")));

    QVERIFY(spy.wait(5000));
    QCOMPARE(spy.at(0).at(0).toBool(), false);
}

QTEST_MAIN(TestMessageSender)
#include "test_messagesender.moc"
```

- [ ] **Step 3: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `messagesender.h: No such file or directory`.

- [ ] **Step 4: Write the implementation**

`src/messagesender.cpp` (GPL header, then):

```cpp
#include "messagesender.h"

MessageSender::MessageSender(QObject *parent)
    : QObject(parent)
{
    // Separate channels, unlike MailSync's MergedChannels: there is no log
    // pane to fill here, and stderr alone is what a failure has to report.
    m_process.setProcessChannelMode(QProcess::SeparateChannels);

    connect(&m_process, &QProcess::finished,
            this, &MessageSender::handleFinished);
    connect(&m_process, &QProcess::errorOccurred,
            this, &MessageSender::handleError);
}

bool MessageSender::isRunning() const
{
    return m_process.state() != QProcess::NotRunning;
}

bool MessageSender::send(const QString &command, const QByteArray &bytes)
{
    if (command.isEmpty() || isRunning())
        return false;

    // splitCommand handles quoted arguments; running through a shell would
    // make every recipient address and display name a potential injection.
    // Nothing from the message reaches the argument list at all: the command
    // reads its recipients from the message's own headers, which is what `-t`
    // means in the documented example.
    const QStringList parts = QProcess::splitCommand(command);
    if (parts.isEmpty())
        return false;

    m_command = command;
    m_reported = false;

    m_process.setProgram(parts.first());
    m_process.setArguments(parts.mid(1));
    m_process.start();

    // The message goes on stdin and the channel is closed, so a command
    // reading to EOF terminates. Without closeWriteChannel() a command like
    // `cat` waits forever and the popup never leaves its Sending stage.
    m_process.write(bytes);
    m_process.closeWriteChannel();

    return true;
}

void MessageSender::handleFinished(int exitCode, QProcess::ExitStatus status)
{
    // errorOccurred may already have reported this failure. Reporting twice
    // would close the popup and then act on a second result.
    if (m_reported)
        return;
    m_reported = true;

    const bool sent = status == QProcess::NormalExit && exitCode == 0;
    if (sent) {
        emit finished(true, QString());
        return;
    }

    // Exit 75 is deliberately NOT special. See the header.
    QString error = QString::fromUtf8(m_process.readAllStandardError()).trimmed();
    if (error.isEmpty()) {
        error = tr("The send command exited with status %1 and said nothing.")
                    .arg(exitCode);
    }
    emit finished(false, error);
}

void MessageSender::handleError(QProcess::ProcessError error)
{
    // QProcess emits errorOccurred(FailedToStart) INSTEAD OF finished(), so
    // without this the caller waits forever. Every other error is followed by
    // finished() and is left to it.
    if (error != QProcess::FailedToStart)
        return;
    if (m_reported)
        return;
    m_reported = true;

    emit finished(false,
                  tr("The send command '%1' could not be started. Check that "
                     "the path is correct and the file is executable.")
                      .arg(m_command));
}
```

- [ ] **Step 5: Register and run**

Add the source and `add_qtmaildir_test(messagesender)`, then:

Run: `ctest --test-dir build -R messagesender --output-on-failure`
Expected: PASS, 6 functions.

- [ ] **Step 6: Commit**

```bash
git add src/messagesender.h src/messagesender.cpp src/CMakeLists.txt \
        tests/test_messagesender.cpp tests/CMakeLists.txt
git commit -S -m "feat(compose): run the account's send command, item 123

The application never learns what SMTP is. Sending is a configured command
receiving the complete message on stdin, on exactly the contract [sync]
command already has, and what the user installs behind it is theirs.

Two security properties. The command is split into an argument list and run
without a shell, so nothing in a message body, a recipient address or a
display name can reach sh. And no message content is placed in an argument
at all: the command reads its recipients from the message's own headers.

Exactly two outcomes, and exit 75 is deliberately not one of them. The sync
path treats 75 as neither success nor failure, which is why item 125 is open
about a spinner that never stops; that exists because mailsync.sh contends
for a lock and there is no lock here. A test asserts 75 is an ordinary
failure so the two paths are not later harmonised.

closeWriteChannel() after writing is not optional: a command reading to EOF
otherwise waits forever and the send popup never leaves its Sending stage."
```

---

### Task 7: ComposeContext

Pure logic, no widgets. The spec says the subtle bugs live in recipient
derivation, which is exactly why this is a separate unit tested apart from the
window.

**Files:**
- Create: `src/composecontext.h`, `src/composecontext.cpp`
- Create: `tests/test_composecontext.cpp`
- Modify: `src/CMakeLists.txt`, `tests/CMakeLists.txt`

Note: the `ComposeContext` STRUCT is already in `types.h` from Task 2. This
task adds the free functions that build one.

- [ ] **Step 1: Write the header**

`src/composecontext.h` (GPL header, then):

```cpp
#pragma once

#include <QList>
#include <QString>
#include <QStringList>

#include "types.h"

class Account;
class Config;
struct ParsedMessage;

/// Builds the ComposeContext that opens a composer.
///
/// Free functions in a namespace: this is pure logic over values, and keeping
/// it apart from ComposeWindow is what lets recipient derivation, subject
/// prefixing and account resolution be tested without a painter.
namespace ComposeContextBuilder {

/// The addresses belonging to the user, across every configured account.
///
/// Every one of them is stripped from a reply-all's recipients. Missing one
/// means the user receives their own reply, which is the failure this is most
/// likely to have.
QStringList ownAddresses(const Config &config);

/// Which account replies to a message whose file lives at \p messagePaths.
///
/// The displayed message's own maildir is the strongest available signal and
/// wins outright: mail sent to an address landed in that address's maildir, so
/// replying from it is what the recipient expects. The account dropdown is NOT
/// consulted.
///
/// A message can be in more than one maildir: on a list twice under two
/// addresses, or duplicated across accounts by mbsync, and notmuch returns
/// several filenames for one id. \p recipients disambiguates by preferring the
/// account matching a To or Cc entry; failing that the first is taken. The From
/// field shows the choice, so an arbitrary resolution is visible rather than
/// hidden.
QString accountForReply(const Config &config, const QStringList &messagePaths,
                        const QStringList &recipients, const QString &mailRoot);

/// Which account a NEW message comes from, by the four fallback rules.
///
/// \p selectedAccount is the dropdown's current account, empty for All
/// accounts. Returns empty only when no account can send at all.
QString accountForNew(const Config &config, const QString &selectedAccount);

/// `Re:` or `Fwd:` prefixed, without doubling an existing prefix.
QString replySubject(const QString &original);
QString forwardSubject(const QString &original);

/// The `>`-prefixed original, with an attribution line.
///
/// Takes a ParsedMessage, NOT a MessageNode: the node carries no body and no
/// date (it holds messageId, threadId, from, subject, tags, filePath and
/// depth), so quoting has to come from what MimeParser produced. Verified
/// against src/types.h and src/mimeparser.h on 2026-08-20.
QString quoteBody(const ParsedMessage &message);

}  // namespace ComposeContextBuilder
```

- [ ] **Step 2: Write the failing test**

Create `tests/test_composecontext.cpp`:

```cpp
#include <QtTest>
#include <QTemporaryDir>

#include "composecontext.h"
#include "config.h"
#include "mimeparser.h"
#include "types.h"

class TestComposeContext : public QObject
{
    Q_OBJECT

private slots:
    void init();

    void everyOwnAddressIsStrippedFromAReplyAll();
    void aReplySubjectDoesNotDoubleItsPrefix();
    void aForwardSubjectDoesNotDoubleItsPrefix();
    void anEmptySubjectStillGetsAPrefix();
    void theReplyAccountComesFromTheMessagesMaildir();
    void anAmbiguousMessagePrefersTheMatchingRecipient();
    void anAmbiguousMessageWithNoMatchTakesTheFirst();
    void aNewMessagePrefersTheSelectedAccount();
    void aNewMessageFallsThroughASelectedAccountThatCannotSend();
    void aNewMessageUsesDefaultAccountFromAllAccounts();
    void aNewMessageFallsBackToTheFirstSendingAccount();
    void aNewMessageReturnsNothingWhenNoAccountCanSend();
    void aQuotedBodyPrefixesEveryLine();

private:
    QString writeConfig(const QString &contents);

    QTemporaryDir m_dir;
};

QString TestComposeContext::writeConfig(const QString &contents)
{
    const QString path = m_dir.filePath(QStringLiteral("qtmaildir.conf"));
    QFile file(path);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Truncate | QIODevice::Text))
        return {};
    file.write(contents.toUtf8());
    return path;
}

void TestComposeContext::init()
{
    // Each test writes its own config; nothing carries over.
}

void TestComposeContext::everyOwnAddressIsStrippedFromAReplyAll()
{
    // All five of the user's addresses. Missing one means they receive their
    // own reply, and with five accounts that is the likeliest bug here.
    const QString path = writeConfig(QStringLiteral(
        "[account.one]\nmaildir=one\ntrash=Trash\naddress=first@example.org\n"
        "[account.two]\nmaildir=two\ntrash=Trash\naddress=second@example.org\n"
        "[account.three]\nmaildir=three\ntrash=Trash\naddress=third@example.org\n"
        "[account.four]\nmaildir=four\ntrash=Trash\naddress=fourth@example.org\n"
        "[account.five]\nmaildir=five\ntrash=Trash\naddress=fifth@example.org\n"));
    QVERIFY(!path.isEmpty());

    Config config;
    QVERIFY(config.load(path));

    const QStringList own = ComposeContextBuilder::ownAddresses(config);
    QCOMPARE(own.size(), 5);
    for (const QString &address : { QStringLiteral("first@example.org"),
                                    QStringLiteral("second@example.org"),
                                    QStringLiteral("third@example.org"),
                                    QStringLiteral("fourth@example.org"),
                                    QStringLiteral("fifth@example.org") }) {
        QVERIFY2(own.contains(address),
                 qPrintable(QStringLiteral("own address %1 was not collected").arg(address)));
    }
}

void TestComposeContext::aReplySubjectDoesNotDoubleItsPrefix()
{
    QCOMPARE(ComposeContextBuilder::replySubject(QStringLiteral("Hello")),
             QStringLiteral("Re: Hello"));
    QCOMPARE(ComposeContextBuilder::replySubject(QStringLiteral("Re: Hello")),
             QStringLiteral("Re: Hello"));
    // Case and spacing vary between clients and neither justifies a second
    // prefix. "RE:" from Outlook is the common one.
    QCOMPARE(ComposeContextBuilder::replySubject(QStringLiteral("RE: Hello")),
             QStringLiteral("RE: Hello"));
    QCOMPARE(ComposeContextBuilder::replySubject(QStringLiteral("re:Hello")),
             QStringLiteral("re:Hello"));
}

void TestComposeContext::aForwardSubjectDoesNotDoubleItsPrefix()
{
    QCOMPARE(ComposeContextBuilder::forwardSubject(QStringLiteral("Hello")),
             QStringLiteral("Fwd: Hello"));
    QCOMPARE(ComposeContextBuilder::forwardSubject(QStringLiteral("Fwd: Hello")),
             QStringLiteral("Fwd: Hello"));
    // "Fw:" is the other common spelling and means the same thing.
    QCOMPARE(ComposeContextBuilder::forwardSubject(QStringLiteral("Fw: Hello")),
             QStringLiteral("Fw: Hello"));
}

void TestComposeContext::anEmptySubjectStillGetsAPrefix()
{
    // A reply to a subjectless message is still a reply. "Re: " alone is
    // correct and is what every other client produces.
    QCOMPARE(ComposeContextBuilder::replySubject(QString()),
             QStringLiteral("Re: "));
}

void TestComposeContext::theReplyAccountComesFromTheMessagesMaildir()
{
    // The dropdown is NOT consulted: replying from the All accounts view to a
    // message that arrived at account B sends from B.
    const QString path = writeConfig(QStringLiteral(
        "[account.work]\nmaildir=work\ntrash=Trash\naddress=work@example.org\n"
        "send_command=/bin/true\n"
        "[account.home]\nmaildir=home\ntrash=Trash\naddress=home@example.org\n"
        "send_command=/bin/true\n"));
    QVERIFY(!path.isEmpty());

    Config config;
    QVERIFY(config.load(path));

    const QString account = ComposeContextBuilder::accountForReply(
        config, { QStringLiteral("/mail/home/INBOX/cur/123") },
        { QStringLiteral("home@example.org") }, QStringLiteral("/mail"));

    QCOMPARE(account, QStringLiteral("home"));
}

void TestComposeContext::anAmbiguousMessagePrefersTheMatchingRecipient()
{
    // One message, two maildirs: on a list twice under two addresses. The
    // recipient headers are the tiebreak.
    const QString path = writeConfig(QStringLiteral(
        "[account.work]\nmaildir=work\ntrash=Trash\naddress=work@example.org\n"
        "send_command=/bin/true\n"
        "[account.home]\nmaildir=home\ntrash=Trash\naddress=home@example.org\n"
        "send_command=/bin/true\n"));
    QVERIFY(!path.isEmpty());

    Config config;
    QVERIFY(config.load(path));

    const QString account = ComposeContextBuilder::accountForReply(
        config,
        { QStringLiteral("/mail/work/Lists/cur/1"),
          QStringLiteral("/mail/home/Lists/cur/1") },
        { QStringLiteral("home@example.org") }, QStringLiteral("/mail"));

    QCOMPARE(account, QStringLiteral("home"));
}

void TestComposeContext::anAmbiguousMessageWithNoMatchTakesTheFirst()
{
    // Arbitrary, and deliberately so: the From field shows the choice, which
    // makes an arbitrary resolution visible rather than hidden.
    const QString path = writeConfig(QStringLiteral(
        "[account.work]\nmaildir=work\ntrash=Trash\naddress=work@example.org\n"
        "send_command=/bin/true\n"
        "[account.home]\nmaildir=home\ntrash=Trash\naddress=home@example.org\n"
        "send_command=/bin/true\n"));
    QVERIFY(!path.isEmpty());

    Config config;
    QVERIFY(config.load(path));

    const QString account = ComposeContextBuilder::accountForReply(
        config,
        { QStringLiteral("/mail/work/Lists/cur/1"),
          QStringLiteral("/mail/home/Lists/cur/1") },
        { QStringLiteral("someone-else@example.org") }, QStringLiteral("/mail"));

    QVERIFY2(!account.isEmpty(), "an ambiguous message resolved to no account");
    QCOMPARE(account, QStringLiteral("work"));
}

void TestComposeContext::aNewMessagePrefersTheSelectedAccount()
{
    const QString path = writeConfig(QStringLiteral(
        "[account.work]\nmaildir=work\ntrash=Trash\nsend_command=/bin/true\n"
        "[account.home]\nmaildir=home\ntrash=Trash\nsend_command=/bin/true\n"));
    Config config;
    QVERIFY(config.load(path));

    QCOMPARE(ComposeContextBuilder::accountForNew(config, QStringLiteral("home")),
             QStringLiteral("home"));
}

void TestComposeContext::aNewMessageFallsThroughASelectedAccountThatCannotSend()
{
    // Rule 1 requires the selected account CAN send. Viewing a receive-only
    // account and pressing compose must produce a working composer from
    // another account, not a broken one from this.
    const QString path = writeConfig(QStringLiteral(
        "[account.listsonly]\nmaildir=listsonly\ntrash=Trash\n"
        "[account.work]\nmaildir=work\ntrash=Trash\nsend_command=/bin/true\n"));
    Config config;
    QVERIFY(config.load(path));

    QCOMPARE(ComposeContextBuilder::accountForNew(config, QStringLiteral("listsonly")),
             QStringLiteral("work"));
}

void TestComposeContext::aNewMessageUsesDefaultAccountFromAllAccounts()
{
    // The All accounts view has no selected account and falls through to rule 2.
    const QString path = writeConfig(QStringLiteral(
        "[account.work]\nmaildir=work\ntrash=Trash\nsend_command=/bin/true\n"
        "[account.home]\nmaildir=home\ntrash=Trash\nsend_command=/bin/true\n"
        "[compose]\ndefault_account=home\n"));
    Config config;
    QVERIFY(config.load(path));

    QCOMPARE(ComposeContextBuilder::accountForNew(config, QString()),
             QStringLiteral("home"));
}

void TestComposeContext::aNewMessageFallsBackToTheFirstSendingAccount()
{
    // Rule 4, arbitrary, and the reason rules 2 and 3 exist. "First" is
    // CONFIGURATION order, which QSettings does not preserve for keys but
    // Config's account list does.
    const QString path = writeConfig(QStringLiteral(
        "[account.listsonly]\nmaildir=listsonly\ntrash=Trash\n"
        "[account.work]\nmaildir=work\ntrash=Trash\nsend_command=/bin/true\n"));
    Config config;
    QVERIFY(config.load(path));

    QCOMPARE(ComposeContextBuilder::accountForNew(config, QString()),
             QStringLiteral("work"));
}

void TestComposeContext::aNewMessageReturnsNothingWhenNoAccountCanSend()
{
    // A valid read-only installation. The compose action is disabled, so this
    // should be unreachable, and returning empty rather than a random account
    // is what makes a mistake visible instead of silent.
    const QString path = writeConfig(QStringLiteral(
        "[account.listsonly]\nmaildir=listsonly\ntrash=Trash\n"));
    Config config;
    QVERIFY(config.load(path));

    QVERIFY(ComposeContextBuilder::accountForNew(config, QString()).isEmpty());
}

void TestComposeContext::aQuotedBodyPrefixesEveryLine()
{
    ParsedMessage message;
    message.from = QStringLiteral("Sender <sender@example.org>");
    message.date = QStringLiteral("Thu, 20 Aug 2026 10:00:00 +0200");
    message.plainBody = QStringLiteral("first line\nsecond line\n\nafter a blank");

    const QString quoted = ComposeContextBuilder::quoteBody(message);

    QVERIFY2(quoted.contains(QStringLiteral("> first line")),
             qPrintable(QStringLiteral("first line not quoted:\n%1").arg(quoted)));
    QVERIFY2(quoted.contains(QStringLiteral("> second line")),
             "second line not quoted");
    // A blank line inside a quote must still carry the marker, or the quote
    // visually ends there in every client that renders it.
    QVERIFY2(quoted.contains(QStringLiteral("\n>\n")) ,
             qPrintable(QStringLiteral("a blank line lost its marker:\n%1").arg(quoted)));
    QVERIFY2(quoted.contains(QStringLiteral("sender@example.org")),
             "no attribution line naming the sender");
}

QTEST_MAIN(TestComposeContext)
#include "test_composecontext.moc"
```

- [ ] **Step 3: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `composecontext.h: No such file or directory`.

- [ ] **Step 4: Write the implementation**

`src/composecontext.cpp` (GPL header, then):

```cpp
#include "composecontext.h"

#include "config.h"
#include "mimeparser.h"

#include <QDir>
#include <QRegularExpression>

namespace {

/// Matches a reply prefix at the start of a subject, in the spellings clients
/// actually produce: "Re:", "RE:", "re:", with or without a space.
const QRegularExpression &replyPrefix()
{
    static const QRegularExpression expression(
        QStringLiteral("^\\s*re\\s*:"), QRegularExpression::CaseInsensitiveOption);
    return expression;
}

/// "Fwd:" and "Fw:" both mean the same thing and both are common.
const QRegularExpression &forwardPrefix()
{
    static const QRegularExpression expression(
        QStringLiteral("^\\s*fwd?\\s*:"), QRegularExpression::CaseInsensitiveOption);
    return expression;
}

/// The account whose maildir contains \p path, or empty.
QString accountOwning(const Config &config, const QString &path,
                      const QString &mailRoot)
{
    for (const Account &account : config.accounts()) {
        const QString prefix =
            QDir(mailRoot).absoluteFilePath(account.maildir) + QLatin1Char('/');
        // Compared as a path prefix with the separator included: without the
        // trailing slash an account "work" would also match a maildir
        // "work-archive".
        if (path.startsWith(prefix))
            return account.key;
    }
    return {};
}

}  // namespace

QStringList ComposeContextBuilder::ownAddresses(const Config &config)
{
    QStringList addresses;
    for (const Account &account : config.accounts()) {
        const QString address = account.address.trimmed();
        if (!address.isEmpty() && !addresses.contains(address, Qt::CaseInsensitive))
            addresses.append(address);
    }
    return addresses;
}

QString ComposeContextBuilder::accountForReply(const Config &config,
                                               const QStringList &messagePaths,
                                               const QStringList &recipients,
                                               const QString &mailRoot)
{
    QStringList candidates;
    for (const QString &path : messagePaths) {
        const QString key = accountOwning(config, path, mailRoot);
        if (!key.isEmpty() && !candidates.contains(key))
            candidates.append(key);
    }

    if (candidates.isEmpty())
        return {};
    if (candidates.size() == 1)
        return candidates.first();

    // Ambiguous: the same message in more than one maildir. Prefer the account
    // whose own address appears among the recipients, which is the reason the
    // copy landed there.
    for (const QString &key : candidates) {
        for (const Account &account : config.accounts()) {
            if (account.key != key || account.address.isEmpty())
                continue;
            for (const QString &recipient : recipients) {
                if (recipient.contains(account.address, Qt::CaseInsensitive))
                    return key;
            }
        }
    }

    // Arbitrary, and visible: the From field shows the choice.
    return candidates.first();
}

QString ComposeContextBuilder::accountForNew(const Config &config,
                                             const QString &selectedAccount)
{
    const auto canSend = [&config](const QString &key) {
        if (key.isEmpty())
            return false;
        for (const Account &account : config.accounts()) {
            if (account.key == key)
                return account.canSend();
        }
        return false;
    };

    // 1. The dropdown's current account, when it is a specific one that can send.
    if (canSend(selectedAccount))
        return selectedAccount;

    // 2. [compose] default_account.
    if (canSend(config.compose().defaultAccount))
        return config.compose().defaultAccount;

    // 3. [general] startup_account, on the same condition.
    if (canSend(config.startupAccount()))
        return config.startupAccount();

    // 4. The first account in configuration order that can send. Arbitrary,
    // which is exactly why rules 2 and 3 exist.
    const QList<Account> sending = config.sendingAccounts();
    if (!sending.isEmpty())
        return sending.first().key;

    // No account can send. A valid read-only installation; the caller's action
    // is disabled and should never have reached this.
    return {};
}

QString ComposeContextBuilder::replySubject(const QString &original)
{
    if (replyPrefix().match(original).hasMatch())
        return original;
    return QStringLiteral("Re: ") + original;
}

QString ComposeContextBuilder::forwardSubject(const QString &original)
{
    if (forwardPrefix().match(original).hasMatch())
        return original;
    return QStringLiteral("Fwd: ") + original;
}

QString ComposeContextBuilder::quoteBody(const ParsedMessage &message)
{
    QStringList quoted;

    // The attribution line. Not translated with a date format that varies by
    // locale: this text is sent to a recipient who may not share the locale.
    quoted.append(QStringLiteral("On %1, %2 wrote:")
                      .arg(message.date, message.from));
    quoted.append(QString());

    const QStringList lines = message.plainBody.split(QLatin1Char('\n'));
    for (const QString &line : lines) {
        // A blank line still carries the marker. Without it the quote
        // visually ends there in every client that renders quoting.
        quoted.append(line.isEmpty() ? QStringLiteral(">")
                                     : QStringLiteral("> ") + line);
    }

    return quoted.join(QLatin1Char('\n'));
}
```

`Config::startupAccount()` is verified to exist at `src/config.h:366`, so rule
3 compiles as written.

- [ ] **Step 5: Register and run**

Add the source and `add_qtmaildir_test(composecontext)`, then:

Run: `ctest --test-dir build -R composecontext --output-on-failure`
Expected: PASS, 13 functions.

- [ ] **Step 6: Commit**

```bash
git add src/composecontext.h src/composecontext.cpp src/CMakeLists.txt \
        tests/test_composecontext.cpp tests/CMakeLists.txt
git commit -S -m "feat(compose): resolve accounts, recipients and subjects, item 123

Pure logic, no widgets, because this is where the subtle bugs live and a
painter-free unit is what lets them be tested.

The account that replies comes from the displayed message's own maildir and
the dropdown is not consulted: mail sent to an address landed in that
address's maildir, so replying from it is what the recipient expects, and
replying from the All accounts view to a message that arrived at account B
sends from B. A message can sit in more than one maildir, on a list twice or
duplicated by mbsync, so the recipient headers break the tie and the first
candidate is taken otherwise. That last rule is arbitrary on purpose: the
From field shows the choice, which makes it visible rather than hidden.

A new message walks four rules and returns nothing when no account can send,
rather than picking one, so a mistake is visible instead of silent.

Every own address is stripped from a reply-all. With five accounts the
likeliest bug here is missing one, and the user then receives their own
reply."
```

---

### Task 8: The formatting transformations

Each toolbar button is a **text transformation over the markdown source**, not
rich-text editing. The buffer stays markdown the user can also type by hand.

The transformations are free functions over (text, selection start, selection
end) so they are tested without a widget. The toolbar that calls them is built
in Task 11 with the composer.

**Files:**
- Create: `src/formattoolbar.h`, `src/formattoolbar.cpp`
- Create: `tests/test_formattoolbar.cpp`
- Modify: `src/CMakeLists.txt`, `tests/CMakeLists.txt`

- [ ] **Step 1: Write the header**

`src/formattoolbar.h` (GPL header, then):

```cpp
#pragma once

#include <QString>

/// The markdown transformations behind the composer's formatting toolbar.
///
/// Free functions over text and a selection, with no widget anywhere, so the
/// grammar is tested without a painter. Each one is a transformation over the
/// SOURCE: nothing about the buffer changes, it stays markdown the user can
/// also type by hand.
namespace MarkdownFormat {

/// The result of a transformation: the new text and where the selection
/// should end up.
struct Edit
{
    QString text;
    int selectionStart = 0;
    int selectionEnd = 0;
};

/// Wraps the selection in \p token, or inserts an empty pair with the cursor
/// BETWEEN the tokens when there is no selection.
///
/// The cursor landing between the tokens is the property a user notices
/// immediately when it is wrong, and it is invisible to a test that only
/// compares the resulting text.
Edit wrap(const QString &text, int start, int end, const QString &token);

/// `[text](url)`. With a selection the selected text becomes the label and
/// the cursor lands inside the empty parentheses, which is where the user has
/// to type next.
Edit link(const QString &text, int start, int end);

/// `> ` on every line the selection touches, including a line the selection
/// only starts or ends on. Line-based rather than a wrap, so it cannot be
/// expressed with wrap().
Edit quote(const QString &text, int start, int end);

}  // namespace MarkdownFormat
```

- [ ] **Step 2: Write the failing test**

Create `tests/test_formattoolbar.cpp`:

```cpp
#include <QtTest>

#include "formattoolbar.h"

class TestFormatToolbar : public QObject
{
    Q_OBJECT

private slots:
    void wrappingASelectionKeepsItSelected();
    void wrappingWithNoSelectionPutsTheCursorBetweenTheTokens();
    void wrappingAppliesTheTokenOnBothSides();
    void aLinkWithASelectionUsesItAsTheLabel();
    void aLinkWithNoSelectionLeavesTheCursorInTheLabel();
    void quotingPrefixesEveryLineTheSelectionTouches();
    void quotingAPartialLineStillQuotesTheWholeLine();
    void quotingASingleLineWithNoSelectionQuotesThatLine();
};

void TestFormatToolbar::wrappingASelectionKeepsItSelected()
{
    // The selection is preserved so a second button press applies a second
    // token to the same words: bold then italic, without reselecting.
    const MarkdownFormat::Edit edit = MarkdownFormat::wrap(
        QStringLiteral("make this bold"), 5, 9, QStringLiteral("**"));

    QCOMPARE(edit.text, QStringLiteral("make **this** bold"));
    QCOMPARE(edit.text.mid(edit.selectionStart,
                           edit.selectionEnd - edit.selectionStart),
             QStringLiteral("this"));
}

void TestFormatToolbar::wrappingWithNoSelectionPutsTheCursorBetweenTheTokens()
{
    // The property a user notices immediately when it is wrong: press Bold,
    // start typing, and the words must appear INSIDE the asterisks. A text
    // comparison alone passes whether the cursor is inside or after.
    const MarkdownFormat::Edit edit = MarkdownFormat::wrap(
        QStringLiteral("ab"), 2, 2, QStringLiteral("**"));

    QCOMPARE(edit.text, QStringLiteral("ab****"));
    QCOMPARE(edit.selectionStart, edit.selectionEnd);
    QCOMPARE(edit.selectionStart, 4);

    // Stated as the behaviour rather than the index: typing "x" here must
    // produce "ab**x**".
    QString typed = edit.text;
    typed.insert(edit.selectionStart, QStringLiteral("x"));
    QCOMPARE(typed, QStringLiteral("ab**x**"));
}

void TestFormatToolbar::wrappingAppliesTheTokenOnBothSides()
{
    QCOMPARE(MarkdownFormat::wrap(QStringLiteral("x"), 0, 1,
                                  QStringLiteral("~~")).text,
             QStringLiteral("~~x~~"));
    QCOMPARE(MarkdownFormat::wrap(QStringLiteral("x"), 0, 1,
                                  QStringLiteral("`")).text,
             QStringLiteral("`x`"));
}

void TestFormatToolbar::aLinkWithASelectionUsesItAsTheLabel()
{
    const MarkdownFormat::Edit edit = MarkdownFormat::link(
        QStringLiteral("see the docs"), 8, 12);

    QCOMPARE(edit.text, QStringLiteral("see the [docs]()"));

    // The cursor goes inside the parentheses: the label is written and the
    // URL is what the user still has to type.
    QCOMPARE(edit.selectionStart, edit.selectionEnd);
    QString typed = edit.text;
    typed.insert(edit.selectionStart, QStringLiteral("https://example.org"));
    QCOMPARE(typed, QStringLiteral("see the [docs](https://example.org)"));
}

void TestFormatToolbar::aLinkWithNoSelectionLeavesTheCursorInTheLabel()
{
    // With nothing selected there is no label yet, so the label is what the
    // user types first.
    const MarkdownFormat::Edit edit = MarkdownFormat::link(QString(), 0, 0);

    QCOMPARE(edit.text, QStringLiteral("[]()"));
    QString typed = edit.text;
    typed.insert(edit.selectionStart, QStringLiteral("label"));
    QCOMPARE(typed, QStringLiteral("[label]()"));
}

void TestFormatToolbar::quotingPrefixesEveryLineTheSelectionTouches()
{
    const MarkdownFormat::Edit edit = MarkdownFormat::quote(
        QStringLiteral("one\ntwo\nthree"), 0, 7);

    QCOMPARE(edit.text, QStringLiteral("> one\n> two\nthree"));
}

void TestFormatToolbar::quotingAPartialLineStillQuotesTheWholeLine()
{
    // A selection from the middle of one line into the middle of the next
    // must quote both whole lines. Quoting half a line produces markdown that
    // means something else entirely.
    const MarkdownFormat::Edit edit = MarkdownFormat::quote(
        QStringLiteral("one\ntwo\nthree"), 1, 5);

    QCOMPARE(edit.text, QStringLiteral("> one\n> two\nthree"));
}

void TestFormatToolbar::quotingASingleLineWithNoSelectionQuotesThatLine()
{
    const MarkdownFormat::Edit edit = MarkdownFormat::quote(
        QStringLiteral("one\ntwo"), 5, 5);

    QCOMPARE(edit.text, QStringLiteral("one\n> two"));
}

QTEST_APPLESS_MAIN(TestFormatToolbar)
#include "test_formattoolbar.moc"
```

- [ ] **Step 3: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `formattoolbar.h: No such file or directory`.

- [ ] **Step 4: Write the implementation**

`src/formattoolbar.cpp` (GPL header, then):

```cpp
#include "formattoolbar.h"

#include <QStringList>

MarkdownFormat::Edit MarkdownFormat::wrap(const QString &text, int start,
                                          int end, const QString &token)
{
    Edit edit;
    const int from = qMin(start, end);
    const int to = qMax(start, end);

    edit.text = text;
    edit.text.insert(to, token);
    edit.text.insert(from, token);

    if (from == to) {
        // No selection: the cursor goes BETWEEN the two tokens so typing
        // continues inside them. Landing after the closing token instead is
        // the mistake a user notices on the first keystroke.
        edit.selectionStart = from + token.size();
        edit.selectionEnd = edit.selectionStart;
    } else {
        // The selection is preserved so a second press applies a second token
        // to the same words without reselecting.
        edit.selectionStart = from + token.size();
        edit.selectionEnd = to + token.size();
    }

    return edit;
}

MarkdownFormat::Edit MarkdownFormat::link(const QString &text, int start, int end)
{
    Edit edit;
    const int from = qMin(start, end);
    const int to = qMax(start, end);
    const QString label = text.mid(from, to - from);

    edit.text = text;
    edit.text.replace(from, to - from,
                      QStringLiteral("[%1]()").arg(label));

    if (label.isEmpty()) {
        // Nothing selected: the label is what gets typed first, so the cursor
        // goes inside the brackets.
        edit.selectionStart = from + 1;
    } else {
        // The label is written; the URL is what remains, so the cursor goes
        // inside the parentheses.
        edit.selectionStart = from + label.size() + 3;
    }
    edit.selectionEnd = edit.selectionStart;

    return edit;
}

MarkdownFormat::Edit MarkdownFormat::quote(const QString &text, int start, int end)
{
    Edit edit;
    const int from = qMin(start, end);
    const int to = qMax(start, end);

    // Line-based, not a wrap. The selection is widened to whole lines first:
    // quoting half a line produces markdown that means something else.
    const int firstLineStart = text.lastIndexOf(QLatin1Char('\n'), from > 0 ? from - 1 : 0) + 1;
    int lastLineEnd = text.indexOf(QLatin1Char('\n'), to);
    if (lastLineEnd < 0)
        lastLineEnd = text.size();

    const QString before = text.left(firstLineStart);
    const QString middle = text.mid(firstLineStart, lastLineEnd - firstLineStart);
    const QString after = text.mid(lastLineEnd);

    QStringList quoted;
    const QStringList lines = middle.split(QLatin1Char('\n'));
    for (const QString &line : lines)
        quoted.append(QStringLiteral("> ") + line);

    const QString replacement = quoted.join(QLatin1Char('\n'));
    edit.text = before + replacement + after;
    edit.selectionStart = firstLineStart;
    edit.selectionEnd = firstLineStart + replacement.size();

    return edit;
}
```

**Note on `lastIndexOf` with `from == 0`:** passing `-1` as the position
searches backwards from the end, which would find the wrong newline. The
`from > 0 ? from - 1 : 0` guard is there for that; verify the
`quotingASingleLineWithNoSelectionQuotesThatLine` case passes, since it is the
one that exercises it.

- [ ] **Step 5: Register and run**

Add the source and `add_qtmaildir_test(formattoolbar)`, then:

Run: `ctest --test-dir build -R formattoolbar --output-on-failure`
Expected: PASS, 8 functions.

- [ ] **Step 6: Commit**

```bash
git add src/formattoolbar.h src/formattoolbar.cpp src/CMakeLists.txt \
        tests/test_formattoolbar.cpp tests/CMakeLists.txt
git commit -S -m "feat(compose): markdown formatting transformations, item 123

Each toolbar button is a text transformation over the markdown source rather
than rich-text editing: nothing about the buffer changes, it stays markdown
the user can also type by hand. Plain-text storage does not mean a bare text
box, and the two are separate decisions.

Free functions over text and a selection, with no widget, so the grammar is
tested without a painter. The toolbar that calls them comes with the
composer.

The cursor landing BETWEEN the tokens when nothing is selected is the
property a user notices on the first keystroke and the one a text comparison
cannot see, so the tests assert it by typing into the result rather than by
comparing an index. Quote is line-based rather than a wrap and widens the
selection to whole lines first, since quoting half a line produces markdown
that means something else."
```

---

### Task 9: The six actions

`CLAUDE.md` enumerates five registration sites and three of them are enforced
by tests that fail in confusing ways. Doing the actions before the window they
open means those tests guard every later task.

**A correction to the spec.** It calls for "a new top-level `Message` menu".
There already IS one, built at `src/mainwindow.cpp:1156`, holding archive,
delete, restore, spam and the thread submenu. Add the six actions to that menu
rather than creating a second one; two menus named Message would be a defect.

**Item 132 changed one of the five sites since the spec was written.** A
shortcut is now a chosen subset rather than a requirement, so `save_message`
ships with no binding. `everyActionIsReachableFromAMenu()` is the rule that
must hold.

**Files:**
- Modify: `src/keymap.cpp` (`knownActions()`, `defaultBindings()`)
- Modify: `src/mainwindow.h` (handler declarations, the composer registry)
- Modify: `src/mainwindow.cpp` (`addAction` calls, the icon table, the menu)
- Modify: `tests/test_mainwindow.cpp`

- [ ] **Step 1: Add the action names to `knownActions()`**

In `src/keymap.cpp`, add to the list returned by `knownActions()`:

```cpp
        QStringLiteral("compose"),
        QStringLiteral("reply"),
        QStringLiteral("reply_all"),
        QStringLiteral("reply_no_quote"),
        QStringLiteral("forward"),
        QStringLiteral("save_message"),
```

- [ ] **Step 2: Add five bindings to `defaultBindings()`**

Five, not six. `save_message` deliberately gets none: it is the rarely-used
escape hatch, and since item 132 an action without a chord is legitimate.

```cpp
        { QStringLiteral("Ctrl+N"),       QStringLiteral("compose") },
        { QStringLiteral("Ctrl+Shift+R"), QStringLiteral("reply") },
        { QStringLiteral("Ctrl+Shift+A"), QStringLiteral("reply_all") },
        { QStringLiteral("Ctrl+Alt+R"),   QStringLiteral("reply_no_quote") },
        { QStringLiteral("Ctrl+Shift+F"), QStringLiteral("forward") },
```

Each was checked against the existing map: `Ctrl+R` is `restore`, `Ctrl+A` is
`select_all`, `Ctrl+Alt+S` is `spam_thread`. These are **provisional**; the user
intends to rework the bindings and `Ctrl+Alt+R` is an imperfect fit, since that
tier elsewhere means "wider scope" rather than "variant".

- [ ] **Step 3: Run the suite to see the assert fire**

Run: `ctest --test-dir build 2>&1 | grep -E 'Failed|passed'`
Expected: FAIL. `Q_ASSERT(m_actions.size() == KeyMap::knownActions().size())` at `src/mainwindow.cpp:1130` fires, because the names exist and nothing implements them. This is the assert `CLAUDE.md` warns surfaces in whichever suite builds a `MainWindow` first.

- [ ] **Step 4: Register the actions with stub handlers**

In `MainWindow`'s action-building block, beside the existing `addAction` calls:

```cpp
    addAction(QStringLiteral("compose"), tr("&New message"),
              tr("Compose a new message"), [this]() { composeNew(); });
    addAction(QStringLiteral("reply"), tr("&Reply"),
              tr("Reply to the displayed message"),
              [this]() { composeReply(ComposeContext::Kind::Reply, true); });
    addAction(QStringLiteral("reply_all"), tr("Reply to &all"),
              tr("Reply to the sender and every other recipient"),
              [this]() { composeReply(ComposeContext::Kind::ReplyAll, true); });
    addAction(QStringLiteral("reply_no_quote"), tr("Reply &without quoting"),
              tr("Reply with an empty body"),
              [this]() { composeReply(ComposeContext::Kind::Reply, false); });
    addAction(QStringLiteral("forward"), tr("&Forward"),
              tr("Forward the displayed message"),
              [this]() { composeReply(ComposeContext::Kind::Forward, true); });
    addAction(QStringLiteral("save_message"), tr("&Save message as..."),
              tr("Write the raw message to a file"),
              [this]() { saveDisplayedMessage(); });
```

Declare the three handlers in `src/mainwindow.h`:

```cpp
    void composeNew();
    void composeReply(ComposeContext::Kind kind, bool quote);
    void saveDisplayedMessage();
```

Implement them as empty bodies for now; Task 12 fills them in. An empty body
satisfies the assert and the reachability tests, and keeps this commit to
registration.

- [ ] **Step 5: Add the icons**

In the `themeIcons` table in `src/mainwindow.cpp`:

```cpp
        { QStringLiteral("compose"),        QStringLiteral("mail-message-new") },
        { QStringLiteral("reply"),          QStringLiteral("mail-reply-sender") },
        { QStringLiteral("reply_all"),      QStringLiteral("mail-reply-all") },
        { QStringLiteral("reply_no_quote"), QStringLiteral("mail-reply-sender") },
        { QStringLiteral("forward"),        QStringLiteral("mail-forward") },
        { QStringLiteral("save_message"),   QStringLiteral("document-save-as") },
```

`reply_no_quote` shares `reply`'s icon, which needs an entry in the
no-duplicate-icons exception list beside the five thread actions, for the same
reason: it never reaches the toolbar and a menu entry always carries text. Find
that list in `tests/test_mainwindow.cpp` and add `reply_no_quote` to it.

- [ ] **Step 6: Add them to the EXISTING Message menu**

At `src/mainwindow.cpp:1156`, after `auto *messageMenu = ...` and before the
existing `archive` entry, so composing sits above organising:

```cpp
    messageMenu->addAction(m_actions.value(QStringLiteral("compose")));
    messageMenu->addSeparator();
    messageMenu->addAction(m_actions.value(QStringLiteral("reply")));
    messageMenu->addAction(m_actions.value(QStringLiteral("reply_all")));
    messageMenu->addAction(m_actions.value(QStringLiteral("reply_no_quote")));
    messageMenu->addAction(m_actions.value(QStringLiteral("forward")));
    messageMenu->addSeparator();
    messageMenu->addAction(m_actions.value(QStringLiteral("save_message")));
    messageMenu->addSeparator();
```

- [ ] **Step 7: Add compose and reply to the toolbar**

Those two only. The rest are menu-and-key, which is what keeps the
no-duplicate-icons rule satisfiable. Find the toolbar construction and add them
at the front, since composing is the most common action a user reaches for.

- [ ] **Step 8: Run the suite**

Run: `ctest --test-dir build --output-on-failure 2>&1 | tail -5`
Expected: PASS. `everyActionIsReachableFromAMenu()`, `everyActionCarriesAnIcon()` and `everyKnownActionIsRegistered()` all now cover the six new actions for free.

- [ ] **Step 9: Refresh the translations**

Run:
```bash
lupdate-qt6 src/ -ts translations/qtmaildir_it_IT.ts -no-obsolete -locations none
```
Expected: zero context warnings. Then translate every new string in the `.ts` file and confirm:
```bash
lrelease-qt6 translations/qtmaildir_it_IT.ts
```
Expected: `0 unfinished`. `lrelease` silently DROPS an unfinished string and ships it as English inside an otherwise Italian UI, so this is not optional.

Run: `ctest --test-dir build -R translations --output-on-failure`
Expected: PASS.

- [ ] **Step 10: Commit**

```bash
git add src/keymap.cpp src/mainwindow.h src/mainwindow.cpp \
        tests/test_mainwindow.cpp translations/qtmaildir_it_IT.ts
git commit -S -m "feat(compose): register the six compose actions, item 123

Handlers are empty for now; this commit is the registration, so the three
coverage tests guard every later task rather than being satisfied at the end.

Two corrections to the spec, both found in the code rather than assumed. It
calls for a new top-level Message menu and one already exists, so these join
it; two menus named Message would be a defect. And it says every action
needs a binding, which item 132 changed while this was being planned:
save_message ships with no chord, since it is the rarely-used escape hatch
and menu reachability is now the rule that must hold.

reply_no_quote shares reply's icon and is added to the no-duplicate-icons
exception list for the same reason the five thread actions are: it never
reaches the toolbar, and a menu entry always carries its text.

Bindings are provisional. The user intends to rework them, and Ctrl+Alt+R
for reply_no_quote is an imperfect fit since that tier elsewhere means a
wider scope rather than a variant."
```

---

### Task 10: SendDialog

The popup that owns the whole send operation, from cancellable countdown to
completion. It uses `BusyIndicator` from item 134, which is already on master
(`af902e0`) and exposes both modes.

**Files:**
- Create: `src/senddialog.h`, `src/senddialog.cpp`
- Create: `tests/test_senddialog.cpp`
- Modify: `src/CMakeLists.txt`, `tests/CMakeLists.txt`

- [ ] **Step 1: Write the header**

`src/senddialog.h` (GPL header, then):

```cpp
#pragma once

#include <QDialog>

class BusyIndicator;
class QLabel;
class QPushButton;
class QTimer;

/// Owns a send from the cancellable countdown through to completion.
///
/// Three rows in every state, so nothing reflows and the window never jumps:
/// a status label, the bar, and Undo.
///
/// The bar CHANGES MODE, it does not change place. Determinate while the
/// countdown drains, because a countdown has measurable progress;
/// indeterminate once the command starts, because a send does not.
///
/// Modal to the composer, NOT to the application: sending from one composer
/// must not freeze a second composer or the main window.
class SendDialog : public QDialog
{
    Q_OBJECT

public:
    /// \p delayMs of zero skips the countdown and sends at once.
    SendDialog(int delayMs, QWidget *parent = nullptr);

    /// The stages, in order. Each sets the label and leaves the bar
    /// indeterminate.
    enum class Stage { CountingDown, Sending, FilingSentCopy, RemovingDraft };

    void setStage(Stage stage);

    /// True once the countdown has elapsed and the command has started, after
    /// which cancelling is no longer possible.
    bool isCommitted() const { return m_committed; }

signals:
    /// The countdown elapsed or was skipped: the caller should start sending.
    void committed();

    /// Undo was pressed during the countdown. NOTHING has been sent.
    void undone();

private:
    void tick();
    void commit();

    QLabel *m_status = nullptr;
    BusyIndicator *m_indicator = nullptr;
    QPushButton *m_undo = nullptr;
    QTimer *m_timer = nullptr;

    int m_remainingMs = 0;
    int m_totalMs = 0;
    bool m_committed = false;
};
```

- [ ] **Step 2: Write the failing test**

Create `tests/test_senddialog.cpp`. The critical property is **negative**: Undo
during the countdown must mean nothing was sent.

```cpp
#include <QtTest>
#include <QLabel>
#include <QPushButton>

#include "busyindicator.h"
#include "senddialog.h"

class TestSendDialog : public QObject
{
    Q_OBJECT

private slots:
    void theBarIsDeterminateWhileCountingDown();
    void theCountdownCommitsWhenItElapses();
    void aZeroDelayCommitsImmediately();
    void undoDuringTheCountdownEmitsUndoneAndNeverCommits();
    void undoDisablesItselfOnceTheCommandStarts();
    void theBarBecomesIndeterminateWhenSending();
    void undoStaysVisibleAfterItDisables();
};

void TestSendDialog::theBarIsDeterminateWhileCountingDown()
{
    // A countdown has measurable progress, so the bar drains rather than
    // animating. This is the half of BusyIndicator MainWindow never uses.
    SendDialog dialog(200);
    dialog.show();

    auto *indicator = dialog.findChild<BusyIndicator *>();
    QVERIFY(indicator);
    QVERIFY2(indicator->isDeterminate(),
             "the countdown bar is indeterminate, so it shows no progress");
}

void TestSendDialog::theCountdownCommitsWhenItElapses()
{
    // A short delay rather than waiting five seconds in a test.
    SendDialog dialog(150);
    QSignalSpy spy(&dialog, &SendDialog::committed);
    dialog.show();

    QVERIFY2(spy.wait(3000), "the countdown never committed");
    QCOMPARE(spy.count(), 1);
    QVERIFY(dialog.isCommitted());
}

void TestSendDialog::aZeroDelayCommitsImmediately()
{
    // send_delay_ms = 0 sends at once, for anyone who finds the delay
    // irritating.
    SendDialog dialog(0);
    QSignalSpy spy(&dialog, &SendDialog::committed);
    dialog.show();

    QVERIFY2(spy.wait(1000), "a zero delay did not commit");
    QCOMPARE(spy.count(), 1);
}

void TestSendDialog::undoDuringTheCountdownEmitsUndoneAndNeverCommits()
{
    // THE test for this feature, and the property that matters is the
    // negative one: committed() must NEVER fire. A test asserting only that
    // undone() fired would pass against a design that started the send and
    // threw the result away, which is the whole failure the delay exists to
    // prevent.
    SendDialog dialog(2000);
    QSignalSpy committedSpy(&dialog, &SendDialog::committed);
    QSignalSpy undoneSpy(&dialog, &SendDialog::undone);
    dialog.show();

    auto *undo = dialog.findChild<QPushButton *>(QStringLiteral("undoSend"));
    QVERIFY(undo);
    QVERIFY2(undo->isEnabled(), "Undo was disabled during the countdown");
    undo->click();

    QCOMPARE(undoneSpy.count(), 1);
    QCOMPARE(committedSpy.count(), 0);

    // And it must still be zero after the original countdown would have
    // elapsed: a timer left running would commit late.
    QTest::qWait(2500);
    QVERIFY2(committedSpy.count() == 0,
             "the countdown committed after Undo was pressed");
}

void TestSendDialog::undoDisablesItselfOnceTheCommandStarts()
{
    // Killing send_command mid-transaction leaves an UNKNOWN send: the
    // message may have reached the server in full before the kill. That is
    // worse than either clean outcome, so there is no cancel after this point.
    SendDialog dialog(100);
    dialog.show();

    auto *undo = dialog.findChild<QPushButton *>(QStringLiteral("undoSend"));
    QVERIFY(undo);

    QSignalSpy spy(&dialog, &SendDialog::committed);
    QVERIFY(spy.wait(3000));

    QVERIFY2(!undo->isEnabled(),
             "Undo was still live after the send command started");
}

void TestSendDialog::theBarBecomesIndeterminateWhenSending()
{
    // A send has no measurable progress, unlike the countdown.
    SendDialog dialog(100);
    dialog.show();
    dialog.setStage(SendDialog::Stage::Sending);

    auto *indicator = dialog.findChild<BusyIndicator *>();
    QVERIFY(indicator);
    QVERIFY2(!indicator->isDeterminate(),
             "the bar still shows a fraction while sending");
}

void TestSendDialog::undoStaysVisibleAfterItDisables()
{
    // A control that vanishes re-lays out the popup mid-operation, and a
    // greyed Undo says why cancelling is no longer possible where an absent
    // one only looks like it was never offered.
    SendDialog dialog(100);
    dialog.show();

    auto *undo = dialog.findChild<QPushButton *>(QStringLiteral("undoSend"));
    QVERIFY(undo);

    QSignalSpy spy(&dialog, &SendDialog::committed);
    QVERIFY(spy.wait(3000));

    QVERIFY2(undo->isVisibleTo(&dialog),
             "Undo disappeared instead of greying out");
}

QTEST_MAIN(TestSendDialog)
#include "test_senddialog.moc"
```

- [ ] **Step 3: Run to verify it fails**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, `senddialog.h: No such file or directory`.

- [ ] **Step 4: Write the implementation**

`src/senddialog.cpp` (GPL header, then):

```cpp
#include "senddialog.h"

#include "busyindicator.h"

#include <QFontMetrics>
#include <QHBoxLayout>
#include <QLabel>
#include <QPushButton>
#include <QTimer>
#include <QVBoxLayout>

namespace {

/// How often the countdown repaints. 100ms is smooth enough for a draining
/// bar without being a busy loop.
constexpr int kTickMs = 100;

}  // namespace

SendDialog::SendDialog(int delayMs, QWidget *parent)
    : QDialog(parent)
    , m_remainingMs(qMax(0, delayMs))
    , m_totalMs(qMax(0, delayMs))
{
    setWindowTitle(tr("Sending"));

    // Modal to the composer, not to the application: sending from one composer
    // must not freeze a second composer or the main window.
    setWindowModality(Qt::WindowModal);

    // No close button and no Escape dismiss. During the countdown a dismissal
    // is ambiguous, since it could mean cancel or send now; during the send
    // there is nothing to dismiss. Undo is the only control.
    setWindowFlags((windowFlags() | Qt::CustomizeWindowHint)
                   & ~Qt::WindowCloseButtonHint);

    auto *layout = new QVBoxLayout(this);

    m_status = new QLabel(this);
    m_status->setObjectName(QStringLiteral("sendStatus"));

    // The label takes its width from the LONGEST string it can hold, in the
    // current language, not from its content. Italian "Rimozione della
    // bozza..." is longer than "Removing draft...", so a label sized to
    // content resizes the popup between stages, which is the jumping the
    // fixed layout exists to avoid.
    const QFontMetrics metrics(m_status->font());
    int widest = 0;
    for (const QString &candidate : { tr("Sending in %1...").arg(99),
                                      tr("Sending..."),
                                      tr("Filing sent copy..."),
                                      tr("Removing draft...") }) {
        widest = qMax(widest, metrics.horizontalAdvance(candidate));
    }
    m_status->setMinimumWidth(widest);
    layout->addWidget(m_status);

    m_indicator = new BusyIndicator(this);
    m_indicator->setObjectName(QStringLiteral("sendProgress"));
    layout->addWidget(m_indicator);

    auto *buttonRow = new QHBoxLayout;
    buttonRow->addStretch();
    m_undo = new QPushButton(tr("Undo"), this);
    m_undo->setObjectName(QStringLiteral("undoSend"));
    connect(m_undo, &QPushButton::clicked, this, [this]() {
        // Stop the timer FIRST. A timer left running commits after the dialog
        // has already reported that nothing was sent.
        m_timer->stop();
        emit undone();
        reject();
    });
    buttonRow->addWidget(m_undo);
    layout->addLayout(buttonRow);

    m_timer = new QTimer(this);
    m_timer->setObjectName(QStringLiteral("sendCountdown"));
    m_timer->setInterval(kTickMs);
    connect(m_timer, &QTimer::timeout, this, &SendDialog::tick);

    if (m_totalMs == 0) {
        // Zero skips the countdown. Queued rather than immediate so the caller
        // can connect to committed() after constructing the dialog.
        QTimer::singleShot(0, this, &SendDialog::commit);
    } else {
        setStage(Stage::CountingDown);
        m_timer->start();
    }
}

void SendDialog::tick()
{
    m_remainingMs -= kTickMs;
    if (m_remainingMs <= 0) {
        commit();
        return;
    }
    setStage(Stage::CountingDown);
}

void SendDialog::commit()
{
    m_timer->stop();
    m_committed = true;

    // Undo disables the moment the command starts and stays VISIBLE. A
    // control that vanishes re-lays out the popup mid-operation.
    m_undo->setEnabled(false);

    setStage(Stage::Sending);
    emit committed();
}

void SendDialog::setStage(Stage stage)
{
    switch (stage) {
    case Stage::CountingDown: {
        const int seconds = (m_remainingMs + 999) / 1000;
        m_status->setText(tr("Sending in %1...").arg(seconds));
        // Determinate: a countdown HAS measurable progress. Drains as the
        // seconds pass.
        m_indicator->setProgress(m_remainingMs, m_totalMs);
        break;
    }
    case Stage::Sending:
        m_status->setText(tr("Sending..."));
        // Indeterminate from here: a send does not report progress.
        m_indicator->setBusy(true);
        break;
    case Stage::FilingSentCopy:
        m_status->setText(tr("Filing sent copy..."));
        m_indicator->setBusy(true);
        break;
    case Stage::RemovingDraft:
        m_status->setText(tr("Removing draft..."));
        m_indicator->setBusy(true);
        break;
    }
}
```

- [ ] **Step 5: Register and run**

Add the source and `add_qtmaildir_test(senddialog)`, then:

Run: `ctest --test-dir build -R senddialog --output-on-failure`
Expected: PASS, 7 functions.

- [ ] **Step 6: Mutation-check the undo test**

The negative property must actually be measured:

```bash
# Make Undo emit undone() but NOT stop the timer, which is the exact bug
# the test exists to catch.
sed -i 's/        m_timer->stop();\n        emit undone();/        emit undone();/' src/senddialog.cpp
```
Do this edit by hand if the `sed` does not match. Rebuild and run; expected: `undoDuringTheCountdownEmitsUndoneAndNeverCommits` FAILS on the post-wait assertion. Restore with `git checkout src/senddialog.cpp`.

- [ ] **Step 7: Commit**

```bash
git add src/senddialog.h src/senddialog.cpp src/CMakeLists.txt \
        tests/test_senddialog.cpp tests/CMakeLists.txt
git commit -S -m "feat(compose): the send popup and its undo window, item 123

Three rows in every state so nothing reflows and the window never jumps. The
bar changes MODE rather than place: determinate while the countdown drains,
because a countdown has measurable progress, and indeterminate once the
command starts, because a send does not. That is the pairing item 134's
widget was extracted to serve.

The delay is where cancelling is safe and it is the only place it is.
Nothing has reached a server during the countdown, so Undo means genuinely
nothing happened; killing send_command once it runs leaves an UNKNOWN send,
which is worse than either clean outcome. Undo therefore disables itself the
moment the command starts, and stays visible while disabled: a control that
vanishes re-lays out the popup mid-operation, and a greyed Undo says why
cancelling is no longer possible where an absent one looks like it was never
offered.

The test for this asserts the NEGATIVE property, that committed() never
fires after Undo, including after the original countdown would have elapsed.
Asserting only that undone() fired would pass against a design that ran the
command and threw the result away, which is the whole failure the delay
exists to prevent.

The status label is sized to the longest string it can hold in the current
language rather than to its content: Italian 'Rimozione della bozza...' is
longer than 'Removing draft...', and a label sized to content resizes the
popup between stages."
```

---

### Task 11: ComposeWindow

**Found during Task 4's code review, and it lands here.** `MessageBuilder::build()`
is SYNCHRONOUS and can block: a large attachment is read and base64-encoded on
the calling thread. Autosave calls it on a timer, on the GUI thread, so a
30-second debounce that hits a 25MB attachment stalls typing. The directory
hang that review found is fixed in `MessageBuilder`, but the blocking read
remains by design. Do not move it to a thread as part of this task, since
nothing here crosses the worker boundary and adding a second threading model
for one call is worse than the stall. Note it in a comment at the autosave call
site so the next person measuring a freeze knows where to look.

The only unit here that owns widgets, and the one that composes the other four.
It contains no MIME and no process logic: a composer bug and a MIME bug are
found in different files.

**Files:**
- Create: `src/composewindow.h`, `src/composewindow.cpp`
- Modify: `src/CMakeLists.txt`
- Modify: `tests/test_mainwindow.cpp` (the composer cases go here, since they need a window)

- [ ] **Step 1: Write the header**

`src/composewindow.h` (GPL header, then):

```cpp
#pragma once

#include <QMainWindow>

#include "config.h"
#include "formattoolbar.h"  // MarkdownFormat::Edit is used by value below, and
                            // a type nested in a namespace cannot be
                            // forward-declared from outside it.
#include "types.h"

class BusyIndicator;
class DraftStore;
class MessageSender;
class QCheckBox;
class QComboBox;
class QLabel;
class QLineEdit;
class QPlainTextEdit;
class QTimer;

/// One draft. A separate top-level window, several open at once.
///
/// A QMainWindow rather than a dialog: a modal dialog cannot consult another
/// message while writing, which is most of what replying is, and taking over
/// the message pane fights the pane that exists to show what is being replied
/// to.
///
/// NO GEOMETRY RESTORE. CLAUDE.md records what saveGeometry does under a
/// tiling compositor: it stores normalGeometry, the compositor owns the tile,
/// and the restore is correct while looking broken. A whole session went into
/// that once. The composer opens at a sensible default size and the
/// compositor places it.
class ComposeWindow : public QMainWindow
{
    Q_OBJECT

public:
    /// \p mailRoot is the Maildir root, passed in rather than derived.
    ///
    /// There is NO Config::maildirPath(). The root comes from
    /// notmuch_config_get(NOTMUCH_CONFIG_MAIL_ROOT), wrapped by mailRootOf()
    /// which is file-static inside notmuchworker.cpp and needs the database
    /// handle. Item 124 records why this matters: notmuch can split the index
    /// from the mail, and under that layout database.path is the INDEX
    /// directory. Composing a destination from the wrong root would write
    /// drafts and sent copies into the Xapian tree. MainWindow already
    /// receives the root from the worker; it passes it here.
    ComposeWindow(const ComposeContext &context, const Config &config,
                  const QString &mailRoot, QWidget *parent = nullptr);

    /// True when the buffer has changed since the last successful autosave.
    /// The quit path asks every open composer this.
    bool hasUnsavedEdits() const { return m_dirty; }

    /// True when the LAST autosave attempt failed. Escalated to its own
    /// dialog on the way out, because saving is what is already not working
    /// and quitting therefore loses that text.
    bool lastSaveFailed() const { return m_saveFailed; }

    /// Writes the current buffer to the drafts folder now. Returns false and
    /// leaves the banner up on failure.
    bool saveDraftNow();

signals:
    /// The composer finished with its message, one way or another, and the
    /// registry should forget it.
    void closed(ComposeWindow *window);

private:
    void buildUi();
    void buildFormatToolbar();
    void seedBody();
    void attachFile(const QString &path);
    void refreshAttachmentBar();
    void setInputsEnabled(bool enabled);
    void showSendFailure(const QString &stderrText);
    void applyEdit(const MarkdownFormat::Edit &edit);
    void markDirty();
    void autosave();
    void send();
    void applyFormat(const QString &token);

    OutgoingMessage currentMessage() const;

    ComposeContext m_context;
    Config m_config;
    QString m_mailRoot;
    QStringList m_attachments;

    QLineEdit *m_to = nullptr;
    QLineEdit *m_cc = nullptr;
    QLineEdit *m_bcc = nullptr;
    QLineEdit *m_subject = nullptr;
    QComboBox *m_from = nullptr;
    QPlainTextEdit *m_body = nullptr;
    QCheckBox *m_sendHtml = nullptr;
    QLabel *m_banner = nullptr;

    QTimer *m_autosaveTimer = nullptr;
    MessageSender *m_sender = nullptr;

    QString m_draftPath;      ///< The revision on disk, unlinked on the next write.
    QByteArray m_savedBytes;  ///< What was last written, for the dirty check.
    bool m_dirty = false;
    bool m_saveFailed = false;
};
```

- [ ] **Step 2: Write the implementation**

`src/composewindow.cpp`. The full file is long; these are the parts that carry
decisions, and the rest is ordinary widget assembly.

```cpp
#include "composewindow.h"

#include "composecontext.h"
#include "draftstore.h"
#include "formattoolbar.h"
#include "messagebuilder.h"
#include "messagesender.h"
#include "senddialog.h"

#include <QCheckBox>
#include <QComboBox>
#include <QDir>
#include <QFormLayout>
#include <QLabel>
#include <QLineEdit>
#include <QMessageBox>
#include <QPlainTextEdit>
#include <QPushButton>
#include <QTimer>
#include <QToolBar>
#include <QVBoxLayout>

ComposeWindow::ComposeWindow(const ComposeContext &context,
                             const Config &config, const QString &mailRoot,
                             QWidget *parent)
    : QMainWindow(parent)
    , m_context(context)
    , m_config(config)
    , m_mailRoot(mailRoot)
{
    // A window in its own right, not a child dialog: it must appear in the
    // task switcher and be reachable while the main window is used.
    setAttribute(Qt::WA_DeleteOnClose);
    setWindowTitle(tr("Compose"));

    // A sensible default. NOT restored and NOT saved; see the header.
    resize(760, 640);

    buildUi();

    m_autosaveTimer = new QTimer(this);
    m_autosaveTimer->setObjectName(QStringLiteral("autosave"));
    m_autosaveTimer->setSingleShot(true);
    m_autosaveTimer->setInterval(m_config.compose().autosaveIntervalMs);
    connect(m_autosaveTimer, &QTimer::timeout, this, &ComposeWindow::autosave);

    m_sender = new MessageSender(this);
}

void ComposeWindow::markDirty()
{
    m_dirty = true;
    // Debounced: the timer restarts on every keystroke, so a write happens
    // once the user has paused, not once per character. Every autosave
    // produces a Maildir write that mbsync uploads, which is what the debounce
    // and the dirty check together keep to a few revisions per message.
    m_autosaveTimer->start();
}

void ComposeWindow::autosave()
{
    if (!m_dirty)
        return;

    const Account account = m_config.account(m_context.accountKey);
    if (account.drafts.isEmpty()) {
        // Configured without a drafts folder. Warned about at startup; there
        // is nothing to do here and nothing to report a second time.
        return;
    }

    const MessageBuilder::Result built =
        MessageBuilder::build(currentMessage(), account);
    if (!built.ok()) {
        m_saveFailed = true;
        m_banner->setText(tr("The draft could not be saved: %1").arg(built.error));
        m_banner->show();
        return;
    }

    // The dirty CHECK, not just the flag: identical bytes mean nothing
    // changed that matters, so no file is written and no sync is provoked.
    if (built.bytes == m_savedBytes) {
        m_dirty = false;
        return;
    }

    const QString folder =
        QDir(m_mailRoot).absoluteFilePath(
            account.maildir + QLatin1Char('/') + account.drafts);

    const DraftStore::Result written = DraftStore::write(
        folder, built.bytes, QStringLiteral("D"), m_draftPath);

    if (!written.ok()) {
        // A PERSISTENT banner, not a modal and not a status-bar line that
        // fades. A modal mid-sentence is hostile while the user is typing,
        // but the warning must survive until it is dealt with, because the
        // quit path's honesty depends on it.
        m_saveFailed = true;
        m_banner->setText(tr("The draft could not be saved: %1").arg(written.error));
        m_banner->show();
        return;
    }

    m_draftPath = written.path;
    m_savedBytes = built.bytes;
    m_dirty = false;
    m_saveFailed = false;
    m_banner->hide();
}

void ComposeWindow::applyFormat(const QString &token)
{
    QTextCursor cursor = m_body->textCursor();
    const MarkdownFormat::Edit edit = MarkdownFormat::wrap(
        m_body->toPlainText(), cursor.selectionStart(), cursor.selectionEnd(),
        token);

    m_body->setPlainText(edit.text);

    // Restore the selection the transformation asked for. setPlainText resets
    // the cursor to the start, so without this every button press sends the
    // cursor to the top of the message.
    QTextCursor restored = m_body->textCursor();
    restored.setPosition(edit.selectionStart);
    restored.setPosition(edit.selectionEnd, QTextCursor::KeepAnchor);
    m_body->setTextCursor(restored);
    m_body->setFocus();
}

void ComposeWindow::send()
{
    const Account account = m_config.account(m_context.accountKey);

    const MessageBuilder::Result built =
        MessageBuilder::build(currentMessage(), account);
    if (!built.ok()) {
        // A missing attachment lands here, before anything runs.
        QMessageBox::warning(this, tr("Cannot send"), built.error);
        return;
    }

    // Every input is disabled for the WHOLE operation, countdown included.
    // The message must not change between the user pressing Send and the
    // bytes being built.
    setInputsEnabled(false);

    auto *dialog = new SendDialog(m_config.compose().sendDelayMs, this);

    connect(dialog, &SendDialog::undone, this, [this, dialog]() {
        // Nothing reached a server. The composer returns exactly as it was,
        // editable, popup gone, nothing sent.
        setInputsEnabled(true);
        dialog->deleteLater();
    });

    connect(dialog, &SendDialog::committed, this, [this, dialog, built, account]() {
        m_sender->send(account.sendCommand, built.bytes);

        connect(m_sender, &MessageSender::finished, this,
                [this, dialog, built, account](bool sent, const QString &error) {
            if (!sent) {
                dialog->accept();
                dialog->deleteLater();
                setInputsEnabled(true);
                // The draft STAYS. No retry loop.
                showSendFailure(error);
                return;
            }

            dialog->setStage(SendDialog::Stage::FilingSentCopy);
            bool sentCopyFailed = false;
            QString sentCopyError;

            if (!account.sent.isEmpty()) {
                const QString folder =
                    QDir(m_mailRoot).absoluteFilePath(
                        account.maildir + QLatin1Char('/') + account.sent);
                const DraftStore::Result filed = DraftStore::write(
                    folder, built.bytes, QStringLiteral("S"));
                if (!filed.ok()) {
                    sentCopyFailed = true;
                    sentCopyError = filed.error;
                }
            }

            dialog->setStage(SendDialog::Stage::RemovingDraft);
            if (!m_draftPath.isEmpty())
                QFile::remove(m_draftPath);

            dialog->accept();
            dialog->deleteLater();

            if (sentCopyFailed) {
                // A MODAL, never a status-bar line, and never reported as a
                // send failure. The message went; reporting otherwise makes
                // someone send it twice. This is the one failure in the whole
                // design that produces a silent divergence between what the
                // recipient received and what the local archive shows, and
                // nobody discovers a missing sent copy by noticing a line
                // that appeared for a few seconds.
                QMessageBox::warning(
                    this, tr("Sent, but not filed"),
                    tr("The message was sent, but the copy could not be "
                       "written to '%1' for account '%2':\n\n%3\n\n"
                       "The message HAS been sent. Do not send it again.")
                        .arg(account.sent, account.key, sentCopyError));
            }

            // The composer closes either way: the message went, and holding a
            // composer open for a message already sent invites sending it
            // twice.
            emit closed(this);
            close();
        }, Qt::SingleShotConnection);
    });

    dialog->open();
}
```

- [ ] **Step 2b: Consume the three settings that are otherwise parsed and ignored**

Task 2 parses `quote_position`, `attachment_warn_bytes` and the toolbar's
shortcuts; without this step all three are dead configuration. Each is one
small piece of `ComposeWindow`.

**The quote position**, applied when the window opens and never again. The
buffer is text the user owns after that, and there is deliberately no live
toggle: tracking "my text" and "the quote" as separate pieces to make a toggle
reversible is machinery for a case answered by closing the composer and
reopening it.

```cpp
void ComposeWindow::seedBody()
{
    if (m_context.quotedBody.isEmpty())
        return;

    if (m_config.compose().quotePosition == ComposeSettings::QuotePosition::Above) {
        // The quote first, then a blank line for the reply to be typed into,
        // and the cursor at the very top.
        m_body->setPlainText(m_context.quotedBody + QStringLiteral("\n\n"));
        m_body->moveCursor(QTextCursor::Start);
    } else {
        m_body->setPlainText(QStringLiteral("\n\n") + m_context.quotedBody);
        m_body->moveCursor(QTextCursor::Start);
    }
}
```

**The attachment size warning**, at attach time. A warning rather than a
refusal: the limit belongs to the recipient's server, which this application
cannot know, so the user decides.

```cpp
void ComposeWindow::attachFile(const QString &path)
{
    const QFileInfo info(path);
    const qint64 limit = m_config.compose().attachmentWarnBytes;

    if (limit > 0 && info.size() > limit) {
        const auto answer = QMessageBox::question(
            this, tr("Large attachment"),
            tr("'%1' is %2 MB. Many mail servers refuse messages above about "
               "%3 MB. Attach it anyway?")
                .arg(info.fileName())
                .arg(info.size() / (1024 * 1024))
                .arg(limit / (1024 * 1024)),
            QMessageBox::Yes | QMessageBox::No);
        if (answer != QMessageBox::Yes)
            return;
    }

    m_attachments.append(path);
    refreshAttachmentBar();
    markDirty();
}
```

**The formatting toolbar**, whose shortcuts live in the composer's own scope
and NOT in `KeyMap`. That separation is the point: `Ctrl+B` here does not
consume `Ctrl+B` from the main window's map, and these six do not participate
in the reachability rule item 132 reshaped.

```cpp
void ComposeWindow::buildFormatToolbar()
{
    auto *toolbar = addToolBar(tr("Formatting"));
    toolbar->setObjectName(QStringLiteral("formatToolbar"));

    // A QAction parented to THIS WINDOW, not registered in KeyMap. Its
    // shortcut is therefore scoped to the composer: Qt dispatches a
    // WindowShortcut to the active window only, so the main window's Ctrl+B
    // is untouched and the two namespaces stay apart.
    const auto addFormat = [this, toolbar](const QString &name, const QString &text,
                                           const QString &token,
                                           const QKeySequence &shortcut) {
        auto *action = toolbar->addAction(text);
        action->setObjectName(name);
        if (!shortcut.isEmpty())
            action->setShortcut(shortcut);
        connect(action, &QAction::triggered, this,
                [this, token]() { applyFormat(token); });
    };

    addFormat(QStringLiteral("format_bold"), tr("Bold"),
              QStringLiteral("**"), QKeySequence(QStringLiteral("Ctrl+B")));
    addFormat(QStringLiteral("format_italic"), tr("Italic"),
              QStringLiteral("*"), QKeySequence(QStringLiteral("Ctrl+I")));
    addFormat(QStringLiteral("format_code"), tr("Code"),
              QStringLiteral("`"), QKeySequence(QStringLiteral("Ctrl+`")));
    // No shortcut, per the spec's table.
    addFormat(QStringLiteral("format_strike"), tr("Strikethrough"),
              QStringLiteral("~~"), QKeySequence());

    // Link and Quote are not wraps and cannot go through applyFormat().
    auto *link = toolbar->addAction(tr("Link"));
    link->setObjectName(QStringLiteral("format_link"));
    link->setShortcut(QKeySequence(QStringLiteral("Ctrl+K")));
    connect(link, &QAction::triggered, this, [this]() {
        QTextCursor cursor = m_body->textCursor();
        applyEdit(MarkdownFormat::link(m_body->toPlainText(),
                                       cursor.selectionStart(),
                                       cursor.selectionEnd()));
    });

    auto *quote = toolbar->addAction(tr("Quote"));
    quote->setObjectName(QStringLiteral("format_quote"));
    connect(quote, &QAction::triggered, this, [this]() {
        QTextCursor cursor = m_body->textCursor();
        applyEdit(MarkdownFormat::quote(m_body->toPlainText(),
                                        cursor.selectionStart(),
                                        cursor.selectionEnd()));
    });
}
```

Refactor `applyFormat()` to call a shared `applyEdit(const MarkdownFormat::Edit &)`
that sets the text and restores the selection, since all three paths need it.

Declare `setInputsEnabled(bool)` and `showSendFailure(const QString &)` in the
header and implement them: the first toggles every input including the
formatting toolbar and Send, the second shows the command's stderr in a pane
below the body, in the shape `MailSync`'s log pane already has.

`Qt::SingleShotConnection` requires Qt 6.0+; this project is on 6.11. Without
it, a second send from the same composer would connect the lambda twice.

- [ ] **Step 3: Build and check it compiles**

Run: `cmake --build build 2>&1 | grep -E 'error' | head`
Expected: no output.

- [ ] **Step 4: Commit**

```bash
git add src/composewindow.h src/composewindow.cpp src/CMakeLists.txt
git commit -S -m "feat(compose): the composer window, item 123

A separate top-level QMainWindow, one per draft, several open at once. A
modal dialog cannot consult another message while writing, which is most of
what replying is, and taking over the message pane fights the pane that
exists to show what is being replied to.

No geometry save and no restore, deliberately. Under a tiling compositor
saveGeometry stores normalGeometry while the compositor owns the tile, so
the restore is correct and looks broken; a whole session went into that
once.

Autosave is a 30 second debounce AND a dirty check on the built bytes:
identical bytes mean no file is written and no sync is provoked. Every
autosave produces a Maildir write that mbsync uploads, which is what those
two together keep to a few revisions per message rather than dozens.

A failed draft write raises a persistent banner rather than a modal or a
fading status line. A modal mid-sentence is hostile while the user is
typing, but the warning must survive until it is dealt with, because the
quit path escalates exactly this state to a dialog on the way out.

A failed sent copy after a successful send is a modal, and never a send
failure: the message went, and reporting otherwise makes someone send it
twice. It is the one failure here that silently diverges what the recipient
received from what the local archive shows, and nobody discovers a missing
sent copy by noticing a line that appeared for a few seconds."
```

---

### Task 12: Wire it into MainWindow

The action handlers left empty in Task 9, the composer registry, the
receive-only ribbon and the quit path.

**Files:**
- Modify: `src/mainwindow.h`, `src/mainwindow.cpp`
- Modify: `src/messageview.h`, `src/messageview.cpp`
- Modify: `tests/test_mainwindow.cpp`

- [ ] **Step 1: Write the failing tests**

Add to `tests/test_mainwindow.cpp`, declaring each in `private slots:`.

`WorkerBackedWindow` gains a knob for an account without `send_command` rather
than a new fixture class. Find its config-writing helper and add a parameter
for it.

```cpp
void TestMainWindow::replyIsDisabledOnAReceiveOnlyAccountsMail()
{
    // The capability IS the send_command's presence. One of the user's five
    // accounts is receive-only on purpose.
    WorkerBackedWindow fixture;
    fixture.addAccount(QStringLiteral("listsonly"), /*canSend=*/false);
    fixture.build();

    // Select a message that arrived at the receive-only account.
    fixture.selectMessageIn(QStringLiteral("listsonly"));

    for (const QString &name : { QStringLiteral("reply"),
                                 QStringLiteral("reply_all"),
                                 QStringLiteral("reply_no_quote"),
                                 QStringLiteral("forward") }) {
        auto *action = fixture.window->findChild<QAction *>(name);
        QVERIFY2(action, qPrintable(QStringLiteral("no action %1").arg(name)));
        QVERIFY2(!action->isEnabled(),
                 qPrintable(QStringLiteral("%1 was live on receive-only mail").arg(name)));
    }

    // save_message is NEVER disabled, including here. It is the escape hatch
    // for exactly this case: write the raw message out and attach it to a new
    // message from an account that can send.
    auto *save = fixture.window->findChild<QAction *>(QStringLiteral("save_message"));
    QVERIFY(save);
    QVERIFY2(save->isEnabled(),
             "save_message was disabled, removing the escape hatch");
}

void TestMainWindow::theReceiveOnlyRibbonNamesTheAccount()
{
    // The ribbon is a WIDGET in MessageView's layout, not markup inside the
    // web view. Composing HTML from configuration into the one document that
    // renders input from strangers is the wrong direction.
    WorkerBackedWindow fixture;
    fixture.addAccount(QStringLiteral("listsonly"), /*canSend=*/false);
    fixture.build();
    fixture.selectMessageIn(QStringLiteral("listsonly"));

    auto *ribbon = fixture.window->findChild<QLabel *>(
        QStringLiteral("receiveOnlyRibbon"));
    QVERIFY2(ribbon, "no ribbon widget exists");
    QVERIFY2(ribbon->isVisibleTo(fixture.window),
             "the ribbon did not appear on receive-only mail");
    QVERIFY2(ribbon->text().contains(QStringLiteral("listsonly")),
             qPrintable(QStringLiteral("the ribbon does not name the account: %1")
                            .arg(ribbon->text())));
}

void TestMainWindow::composeIsDisabledOnlyWhenNoAccountCanSend()
{
    // An installation with no send_command anywhere is a valid read-only
    // installation and is not warned about; compose is simply unavailable.
    {
        WorkerBackedWindow fixture;
        fixture.addAccount(QStringLiteral("listsonly"), /*canSend=*/false);
        fixture.build();

        auto *compose = fixture.window->findChild<QAction *>(QStringLiteral("compose"));
        QVERIFY(compose);
        QVERIFY2(!compose->isEnabled(),
                 "compose was live with no account able to send");
    }
    {
        WorkerBackedWindow fixture;
        fixture.addAccount(QStringLiteral("listsonly"), /*canSend=*/false);
        fixture.addAccount(QStringLiteral("work"), /*canSend=*/true);
        fixture.build();

        auto *compose = fixture.window->findChild<QAction *>(QStringLiteral("compose"));
        QVERIFY(compose);
        QVERIFY2(compose->isEnabled(),
                 "compose was disabled although one account can send");
    }
}

void TestMainWindow::quittingWithACleanComposerAsksNothing()
{
    // Case 1: every composer clean, quit directly, no dialog. A dialog here
    // would be the "are you sure" this project deliberately does not do.
    WorkerBackedWindow fixture;
    fixture.addAccount(QStringLiteral("work"), /*canSend=*/true);
    fixture.build();

    fixture.window->openComposerForTest();
    QCOMPARE(fixture.window->openComposerCount(), 1);

    QVERIFY2(fixture.window->composersBlockingQuit().isEmpty(),
             "a clean composer was reported as blocking quit");
}

void TestMainWindow::quittingWithUnsavedEditsAsksOnce()
{
    // Case 2: ONE dialog whatever the count. Three modals in a row is worse
    // than a coarse answer, so there is no per-draft choice.
    WorkerBackedWindow fixture;
    fixture.addAccount(QStringLiteral("work"), /*canSend=*/true);
    fixture.build();

    fixture.window->openComposerForTest();
    fixture.window->openComposerForTest();
    fixture.window->markComposersDirtyForTest();

    QCOMPARE(fixture.window->composersBlockingQuit().size(), 2);
}
```

The `openComposerForTest`, `openComposerCount`, `composersBlockingQuit` and
`markComposersDirtyForTest` helpers go on `MainWindow` as test seams; declare
them in the header. `composersBlockingQuit()` is production code the quit path
itself uses, not a test-only accessor.

- [ ] **Step 2: Run to verify they fail**

Run: `cmake --build build 2>&1 | tail -3`
Expected: FAIL, the helpers do not exist.

- [ ] **Step 3: Add the composer registry to MainWindow**

In `src/mainwindow.h`:

```cpp
    /// Every open composer, so the quit path can see them.
    ///
    /// QPointer rather than a raw list: a composer is WA_DeleteOnClose and
    /// deletes itself, so a raw pointer here would dangle the moment a user
    /// closed one window.
    QList<QPointer<ComposeWindow>> m_composers;
```

- [ ] **Step 4: Implement the three action handlers**

```cpp
void MainWindow::composeNew()
{
    // m_accountBox->currentData() is how the selected account is read
    // everywhere else in this file; there is no currentAccountKey() accessor.
    // Empty means the All accounts view, which falls through to rule 2.
    const QString accountKey = ComposeContextBuilder::accountForNew(
        m_config, m_accountBox->currentData().toString());
    if (accountKey.isEmpty())
        return;  // No account can send; the action is disabled and this is unreachable.

    ComposeContext context;
    context.kind = ComposeContext::Kind::New;
    context.accountKey = accountKey;
    context.seedHtml = m_config.compose().sendHtml;

    openComposer(context);
}

void MainWindow::composeReply(ComposeContext::Kind kind, bool quote)
{
    // messageScopeFor() semantics, NOT threadFor(): a thread row means the one
    // message its card shows, a reply row means itself. Replying to a thread
    // is meaningless; a reply answers a message.
    //
    // It takes a QModelIndexList (src/threadlistmodel.h:338), not a single
    // index, so the current index is wrapped rather than passed bare.
    const ActionScope scope =
        m_model->messageScopeFor({ m_threadView->currentIndex() });
    if (scope.messageIds.isEmpty())
        return;

    // Built from the DATABASE, never from the model. The model's data comes
    // from the query, so a row whose state has not been re-queried carries
    // stale values, and a reply built from a stale row would carry the wrong
    // recipients. This is the rule Restore already follows.
    requestMessageForCompose(scope.messageIds.first(), kind, quote);
}
```

`requestMessageForCompose` asks the worker for the message's parsed content and
file paths, and builds the `ComposeContext` in its reply slot using
`ComposeContextBuilder`. It reuses the existing message-load path rather than
adding a worker signal, since the composer never touches `NotmuchWorker`
directly.

- [ ] **Step 5: Implement action enablement**

Wherever the other actions' enabled state is updated:

```cpp
    // The reply family is disabled on mail that arrived at an account which
    // cannot send. save_message is deliberately NOT in this list: it is the
    // escape hatch for exactly that case.
    const QString replyAccount = accountForCurrentMessage();
    const bool canReply = !replyAccount.isEmpty()
                          && m_config.account(replyAccount).canSend();
    for (const QString &name : { QStringLiteral("reply"),
                                 QStringLiteral("reply_all"),
                                 QStringLiteral("reply_no_quote"),
                                 QStringLiteral("forward") }) {
        if (QAction *action = m_actions.value(name))
            action->setEnabled(canReply);
    }

    // compose is disabled only when NO account can send. A read-only
    // installation is valid and is not warned about.
    if (QAction *compose = m_actions.value(QStringLiteral("compose")))
        compose->setEnabled(!m_config.sendingAccounts().isEmpty());
```

- [ ] **Step 6: Add the ribbon to MessageView**

In `src/messageview.h` add `QLabel *m_receiveOnlyRibbon = nullptr;` and a
setter:

```cpp
    /// Shows or hides the receive-only explanation.
    ///
    /// A WIDGET in this layout, never markup inside the web view: composing
    /// HTML from configuration into the one document that renders input from
    /// strangers is the wrong direction, and the header row is already a
    /// widget for the same reason.
    void setReceiveOnlyAccount(const QString &accountKey);
```

```cpp
void MessageView::setReceiveOnlyAccount(const QString &accountKey)
{
    if (accountKey.isEmpty()) {
        m_receiveOnlyRibbon->hide();
        return;
    }

    // Qt::PlainText explicitly: the account key comes from configuration
    // rather than from a stranger, but a QLabel guesses under Qt::AutoText and
    // this is the same protection MessageDetailsDialog states everywhere.
    m_receiveOnlyRibbon->setTextFormat(Qt::PlainText);
    m_receiveOnlyRibbon->setText(
        tr("This account is receive-only. Add send_command to [account.%1] "
           "to send from it.")
            .arg(accountKey));
    m_receiveOnlyRibbon->show();
}
```

Build the label in `MessageView`'s constructor with
`setObjectName(QStringLiteral("receiveOnlyRibbon"))`, hidden, above the web view.

- [ ] **Step 7: Implement the quit path**

```cpp
QList<ComposeWindow *> MainWindow::composersBlockingQuit() const
{
    QList<ComposeWindow *> blocking;
    for (const QPointer<ComposeWindow> &composer : m_composers) {
        if (composer && composer->hasUnsavedEdits())
            blocking.append(composer.data());
    }
    return blocking;
}
```

In `closeEvent`, before the existing pending-edits check:

```cpp
    // Case 3 FIRST, because it is the one where saving is what is already not
    // working: in case 2 nothing is lost by saving, here quitting loses that
    // text, so the dialog must say so plainly rather than offering a save that
    // will fail again.
    QStringList failedSaves;
    for (const QPointer<ComposeWindow> &composer : m_composers) {
        if (composer && composer->lastSaveFailed())
            failedSaves.append(composer->windowTitle());
    }
    if (!failedSaves.isEmpty()) {
        const auto answer = QMessageBox::warning(
            this, tr("A draft could not be saved"),
            tr("%n message(s) could not be saved to the drafts folder. "
               "Quitting now loses that text.", "", failedSaves.size()),
            QMessageBox::Retry | QMessageBox::Discard | QMessageBox::Cancel);
        if (answer == QMessageBox::Cancel) {
            event->ignore();
            return;
        }
        if (answer == QMessageBox::Retry) {
            bool allSaved = true;
            for (const QPointer<ComposeWindow> &composer : m_composers) {
                if (composer && composer->lastSaveFailed() && !composer->saveDraftNow())
                    allSaved = false;
            }
            if (!allSaved) {
                event->ignore();
                return;
            }
        }
    }

    // Case 2: ONE dialog whatever the count. Three modals in a row is worse
    // than a coarse answer, so it applies to all of them and there is no
    // per-draft choice.
    const QList<ComposeWindow *> blocking = composersBlockingQuit();
    if (!blocking.isEmpty()) {
        const auto answer = QMessageBox::question(
            this, tr("Messages still being composed"),
            // "Discard" discards UNSAVED EDITS, not drafts: a draft already
            // autosaved stays in the folder. The wording must not read as
            // "delete my three messages".
            tr("%n message(s) are still being composed. Drafts already saved "
               "stay in the drafts folder either way.", "", blocking.size()),
            QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);

        if (answer == QMessageBox::Cancel) {
            event->ignore();
            return;
        }
        if (answer == QMessageBox::Save) {
            for (ComposeWindow *composer : blocking)
                composer->saveDraftNow();
        }
    }
```

- [ ] **Step 8: Run the suite**

Run: `ctest --test-dir build --output-on-failure 2>&1 | tail -5`
Expected: PASS, all tests.

- [ ] **Step 9: Refresh translations again**

Run `lupdate-qt6` and `lrelease-qt6` as in Task 9 Step 9, translate the new strings, and confirm `0 unfinished`.

Note the `%n` plural forms: Italian has different plural rules from English and
`lrelease` will report them as unfinished until both forms are given.

- [ ] **Step 10: Commit**

```bash
git add src/mainwindow.h src/mainwindow.cpp src/messageview.h \
        src/messageview.cpp tests/test_mainwindow.cpp \
        translations/qtmaildir_it_IT.ts
git commit -S -m "feat(compose): wire the composer into the main window, item 123

The reply family is disabled on mail that arrived at an account with no
send_command, behind a ribbon in MessageView naming the account and the key
to add. save_message is deliberately never disabled: it is the escape hatch
for exactly that case.

The ribbon is a WIDGET in the pane's layout, never markup inside the web
view. Composing HTML from configuration into the one document that renders
input from strangers is the wrong direction, and the header row is already a
widget for the same reason.

Compose itself is disabled only when NO account can send, and that state is
not warned about at startup: an installation with no send_command anywhere
is a valid read-only installation.

Every reply resolves through messageScopeFor(), not threadFor(): a thread
row means the one message its card shows. Replying to a thread is
meaningless; a reply answers a message. The context is built from the
DATABASE rather than the model, the rule Restore already follows, because a
row whose state has not been re-queried carries stale values and a reply
built from one would carry the wrong recipients.

The quit path checks the failed-save case FIRST. In the ordinary case
nothing is lost by saving; there, saving is what is already not working, so
the dialog says plainly that quitting loses that text rather than offering a
save that will fail again. The ordinary case asks once whatever the count,
because three modals in a row is worse than a coarse answer, and its wording
says drafts already saved stay in the folder so Discard cannot read as
'delete my three messages'."
```

---

### Task 13: Close out

Documentation, the backlog, and the hand test that no automated test can
replace.

**Files:**
- Modify: `CHANGELOG.md`
- Modify: `CLAUDE.md`
- Modify: `docs/superpowers/plans/2026-08-03-post-0.1.0-usability.md`
- Modify: `docs/superpowers/specs/2026-08-20-compose-and-send-design.md`

- [ ] **Step 0: Document the new keys in the README**

Found during Task 2's code review and assigned here rather than there. The
README's sample config at `README.md:150-215` documents EVERY other
configuration key, including recently added ones, and has nothing for
`send_command` or the `[compose]` section. Without this the keys ship
undiscoverable: a user has no way to learn that sending exists.

Take the block from the spec at
`docs/superpowers/specs/2026-08-20-compose-and-send-design.md:552-560` and
adapt it to the README's existing commented style, showing `send_command` in
an account section and every `[compose]` key with its default. Say plainly
that an account without `send_command` is receive-only, since that is the
part no reader would guess.

- [ ] **Step 1: Add the changelog entry**

Under `## [Unreleased]`, in the existing `### Added` section or a new one:

```markdown
### Added

- Compose, reply, reply-all, reply-without-quoting and forward, in a separate
  composer window per draft. Bodies are markdown, rendered to an HTML part
  with cmark-gfm, and the plain part carries the markdown source unchanged.
- Sending is a per-account `send_command` receiving the message on stdin, on
  the same contract `[sync] command` already uses. The application speaks no
  network protocol; what sits behind that command is yours to choose. An
  account without one is receive-only, and the reply actions are disabled on
  its mail behind an explanation naming the account.
- Drafts autosave to the account's own drafts folder, so they are visible to
  every other client that reads the same Maildir.
- Send runs behind a cancellable countdown with an Undo button. Cancelling
  during the countdown means nothing was sent at all.
- `Save message as...` writes the raw message to a file.

### Upgrading

Sending needs a `send_command` in each account that should be able to send:

    [account.work]
    send_command = msmtp -a work -t

Nothing else is required; every `[compose]` key is optional. An installation
that adds no `send_command` anywhere keeps working exactly as before, with the
compose actions unavailable.
```

The `### Upgrading` section makes this a **minor** version bump, not a patch,
per the release procedure in `CLAUDE.md`.

- [ ] **Step 2: Update CLAUDE.md**

Two things there are now wrong. Find and fix both:

1. **"v1 is read-and-organize only. Compose and send are v2."** — that is no longer true.
2. The architecture diagram lists no compose units. Add them to the tree, and add a paragraph recording the traps this work found, in the style of the existing ones:

```markdown
**GMime's defaults are wrong for this application in three ways, and all three
fail only on accented text.** It encodes as iso-8859-1 unless an explicit
charset argument is passed, so `g_mime_message_set_subject(msg, text, "utf-8")`
carries that third argument for a reason. `g_mime_text_part_set_text()` encodes
using the charset set at the moment it is CALLED, so setting the charset
afterwards relabels a part without re-encoding it and produces
`charset=utf-8` over latin-1 bytes: mojibake that looks correct in the headers.
`MessageBuilder::makeTextPart()` builds the content stream directly for that
reason and must not be "simplified" back. And neither `Date` nor `Message-ID`
is generated unless asked for; a message without a Message-ID cannot be
threaded by anything that receives it. This user writes Italian, so every one
of these is every message rather than an edge case.

**`libcmark-gfm-extensions` has no pkg-config file**, though `libcmark-gfm`
does. CMake finds the core with `pkg_check_modules` and the extensions with
`find_library`, the way notmuch is found. All three enabled extensions
(autolink, strikethrough, tasklist) live in that second library, so a build
that finds only the first compiles and silently renders plain CommonMark.

**Cancelling a send is safe during the countdown and at no other time.** Undo
disables itself the moment `send_command` starts, because killing it
mid-transaction leaves an *unknown* send: the message may have reached the
server in full before the kill, which is worse than either clean outcome. The
test for this asserts the NEGATIVE property, that `committed()` never fires
after Undo including after the original countdown would have elapsed; a test
asserting only that `undone()` fired passes against a design that runs the
command and discards the result.
```

- [ ] **Step 3: Close item 123 in the backlog**

Change its status cell to `done, <date>, <commit>` with a one-line summary of
what shipped, in the style of the other closed rows. Then **move its section**
to `2026-08-03-post-0.1.0-usability-closed.md` on the same commit, per the rule
in `CLAUDE.md`: leaving it for a later cleanup is how the file reached five
thousand lines the first time.

Leave items 128 to 133 open. They are the follow-ups this work deliberately did
not do.

- [ ] **Step 4: Mark the spec as implemented**

Change its `**Status: design only.**` line to name the implementing commits, so
a later reader knows the document describes shipped code rather than a plan.

- [ ] **Step 5: Run the full suite one last time**

Run: `ctest --test-dir build --output-on-failure`
Expected: every test passes. Note the count; it should be 25 before this work plus the seven new binaries.

- [ ] **Step 6: Commit**

```bash
git add CHANGELOG.md CLAUDE.md docs/
git commit -S -m "docs: record compose and send, item 123

Closes item 123 and moves its section to the closed file on the same commit,
per the rule that leaving it is how the backlog reached five thousand lines
the first time.

CLAUDE.md said 'v1 is read-and-organize only, compose and send are v2',
which is no longer true, and gains the three traps this work found: GMime's
iso-8859-1 default and its set_text() ordering, both of which fail only on
accented text and therefore on every message this user writes; the missing
pkg-config file for cmark-gfm's extensions, which makes a build that finds
only the core render plain CommonMark silently; and why cancelling a send is
safe only during the countdown.

The changelog carries an Upgrading section, which makes this a minor bump
rather than a patch."
```

- [ ] **Step 7: Hand it to the user**

**Do not merge and do not cut a release.** Report what was built and what was
verified, and say plainly what no test here covers:

- **The actual send.** There is no MTA on this machine and there will not be
  one in CI. Every test uses stub commands.
- **How the HTML part renders in a real mail client.** A hand test, and the
  user's to make.
- **Composer window geometry.** The offscreen platform returns an identical
  frame for a correct layout and a broken one, verified in a standalone
  program containing none of this project's code.

Suggest the first hand test: configure `send_command` on one account, write a
message to themselves with an accented subject and body, send it, and confirm
that it arrives readable, that the sent copy is filed, and that the draft is
gone.