2 files changed, 169 insertions, 0 deletions

diff --git a/src/composewindow.cpp b/src/composewindow.cpp
index a64736f..8236d79 100644
--- a/src/composewindow.cpp
+++ b/src/composewindow.cpp
@@ -25,6 +25,7 @@
 #include "mimeparser.h"
 #include "messagesender.h"
 #include "senddialog.h"
+#include "signatures.h"
 
 #include <QAction>
 #include <QCheckBox>
@@ -40,9 +41,11 @@
 #include <QLabel>
 #include <QLineEdit>
 #include <QListWidget>
+#include <QMenu>
 #include <QMessageBox>
 #include <QPlainTextEdit>
 #include <QPushButton>
+#include <QStandardPaths>
 #include <QTextCursor>
 #include <QTimer>
 #include <QToolBar>
@@ -128,6 +131,7 @@ ComposeWindow::ComposeWindow(const ComposeContext &context,
     buildFormatToolbar();
     seedFields();
     seedBody();
+    seedSignature();
 
     // AFTER buildUi(), which creates m_banner, and BEFORE
     // refreshAttachmentList(), which renders m_attachments: extraction appends
@@ -536,6 +540,29 @@ void ComposeWindow::buildFormatToolbar()
         m_sendHtml->setIcon(htmlIcon);
     m_formatToolbar->addWidget(m_sendHtml);
 
+    // The signature switch rides at the right end with Attach and the HTML
+    // toggle: item 142 put the controls OF THE EDITOR on this side, as against
+    // the formatting buttons on the left, and choosing a signature is one of
+    // those.
+    //
+    // A QToolButton with a menu rather than a QComboBox, matching the bar's
+    // other controls; a combo would read as a different class of thing. Not
+    // registered in KeyMap: it is parented to this window, exactly as the
+    // formatting actions are, so its scope is the composer and item 132's
+    // reachability rule does not apply.
+    m_signatureSwitch = new QToolButton(m_formatToolbar);
+    m_signatureSwitch->setObjectName(QStringLiteral("signatureSwitch"));
+    m_signatureSwitch->setText(tr("Signature"));
+    m_signatureSwitch->setToolTip(
+        tr("Chooses the signature added to this message."));
+    m_signatureSwitch->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
+    m_signatureSwitch->setPopupMode(QToolButton::InstantPopup);
+    const QIcon signatureIcon = QIcon::fromTheme(QStringLiteral("insert-text"));
+    if (!signatureIcon.isNull())
+        m_signatureSwitch->setIcon(signatureIcon);
+    m_signatureSwitch->setMenu(new QMenu(m_signatureSwitch));
+    m_formatToolbar->addWidget(m_signatureSwitch);
+
     // Send is NOT on this row: it is the terminal action, and it lives on the
     // button beside the headers. The QAction survives because it carries the
     // shortcut and is what the button triggers.
@@ -664,6 +691,114 @@ void ComposeWindow::seedBody()
     m_body->document()->clearUndoRedoStacks();
 }
 
+void ComposeWindow::setSignatureDir(const QString &dir)
+{
+    m_signatureDir = dir;
+}
+
+QStringList ComposeWindow::knownSignatures() const
+{
+    QStringList known;
+    const QStringList names = Signatures::names(m_signatureDir);
+    known.reserve(names.size());
+    for (const QString &name : names)
+        known.append(Signatures::text(m_signatureDir, name));
+    return known;
+}
+
+QString ComposeWindow::seededSignatureName() const
+{
+    // The account SEEDS, it does not bind: this is a starting value, and the
+    // switch keeps every signature reachable whichever account is selected.
+    const Account account = m_config.account(m_context.accountKey);
+    if (!account.signature.isEmpty())
+        return account.signature;
+    return m_config.compose().signature;
+}
+
+void ComposeWindow::applySignature(const QString &name)
+{
+    const QString text =
+        name.isEmpty() ? QString() : Signatures::text(m_signatureDir, name);
+
+    // A QTextCursor replacement rather than setPlainText(), for the reason
+    // recorded at applyEdit(): setPlainText() destroys the document's undo
+    // stack, so a switch would make everything typed before it unrecoverable.
+    const QString replaced = Signatures::replace(
+        m_body->toPlainText(), text, knownSignatures(),
+        m_config.compose().signaturePosition);
+
+    QTextCursor cursor(m_body->document());
+    cursor.select(QTextCursor::Document);
+    cursor.insertText(replaced);
+
+    m_signatureName = name;
+
+    for (QAction *action : m_signatureSwitch->menu()->actions())
+        action->setChecked(action->data().toString() == name);
+}
+
+void ComposeWindow::seedSignature()
+{
+    if (m_signatureDir.isEmpty()) {
+        const QString base =
+            QStandardPaths::writableLocation(QStandardPaths::ConfigLocation);
+        m_signatureDir = base + QStringLiteral("/qtmaildir/signatures");
+    }
+
+    QMenu *menu = m_signatureSwitch->menu();
+    menu->clear();
+
+    auto *none = menu->addAction(tr("None"));
+    none->setCheckable(true);
+    none->setData(QString());
+    connect(none, &QAction::triggered, this, [this]() {
+        m_signatureChosen = true;
+        applySignature(QString());
+        markDirty();
+    });
+
+    const QStringList names = Signatures::names(m_signatureDir);
+    for (const QString &name : names) {
+        auto *action = menu->addAction(name);
+        action->setCheckable(true);
+        action->setData(name);
+        connect(action, &QAction::triggered, this, [this, name]() {
+            m_signatureChosen = true;
+            applySignature(name);
+            markDirty();
+        });
+    }
+
+    // A resumed draft is the message ITSELF and already carries whatever
+    // signature it was saved with, exactly as seedBody() takes its body
+    // verbatim. Seeding again would append a second one.
+    if (m_context.kind == ComposeContext::Kind::Draft) {
+        none->setChecked(true);
+        return;
+    }
+
+    const QString seeded = seededSignatureName();
+    if (seeded.isEmpty()) {
+        none->setChecked(true);
+        return;
+    }
+    if (!names.contains(seeded)) {
+        // Reported by Config as a problem; the composer still opens, with no
+        // signature, and the switch still works.
+        none->setChecked(true);
+        return;
+    }
+
+    applySignature(seeded);
+
+    // The seeded signature is not an edit the user made, so it must not
+    // survive as an undo step: one Ctrl+Z on a fresh composer would otherwise
+    // wipe content they never typed. Same reason seedBody() clears after the
+    // quote.
+    m_body->document()->clearUndoRedoStacks();
+}
+
 void ComposeWindow::refreshAttachmentList()
 {
     m_attachmentList->clear();
@@ -897,6 +1032,7 @@ void ComposeWindow::setInputsEnabled(bool enabled)
     m_from->setEnabled(enabled);
     m_body->setReadOnly(!enabled);
     m_sendHtml->setEnabled(enabled);
+    m_signatureSwitch->setEnabled(enabled);
     m_attachmentList->setEnabled(enabled);
     m_formatToolbar->setEnabled(enabled);
 
diff --git a/src/composewindow.h b/src/composewindow.h
index c44fcda..918d4e3 100644
--- a/src/composewindow.h
+++ b/src/composewindow.h
@@ -96,6 +96,21 @@ public:
     /// and quitting therefore loses that text.
     bool lastSaveFailed() const { return m_saveFailed; }
 
+    /// Where the signature files live. Defaults to
+    /// <config>/qtmaildir/signatures; a test points it at its own directory.
+    ///
+    /// A setter rather than a config key: nothing yet suggests the user wants
+    /// a second location, and the tests need to not read the real one.
+    void setSignatureDir(const QString &dir);
+
+    /// Seeds the signature from config and fills the switch.
+    ///
+    /// Public and called by the constructor rather than private, so a test can
+    /// drive it after pointing setSignatureDir() somewhere safe. A resumed
+    /// draft seeds nothing: its body already carries the signature it was
+    /// written with.
+    void seedSignature();
+
     /// Writes the current buffer to the drafts folder now. Returns false and
     /// leaves the banner up on failure.
     ///
@@ -176,6 +191,16 @@ private:
     /// a silently wrong send is not among the outcomes.
     void extractForwardedAttachments();
     void seedBody();
+
+    /// Applies \p name to the buffer, replacing whatever is there.
+    void applySignature(const QString &name);
+
+    /// The text of every signature on disk, for replace()'s guard.
+    QStringList knownSignatures() const;
+
+    /// The signature name this account seeds, falling through to [compose].
+    QString seededSignatureName() const;
+
     void refreshAttachmentList();
     void setInputsEnabled(bool enabled);
     void showSendFailure(const QString &stderrText);
@@ -227,6 +252,14 @@ private:
     QComboBox *m_from = nullptr;
     QPlainTextEdit *m_body = nullptr;
     QToolButton *m_sendHtml = nullptr;
+    QToolButton *m_signatureSwitch = nullptr;
+    QString m_signatureDir;
+    QString m_signatureName;  ///< The selected signature, empty for None.
+
+    /// True once the user has used the switch. From then on a From: change
+    /// stops re-seeding, so a deliberate choice is never overwritten. Matches
+    /// how send_html seeds from context and is then left alone.
+    bool m_signatureChosen = false;
     QLabel *m_banner = nullptr;
     QListWidget *m_attachmentList = nullptr;
     QWidget *m_sendLogPane = nullptr;