Merge: searching from the message pane (item 85)

Five surfaces in the message pane offer a search built from what they show:
the header's subject and date, its sender and recipients on a single-message
thread, a tag chip, a body selection, and every header per message in the
details dialog. Each offers Search for this, which replaces the query, and
Add to search, which narrows it.

The details dialog became labelled rows along the way, which the user wanted
independently of this feature.

Hand tested through every surface, including the case the parenthesising
exists for: adding a sender to 'tag:inbox or tag:flagged' narrows it rather
than widening it.

1 files changed, 153 insertions, 0 deletions

diff --git a/src/messagedetailsdialog.cpp b/src/messagedetailsdialog.cpp
new file mode 100644
index 0000000..058814b
--- /dev/null
+++ b/src/messagedetailsdialog.cpp
@@ -0,0 +1,153 @@
+/*
+ * 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 "messagedetailsdialog.h"
+
+#include <QDialogButtonBox>
+#include <QFontDatabase>
+#include <QGridLayout>
+#include <QLabel>
+#include <QMenu>
+#include <QScrollArea>
+#include <QVBoxLayout>
+
+#include "mimeparser.h"
+#include "searchterm.h"
+
+MessageDetailsDialog::MessageDetailsDialog(const QList<ThreadRenderItem> &items,
+                                           QWidget *parent)
+    : QDialog(parent)
+{
+    setWindowTitle(tr("Message details"));
+    setObjectName(QStringLiteral("messageDetailsDialog"));
+
+    buildRows(items);
+
+    auto *layout = new QVBoxLayout(this);
+
+    // Scrollable: a long thread has many rows, and the dialog must not grow
+    // past the screen to show them.
+    auto *scroll = new QScrollArea(this);
+    scroll->setWidgetResizable(true);
+    auto *content = new QWidget(scroll);
+    auto *grid = new QGridLayout(content);
+
+    // A monospaced value keeps a long id or address readable as the record it
+    // is, which is what the text box did well and is worth carrying over.
+    const QFont fixed = QFontDatabase::systemFont(QFontDatabase::FixedFont);
+
+    int gridRow = 0;
+    int lastMessage = -1;
+    for (const HeaderRow &row : std::as_const(m_rows)) {
+        if (items.size() > 1 && row.messageIndex != lastMessage) {
+            lastMessage = row.messageIndex;
+            auto *heading = new QLabel(
+                tr("Message %1 of %2").arg(row.messageIndex + 1)
+                    .arg(items.size()),
+                content);
+            heading->setTextFormat(Qt::PlainText);
+            QFont headingFont = heading->font();
+            headingFont.setBold(true);
+            heading->setFont(headingFont);
+            grid->addWidget(heading, gridRow, 0, 1, 2);
+            ++gridRow;
+        }
+
+        auto *label = new QLabel(row.label, content);
+        label->setTextFormat(Qt::PlainText);
+        label->setAlignment(Qt::AlignTop | Qt::AlignLeft);
+        grid->addWidget(label, gridRow, 0);
+
+        // PlainText stated, not inferred. A QLabel guesses under AutoText, and
+        // this value came from a stranger.
+        auto *value = new QLabel(row.value, content);
+        value->setTextFormat(Qt::PlainText);
+        value->setFont(fixed);
+        value->setWordWrap(true);
+        value->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        if (!row.query.isEmpty()) {
+            value->setContextMenuPolicy(Qt::CustomContextMenu);
+            connect(value, &QWidget::customContextMenuRequested, this,
+                    [this, value, row](const QPoint &pos) {
+                        QMenu menu(this);
+                        auto *replace = menu.addAction(tr("Search for this"));
+                        connect(replace, &QAction::triggered, this,
+                                [this, row]() { requestSearch(row, false); });
+                        auto *narrow = menu.addAction(tr("Add to search"));
+                        connect(narrow, &QAction::triggered, this,
+                                [this, row]() { requestSearch(row, true); });
+                        menu.exec(value->mapToGlobal(pos));
+                    });
+        }
+
+        grid->addWidget(value, gridRow, 1);
+        ++gridRow;
+    }
+
+    grid->setColumnStretch(1, 1);
+    grid->setRowStretch(gridRow, 1);
+    scroll->setWidget(content);
+    layout->addWidget(scroll);
+
+    auto *buttons = new QDialogButtonBox(QDialogButtonBox::Close, this);
+    connect(buttons, &QDialogButtonBox::rejected, this, &QDialog::reject);
+    layout->addWidget(buttons);
+
+    resize(700, 400);
+}
+
+void MessageDetailsDialog::buildRows(const QList<ThreadRenderItem> &items)
+{
+    for (int i = 0; i < items.size(); ++i) {
+        const ParsedMessage &message = items.at(i).message;
+
+        auto add = [this, i](const QString &field, const QString &label,
+                             const QString &value, const QString &query) {
+            if (value.isEmpty())
+                return;   // An empty row reads as a rendering fault.
+            m_rows.append({ field, label, value, query, i });
+        };
+
+        add(QStringLiteral("subject"), tr("Subject:"), message.subject,
+            SearchTerm::field(QStringLiteral("subject"), message.subject));
+        add(QStringLiteral("from"), tr("From:"), message.from,
+            SearchTerm::field(QStringLiteral("from"), message.from));
+        add(QStringLiteral("to"), tr("To:"), message.to,
+            SearchTerm::field(QStringLiteral("to"), message.to));
+        add(QStringLiteral("cc"), tr("Cc:"), message.cc,
+            SearchTerm::field(QStringLiteral("cc"), message.cc));
+
+        // The raw header is shown, but the query is a one-day range: a text
+        // match on an RFC 2822 string would match almost nothing.
+        const QDateTime sent = MimeParser::parseDate(message.date);
+        add(QStringLiteral("date"), tr("Date:"), message.date,
+            sent.isValid() ? SearchTerm::onDate(sent.date()) : QString());
+
+        // Shown but not searchable: an id names one message, and the thread
+        // holding it is already on screen.
+        add(QString(), tr("Message-Id:"), message.messageId, QString());
+    }
+}
+
+void MessageDetailsDialog::requestSearch(const HeaderRow &row, bool extend)
+{
+    if (row.query.isEmpty())
+        return;
+    emit searchRequested(row.query, extend);
+}