Merge branch 'card-list': the thread pane as a list of cards

Replaces the five-column grid with a single column of three-line cards. Item 53
recorded that the columns, not the cues drawn inside them, were what made the
list read as a table of records; item 20 had already shipped finished, tested
and green and been rejected on sight for exactly that reason.

A card is sender and date, subject with the flag, attachment and reply-count
marks, and tags, at one uniform height. Replies indent under a continuous spine
and show only the tags their thread does not carry. The account colour runs down
the card's left edge, replacing the chip that used to eat a third of every
subject line, with matching swatches in the account dropdown. Sorting newest or
oldest first is new and remembered.

Closes items 20, 51, 53 and 60.

The four defects that mattered were all found by rendering cards to an image and
looking at them, with the suite green through every one: a date clipped on unread
cards because bold is wider than the font the layout measured, an accent bar
painted in a colour identical to the background, an expander pill in a palette
role a theme had made equal to Base, and three separate faults from trusting
notmuch's reply depth to mean structure when it only means how notmuch happened
to thread the mail.

1 files changed, 96 insertions, 2 deletions

diff --git a/src/mainwindow.h b/src/mainwindow.h
index d8401a3..ccac5ad 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -41,7 +41,7 @@
 class QAction;
 class QLineEdit;
 class QMenu;
-class QTableView;
+class ThreadListView;
 class QLabel;
 class QPushButton;
 class QComboBox;
@@ -129,6 +129,19 @@ public:
     /// command was pushed, which is what "this did nothing" has to assert.
     int undoDepthForTesting() const { return m_undoStack.count(); }
 
+    /// The ids the last tag change was sent for, and whether they were thread
+    /// ids or message ids.
+    ///
+    /// Exposed because the difference is invisible from outside otherwise: a
+    /// message row routed down the thread path produces the same undo depth and
+    /// the same status text while tagging every sibling in the thread. A
+    /// mutation that made exactly that change passed the whole suite.
+    QStringList pendingThreadIdsForTesting() const { return m_pendingThreadIds; }
+    QStringList pendingMessageIdsForTesting() const
+    {
+        return m_pendingChange.messageIds;
+    }
+
     /// The generation a worker reply must carry to be accepted.
     ///
     /// A test seam: onQueryFinished() discards a reply whose generation is
@@ -164,6 +177,17 @@ private slots:
     /// the click lands inside.
     void showThreadContextMenu(const QPoint &pos);
     void onThreadLoaded(const QVector<MessageRef> &messages, quint64 generation);
+
+    /// Asks the worker for a thread's reply tree when its row is expanded.
+    void onThreadExpanded(const QModelIndex &index);
+
+    /// Fills in the expanded thread's message rows.
+    void onThreadTreeLoaded(const QVector<MessageNode> &nodes,
+                            quint64 generation);
+
+    /// Renders the single message a message row asked for.
+    void onMessageLoaded(const QVector<MessageRef> &messages,
+                         quint64 generation);
     void onWorkerError(const QString &message);
     void onSyncFinished(bool success, int exitCode);
 
@@ -212,6 +236,15 @@ private:
     /// A missing or rejected blob leaves the buildUi() defaults in place.
     void restoreUiState();
 
+    /// The thread row containing an index: itself for a thread row, its parent
+    /// for a message row.
+    QModelIndex threadRowOf(const QModelIndex &index) const;
+
+    /// Selects a whole row. QTreeView has no selectRow of its own.
+    void selectRowAt(const QModelIndex &index);
+
+    /// Selects the top-level thread row at `row`.
+    void selectThreadRow(int row);
     void saveUiState() const;
 
     void registerActions();
@@ -335,6 +368,13 @@ private:
                              const QStringList &remove,
                              const QString &description);
 
+    /// The same for individual MESSAGES, without touching the undo stack.
+    /// Both tagSelected() and MessageTagCommand route through this.
+    void sendMessageTagChange(const QStringList &messageIds,
+                              const QStringList &add,
+                              const QStringList &remove,
+                              const QString &description);
+
     /// Undoes the optimistic model update for a write the worker rejected.
     void revertPendingTagChange();
 
@@ -368,6 +408,7 @@ private:
     QVector<HeldEdit> m_heldEdits;
 
     friend class ThreadTagCommand;
+    friend class MessageTagCommand;
 
     Config m_config;
     KeyMap m_keyMap;
@@ -410,7 +451,10 @@ private:
 
     QLineEdit *m_queryEdit = nullptr;
     QueryCompleter *m_queryCompleter = nullptr;
-    QTableView *m_threadView = nullptr;
+    /// Its own type, not the QTreeView base. The strip painting and the
+    /// expander column are ThreadListView's, and holding the base here only
+    /// hid that from every reader.
+    ThreadListView *m_threadView = nullptr;
 
     /// Right-click menu for the thread list, holding the same QActions the
     /// menu bar does.
@@ -424,6 +468,7 @@ private:
     /// placeholder's own text wraps every couple of words.
     static constexpr int kMinMessagePaneWidth = 300;
     QComboBox *m_accountBox = nullptr;
+    QComboBox *m_sortOrder = nullptr;
     QLabel *m_statusLabel = nullptr;
 
     /// Expires a transient status message. See showTransientStatus().
@@ -495,6 +540,11 @@ private:
     QString m_lastQuery;
     QString m_currentThreadId;
 
+    /// The message a MESSAGE row is showing, empty whenever the pane holds a
+    /// whole thread. The two are mutually exclusive and each clears the other,
+    /// so a late reply can tell which kind of selection it belongs to.
+    QString m_currentMessageId;
+
     /// The selection count last written to the status bar, so it can be taken
     /// back without clobbering a message some other action put there.
     QString m_selectionMessage;
@@ -601,3 +651,47 @@ private:
     QString m_description;
     bool m_firstRedo = true;
 };
+
+/// Undo entry for a tag change over individual MESSAGES.
+///
+/// Stores message ids, unlike ThreadTagCommand, and that difference is the
+/// point rather than an inconsistency: a message row acts on one message, so
+/// re-resolving its thread on undo would restore tags across every sibling the
+/// action never touched.
+class MessageTagCommand : public QUndoCommand
+{
+public:
+    MessageTagCommand(MainWindow *window, const QStringList &messageIds,
+                      const QStringList &add, const QStringList &remove,
+                      const QString &description)
+        : QUndoCommand(description), m_window(window),
+          m_messageIds(messageIds), m_add(add), m_remove(remove),
+          m_description(description) {}
+
+    /// The stack calls redo() when the command is pushed, by which point the
+    /// change has already been sent, so the first call is skipped.
+    void redo() override
+    {
+        if (m_firstRedo) {
+            m_firstRedo = false;
+            return;
+        }
+        m_window->sendMessageTagChange(m_messageIds, m_add, m_remove,
+                                       m_description);
+    }
+
+    void undo() override
+    {
+        m_window->sendMessageTagChange(
+            m_messageIds, m_remove, m_add,
+            QStringLiteral("Undo %1").arg(m_description));
+    }
+
+private:
+    MainWindow *m_window;
+    QStringList m_messageIds;
+    QStringList m_add;
+    QStringList m_remove;
+    QString m_description;
+    bool m_firstRedo = true;
+};