AutoDJProcessor: Calculate and expose the number of tracks and accurate total duration in the Auto DJ queue

src/library/autodj/autodjfeature.cpp

@@ -28,18 +28,43 @@ const QString kViewName = QStringLiteral("Auto DJ");
 namespace {
 constexpr int kMaxRetrieveAttempts = 3;
 
-    int findOrCrateAutoDjPlaylistId(PlaylistDAO& playlistDAO) {
-        int playlistId = playlistDAO.getPlaylistIdFromName(AUTODJ_TABLE);
-        // If the AutoDJ playlist does not exist yet then create it.
-        if (playlistId < 0) {
-            playlistId = playlistDAO.createPlaylist(
-                    AUTODJ_TABLE, PlaylistDAO::PLHT_AUTO_DJ);
-            VERIFY_OR_DEBUG_ASSERT(playlistId >= 0) {
-                qWarning() << "Failed to create Auto DJ playlist!";
-            }
+int findOrCreateAutoDjPlaylistId(PlaylistDAO& playlistDAO) {
+    int playlistId = playlistDAO.getPlaylistIdFromName(AUTODJ_TABLE);
+    // If the AutoDJ playlist does not exist yet then create it.
+    if (playlistId < 0) {
+        playlistId = playlistDAO.createPlaylist(
+                AUTODJ_TABLE, PlaylistDAO::PLHT_AUTO_DJ);
+        VERIFY_OR_DEBUG_ASSERT(playlistId >= 0) {
+            qWarning() << "Failed to create Auto DJ playlist!";
         }
-        return playlistId;
     }
+    return playlistId;
+}
+
+/// Create a title for the Auto DJ node
+QString createAutoDjTitle(const QString& name,
+        int count,
+        mixxx::Duration duration,
+        bool showCountRemaining,
+        bool showTimeRemaining) {
+    QString result(name);
+
+    // Show duration and track count only if Auto DJ queue has tracks
+    if (count > 0 && showCountRemaining) {
+        result.append(QStringLiteral(" ("));
+        result.append(QString::number(count));
+        result.append(QStringLiteral(")"));
+    }
+
+    if (count > 0 && showTimeRemaining) {
+        result.append(QStringLiteral(" "));
+        result.append(mixxx::Duration::formatTime(
+                duration.toDoubleSeconds(),
+                mixxx::Duration::Precision::SECONDS));
+    }
+
+    return result;
+}
 } // anonymous namespace
 
 AutoDJFeature::AutoDJFeature(Library* pLibrary,
@@ -48,7 +73,7 @@ AutoDJFeature::AutoDJFeature(Library* pLibrary,
         : LibraryFeature(pLibrary, pConfig, QStringLiteral("autodj")),
           m_pTrackCollection(pLibrary->trackCollectionManager()->internalCollection()),
           m_playlistDao(m_pTrackCollection->getPlaylistDAO()),
-          m_iAutoDJPlaylistId(findOrCrateAutoDjPlaylistId(m_playlistDao)),
+          m_iAutoDJPlaylistId(findOrCreateAutoDjPlaylistId(m_playlistDao)),
           m_pAutoDJProcessor(nullptr),
           m_pSidebarModel(make_parented<TreeItemModel>(this)),
           m_pAutoDJView(nullptr),
@@ -68,6 +93,13 @@ AutoDJFeature::AutoDJFeature(Library* pLibrary,
             &LibraryFeature::loadTrackToPlayer,
             Qt::QueuedConnection);
 
+    // Update the title of the "Auto DJ" node when the
+    // list of queued tracks or their properties have changed.
+    connect(m_pAutoDJProcessor,
+            &AutoDJProcessor::remainingTimeChanged,
+            this,
+            &AutoDJFeature::slotRemainingQueueDurationChanged);
+
     m_playlistDao.setAutoDJProcessor(m_pAutoDJProcessor);
 
     // Create the "Crates" tree-item under the root item.
@@ -94,8 +126,8 @@ AutoDJFeature::AutoDJFeature(Library* pLibrary,
             this,
             &AutoDJFeature::slotCrateChanged);
 
-    // Create context-menu items to allow crates to be added to, and removed
-    // from, the auto-DJ queue.
+    // Create context menu items to allow crates to be added to,
+    // and removed from, the auto-DJ queue.
     m_pRemoveCrateFromAutoDj = new QAction(tr("Remove Crate as Track Source"), this);
     connect(m_pRemoveCrateFromAutoDj,
             &QAction::triggered,
@@ -109,7 +141,20 @@ AutoDJFeature::~AutoDJFeature() {
 }
 
 QVariant AutoDJFeature::title() {
-    return tr("Auto DJ");
+    return createAutoDjTitle(tr("Auto DJ"),
+            m_pAutoDJProcessor->getRemainingTracks(),
+            m_pAutoDJProcessor->getRemainingTime(),
+            true,
+            true);
+}
+
+void AutoDJFeature::slotRemainingQueueDurationChanged(int numTracks, mixxx::Duration duration) {
+    Q_UNUSED(numTracks);
+    Q_UNUSED(duration);
+
+    // As documented by the code docs for featureIsLoading,
+    // it is intended to indicate when the title() has changed.
+    emit featureIsLoading(this, false);
 }
 
 void AutoDJFeature::bindLibraryWidget(

src/library/autodj/autodjfeature.h

@@ -10,6 +10,7 @@
 #include "library/libraryfeature.h"
 #include "library/trackset/crate/crate.h"
 #include "preferences/usersettings.h"
+#include "util/duration.h"
 #include "util/parented_ptr.h"
 
 class DlgAutoDJ;
@@ -99,4 +100,9 @@ class AutoDJFeature : public LibraryFeature {
     // Adds a random track from the queue upon hitting minimum number
     // of tracks in the playlist
     void slotRandomQueue(int numTracksToAdd);
+
+    // Updates the title of the "Auto DJ" node with the number of tracks
+    // and remaining duration when tracks are added to or removed from
+    // the Auto DJ queue.
+    void slotRemainingQueueDurationChanged(int len, mixxx::Duration duration);
 };