When dragging a clip in insert mode, don't allow leaving empty space in timeline.

Related to #673

src/timeline2/model/timelinemodel.cpp

@@ -727,6 +727,14 @@ QVariantList TimelineModel::suggestItemMove(int itemId, int trackId, int positio
     return suggestCompositionMove(itemId, trackId, position, cursorPosition, snapDistance);
 }
 
+int TimelineModel::adjustFrame(int frame, int trackId)
+{
+    if (m_editMode == TimelineMode::InsertEdit && isTrack(trackId)) {
+        frame = qMin(frame, getTrackById_const(trackId)->trackDuration());
+    }
+    return frame;
+}
+
 QVariantList TimelineModel::suggestClipMove(int clipId, int trackId, int position, int cursorPosition, int snapDistance, bool moveMirrorTracks)
 {
     QWriteLocker locker(&m_lock);
@@ -744,6 +752,14 @@ QVariantList TimelineModel::suggestClipMove(int clipId, int trackId, int positio
         TRACE_RES(position);
         return {position, trackId};
     }
+    if (m_editMode == TimelineMode::InsertEdit) {
+        int maxPos = getTrackById_const(trackId)->trackDuration();
+        if (m_allClips[clipId]->getCurrentTrackId() == trackId) {
+            maxPos -= m_allClips[clipId]->getPlaytime();
+        }
+        qDebug()<<"=== TRYING CLIP MOVE AT: "<<position<<", MAX TK: "<<getTrackById_const(trackId)->trackDuration();
+        position = qMin(position, maxPos);
+    }
     bool after = position > currentPos;
     if (snapDistance > 0) {
         std::vector<int> ignored_pts;

src/timeline2/model/timelinemodel.hpp

@@ -389,6 +389,9 @@ public:
     Q_INVOKABLE QVariantList suggestItemMove(int itemId, int trackId, int position, int cursorPosition, int snapDistance = -1);
     Q_INVOKABLE QVariantList suggestClipMove(int clipId, int trackId, int position, int cursorPosition, int snapDistance = -1, bool moveMirrorTracks = true);
     Q_INVOKABLE QVariantList suggestCompositionMove(int compoId, int trackId, int position, int cursorPosition, int snapDistance = -1);
+    /** @brief returns the frame pos adjusted to edit mode
+    */
+    Q_INVOKABLE int adjustFrame(int frame, int trackId);
 
     /* @brief Request clip insertion at given position. This action is undoable
        Returns true on success. If it fails, nothing is modified.

src/timeline2/view/qml/timeline.qml

@@ -514,7 +514,8 @@ Rectangle {
                         clipBeingDroppedId = insertAndMaybeGroup(timeline.activeTrack, frame, clipBeingDroppedData)
                     } else {
                         // we want insert/overwrite mode, make a fake insert at end of timeline, then move to position
-                        clipBeingDroppedId = insertAndMaybeGroup(timeline.activeTrack, timeline.fullDuration, clipBeingDroppedData)
+                        frame = controller.adjustFrame(frame, timeline.activeTrack)
+                        clipBeingDroppedId = insertAndMaybeGroup(timeline.activeTrack, frame, clipBeingDroppedData)
                         if (clipBeingDroppedId > -1) {
                             var moveData = controller.suggestClipMove(clipBeingDroppedId, timeline.activeTrack, frame, root.consumerPosition, root.snapping)
                             fakeFrame = moveData[0]