oak-editor/docs/plans/eliminate-event-bridge-issues.md

Eliminating EventBridge: Good First Issues

Goal: the app stops receiving engine events via EngineEventBridge / oakengine_event_subscribe; the engine becomes a pure library (its internal Qt signals are for its own use only).

Each issue is independent and can be claimed and shipped separately (do the two infrastructure ones first — they simplify everything else).

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Ground rules

• Run the tests before submitting, every time:

  cmake --build cmake-build-debug -j8 && cd cmake-build-debug && ctest -j4
  

  Zero build errors and 122/122 tests passing are the definition of done, plus the manual acceptance checks listed in each issue.
• Only three migration patterns, copy them:
  • A. app-internal Qt signal: the event is app-initiated (playhead, edits, undo) — emit an app-internal signal at the origin and re-point subscribers to it.
  • B. keep async: truly async events (tasks, caches, audio beats) go through one dispatcher (issue 0b) that queues everything back to the GUI thread.
  • C. delete: the call site already knows — refresh inline and drop the subscription.
• When done: remove the matching bridge_->subscribe / oakengine_event_subscribe calls and check off the item here.
• Architecture background: docs/zh/plans/eliminate-event-bridge.md

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Infrastructure (do first)

issue 0a — Fix the audio event ID collision (real bug, half a day)

engine/include/oakengine/events.h:210: AUDIO_MANAGER_OUTPUT_NOTIFY = 141 collides with PLAYBACK_CACHE_INVALIDATED = 141 at :213; the case 141 in events.cpp only performs the PlaybackCache conversion, AudioManager::output_notify is never wired up, and the audio keep-alive subscription in viewer.cpp:1406 never actually fires.

In other words: AUDIO_MANAGER_OUTPUT_NOTIFY shares ID 141 with PLAYBACK_CACHE_INVALIDATED; the audio notification is never wired up, so the viewer's audio keep-alive subscription never fires.

• Change: assign OUTPUT_NOTIFY a fresh ID (>=144) and wire up AudioManager in events.cpp.
• Acceptance: audio keeps playing past 5 seconds on long footage without cutting out.
• Required: build + ctest all green (see ground rules).

issue 0b — Single async event dispatcher (1 day)

Create app/asyncengineevents.{h,cpp} (a QObject held as a Core singleton) subscribing only to the TASK family (120–127), PLAYBACK_CACHE_VALIDATED/INVALIDATED, FRAME_CACHE_INVALIDATED, and AUDIO_OUTPUT_PARAMS/NOTIFY. C callbacks just do QMetaObject::invokeMethod(this, ..., Qt::QueuedConnection) and then emit typed Qt signals.

In other words: one dispatcher subscribing only to the truly async events; C callbacks just queue to the GUI thread and re-emit typed Qt signals.

• Acceptance: transcode once — the status bar progress still works. All later (b) migrations must use it instead of their own subscriptions.
• Required: build + ctest all green.

issue 0c ✅ (done) — App-internal PlaybackController (1 day)

Create app/playback/playbackcontroller.{h,cpp} with a playhead_changed(oak::Node viewer, Rational) signal. Route every oakengine_viewer_set_playhead call site in the app (ViewerWidget playback loop, timelinewidget, timeruler, multicam, export) through it and emit the signal there.

In other words: one app-side controller that every oakengine_viewer_set_playhead call site goes through; it re-broadcasts playhead_changed as an app-internal Qt signal.

• Acceptance: all views keep updating during playback/drag/seek (bridge may coexist until later issues migrate each subscriber).
• Required: build + ctest all green.

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Playhead migrations (pattern A, about half a day each)

issue 1 ✅ (done) — timebasedview playhead subscription

app/widget/timebased/timebasedview.cpp:168 (raw C callback). Reconnect to PlaybackController::playhead_changed.

• Acceptance: the ruler playhead line moves during playback; no raw C subscription remains.
• Required: build + ctest all green.

issue 2 ✅ (done) — NodeParamViewWidgetBridge playhead

app/widget/nodeparamview/nodeparamviewwidgetbridge.cpp:1140 (raw C).

• Acceptance: keyframe-interpolated slider values follow the playhead during playback.
• Required: build + ctest all green.

issue 3 ✅ (done) — NodeParamViewKeyframeControl playhead

app/widget/nodeparamview/nodeparamviewkeyframecontrol.cpp:222 (raw C).

• Acceptance: prev/next/toggle keyframe buttons have the correct state as the playhead moves.
• Required: build + ctest all green.

issue 4 ✅ (done) — NodeParamViewConnectedLabel playhead

app/widget/nodeparamview/nodeparamviewconnectedlabel.cpp:131 (raw C).

• Acceptance: the value tree refreshes with the playhead.
• Required: build + ctest all green.

issue 5 — ExportDialog playhead

app/dialog/export/export.cpp:311 (raw C).

• Acceptance: the export dialog's in/out times stay in sync with the playhead.
• Required: build + ctest all green.

issue 6 — timelinewidget / viewerdisplay playhead family (bridge subscriptions)

app/widget/timelinewidget/timelinewidget.cpp (around :741-743) and the related viewerdisplay subscriptions. Reconnect to PlaybackController.

• Acceptance: timeline timecode/playhead position display correctly.
• Required: build + ctest all green.

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Undo & modified migrations (pattern A, about half a day each)

issue 7 — historywidget UNDO_INDEX_CHANGED

app/widget/history/historywidget.cpp:33,127 (two raw C callbacks). Emit an app-internal undo_index_changed(int) at Core's undo/redo/push exit points and reconnect historywidget to it.

• Acceptance: after undo/redo the history list resets its model and selects the correct row.
• Required: build + ctest all green.

issue 8 — core.cpp PROJECT_MODIFIED_CHANGED

app/core.cpp:1108 (raw C). The modified flag is driven by the undo stack, so the app can derive it at push/undo/redo/load; drive setWindowModified from an app-internal signal instead.

• Acceptance: the title bar modified marker is correct after edit/undo/save.
• Required: build + ctest all green.

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Structure migrations (patterns C/A, 0.5–1 day each)

issue 9 — seekablewidget marker/workarea subscriptions

app/widget/seekable/seekablewidget.cpp:95-101,146-154. Edits go through undo commands: call viewport()->update() directly where the command runs; also refresh after undo (reuse the issue 7 signal).

• Acceptance: the ruler refreshes immediately after adding/removing markers or changing the workarea; undo is equally correct.
• Required: build + ctest all green.

issue 10 — resizabletimelinescrollbar marker/workarea

app/widget/resizablescrollbar/resizabletimelinescrollbar.cpp:83-98,124-129.

• Acceptance: markers render correctly on the scrollbar.
• Required: build + ctest all green.

issue 11 — nodeviewitem label/color/message/array subscriptions

app/widget/nodeview/nodeviewitem.cpp:85-119. label/color edits refresh in place; array size goes through the structure command call sites; undo is covered by the issue 7 signal.

• Acceptance: node blocks refresh immediately after rename/recolor/array add/remove.
• Required: build + ctest all green.

issue 12 — NodeParamViewItem / arraywidget / keyframecontrol bridge subscriptions

app/widget/nodeparamview/nodeparamviewitem.cpp:95-296, nodeparamviewarraywidget.cpp:43-45, and the keyframe family in keyframecontrol.

• Acceptance: parameter item label/flags/array/keyframe buttons refresh correctly with edits and undo.
• Required: build + ctest all green.

issue 13 — nodeparamviewwidgetbridge parameter value subscriptions

app/widget/nodeparamview/nodeparamviewwidgetbridge.cpp:161-178. The slider edit path sets values directly; re-read uniformly after undo/load.

• Acceptance: slider values are correct after edit, undo, and load.
• Required: build + ctest all green.

issue 14 — NodeParamView group passthrough / context subscriptions

app/widget/nodeparamview/nodeparamview.cpp:189-205,350-352,871-874.

• Acceptance: the parameter panel rebuilds correctly when groups open/close or nodes are added to/removed from contexts.
• Required: build + ctest all green.

issue 15 — nodeviewcontext node/edge add-remove subscriptions (structure core)

app/widget/nodeview/nodeviewcontext.cpp:99-138,180-183,427-430. Additions/removals come from: app edit commands (handled at call sites), undo (rebuild covered by the issue 7 signal), and project load (add a new "project load finished" hook — Core broadcasts it after TaskDialog success, replacing the batch event-driven graph build).

• Acceptance: node/edge add/remove refreshes immediately; undo restores correctly; reopening a project shows the complete view.
• Required: build + ctest all green.

issue 16 — nodeview NODE_REMOVED_FROM_GRAPH

app/widget/nodeview/nodeview.cpp:91,1911 and mainwindow.cpp:58,351. Handle at the delete-node command site plus the undo signal.

• Acceptance: after deleting a node its item/ViewerPanel closes; undo restores it.
• Required: build + ctest all green.

issue 17 — timelinewidget track/block structure subscriptions

app/widget/timelinewidget/timelinewidget.cpp:665-753,2177-2228. block/track add/remove creates/removes items directly at the timeline command sites; undo and load rebuild uniformly.

• Acceptance: clip/track add/remove refreshes immediately; undo/load is correct.
• Required: build + ctest all green.

issue 18 — trackviewitem index/muted

app/widget/timelinewidget/trackview/trackviewitem.cpp:66,117.

• Acceptance: track move/mute state refreshes immediately.
• Required: build + ctest all green.

issue 19 — projectviewmodel folder/label subscriptions

app/panel/project/projectviewmodel.cpp:45-61,505-512. Import/create-folder/rename go through the command sites; on load completion do a uniform model reset (reuse the issue 15 hook).

• Acceptance: the project browser refreshes immediately on add/remove/ rename.
• Required: build + ctest all green.

issue 20 — misc leftovers

multicamwidget (:107/114 raw C), manageddisplay (OCIO, :143), audiowaveformview (:57,76), viewerdisplay (subtitles, :100,264), panel/timebased (label, :162).

• Acceptance: each UI refreshes with edits.
• Required: build + ctest all green.

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Async migrations (pattern B, about half a day each, depends on 0b)

issue 21 — mainstatusbar / taskmanager / taskviewitem / task dialog

app/window/mainwindow/mainstatusbar.cpp:88-146, app/panel/taskmanager/taskmanager.cpp:41-56, app/widget/taskview/taskviewitem.cpp:82-88, app/dialog/task/task.cpp:47-48. Reconnect all of them to the dispatcher's task signals.

• Acceptance: transcode/export task progress bars and the task list update in real time.
• Required: build + ctest all green.

issue 22 — timeruler cache bar + viewer cache invalidated

app/widget/timeruler/timeruler.cpp:82-113, app/widget/viewer/viewer.cpp:366-394.

• Acceptance: the green cache bar grows with background rendering during playback; edits invalidate the cache bar correctly.
• Required: build + ctest all green.

issue 23 — viewer audio keep-alive (AUDIO_OUTPUT_NOTIFY)

app/widget/viewer/viewer.cpp:1406 (raw C, currently broken by the ID collision). Depends on 0a+0b.

• Acceptance: audio keeps playing continuously on long footage.
• Required: build + ctest all green.

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Final teardown (do last)

issue 24 — Delete EngineEventBridge

After every issue above is checked off: grep -rn "EngineEventBridge\|bridge_->subscribe" app should find zero references. Delete app/engineeventbridge.{h,cpp} and its CMake entries.

• Acceptance: build passes; full functional regression (playback/node graph/timeline/params/history/tasks).
• Required: build + ctest all green + complete manual regression.

issue 25 — Narrow the engine event surface

engine/src/capi/events.cpp keeps only the async events the dispatcher needs plus UNDO_INDEX_CHANGED / PROJECT_MODIFIED_CHANGED (the minimal exception reserved for external writers such as a future AI assistant); the synchronous event constants in engine/include/oakengine/events.h are deleted or moved to an internal header; the engine's internal Qt signals stay unchanged.

• Acceptance: ctest all green; nm confirms the C ABI no longer exposes the synchronous event subscription surface.
• Required: build + ctest all green.