booru-viewer/booru_viewer
pax 45e6042ebb popout/window: wire eventFilter to StateMachine.dispatch (parallel)
**Commit 14a of the pre-emptive 14a/14b split.**

Adds the popout's pure-Python state machine as a parallel side
channel to the legacy imperative event handling. The state machine
runs alongside the existing code: every Qt event handler / mpv
signal / button click below dispatches a state machine event AND
continues to run the existing imperative action. The state machine's
returned effects are LOGGED at DEBUG, not applied to widgets.

**The legacy path stays authoritative through commit 14a; commit
14b switches the authority to the dispatch path.**

This is the bisect-safe-by-construction split the refactor plan
called for. 197 lines added, 0 removed. No widget side effects from
the dispatch path. App is byte-identical from the user's perspective.

Wired wire-points (every Qt event the state machine cares about):

  __init__:
    - Constructs StateMachine, sets grid_cols
    - Dispatches Open(saved_geo, saved_fullscreen, monitor) using
      the class-level cross-popout-session state
    - Connects VideoPlayer.playback_restart Signal (added in
      commit 1) to _on_video_playback_restart, which routes to
      VideoStarted (LoadingVideo) or SeekCompleted (SeekingVideo)
      based on current state machine state
    - Connects VideoPlayer.play_next → VideoEofReached dispatch
    - Connects VideoPlayer.video_size → VideoSizeKnown dispatch
    - Connects VideoPlayer._seek_slider.clicked_position → SeekRequested
    - Connects VideoPlayer._mute_btn.clicked → MuteToggleRequested
    - Connects VideoPlayer._vol_slider.valueChanged → VolumeSet
    - Connects VideoPlayer._loop_btn.clicked → LoopModeSet

  set_media:
    - Detects MediaKind from is_video / .gif suffix
    - Builds referer for streaming URLs
    - Dispatches ContentArrived(path, info, kind, width, height, referer)
      BEFORE the legacy imperative load path runs

  eventFilter (key + wheel):
    - Esc/Q → CloseRequested
    - Left/H → NavigateRequested(-1)
    - Right/L → NavigateRequested(+1)
    - Up/K → NavigateRequested(-grid_cols)
    - Down/J → NavigateRequested(+grid_cols)
    - F11 → FullscreenToggled
    - Space (video) → TogglePlayRequested
    - Wheel horizontal tilt → NavigateRequested(±1)
    - Wheel vertical (video) → VolumeSet(new_value)
    - Period/Comma keys (relative seek) explicitly NOT dispatched —
      they go straight to mpv via the legacy path. The state
      machine's SeekRequested is for slider-driven seeks; commit 14b
      will route the relative-seek keys through SeekRequested with
      a target_ms computed from current position.

  resizeEvent (non-Hyprland branch):
    - WindowResized(rect) dispatched after the legacy viewport update

  moveEvent (non-Hyprland branch):
    - WindowMoved(rect) dispatched after the legacy viewport update

  closeEvent:
    - CloseRequested dispatched at entry

The _fsm_dispatch helper centralizes the dispatch + log path so every
wire-point is one line. Logs at DEBUG level via a new
`booru.popout.adapter` logger:

    POPOUT_FSM <event_name> | <old_state> -> <new_state> | effects=[...]

Filter the log output by `POPOUT_FSM` substring to see only the
state machine activity during the manual sweep.

The _on_video_playback_restart helper is the ONE place the adapter
peeks at state machine state to choose between two event types
(VideoStarted vs SeekCompleted from the same mpv playback-restart
event). It's a read, not a write — the state machine's dispatch
remains the only mutation point.

Tests passing after this commit: 81 / 81 (16 Phase A + 65 state).
Phase A still green.

**Verification gate (next):**

Before commit 14b lands, the user runs the popout in their own
interactive Hyprland session and walks through the 11 race scenarios:

  1. P↔L navigation cycles drift toward corner
  2. Super+drag externally then nav
  3. Corner-resize externally then nav
  4. F11 same-aspect round-trip
  5. F11 across-aspect round-trip
  6. First-open from saved geometry
  7. Restart persistence across app sessions
  8. Rapid Right-arrow spam
  9. Uncached video click
  10. Mute toggle before mpv exists
  11. Seek mid-playback

For each scenario, capture the POPOUT_FSM log lines and verify the
state machine's dispatch sequence matches what the legacy path
actually did. Any discrepancy is a state machine logic bug that
must be fixed in state.py BEFORE 14b lands and switches authority
to the dispatch path. Fix in state.py, not in window.py — state.py
is still the source of truth.

The bisect-safe property: even if the user finds a discrepancy
during the sweep, this commit DOES NOT change app behavior. App is
fully functional through the legacy path. The dispatch path is
diagnostic-only.

Test cases for commit 14b:
  - Each effect type pattern-matches to a real widget action
  - Manual 11-scenario sweep with the dispatch path authoritative
2026-04-08 19:50:40 -05:00
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