refactor(watch-together): share core primitives

lib/watch_together/models/playback_state.dart

@@ -1,5 +1,4 @@
-import 'package:collection/collection.dart';
-
+import '../primitives.dart';
 import 'watch_session.dart';
 
 /// Playback lifecycle phase broadcast by the host.
@@ -146,7 +145,7 @@ class PlaybackState {
       other.anchorHostTimeMs == anchorHostTimeMs &&
       other.rate == rate &&
       other.controlMode == controlMode &&
-      const ListEquality<String>().equals(other.waitingOn, waitingOn) &&
+      orderedStringListsEqual(other.waitingOn, waitingOn) &&
       other.actorPeerId == actorPeerId &&
       other.actionHint == actionHint;
 

lib/watch_together/primitives.dart

@@ -0,0 +1,9 @@
+int watchTogetherSystemNowMs() => DateTime.now().millisecondsSinceEpoch;
+
+bool orderedStringListsEqual(List<String> first, List<String> second) {
+  if (first.length != second.length) return false;
+  for (var i = 0; i < first.length; i++) {
+    if (first[i] != second[i]) return false;
+  }
+  return true;
+}

lib/watch_together/services/attached_player.dart

@@ -4,6 +4,7 @@ import 'package:flutter/services.dart';
 
 import '../../mpv/mpv.dart';
 import '../../utils/app_logger.dart';
+import '../primitives.dart';
 
 enum _ExpectationKind { playing, rate }
 
@@ -44,7 +45,7 @@ class _Expectation {
 class AttachedPlayer {
   AttachedPlayer({required Player player, required this._onLost, this._remoteSeek, int Function()? nowMs})
     : _player = player,
-      _nowMs = nowMs ?? _systemNowMs {
+      _nowMs = nowMs ?? watchTogetherSystemNowMs {
     _lastPlaying = player.state.playing;
     _lastBuffering = player.state.buffering;
     _lastRate = player.state.rate;
@@ -59,8 +60,6 @@ class AttachedPlayer {
     );
   }
 
-  static int _systemNowMs() => DateTime.now().millisecondsSinceEpoch;
-
   /// How long an issued command may wait for its property event before the
   /// expectation is considered dead (covers silently-swallowed commands).
   static const int _expectationTtlMs = 3000;

lib/watch_together/services/clock_sync.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
 
 import '../../utils/app_logger.dart';
+import '../primitives.dart';
 
 /// NTP-style clock-offset estimation against the session host (guest side).
 ///
@@ -12,9 +13,7 @@ import '../../utils/app_logger.dart';
 /// All time reads go through the injected [nowMs] so tests can virtualize
 /// time alongside `fakeAsync`.
 class ClockSync {
-  ClockSync({required this._sendPing, int Function()? nowMs}) : _nowMs = nowMs ?? _systemNowMs;
-
-  static int _systemNowMs() => DateTime.now().millisecondsSinceEpoch;
+  ClockSync({required this._sendPing, int Function()? nowMs}) : _nowMs = nowMs ?? watchTogetherSystemNowMs;
 
   static const int _windowSize = 8;
   static const int _maxAcceptedRttMs = 1000;

lib/watch_together/services/guest_playback_reconciler.dart

@@ -4,6 +4,7 @@ import '../../utils/app_logger.dart';
 import '../models/playback_state.dart';
 import '../models/sync_message.dart';
 import '../models/watch_session.dart';
+import '../primitives.dart';
 import 'attached_player.dart';
 import 'clock_sync.dart';
 
@@ -52,9 +53,7 @@ class GuestPlaybackReconciler {
     this._callbacks = const GuestReconcilerCallbacks(),
     int Function()? nowMs,
   }) : _clock = clockSync,
-       _nowMs = nowMs ?? _systemNowMs;
-
-  static int _systemNowMs() => DateTime.now().millisecondsSinceEpoch;
+       _nowMs = nowMs ?? watchTogetherSystemNowMs;
 
   // Tuning constants.
   static const int tickMs = 500;
@@ -238,7 +237,7 @@ class GuestPlaybackReconciler {
       _reportedPhase = state.phase;
       _callbacks.onPhaseChanged?.call(state.phase);
     }
-    if (!_listEquals(state.waitingOn, _reportedWaitingOn)) {
+    if (!orderedStringListsEqual(state.waitingOn, _reportedWaitingOn)) {
       _reportedWaitingOn = state.waitingOn;
       _callbacks.onWaitingOnChanged?.call(state.waitingOn);
     }
@@ -585,12 +584,4 @@ class GuestPlaybackReconciler {
     _lastSentStatus = status;
     _sendToHost(SyncMessage.status(status, peerId: myPeerId));
   }
-
-  static bool _listEquals(List<String> a, List<String> b) {
-    if (a.length != b.length) return false;
-    for (var i = 0; i < a.length; i++) {
-      if (a[i] != b[i]) return false;
-    }
-    return true;
-  }
 }

lib/watch_together/services/host_playback_coordinator.dart

@@ -4,6 +4,7 @@ import 'dart:math';
 import '../../utils/app_logger.dart';
 import '../models/playback_state.dart';
 import '../models/watch_session.dart';
+import '../primitives.dart';
 import 'attached_player.dart';
 
 /// Callbacks the coordinator surfaces to the provider/UI layer.
@@ -45,9 +46,7 @@ class HostPlaybackCoordinator {
     required this._sendState,
     this._callbacks = const HostCoordinatorCallbacks(),
     int Function()? nowMs,
-  }) : _nowMs = nowMs ?? _systemNowMs;
-
-  static int _systemNowMs() => DateTime.now().millisecondsSinceEpoch;
+  }) : _nowMs = nowMs ?? watchTogetherSystemNowMs;
 
   // Tuning constants.
   static const int stallGraceMs = 500;
@@ -785,18 +784,10 @@ class HostPlaybackCoordinator {
     if (toPeerId == null) {
       final previousWaiting = _lastBroadcast?.waitingOn ?? const [];
       _lastBroadcast = state;
-      if (!_listEquals(previousWaiting, waitingOn)) {
+      if (!orderedStringListsEqual(previousWaiting, waitingOn)) {
         _callbacks.onWaitingOnChanged?.call(waitingOn);
       }
     }
     _sendState(state, toPeerId: toPeerId);
   }
-
-  static bool _listEquals(List<String> a, List<String> b) {
-    if (a.length != b.length) return false;
-    for (var i = 0; i < a.length; i++) {
-      if (a[i] != b[i]) return false;
-    }
-    return true;
-  }
 }

lib/watch_together/services/watch_together_controller.dart

@@ -5,6 +5,7 @@ import '../../utils/app_logger.dart';
 import '../models/playback_state.dart';
 import '../models/sync_message.dart';
 import '../models/watch_session.dart';
+import '../primitives.dart';
 import 'attached_player.dart';
 import 'clock_sync.dart';
 import 'guest_playback_reconciler.dart';
@@ -28,7 +29,7 @@ class WatchTogetherController {
     int Function()? nowMs,
   }) : _peerService = peerService,
        _session = session,
-       _nowMs = nowMs ?? _systemNowMs {
+       _nowMs = nowMs ?? watchTogetherSystemNowMs {
     if (session.isHost) {
       _coordinator = HostPlaybackCoordinator(
         myPeerId: peerService.myPeerId ?? '',
@@ -65,8 +66,6 @@ class WatchTogetherController {
     _subscriptions.add(peerService.onPeerDisconnected.listen(_handlePeerDisconnected));
   }
 
-  static int _systemNowMs() => DateTime.now().millisecondsSinceEpoch;
-
   final WatchTogetherPeerService _peerService;
   final int Function() _nowMs;
   WatchSession _session;

test/watch_together/primitives_test.dart

@@ -0,0 +1,19 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:plezy/watch_together/primitives.dart';
+
+void main() {
+  test('orderedStringListsEqual preserves order and multiplicity', () {
+    expect(orderedStringListsEqual(const ['a', 'b'], const ['a', 'b']), isTrue);
+    expect(orderedStringListsEqual(const ['a'], const ['a', 'b']), isFalse);
+    expect(orderedStringListsEqual(const ['a', 'b'], const ['b', 'a']), isFalse);
+    expect(orderedStringListsEqual(const ['a', 'a'], const ['a', 'b']), isFalse);
+  });
+
+  test('watchTogetherSystemNowMs returns wall-clock milliseconds', () {
+    final before = DateTime.now().millisecondsSinceEpoch;
+    final value = watchTogetherSystemNowMs();
+    final after = DateTime.now().millisecondsSinceEpoch;
+
+    expect(value, inInclusiveRange(before, after));
+  });
+}