fix: 登录同步后首页恢复课程位置与复习卡片

- 拉取合并时还原当前课程与分段位置，位置只前进不后退，跳过其他设备已完成的课 - 由云端掌握项重建复习卡片，并纠正旧客户端写坏的首次复习到期时间 - 同 checkpoint 时以证据更多的一方为准；推送缺卡片项时不再用当前时间作到期时间 - 登录/注册及合并逻辑升级后强制全量拉取一次 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-16 17:05:15 +09:00
parent 6710a80fa5
commit 8ed52312fb
4 changed files with 324 additions and 38 deletions
@@ -1081,6 +1081,73 @@ class AppState extends ChangeNotifier {
    SyncCoordinator.instance.triggerBackgroundSync(this);
  }

+  /// Merges lesson progress pulled from the sync server.
+  ///
+  /// Completed lessons/segments are unioned, and the learner's position only
+  /// ever moves forward: a device that has not caught up yet must never drag
+  /// another device back to an earlier lesson or segment.
+  bool mergeSyncedLessonProgress({
+    required Iterable<String> completedLessons,
+    required Iterable<String> completedSegments,
+    required String remoteActiveLessonId,
+  }) {
+    var changed = false;
+    final completedBefore = completedLessonIds.toSet();
+    for (final id in completedLessons) {
+      if (completedLessonIds.add(id)) changed = true;
+    }
+    for (final id in completedSegments) {
+      if (completedSegmentIds.add(id)) changed = true;
+    }
+    if (this.completedLessons != completedLessonIds.length) {
+      this.completedLessons = completedLessonIds.length;
+      changed = true;
+    }
+
+    int lessonIndex(String id) =>
+        a0SeedLessons.indexWhere((lesson) => lesson.id == id);
+
+    var targetIndex = lessonIndex(activeLessonId);
+    final remoteIndex = lessonIndex(remoteActiveLessonId);
+    if (remoteIndex > targetIndex && isLessonUnlocked(remoteActiveLessonId)) {
+      targetIndex = remoteIndex;
+    }
+    // The server's active lesson can itself be stale. Skip lessons that only
+    // became complete through this pull, but leave a lesson alone when the
+    // learner deliberately reopened it locally after finishing it.
+    while (targetIndex >= 0 &&
+        targetIndex < a0SeedLessons.length - 1 &&
+        !completedBefore.contains(a0SeedLessons[targetIndex].id) &&
+        completedLessonIds.contains(a0SeedLessons[targetIndex].id)) {
+      targetIndex++;
+    }
+
+    var positionChanged = false;
+    if (targetIndex >= 0 && a0SeedLessons[targetIndex].id != activeLessonId) {
+      activeLessonId = a0SeedLessons[targetIndex].id;
+      positionChanged = true;
+    }
+
+    for (final lesson in a0SeedLessons) {
+      final segments = lesson.segments;
+      var firstOpen = segments.indexWhere(
+        (segment) => !completedSegmentIds.contains(segment.id),
+      );
+      if (firstOpen < 0) firstOpen = segments.length - 1;
+      if (firstOpen > activeSegmentIndexFor(lesson.id)) {
+        activeSegmentIndexes[lesson.id] = firstOpen;
+        if (lesson.id == activeLessonId) positionChanged = true;
+        changed = true;
+      }
+    }
+
+    if (positionChanged) {
+      _resetLessonFlow();
+      changed = true;
+    }
+    return changed;
+  }
+
  void _resetLessonFlow() {
    lessonStep = LessonStep.preview;
    previewIndex = 0;