fix: ssl error & offline teacher schedule

app/src/main/java/agzam/vyatsu/data/local/TeacherScheduleDao.kt

@@ -33,6 +33,9 @@ interface TeacherScheduleDao {
     @Query("DELETE FROM teacher_schedules")
     suspend fun deleteAll()
 
+    @Query("SELECT lastSyncedAt FROM teacher_schedules WHERE departmentId = :departmentId AND season = :season AND weekStart = :weekStart")
+    suspend fun lastSyncedAt(departmentId: String, season: String, weekStart: Long): Long?
+
     @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insertDays(days: List<TeacherDayEntity>): List<Long>
 
@@ -41,6 +44,7 @@ interface TeacherScheduleDao {
 
     @Transaction
     suspend fun replaceSchedule(schedule: TeacherScheduleEntity, days: List<TeacherDayEntity>, lessons: List<TeacherLessonEntity>) {
+        deleteSchedule(schedule.departmentId, schedule.season.name, schedule.weekStart)
         val scheduleId = insertSchedule(schedule)
         val daysWithScheduleId = days.map { it.copy(scheduleId = scheduleId) }
         deleteDaysForSchedule(scheduleId)

app/src/main/java/agzam/vyatsu/data/repository/TeacherScheduleRepositoryImpl.kt

@@ -56,7 +56,7 @@ class TeacherScheduleRepositoryImpl(
         scheduleDao.observeDistinctTeachers(period.season.name, period.weekStart.toEpochDay())
             .map { names -> names.map { name -> Teacher(name = name) } }
 
-    override suspend fun syncPeriod(date: LocalDate): Flow<BulkSyncProgress> = flow {
+    override suspend fun syncPeriod(date: LocalDate, force: Boolean): Flow<BulkSyncProgress> = flow {
         // Unique index (departmentId, season, weekStart) breaks on interleaved
         // delete+insert from concurrent syncPeriod() callers.
         syncMutex.withLock {
@@ -68,18 +68,27 @@ class TeacherScheduleRepositoryImpl(
                 return@withLock
             }
 
-            targets.map { it.season to it.weekStart }
-                .distinct()
-                .forEach { (season, weekStart) ->
-                    withContext(Dispatchers.IO) {
-                        scheduleDao.deletePeriod(season.name, weekStart)
-                    }
+            val now = now()
+            var skippedCount = 0
+            val nonSkipped = mutableListOf<DepartmentPeriodEntity>()
+            for (target in targets) {
+                val last = withContext(Dispatchers.IO) {
+                    scheduleDao.lastSyncedAt(target.departmentId, target.season.name, target.weekStart)
                 }
+                val shouldSkip = !force && last != null && now - last < STALE_WINDOW_MS
+                if (shouldSkip) {
+                    skippedCount++
+                } else {
+                    nonSkipped.add(target)
+                }
+            }
+
+            emit(BulkSyncProgress(total = targets.size, done = skippedCount, failed = 0))
 
             val total = targets.size
             val semaphore = Semaphore(PARALLELISM)
             val jobs = coroutineScope {
-                targets.map { target ->
+                nonSkipped.map { target ->
                     async {
                         semaphore.withPermit {
                             try {
@@ -102,7 +111,7 @@ class TeacherScheduleRepositoryImpl(
                 }
             }
 
-            var done = 0
+            var done = skippedCount
             var failed = 0
             for (job in jobs) {
                 if (job.await()) done++ else failed++