feat(data): add TeacherRepositoryImpl

app/src/main/java/agzam/vyatsu/data/remote/VyatsuUrls.kt

@@ -10,4 +10,9 @@ object VyatsuUrls {
 
     fun groupPdfUrl(groupId: String, season: Season, range: DateRange): String = "$PDF_BASEURL/${groupId}_${season.apiKey}_${range.first}_${range.second}.pdf"
 
+    const val TEACHER_PAGE = "https://www.vyatsu.ru/studentu-1/spravochnaya-informatsiya/teacher.html"
+    const val PREPOD_BASEURL = "https://www.vyatsu.ru/reports/schedule/prepod"
+
+    fun teacherPrepodUrl(departmentId: String, season: Season, range: DateRange): String = "$PREPOD_BASEURL/${departmentId}_${season.apiKey}_${range.first}_${range.second}.html"
+
 }

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

@@ -0,0 +1,86 @@
+package agzam.vyatsu.data.repository
+
+import agzam.vyatsu.data.local.DepartmentEntity
+import agzam.vyatsu.data.local.DepartmentPeriodEntity
+import agzam.vyatsu.data.local.TeacherDao
+import agzam.vyatsu.data.remote.TeachersParser
+import agzam.vyatsu.data.remote.VyatsuHttpClient
+import agzam.vyatsu.data.remote.VyatsuUrls
+import agzam.vyatsu.domain.ScheduleDates
+import agzam.vyatsu.domain.model.Department
+import agzam.vyatsu.domain.repository.TeacherRepository
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.withContext
+
+class TeacherRepositoryImpl(
+    private val teacherDao: TeacherDao,
+) : TeacherRepository {
+
+    override fun observeDepartments(): Flow<List<Department>> =
+        teacherDao.observeDepartments().map { list -> list.map { it.toDomain() } }
+
+    override suspend fun getDepartments(): List<Department> =
+        teacherDao.observeDepartments().first().map { it.toDomain() }
+
+    override suspend fun getFaculties(): List<String> = teacherDao.getFaculties()
+
+    override suspend fun refreshIfStale(): Boolean {
+        val last = teacherDao.maxSyncedAt()
+        if (last != null && now() - last < STALE_WINDOW_MS) {
+            return true
+        }
+        refresh()
+        return true
+    }
+
+    override suspend fun forceRefresh(): Boolean {
+        refresh()
+        return true
+    }
+
+    private suspend fun refresh() {
+        val parsed = withContext(Dispatchers.IO) {
+            VyatsuHttpClient.openStream(VyatsuUrls.TEACHER_PAGE).use(TeachersParser::parseStream)
+        }
+        val now = now()
+        teacherDao.insertAll(
+            parsed.departments.map { department ->
+                DepartmentEntity(
+                    departmentId = department.departmentId,
+                    name = department.name,
+                    faculty = department.faculty,
+                    lastSyncedAt = now
+                )
+            }
+        )
+        val periods = parsed.departments.flatMap { department ->
+            parsed.dateRanges[department.departmentId].orEmpty().flatMap { (season, ranges) ->
+                ranges.map { range ->
+                    DepartmentPeriodEntity(
+                        departmentId = department.departmentId,
+                        season = season,
+                        weekStart = ScheduleDates.asDate(range.first).toEpochDay(),
+                        weekEnd = ScheduleDates.asDate(range.second).toEpochDay()
+                    )
+                }
+            }
+        }
+        teacherDao.deleteAllPeriods()
+        teacherDao.insertPeriods(periods)
+    }
+
+    private fun now(): Long = System.currentTimeMillis()
+
+    private fun DepartmentEntity.toDomain(): Department = Department(
+        departmentId = departmentId,
+        name = name,
+        faculty = faculty
+    )
+
+    companion object {
+        private const val STALE_WINDOW_MS = 12 * 60 * 60 * 1000L
+    }
+}