feat: ViewModel in Schedule.kt

app/src/main/java/ru/sweetbread/unn/ui/composes/Schedule.kt

@@ -2,7 +2,6 @@
 
 package ru.sweetbread.unn.ui.composes
 
-import android.util.Log
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateColorAsState
 import androidx.compose.foundation.Canvas
@@ -24,12 +23,11 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableIntStateOf
-import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -43,9 +41,22 @@ import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.zIndex
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import androidx.lifecycle.viewmodel.compose.viewModel
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.delay
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.withContext
 import ru.sweetbread.unn.R
 import ru.sweetbread.unn.api.Auditorium
 import ru.sweetbread.unn.api.Building
@@ -55,6 +66,8 @@ import ru.sweetbread.unn.api.Lecturer
 import ru.sweetbread.unn.api.LecturerRank
 import ru.sweetbread.unn.api.ScheduleUnit
 import ru.sweetbread.unn.api.getScheduleDay
+import ru.sweetbread.unn.db.cacheDb
+import ru.sweetbread.unn.db.toModel
 import ru.sweetbread.unn.ui.theme.UNNTheme
 import splitties.resources.appStr
 import java.time.LocalDate
@@ -64,32 +77,83 @@ import java.time.ZoneId
 import java.time.format.DateTimeFormatter
 import java.util.Calendar
 
+
+class ScheduleRepository {
+    fun getFromDb(date: LocalDate): List<ScheduleUnit> =
+        cacheDb.scheduleDao()
+            .getSchedule(date.format(DateTimeFormatter.ISO_DATE))
+            .mapNotNull { it.toModel() }
+    suspend fun getFromApi(date: LocalDate): List<ScheduleUnit> = getScheduleDay(date)
+}
+
+sealed class ScheduleState {
+    object Loading : ScheduleState()
+    data class Success(val data: List<ScheduleUnit>) : ScheduleState()
+    data class Error(val message: String) : ScheduleState()
+}
+
+class ScheduleViewModel : ViewModel() {
+    private val repository = ScheduleRepository()
+
+    private val _date = MutableStateFlow(LocalDate.now())
+    val date: StateFlow<LocalDate> = _date.asStateFlow()
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    val scheduleState: StateFlow<ScheduleState> = _date
+        .flatMapLatest { date ->
+            flow {
+                emit(ScheduleState.Loading)
+                val cached = withContext(Dispatchers.IO) {
+                    repository.getFromDb(date)
+                }
+                emit(ScheduleState.Success(cached))
+
+                try {
+                    val fresh = repository.getFromApi(date)
+                    if (fresh != cached) {
+                        emit(ScheduleState.Success(fresh))
+                    }
+                } catch (e: Exception) {
+                    emit(ScheduleState.Error("Ошибка загрузки: ${e.message}"))
+                }
+            }.flowOn(Dispatchers.IO)
+        }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5000),
+            initialValue = ScheduleState.Loading
+        )
+
+    fun updateDate(newDate: LocalDate) {
+        _date.update { newDate }
+    }
+}
+
 @Composable
 fun Schedule() {
-    var selectedDate by remember { mutableStateOf(LocalDate.now()) }
+    val viewModel: ScheduleViewModel = viewModel()
 
     Column {
         BoundedWeekPicker(
             modifier = Modifier
                 .fillMaxWidth()
                 .padding(vertical = 8.dp),
-            selectedDate = selectedDate,
-            onDateSelected = { selectedDate = it }
+            selectedDate = viewModel.date.collectAsState().value,
+            onDateSelected = { viewModel.updateDate(it) }
         )
 
-        ScheduleDay(date = selectedDate)
+        ScheduleDay(viewModel = viewModel)
     }
 }
 
 @Composable
-fun ScheduleDay(modifier: Modifier = Modifier, date: LocalDate) {
-    val scope = rememberCoroutineScope()
-    var loadedDate by remember { mutableStateOf(LocalDate.MIN) }
-    val lessons = remember { mutableListOf<ScheduleUnit>() }
+fun ScheduleDay(modifier: Modifier = Modifier, viewModel: ScheduleViewModel) {
     var expanded by remember { mutableIntStateOf(0) }
+    val state by viewModel.scheduleState.collectAsState()
 
-    if (loadedDate == date) {
-        Log.d("Loaded", "${date.format(DateTimeFormatter.ISO_DATE)} ${lessons.size}")
+    when (state) {
+        is ScheduleState.Success -> {
+            val lessons = (state as ScheduleState.Success).data
             LazyColumn(modifier) {
                 items(lessons) {
                     ScheduleItem(unit = it, modifier = Modifier.clickable {
@@ -101,7 +165,8 @@ fun ScheduleDay(modifier: Modifier = Modifier, date: LocalDate) {
                 if (lessons.isEmpty())
                     item { Text(appStr(R.string.noData)) }
             }
-    } else {
+        }
+        is ScheduleState.Loading ->
             LinearProgressIndicator(
                 modifier = Modifier
                     .fillMaxWidth()
@@ -109,13 +174,8 @@ fun ScheduleDay(modifier: Modifier = Modifier, date: LocalDate) {
                 color = MaterialTheme.colorScheme.surfaceVariant,
                 trackColor = MaterialTheme.colorScheme.secondary,
             )
-        LaunchedEffect(date != loadedDate) {
-            scope.launch(Dispatchers.IO) {
-                lessons.clear()
-                lessons.addAll(getScheduleDay(date = date))
-                loadedDate = date
-            }
-        }
+        is ScheduleState.Error ->
+            Text((state as ScheduleState.Error).message, color = MaterialTheme.colorScheme.error)
     }
 }