refactor(quiz): extract QuizTimerController from QuizViewModel

Author: leanite

dynaquiz/composeApp/src/commonMain/kotlin/com/leanite/dynaquiz/feature/quiz/QuizTimerController.kt

@@ -0,0 +1,53 @@
+package com.leanite.dynaquiz.feature.quiz
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlin.time.Duration.Companion.seconds
+
+class QuizTimerController {
+    private val _timeRemaining = MutableStateFlow<Int?>(null)
+    val timeRemaining: StateFlow<Int?> = _timeRemaining.asStateFlow()
+
+    private var job: Job? = null
+
+    fun start(
+        scope: CoroutineScope,
+        durationSec: Int,
+        onTimeout: () -> Unit,
+    ) {
+        job?.cancel()
+        job =
+            scope.launch {
+                for (sec in durationSec downTo 1) {
+                    _timeRemaining.value = sec
+                    delay(1.seconds)
+                }
+                _timeRemaining.value = 0
+                onTimeout()
+            }
+    }
+
+    fun stop() {
+        cancel()
+        _timeRemaining.value = null
+    }
+
+    fun cancel() {
+        job?.cancel()
+    }
+
+    suspend fun runCountdown(
+        secondsFrom: Int,
+        onTick: (Int) -> Unit,
+    ) {
+        for (sec in secondsFrom downTo 1) {
+            onTick(sec)
+            delay(1.seconds)
+        }
+    }
+}

dynaquiz/composeApp/src/commonMain/kotlin/com/leanite/dynaquiz/feature/quiz/QuizViewModel.kt

@@ -17,33 +17,39 @@ import com.leanite.dynaquiz.core.domain.usecase.SaveQuizSessionUseCase
 import com.leanite.dynaquiz.core.domain.usecase.SubmitAnswerUseCase
 import kotlinx.collections.immutable.toImmutableList
 import kotlinx.coroutines.Deferred
-import kotlinx.coroutines.Job
 import kotlinx.coroutines.async
 import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
-import kotlin.time.Duration.Companion.seconds
 
 class QuizViewModel(
     private val setup: QuizSetup,
     private val getRandomQuestionUseCase: GetRandomQuestionUseCase,
     private val submitAnswerUseCase: SubmitAnswerUseCase,
     private val saveQuizSessionUseCase: SaveQuizSessionUseCase,
+    private val timer: QuizTimerController,
 ) : ViewModel() {
     private val _uiState = MutableStateFlow(QuizUiState(challengeMode = setup.challengeMode))
     val uiState: StateFlow<QuizUiState> = _uiState.asStateFlow()
 
     private val _events = Channel<QuizEvent>(Channel.BUFFERED)
     val events = _events.receiveAsFlow()
 
-    private var timerJob: Job? = null
     private var prefetchedNextQuestion: Deferred<Question?>? = null
 
+    init {
+        // Reflete o timer no UiState sem o VM gerenciar a coroutine
+        viewModelScope.launch {
+            timer.timeRemaining.collect { sec ->
+                _uiState.update { it.copy(timeRemainingSec = sec) }
+            }
+        }
+    }
+
     fun onIntent(intent: QuizIntent) {
         when (intent) {
             QuizIntent.Started -> start()
@@ -73,38 +79,23 @@ class QuizViewModel(
     }
 
     private suspend fun runCountdown() {
-        for (sec in QuizRules.INITIAL_COUNTDOWN_SECONDS downTo 1) {
+        timer.runCountdown(QuizRules.INITIAL_COUNTDOWN_SECONDS) { sec ->
             _uiState.update { it.copy(phase = QuizPhase.Countdown(sec)) }
-            delay(1.seconds)
         }
         _uiState.update { it.copy(phase = QuizPhase.Loading) }
     }
 
     private fun startPlaying(question: Question) {
         _uiState.update { it.copy(phase = QuizPhase.Playing(question = question)) }
-        startTimer()
+        startQuestionTimer()
         schedulePrefetchOfNextQuestion()
     }
 
-    private fun startTimer() {
-        timerJob?.cancel()
+    private fun startQuestionTimer() {
         val mode = _uiState.value.challengeMode
-
-        if (mode !is ChallengeMode.Timed) {
-            _uiState.update { it.copy(timeRemainingSec = null) }
-            return
+        if (mode is ChallengeMode.Timed) {
+            timer.start(viewModelScope, mode.perQuestionSeconds) { onTimeOut() }
         }
-
-        val totalSeconds = mode.perQuestionSeconds
-        timerJob =
-            viewModelScope.launch {
-                for (sec in totalSeconds downTo 1) {
-                    _uiState.update { it.copy(timeRemainingSec = sec) }
-                    delay(1.seconds)
-                }
-                _uiState.update { it.copy(timeRemainingSec = 0) }
-                onTimeOut()
-            }
     }
 
     private fun onTimeOut() {
@@ -150,7 +141,7 @@ class QuizViewModel(
         playing: QuizPhase.Playing,
         answer: String,
     ) {
-        timerJob?.cancel()
+        timer.cancel()
         _uiState.update {
             it.copy(phase = playing.copy(selectedAnswer = answer, isSubmitting = true))
         }
@@ -194,12 +185,12 @@ class QuizViewModel(
         finalIndex: Int,
     ) {
         val mode = _uiState.value.challengeMode
+        timer.stop()
         _uiState.update {
             it.copy(
                 phase = QuizPhase.Completed,
                 answerLog = answerLog.toImmutableList(),
                 currentQuestionIndex = finalIndex,
-                timeRemainingSec = null,
             )
         }
 
@@ -248,7 +239,7 @@ class QuizViewModel(
                 currentQuestionIndex = nextIndex,
             )
         }
-        startTimer()
+        startQuestionTimer()
         schedulePrefetchOfNextQuestion()
     }
 
@@ -266,7 +257,7 @@ class QuizViewModel(
     private fun currentPlaying(): QuizPhase.Playing? = _uiState.value.phase as? QuizPhase.Playing
 
     override fun onCleared() {
-        timerJob?.cancel()
+        timer.cancel()
         prefetchedNextQuestion?.cancel()
         super.onCleared()
     }

dynaquiz/composeApp/src/commonMain/kotlin/com/leanite/dynaquiz/feature/quiz/di/FeatureQuizModule.kt

@@ -1,17 +1,20 @@
 package com.leanite.dynaquiz.feature.quiz.di
 
+import com.leanite.dynaquiz.feature.quiz.QuizTimerController
 import com.leanite.dynaquiz.feature.quiz.QuizViewModel
 import org.koin.core.module.dsl.viewModel
 import org.koin.dsl.module
 
 val featureQuizModule =
     module {
+        factory { QuizTimerController() }
         viewModel { params ->
             QuizViewModel(
                 setup = params.get(),
                 getRandomQuestionUseCase = get(),
                 submitAnswerUseCase = get(),
                 saveQuizSessionUseCase = get(),
+                timer = get(),
             )
         }
     }

dynaquiz/composeApp/src/commonTest/kotlin/com/leanite/dynaquiz/feature/quiz/QuizViewModelTest.kt

@@ -74,6 +74,7 @@ class QuizViewModelTest {
             getRandomQuestionUseCase = getRandomQuestionUseCase,
             submitAnswerUseCase = submitAnswerUseCase,
             saveQuizSessionUseCase = saveQuizSessionUseCase,
+            timer = QuizTimerController(),
         )
 
     private fun question(