feat: conserver la sélection de l'accueil entre les lancements

Les steppers de l'accueil vivaient dans des remember simples : la sélection
était perdue à la fin de chaque partie et à chaque redémarrage de l'app.
Remonter l'état dans App() et le persister via un ConfigRepository
(config.json, même pattern que HistoryRepository) sauvegardé à chaque
changement et rechargé au lancement.

sharedUI/src/commonMain/kotlin/com/livrets/App.kt

@@ -8,6 +8,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.backhandler.BackHandler
+import com.livrets.data.ConfigRepository
 import com.livrets.data.HistoryRepository
 import com.livrets.game.GameConfig
 import com.livrets.game.GameResult
@@ -48,8 +49,14 @@ fun App(
 ) = AppTheme(onThemeChanged) {
     val scope = rememberCoroutineScope()
     val history = remember { HistoryRepository("$filesDirPath/history.json".toPath()) }
+    val configRepository = remember { ConfigRepository("$filesDirPath/config.json".toPath()) }
     var screen by remember { mutableStateOf<Screen>(Screen.Home) }
     var playerName by remember { mutableStateOf<String?>(null) }
+    var config by remember { mutableStateOf(GameConfig(10, 5, 12)) }
+
+    LaunchedEffect(configRepository) {
+        configRepository.load()?.let { config = it }
+    }
 
     LaunchedEffect(gamesServices) {
         gamesServices.signIn()
@@ -57,7 +64,13 @@ fun App(
     }
 
     val homePreview: @Composable () -> Unit = {
-        HomeScreen(onPlay = {}, onHistory = {}, onLeaderboard = {})
+        HomeScreen(
+            onPlay = {},
+            onHistory = {},
+            onLeaderboard = {},
+            config = GameConfig(10, 5, 12),
+            onConfigChanged = {},
+        )
     }
 
     screen.backTarget()?.let { target ->
@@ -67,14 +80,21 @@ fun App(
 
     when (val current = screen) {
         Screen.Home -> HomeScreen(
-            onPlay = { config -> screen = Screen.Game(config) },
+            onPlay = { screen = Screen.Game(it) },
             onHistory = { screen = Screen.History },
+            config = config,
+            onConfigChanged = { updated ->
+                config = updated
+                scope.launch {
+                    withContext(NonCancellable) { configRepository.save(updated) }
+                }
+            },
             playerName = playerName,
-            onLeaderboard = { config ->
+            onLeaderboard = { current ->
                 scope.launch {
                     if (gamesServices.isSignedIn() || gamesServices.signIn()) {
                         if (playerName == null) playerName = gamesServices.playerDisplayName()
-                        config.leaderboardId()?.let { gamesServices.showLeaderboard(it) }
+                        current.leaderboardId()?.let { gamesServices.showLeaderboard(it) }
                     }
                 }
             },

sharedUI/src/commonMain/kotlin/com/livrets/data/ConfigRepository.kt

@@ -0,0 +1,32 @@
+package com.livrets.data
+
+import com.livrets.game.GameConfig
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import kotlinx.serialization.json.Json
+import okio.FileSystem
+import okio.Path
+
+class ConfigRepository(
+    private val filePath: Path,
+    private val fileSystem: FileSystem = systemFileSystem,
+) {
+    private val json = Json { ignoreUnknownKeys = true }
+
+    suspend fun load(): GameConfig? = withContext(Dispatchers.Default) {
+        if (!fileSystem.exists(filePath)) return@withContext null
+        runCatching {
+            fileSystem.read(filePath) { readUtf8() }
+                .let { json.decodeFromString(GameConfig.serializer(), it) }
+        }.getOrNull()
+    }
+
+    suspend fun save(config: GameConfig) {
+        withContext(Dispatchers.Default) {
+            filePath.parent?.let { fileSystem.createDirectories(it) }
+            fileSystem.write(filePath) {
+                writeUtf8(json.encodeToString(GameConfig.serializer(), config))
+            }
+        }
+    }
+}

sharedUI/src/commonMain/kotlin/com/livrets/ui/HomeScreen.kt

@@ -17,10 +17,6 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.style.TextAlign
@@ -33,12 +29,10 @@ fun HomeScreen(
     onPlay: (GameConfig) -> Unit,
     onHistory: () -> Unit,
     onLeaderboard: (GameConfig) -> Unit,
+    config: GameConfig,
+    onConfigChanged: (GameConfig) -> Unit,
     playerName: String? = null,
 ) {
-    var questionCount by remember { mutableStateOf(10) }
-    var secondsPerQuestion by remember { mutableStateOf(5) }
-    var maxTable by remember { mutableStateOf(12) }
-
     Column(
         modifier = Modifier
             .fillMaxSize()
@@ -50,20 +44,26 @@ fun HomeScreen(
         Text("Livrets", style = MaterialTheme.typography.displayMedium)
         Spacer(Modifier.height(32.dp))
 
-        StepperRow("Nombre de questions", questionCount, 5..50, step = 5) { questionCount = it }
-        StepperRow("Secondes par question", secondsPerQuestion, 3..30, step = 1) { secondsPerQuestion = it }
-        StepperRow("Jusqu'à la table de", maxTable, 1..12, step = 1) { maxTable = it }
+        StepperRow("Nombre de questions", config.questionCount, 5..50, step = 5) {
+            onConfigChanged(config.copy(questionCount = it))
+        }
+        StepperRow("Secondes par question", config.secondsPerQuestion, 3..30, step = 1) {
+            onConfigChanged(config.copy(secondsPerQuestion = it))
+        }
+        StepperRow("Jusqu'à la table de", config.maxTable, 1..12, step = 1) {
+            onConfigChanged(config.copy(maxTable = it))
+        }
 
         Spacer(Modifier.height(32.dp))
         Button(
-            onClick = { onPlay(GameConfig(questionCount, secondsPerQuestion, maxTable)) },
+            onClick = { onPlay(config) },
             modifier = Modifier.fillMaxWidth().height(56.dp),
         ) {
             Text("Jouer", fontSize = 20.sp)
         }
         TextButton(onClick = onHistory) { Text("Historique") }
         TextButton(
-            onClick = { onLeaderboard(GameConfig(questionCount, secondsPerQuestion, maxTable)) },
+            onClick = { onLeaderboard(config) },
         ) { Text("Classement") }
         playerName?.let { name ->
             Spacer(Modifier.height(8.dp))

sharedUI/src/commonTest/kotlin/com/livrets/data/ConfigRepositoryTest.kt

@@ -0,0 +1,39 @@
+package com.livrets.data
+
+import com.livrets.game.GameConfig
+import kotlinx.coroutines.test.runTest
+import okio.fakefilesystem.FakeFileSystem
+import okio.Path.Companion.toPath
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+
+class ConfigRepositoryTest {
+
+    @Test
+    fun `chargement nul quand aucun fichier`() = runTest {
+        val repo = ConfigRepository("/docs/config.json".toPath(), FakeFileSystem())
+        assertNull(repo.load())
+    }
+
+    @Test
+    fun `aller-retour sauvegarde puis chargement`() = runTest {
+        val repo = ConfigRepository("/docs/config.json".toPath(), FakeFileSystem())
+        val first = GameConfig(5, 3, 8)
+        repo.save(first)
+        assertEquals(first, repo.load())
+
+        val second = GameConfig(25, 7, 10)
+        repo.save(second)
+        assertEquals(second, repo.load())
+    }
+
+    @Test
+    fun `chargement nul si fichier invalide`() = runTest {
+        val fs = FakeFileSystem()
+        fs.createDirectories("/docs".toPath())
+        fs.write("/docs/config.json".toPath()) { writeUtf8("n'importe quoi") }
+        val repo = ConfigRepository("/docs/config.json".toPath(), fs)
+        assertNull(repo.load())
+    }
+}