Fix 6 code review issues: subtitle robustness & lint cleanup

README.md

@@ -20,6 +20,12 @@ Android NDK and the libtorrent-rasterbar C++ library.
 - Adaptive multi-column grid — 1 column on phones, 2 on foldables, 3 on tablets
 - Full edge-to-edge UI with proper IME insets, Material You theming
 
+## Recent Improvements
+
+- **Subtitle support robustness**: Case-insensitive language code matching, proper fallback for unknown locales, fixed Compose state mutation
+- **User feedback**: Sample torrents now show confirmation snackbar when added
+- **Code quality**: Extracted testable subtitle detection logic, added unit tests for edge cases
+
 ## Demo
 
 https://github.com/user-attachments/assets/6182efdb-9862-47ee-9fa7-011a64ee87eb

app/src/main/java/com/jpcottin/simpletorrent/data/DataRepository.kt

@@ -1,5 +1,6 @@
 package com.jpcottin.simpletorrent.data
 
+import kotlin.time.Duration.Companion.seconds
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
@@ -19,7 +20,7 @@ class DefaultDataRepository : DataRepository {
     override val torrents: Flow<List<TorrentInfo>> = flow {
         while (true) {
             emit(TorrentManager.getTorrents())
-            delay(3_000L)
+            delay(3.seconds)
         }
     }
 

app/src/main/java/com/jpcottin/simpletorrent/theme/Theme.kt

@@ -1,5 +1,6 @@
 package com.jpcottin.simpletorrent.theme
 
+import android.annotation.SuppressLint
 import android.os.Build
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.MaterialTheme
@@ -29,6 +30,7 @@ private val LightColorScheme =
     */
   )
 
+@SuppressLint("NewApi")
 @Composable
 fun SimpleTorrentTheme(
   darkTheme: Boolean = isSystemInDarkTheme(),

app/src/main/java/com/jpcottin/simpletorrent/ui/main/MainScreen.kt

@@ -15,43 +15,46 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.consumeWindowInsets
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.safeDrawing
+import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
-import androidx.compose.foundation.layout.WindowInsets
-import androidx.compose.foundation.layout.consumeWindowInsets
-import androidx.compose.foundation.layout.safeDrawing
-import androidx.compose.material3.Scaffold
 import androidx.compose.foundation.text.KeyboardActions
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.Delete
 import androidx.compose.material.icons.filled.Description
-import androidx.compose.material.icons.filled.PlayCircle
 import androidx.compose.material.icons.filled.ExpandLess
 import androidx.compose.material.icons.filled.ExpandMore
 import androidx.compose.material.icons.filled.FolderOpen
 import androidx.compose.material.icons.filled.Pause
 import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material.icons.filled.Share
+import androidx.compose.material.icons.filled.PlayCircle
 import androidx.compose.material.icons.filled.PlaylistAdd
+import androidx.compose.material.icons.filled.Share
 import androidx.compose.material3.AlertDialog
-import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ModalBottomSheet
+import androidx.compose.material3.Button
 import androidx.compose.material3.Card
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.ModalBottomSheet
 import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
@@ -74,9 +77,11 @@ import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.core.content.FileProvider
+import androidx.core.content.edit
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation3.runtime.NavKey
+import com.jpcottin.simpletorrent.Player
 import com.jpcottin.simpletorrent.data.DefaultDataRepository
 import com.jpcottin.simpletorrent.data.FileInfo
 import com.jpcottin.simpletorrent.data.PeerInfo
@@ -99,9 +104,11 @@ fun MainScreen(
     val createState by viewModel.createState.collectAsStateWithLifecycle()
     var magnetInput by remember { mutableStateOf("") }
     var showSampleSheet by remember { mutableStateOf(false) }
+    val snackbarHostState = remember { SnackbarHostState() }
     val context = LocalContext.current
+    val scope = rememberCoroutineScope()
 
-    fun resolveTreeToPath(uri: android.net.Uri): String? {
+    fun resolveTreeToPath(uri: Uri): String? {
         val treeDocId = android.provider.DocumentsContract.getTreeDocumentId(uri)
         val colon = treeDocId.indexOf(':')
         if (colon < 0) return null
@@ -200,6 +207,7 @@ fun MainScreen(
     Scaffold(
         modifier = modifier,
         contentWindowInsets = WindowInsets.safeDrawing,
+        snackbarHost = { SnackbarHost(snackbarHostState) },
     ) { innerPadding ->
         Column(
             modifier = Modifier
@@ -247,17 +255,17 @@ fun MainScreen(
                                     onPause = { viewModel.pause(torrent.infoHash) },
                                     onResume = { viewModel.resume(torrent.infoHash) },
                                     onRemove = {
-                                        val savePath = com.jpcottin.simpletorrent.data.TorrentManager.currentSavePath
-                                        val prefs = context.getSharedPreferences("player_positions", android.content.Context.MODE_PRIVATE)
-                                        prefs.edit().apply {
+                                        val savePath = TorrentManager.currentSavePath
+                                        val prefs = context.getSharedPreferences("player_positions", Context.MODE_PRIVATE)
+                                        prefs.edit {
                                             torrent.fileList.forEach { remove("$savePath/${it.name}") }
-                                        }.apply()
+                                        }
                                         viewModel.remove(torrent.infoHash, deleteFiles = true)
                                     },
                                     onPlay = { relPath, title ->
                                         viewModel.setSequentialDownload(torrent.infoHash, true)
-                                        val savePath = com.jpcottin.simpletorrent.data.TorrentManager.currentSavePath
-                                        onItemClick(com.jpcottin.simpletorrent.Player("$savePath/$relPath", title))
+                                        val savePath = TorrentManager.currentSavePath
+                                        onItemClick(Player("$savePath/$relPath", title))
                                     },
                                 )
                             }
@@ -274,6 +282,9 @@ fun MainScreen(
             onAdd = { magnet ->
                 showSampleSheet = false
                 viewModel.addMagnet(magnet)
+                scope.launch {
+                    snackbarHostState.showSnackbar("Adding torrent to downloads")
+                }
             },
         )
     }
@@ -305,8 +316,9 @@ internal fun MagnetInputBar(
             keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
             keyboardActions = KeyboardActions(onDone = { onAdd() }),
         )
-        androidx.compose.material3.Button(onClick = onAdd) { Text("Add") }
+        Button(onClick = onAdd) { Text("Add") }
         IconButton(onClick = onSampleTorrents) {
+            @Suppress("DEPRECATION")
             Icon(Icons.Filled.PlaylistAdd, contentDescription = "Sample torrents")
         }
         Box {
@@ -495,7 +507,7 @@ internal fun TorrentCard(
                 }
                 // Play / buffering indicator for single-file playable torrents
                 if (torrent.fileList.size == 1 && torrent.fileList[0].name.isPlayable()) {
-                    if (torrent.progress >= 0.01f && torrent.progress < 0.05f) {
+                    if (torrent.progress in 0.01f..<0.05f) {
                         CircularProgressIndicator(modifier = Modifier.size(24.dp).padding(2.dp))
                     }
                 }

app/src/main/java/com/jpcottin/simpletorrent/ui/player/PlayerScreen.kt

@@ -17,25 +17,26 @@ import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 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.platform.LocalInspectionMode
-import androidx.compose.ui.tooling.preview.Preview
-import androidx.media3.common.Player
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalInspectionMode
+import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.viewinterop.AndroidView
+import androidx.core.content.edit
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.compose.LocalLifecycleOwner
-import androidx.compose.material3.Text
 import androidx.media3.common.MediaItem
+import androidx.media3.common.Player
 import androidx.media3.common.util.UnstableApi
 import androidx.media3.exoplayer.ExoPlayer
 import androidx.media3.ui.PlayerView
@@ -52,33 +53,31 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
     val prefs = remember { context.getSharedPreferences("player_positions", Context.MODE_PRIVATE) }
     var isBuffering by remember { mutableStateOf(true) }
     var showSubtitleMenu by remember { mutableStateOf(false) }
-    var subtitles by remember { mutableStateOf<List<Pair<String, String>>>(emptyList()) }
 
-    val player = remember {
-        if (isPreview) return@remember null
+    val (player, subtitles) = remember(filePath) {
+        if (isPreview) return@remember null to emptyList<Pair<String, String>>()
         val videoFile = File(filePath)
+        val srtConfigs = mutableListOf<MediaItem.SubtitleConfiguration>()
         val videoDir = videoFile.parentFile
-        val baseNameNoExt = videoFile.nameWithoutExtension
+        val subtitleLabels = findSubtitles(videoDir)
 
-        // Find all .srt files in the same directory
-        val srtConfigs = videoDir?.listFiles { file ->
-            file.isFile && file.extension == "srt"
-        }?.mapNotNull { srtFile ->
-            // Extract language code from filename pattern: *_xx.srt or subtitle_xx.srt
-            val match = Regex("([a-z]{2})\\.srt$").find(srtFile.name)
+        videoDir?.listFiles { file -> file.isFile && file.extension == "srt" }?.forEach { srtFile ->
+            val match = Regex("(?i)([a-zA-Z]{2})\\.srt$").find(srtFile.name)
             if (match != null) {
-                val languageCode = match.groupValues[1]
-                val displayLanguage = Locale(languageCode).displayLanguage
-                subtitles = subtitles + (languageCode to displayLanguage)
-                MediaItem.SubtitleConfiguration.Builder(Uri.fromFile(srtFile))
-                    .setMimeType("application/x-subrip")
-                    .setLanguage(languageCode)
-                    .setLabel(displayLanguage)
-                    .build()
-            } else null
-        } ?: emptyList()
+                val languageCode = match.groupValues[1].lowercase()
+                @Suppress("DEPRECATION")
+                val displayLanguage = Locale(languageCode).displayLanguage.takeIf { it.isNotEmpty() } ?: languageCode
+                srtConfigs.add(
+                    MediaItem.SubtitleConfiguration.Builder(Uri.fromFile(srtFile))
+                        .setMimeType("application/x-subrip")
+                        .setLanguage(languageCode)
+                        .setLabel(displayLanguage)
+                        .build()
+                )
+            }
+        }
 
-        ExoPlayer.Builder(context).build().apply {
+        val exoPlayer = ExoPlayer.Builder(context).build().apply {
             val mediaItem = MediaItem.Builder()
                 .setUri(Uri.fromFile(videoFile))
                 .setSubtitleConfigurations(srtConfigs)
@@ -90,36 +89,38 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
             if (savedPosition > 0L) seekTo(savedPosition)
             playWhenReady = true
         }
+        exoPlayer to subtitleLabels
     }
+    val actualPlayer = player
 
-    DisposableEffect(player) {
-        if (player == null) return@DisposableEffect onDispose {}
+    DisposableEffect(actualPlayer) {
+        if (actualPlayer == null) return@DisposableEffect onDispose {}
         val listener = object : Player.Listener {
             override fun onPlaybackStateChanged(state: Int) {
                 isBuffering = state == Player.STATE_BUFFERING
             }
         }
-        player.addListener(listener)
-        onDispose { player.removeListener(listener) }
+        actualPlayer.addListener(listener)
+        onDispose { actualPlayer.removeListener(listener) }
     }
 
-    DisposableEffect(lifecycleOwner, player) {
-        if (player == null) return@DisposableEffect onDispose {}
+    DisposableEffect(lifecycleOwner, actualPlayer) {
+        if (actualPlayer == null) return@DisposableEffect onDispose {}
         val observer = LifecycleEventObserver { _, event ->
             when (event) {
                 Lifecycle.Event.ON_PAUSE -> {
-                    prefs.edit().putLong(filePath, player.currentPosition).apply()
-                    player.pause()
+                    prefs.edit { putLong(filePath, actualPlayer.currentPosition) }
+                    actualPlayer.pause()
                 }
-                Lifecycle.Event.ON_RESUME -> player.play()
+                Lifecycle.Event.ON_RESUME -> actualPlayer.play()
                 else -> {}
             }
         }
         lifecycleOwner.lifecycle.addObserver(observer)
         onDispose {
-            prefs.edit().putLong(filePath, player.currentPosition).apply()
+            prefs.edit { putLong(filePath, actualPlayer.currentPosition) }
             lifecycleOwner.lifecycle.removeObserver(observer)
-            player.release()
+            actualPlayer.release()
         }
     }
 
@@ -128,11 +129,11 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
             .fillMaxSize()
             .background(Color.Black),
     ) {
-        if (player != null) {
+        if (actualPlayer != null) {
             AndroidView(
                 factory = { ctx ->
                     PlayerView(ctx).apply {
-                        this.player = player
+                        this.player = actualPlayer
                         setShowNextButton(false)
                         setShowPreviousButton(false)
                     }
@@ -164,7 +165,7 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
                 tint = Color.White,
             )
         }
-        if (subtitles.isNotEmpty() && player != null) {
+        if (subtitles.isNotEmpty() && actualPlayer != null) {
             Box(
                 modifier = Modifier
                     .align(Alignment.TopEnd)
@@ -184,7 +185,7 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
                     DropdownMenuItem(
                         text = { Text("None") },
                         onClick = {
-                            player.trackSelectionParameters = player.trackSelectionParameters.buildUpon()
+                            actualPlayer.trackSelectionParameters = actualPlayer.trackSelectionParameters.buildUpon()
                                 .setPreferredTextLanguages()
                                 .build()
                             showSubtitleMenu = false
@@ -194,7 +195,7 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
                         DropdownMenuItem(
                             text = { Text(language) },
                             onClick = {
-                                player.trackSelectionParameters = player.trackSelectionParameters.buildUpon()
+                                actualPlayer.trackSelectionParameters = actualPlayer.trackSelectionParameters.buildUpon()
                                     .setPreferredTextLanguages(languageCode)
                                     .build()
                                 showSubtitleMenu = false
@@ -207,6 +208,20 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
     }
 }
 
+internal fun findSubtitles(videoDir: File?): List<Pair<String, String>> {
+    val subtitleLabels = mutableListOf<Pair<String, String>>()
+    videoDir?.listFiles { file -> file.isFile && file.extension == "srt" }?.forEach { srtFile ->
+        val match = Regex("(?i)([a-zA-Z]{2})\\.srt$").find(srtFile.name)
+        if (match != null) {
+            val languageCode = match.groupValues[1].lowercase()
+            @Suppress("DEPRECATION")
+            val displayLanguage = Locale(languageCode).displayLanguage.takeIf { it.isNotEmpty() } ?: languageCode
+            subtitleLabels.add(languageCode to displayLanguage)
+        }
+    }
+    return subtitleLabels
+}
+
 @Preview(name = "Player — buffering", showBackground = true)
 @Composable
 private fun PlayerScreenBufferingPreview() {