fix: clean up orphaned and partial files after cancelled downloads

Treat inactive download contexts as cancellation, delete the partial file, and
rethrow the cancellation so the pipeline does not retain an incomplete payload.
Also remove orphaned .dsl/.dz files left behind by cancelled downloads.
Run the partial/orphan deletions on NonCancellable: the cleanup is invoked from
already-cancelled coroutines, where withContext(Dispatchers.IO) aborts before
executing the block and silently leaves the files behind.

app/src/main/java/com/example/research/MainActivity.kt

@@ -83,6 +83,7 @@ class MainActivity : ComponentActivity() {
         val app = application as ReSearchApplication
         val initialTheme = loadInitialTheme(app)
         val initialLanguage = loadInitialLanguage(app)
+        val initialHadNoDictionaries = loadInitialHadNoDictionaries(app)
 
         handleIntent(intent)
         setContent {
@@ -104,7 +105,8 @@ class MainActivity : ComponentActivity() {
                         ) {
                             AppNavigation(
                                 searchViewModel = searchViewModel,
-                                settingsViewModel = settingsViewModel
+                                settingsViewModel = settingsViewModel,
+                                seedNoDictionaries = initialHadNoDictionaries
                             )
                         }
                     }
@@ -165,6 +167,16 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    private fun loadInitialHadNoDictionaries(app: ReSearchApplication): Boolean {
+        return try {
+            runBlocking {
+                app.preferencesManager.hadNoDictionaries.first()
+            }
+        } catch (e: Exception) {
+            true
+        }
+    }
+
     override fun onNewIntent(intent: Intent) {
         super.onNewIntent(intent)
         handleIntent(intent)

app/src/main/java/com/example/research/ReSearchApplication.kt

@@ -37,12 +37,17 @@ class ReSearchApplication : Application() {
         private set
     lateinit var dictionaryProgressStateHolder: DictionaryProgressStateHolder
         private set
+    lateinit var dictionaryProgressPresenter: com.example.research.common.progress.DictionaryProgressPresenter
+        private set
+    lateinit var dictionaryPipelineCoordinator: com.example.research.common.progress.DictionaryPipelineCoordinator
+        private set
     private val applicationScope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
 
     override fun onCreate() {
         super.onCreate()
 
-        NotificationHelper(this).cancelNotification()
+        val notificationHelper = NotificationHelper(this)
+        notificationHelper.cancelProgressNotification()
 
         preferencesManager = PreferencesManager(this)
         applicationScope.launch(Dispatchers.IO) {
@@ -80,6 +85,40 @@ class ReSearchApplication : Application() {
             localDictionaryRepository = localDictionaryRepository,
         )
 
+        dictionaryProgressPresenter = com.example.research.common.progress.DictionaryProgressPresenter(
+            scope = applicationScope,
+            progressSnapshot = dictionaryProgressStateHolder.progressSnapshot,
+            notifications = notificationHelper,
+        )
+
+        dictionaryPipelineCoordinator = com.example.research.common.progress.DictionaryPipelineCoordinator(
+            scope = applicationScope,
+            steps = com.example.research.common.progress.DefaultReindexingSteps(
+                localDictionaryRepository = localDictionaryRepository,
+                downloadDictionaryRepository = downloadDictionaryRepository,
+            ),
+            importOperations = dictionaryImportManager,
+            ui = dictionaryProgressPresenter,
+            dictionaryPath = { preferencesManager.dictionaryPath },
+            finishService = {
+                val intent = android.content.Intent(
+                    this,
+                    com.example.research.feature.download.service.DictionaryForegroundService::class.java
+                ).apply {
+                    action = com.example.research.feature.download.service.DictionaryForegroundService.ACTION_FINISH
+                }
+                try {
+                    startService(intent)
+                } catch (_: Exception) {
+                }
+            },
+        )
+
+        dictionaryImportManager.onFlowStarted = { dictionaryProgressPresenter.beginFlow() }
+        dictionaryImportManager.onTerminal = dictionaryPipelineCoordinator::onImportTerminal
+        downloadManager.onFlowStarted = { dictionaryProgressPresenter.beginFlow() }
+        downloadManager.onDownloadSuccess = dictionaryPipelineCoordinator::onDownloadSuccess
+        downloadManager.onTerminal = dictionaryPipelineCoordinator::onDownloadTerminal
     }
 
     override fun onTrimMemory(level: Int) {

app/src/main/java/com/example/research/common/progress/DictionaryPipelineCoordinator.kt

@@ -0,0 +1,151 @@
+package com.example.research.common.progress
+
+import com.example.research.core.util.OperationResult
+import com.example.research.feature.download.model.DownloadState
+import com.example.research.ui.settings.ImportState
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.io.File
+import kotlin.time.Duration.Companion.seconds
+
+class DictionaryPipelineCoordinator(
+    private val scope: CoroutineScope,
+    private val steps: ReindexingSteps,
+    private val importOperations: ImportFlowOperations,
+    private val ui: PipelineTerminalUi,
+    private val dictionaryPath: () -> String,
+    private val finishService: () -> Unit,
+    private val launchDispatcher: CoroutineDispatcher = Dispatchers.Main,
+    private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
+) {
+    private var pipelineJob: Job? = null
+
+    fun onImportTerminal(state: ImportState) {
+        when (state) {
+            is ImportState.Success -> runPipeline(isImport = true)
+            is ImportState.Error -> {
+                ui.showError()
+                finishService()
+            }
+            else -> {}
+        }
+    }
+
+    fun onDownloadSuccess() = runPipeline(isImport = false)
+
+    fun onDownloadTerminal(state: DownloadState) {
+        when (state) {
+            is DownloadState.Error -> {
+                ui.showError()
+                finishService()
+            }
+            is DownloadState.Cancelled -> {
+                ui.cancelProgress()
+                finishService()
+            }
+            else -> {}
+        }
+    }
+
+    fun cancelPipeline() {
+        pipelineJob?.cancel()
+        pipelineJob = null
+    }
+
+    private fun runPipeline(isImport: Boolean) {
+        pipelineJob?.cancel()
+        pipelineJob = scope.launch(launchDispatcher) {
+            val dir = File(dictionaryPath())
+            val filesBeforeReindex = dir?.listFiles()?.map { it.name }?.toSet() ?: emptySet()
+            try {
+                triggerReindexing(isImport)
+                if (isImport) {
+                    importOperations.getAndClearImportedFiles()
+                    importOperations.clearImportState()
+                    ui.showImportSuccess()
+                } else {
+                    ui.showDownloadSuccess()
+                }
+            } catch (e: CancellationException) {
+                if (isImport) {
+                    val filesToCleanup = importOperations.getAndClearImportedFiles()
+                    filesToCleanup.forEach { file ->
+                        try {
+                            if (file.exists()) file.delete()
+                        } catch (_: Exception) {
+                        }
+                    }
+                    cleanupNewFiles(dir, filesBeforeReindex)
+                }
+                cleanupOrphanedFiles(dir)
+                throw e
+            } catch (e: Exception) {
+                ui.showError()
+            } finally {
+                finishService()
+            }
+        }
+    }
+
+    private suspend fun triggerReindexing(isImport: Boolean) = withContext(ioDispatcher) {
+        steps.waitForIndexingCompletion()
+        delay(1.seconds)
+
+        val path = dictionaryPath()
+        if (isImport) {
+            importOperations.updateExtractionProgress(0f)
+        }
+        steps.extractArchives(onProgress = { progress ->
+            if (isImport) {
+                importOperations.updateExtractionProgress(progress)
+            }
+        })
+        val result = steps.scanDirectory(path)
+        if (result is OperationResult.Success && result.data > 0) {
+            steps.warmupIndexes()
+            steps.performAllCleanup()
+        }
+        if (isImport) {
+            importOperations.markImportPipelineSuccess()
+        }
+    }
+
+    private fun cleanupOrphanedFiles(dir: File?) {
+        try {
+            dir?.listFiles()?.forEach { file ->
+                val n = file.name.lowercase()
+                val isRawDsl = n.endsWith(".dsl") && !n.endsWith(".dsl.dz") && !n.endsWith(".dsl.gz")
+                val isBareDz = n.endsWith(".dz") && !n.endsWith(".dsl.dz")
+                val orphaned = when {
+                    isBareDz -> true
+                    isRawDsl -> !File(file.parent, file.name + ".dz").exists()
+                    else -> false
+                }
+                if (orphaned) {
+                    try { file.delete() } catch (_: Exception) {}
+                }
+            }
+        } catch (_: Exception) {
+        }
+    }
+
+    private fun cleanupNewFiles(dir: File?, filesBeforeSnapshot: Set<String>) {
+        try {
+            dir?.listFiles()?.forEach { file ->
+                if (file.name !in filesBeforeSnapshot) {
+                    try {
+                        file.delete()
+                    } catch (_: Exception) {
+                    }
+                }
+            }
+        } catch (_: Exception) {
+        }
+    }
+}

app/src/main/java/com/example/research/common/progress/DictionaryProgressPresenter.kt

@@ -0,0 +1,56 @@
+package com.example.research.common.progress
+
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+
+class DictionaryProgressPresenter(
+    private val scope: CoroutineScope,
+    private val progressSnapshot: StateFlow<DictionaryProgressModel.Snapshot?>,
+    private val notifications: NotificationPort,
+    mainDispatcher: CoroutineDispatcher = Dispatchers.Main,
+) : PipelineTerminalUi {
+    @Volatile
+    private var terminalActive = false
+
+    init {
+        scope.launch(mainDispatcher) {
+            progressSnapshot.collect { snapshot ->
+                when {
+                    snapshot == null -> {
+                        if (!terminalActive && notifications.hasActiveProgressNotification()) {
+                            notifications.cancelProgressNotification()
+                        }
+                    }
+                    !terminalActive -> notifications.showProgress(snapshot.percent, snapshot.titleRes)
+                }
+            }
+        }
+    }
+
+    fun beginFlow() {
+        terminalActive = false
+    }
+
+    override fun showImportSuccess() {
+        notifications.showImportSuccess()
+        terminalActive = true
+    }
+
+    override fun showDownloadSuccess() {
+        notifications.showDownloadSuccess()
+        terminalActive = true
+    }
+
+    override fun showError() {
+        notifications.showError()
+        terminalActive = true
+    }
+
+    override fun cancelProgress() {
+        terminalActive = false
+        notifications.cancelProgressNotification()
+    }
+}

app/src/main/java/com/example/research/common/progress/NotificationPort.kt

@@ -0,0 +1,10 @@
+package com.example.research.common.progress
+
+interface NotificationPort {
+    fun showProgress(percent: Int, titleRes: Int)
+    fun showImportSuccess()
+    fun showDownloadSuccess()
+    fun showError()
+    fun cancelProgressNotification()
+    fun hasActiveProgressNotification(): Boolean
+}

app/src/main/java/com/example/research/common/progress/PipelineContracts.kt

@@ -0,0 +1,65 @@
+package com.example.research.common.progress
+
+import com.example.research.core.util.OperationResult
+import com.example.research.data.repository.LocalDictionaryRepository
+import com.example.research.feature.download.repository.DictionaryRepository
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.first
+import java.io.File
+import kotlin.time.Duration.Companion.milliseconds
+
+interface PipelineTerminalUi {
+    fun showImportSuccess()
+    fun showDownloadSuccess()
+    fun showError()
+    fun cancelProgress()
+}
+
+interface ImportFlowOperations {
+    fun updateExtractionProgress(progress: Float)
+    fun markImportPipelineSuccess()
+    fun clearImportState()
+    fun getAndClearImportedFiles(): List<File>
+}
+
+interface ReindexingSteps {
+    suspend fun waitForIndexingCompletion(): Boolean
+    suspend fun extractArchives(onProgress: (Float) -> Unit)
+    suspend fun scanDirectory(path: String): OperationResult<Int>
+    suspend fun warmupIndexes()
+    suspend fun performAllCleanup()
+}
+
+class DefaultReindexingSteps(
+    private val localDictionaryRepository: LocalDictionaryRepository,
+    private val downloadDictionaryRepository: DictionaryRepository,
+) : ReindexingSteps {
+
+    override suspend fun waitForIndexingCompletion(): Boolean {
+        if (!localDictionaryRepository.indexingProgress.first().isIndexing) return true
+        var waitCount = 0
+        while (localDictionaryRepository.indexingProgress.first().isIndexing && waitCount < MAX_POLL) {
+            delay(POLL_INTERVAL)
+            waitCount++
+        }
+        return waitCount < MAX_POLL
+    }
+
+    override suspend fun extractArchives(onProgress: (Float) -> Unit) {
+        downloadDictionaryRepository.extractArchives(onProgress = onProgress)
+    }
+
+    override suspend fun scanDirectory(path: String): OperationResult<Int> =
+        localDictionaryRepository.scanDirectory(path)
+
+    override suspend fun warmupIndexes() = localDictionaryRepository.warmupIndexes()
+
+    override suspend fun performAllCleanup() {
+        downloadDictionaryRepository.performAllCleanup()
+    }
+
+    private companion object {
+        const val MAX_POLL = 100
+        val POLL_INTERVAL = 200.milliseconds
+    }
+}

app/src/main/java/com/example/research/common/util/NotificationHelper.kt

@@ -7,8 +7,9 @@ import androidx.core.app.*
 import androidx.core.content.ContextCompat
 import com.example.research.MainActivity
 import com.example.research.R
+import com.example.research.common.progress.NotificationPort
 import com.example.research.feature.download.receiver.DownloadCancelReceiver
-class NotificationHelper(private val context: Context) {
+class NotificationHelper(private val context: Context) : NotificationPort {
     companion object {
         const val CHANNEL_ID = "download_progress_channel"
         const val NOTIFICATION_ID = 1
@@ -64,6 +65,22 @@ class NotificationHelper(private val context: Context) {
             android.Manifest.permission.POST_NOTIFICATIONS
         ) == android.content.pm.PackageManager.PERMISSION_GRANTED
     }
+    override fun showProgress(percent: Int, titleRes: Int) {
+        showUnifiedProgressNotification(
+            title = context.getString(titleRes),
+            contentText = "$percent%",
+            progressPercent = percent,
+        )
+    }
+
+    override fun showDownloadSuccess() = showSuccessNotification()
+
+    override fun showImportSuccess() = showImportSuccessNotification()
+
+    override fun showError() = showErrorNotification()
+
+    override fun cancelProgressNotification() = cancelNotification()
+
     fun showSuccessNotification() {
         if (!canShowNotification()) return
         lastNotificationKey = 0
@@ -93,6 +110,8 @@ class NotificationHelper(private val context: Context) {
         notificationManager.cancel(NOTIFICATION_ID)
     }
 
+    override fun hasActiveProgressNotification(): Boolean = lastNotificationKey != 0
+
     fun showUnifiedProgressNotification(
         title: String,
         contentText: String,

app/src/main/java/com/example/research/core/domain/model/IndexingProgress.kt

@@ -1,45 +1,16 @@
 package com.example.research.core.domain.model
-import kotlin.math.roundToInt
 
 import androidx.compose.runtime.Immutable
 
 /**
  * Snapshot of an ongoing indexing operation.
  *
- * [progress] is the authoritative [0f, 1f] completion value and is O(1) to
- * compute: the repository's internal `ProgressTracker` maintains a running
- * sum across files incrementally and stores it in [aggregateSum], avoiding
- * an O(n) walk over [perFileProgress] on every read.
- * [perFileProgress] is kept for diagnostics; callers should prefer
- * [progress] / [progressPercent].
+ * [progress] is the authoritative [0f, 1f] completion value: the repository
+ * aggregates a file-size-weighted sum across files incrementally while
+ * indexing, so reading it is O(1).
  */
 @Immutable
 data class IndexingProgress(
-    val currentFile: String = "",
-    val currentIndex: Int = 0,
-    val totalFiles: Int = 0,
     val isIndexing: Boolean = false,
-    val currentFileProgress: Float = 0f,
-    val label: String = "",
-    val perFileProgress: Map<String, Float> = emptyMap(),
-    /** Pre-aggregated sum in [0f, totalFiles] supplied by the producer; -1f = unknown. */
-    val aggregateSum: Float = -1f,
-) {
-    val progress: Float
-        get() = if (totalFiles > 0) {
-            when {
-                aggregateSum >= 0f -> (aggregateSum / totalFiles).coerceIn(0f, 1f)
-                perFileProgress.isNotEmpty() -> {
-                    val totalProgress = perFileProgress.values.sum()
-                    (totalProgress / totalFiles).coerceIn(0f, 1f)
-                }
-                else -> {
-                    val completedFiles = (currentIndex - 1).coerceAtLeast(0)
-                    ((completedFiles + currentFileProgress) / totalFiles).coerceIn(0f, 1f)
-                }
-            }
-        } else 0f
-
-    val progressPercent: Int
-        get() = (progress * 100).roundToInt().coerceIn(0, 100)
-}
+    val progress: Float = 0f,
+)

app/src/main/java/com/example/research/data/local/preferences/PreferencesManager.kt

@@ -25,6 +25,7 @@ class PreferencesManager(private val context: Context) {
         val IS_LANGUAGE_EXPANDED = booleanPreferencesKey("is_language_expanded")
         val IS_DICTIONARIES_EXPANDED = booleanPreferencesKey("is_dictionaries_expanded")
         val DISABLED_DICTIONARY_PATHS = stringSetPreferencesKey("disabled_dictionary_paths")
+        val HAD_NO_DICTIONARIES = booleanPreferencesKey("had_no_dictionaries")
     }
 
     private val json = Json { ignoreUnknownKeys = true }
@@ -67,6 +68,17 @@ class PreferencesManager(private val context: Context) {
             preferences[PreferencesKeys.DISABLED_DICTIONARY_PATHS] ?: emptySet()
         }
 
+    val hadNoDictionaries: Flow<Boolean> = context.dataStore.data
+        .map { preferences ->
+            preferences[PreferencesKeys.HAD_NO_DICTIONARIES] ?: true
+        }
+
+    suspend fun setHadNoDictionaries(value: Boolean) {
+        context.dataStore.edit { preferences ->
+            preferences[PreferencesKeys.HAD_NO_DICTIONARIES] = value
+        }
+    }
+
     suspend fun setDictionaryActive(path: String, isActive: Boolean) {
         context.dataStore.edit { preferences ->
             val disabledPaths = preferences[PreferencesKeys.DISABLED_DICTIONARY_PATHS]

app/src/main/java/com/example/research/data/paging/IndexEntryPagingSource.kt

@@ -46,9 +46,8 @@ class IndexEntryPagingSource(
 
     private data class EmittedKey(
         val dictPosition: Int,
-        val originalWord: String,
-        val offset: Long,
-        val length: Int
+        val word: String,
+        val offset: Long
     )
 
     private val emittedArticles = HashSet<EmittedKey>()
@@ -103,6 +102,7 @@ class IndexEntryPagingSource(
                 val normalizedQuery = query.sanitizeQuery().lowercase().trim()
                 val ranked = rawResults.map { it.second }
                     .rankBySearchRelevance(SearchRankingContext(normalizedQuery))
+                    .distinctBy { Triple(it.dictionaryPath, it.word, it.offset.value) }
 
                 rawResults.forEach { (position, entry) -> emittedArticles.add(entry.emittedKey(position)) }
 
@@ -184,7 +184,7 @@ class IndexEntryPagingSource(
     }
 
     private fun IndexEntry.emittedKey(dictPosition: Int) =
-        EmittedKey(dictPosition, originalWord, offset.value, length.value)
+        EmittedKey(dictPosition, word, offset.value)
 
     override fun getRefreshKey(state: PagingState<TailKey, IndexEntry>): TailKey? {
         return null

app/src/main/java/com/example/research/data/repository/LocalDictionaryRepository.kt

@@ -70,13 +70,9 @@ private class ProgressTracker(files: List<LocalDictionaryRepository.DiscoveredFi
         aggregateWeightedMicros.addAndGet(newMicros - prevMicros)
     }
 
-    /**
-     * Current weighted sum mapped back to [0f, totalFiles] so the existing
-     * IndexingProgress model can keep deriving progress as aggregate/total.
-     */
-    fun aggregateSum(): Float {
+    fun progress(): Float {
         val weightedProgress = aggregateWeightedMicros.get().toDouble() / (totalWeight.toDouble() * 1_000_000.0)
-        return (weightedProgress.coerceIn(0.0, 1.0) * totalFiles).toFloat()
+        return weightedProgress.coerceIn(0.0, 1.0).toFloat()
     }
 
     fun reset() {
@@ -192,61 +188,59 @@ class LocalDictionaryRepository(
                 mutableIndexingProgress.emit(
                     IndexingProgress(
                         isIndexing = true,
-                        currentFile = context.getString(R.string.indexing_label),
-                        totalFiles = filesToScan.size,
-                        currentIndex = filesToScan.size - filesToIndex.size,
-                        aggregateSum = progressTracker?.aggregateSum() ?: -1f,
+                        progress = progressTracker?.progress() ?: 0f,
                     )
                 )
 
                 val lastEmittedPercent = AtomicInteger(-1)
                 val lastProgressEmitMs = AtomicLong(0L)
 
+                val publishCurrentProgress = {
+                    val tracker = progressTracker
+                    if (tracker != null) {
+                        val progress = tracker.progress()
+                        lastEmittedPercent.set((progress * 100f).toInt().coerceIn(0, 100))
+                        lastProgressEmitMs.set(SystemClock.elapsedRealtime())
+                        mutableIndexingProgress.update { p ->
+                            p.copy(progress = progress)
+                        }
+                    }
+                }
+
                 supervisorScope {
-                    filesToIndex.mapIndexed { index, file ->
+                    filesToIndex.map { file ->
                         async {
                             indexingSemaphore.withPermit {
                                 coroutineContext.ensureActive()
                                 yield()
 
-                                val res = indexDictionary(file) { _, op, prog ->
+                                val res = indexDictionary(file) { _, _, prog ->
                                     if (prog >= 0f) {
                                         progressTracker?.updateFileProgress(file.name, prog)
                                     }
 
-                                    val tracker = progressTracker
-                                    val aggregate = tracker?.aggregateSum() ?: -1f
-                                    val newPercent = if (filesToScan.isNotEmpty() && aggregate >= 0f) {
-                                        ((aggregate / filesToScan.size) * 100f).toInt().coerceIn(0, 100)
-                                    } else -1
+                                    val progress = progressTracker?.progress() ?: 0f
+                                    val newPercent = (progress * 100f).toInt().coerceIn(0, 100)
 
-                                    val currentIdx = filesToScan.size - filesToIndex.size + index + 1
-                                    val previous = mutableIndexingProgress.value
                                     val now = SystemClock.elapsedRealtime()
-                                    val percentChanged = newPercent >= 0 && newPercent != lastEmittedPercent.get()
-                                    val fileChanged = previous.currentFile != file.name
+                                    val percentChanged = newPercent != lastEmittedPercent.get()
                                     val completed = newPercent >= 100 || prog >= 1f
                                     val intervalElapsed =
                                         now - lastProgressEmitMs.get() >= MIN_PROGRESS_EMIT_INTERVAL_MS
-                                    val shouldEmit = fileChanged || completed || (percentChanged && intervalElapsed)
+                                    val shouldEmit = completed || (percentChanged && intervalElapsed)
 
                                     if (shouldEmit) {
-                                        if (newPercent >= 0) lastEmittedPercent.set(newPercent)
+                                        lastEmittedPercent.set(newPercent)
                                         lastProgressEmitMs.set(now)
                                         mutableIndexingProgress.update { p ->
-                                            p.copy(
-                                                currentFile = file.name,
-                                                currentIndex = currentIdx,
-                                                currentFileProgress = prog,
-                                                label = op.ifEmpty { p.label },
-                                                aggregateSum = aggregate,
-                                            )
+                                            p.copy(progress = progress)
                                         }
                                     }
                                 }
 
                                 if (res is OperationResult.Success) {
                                     progressTracker?.updateFileProgress(file.name, 1.0f)
+                                    publishCurrentProgress()
                                     totalArticlesIndexed.addAndGet(res.data.articleCount)
                                     val dictionary = res.data
                                     addDictionary(dictionary)
@@ -396,12 +390,15 @@ class LocalDictionaryRepository(
         } ?: emptyList()
     }
 
-    private fun isDictionaryPayloadFile(file: File): Boolean =
-        file.isFile && (
-            file.name.endsWith(".dsl") ||
-                file.name.endsWith(".dsl.dz") ||
-                file.name.endsWith(".dsl.gz")
-            )
+    private fun isDictionaryPayloadFile(file: File): Boolean {
+        if (!file.isFile) return false
+        val n = file.name.lowercase()
+        if (n.endsWith(".dsl.dz") || n.endsWith(".dsl.gz")) return true
+        if (n.endsWith(".dsl")) {
+            return File(file.parent, file.name + ".dz").exists()
+        }
+        return false
+    }
 
     suspend fun search(query: String): OperationResult<List<IndexEntry>> = withContext(defaultDispatcher) {
         if (query.isBlank()) return@withContext OperationResult.Success(emptyList())

app/src/main/java/com/example/research/feature/download/DownloadManager.kt

@@ -41,11 +41,21 @@ class DownloadManager(
         val clampedProgress = progress.coerceIn(0f, 1f)
         mutableDownloadProgressState.value = DownloadProgressState(state, clampedProgress)
         mutableDownloadState.value = state
+        if (state is DownloadState.Success) {
+            onDownloadSuccess?.invoke()
+        } else if (state is DownloadState.Error || state is DownloadState.Cancelled) {
+            onTerminal?.invoke(state)
         }
+    }
+
+    var onFlowStarted: (() -> Unit)? = null
+    var onDownloadSuccess: (() -> Unit)? = null
+    var onTerminal: ((DownloadState) -> Unit)? = null
 
     fun startDownload() {
         if (downloadState.value is DownloadState.Loading) return
         if (!downloadScope.isActive) return
+        onFlowStarted?.invoke()
         cancelCleanupJob = null
         downloadJob = downloadScope.launch {
             mutex.withLock {
@@ -137,6 +147,7 @@ class DownloadManager(
     fun startDownloadForSources(sourceUrls: List<String>) {
         if (downloadState.value is DownloadState.Loading) return
         if (!downloadScope.isActive) return
+        onFlowStarted?.invoke()
         cancelCleanupJob = null
         downloadJob = downloadScope.launch {
             mutex.withLock {

app/src/main/java/com/example/research/feature/download/model/DownloadState.kt

@@ -11,3 +11,6 @@ sealed class DownloadState {
     data class Error(val message: String) : DownloadState()
     data object Cancelled : DownloadState()
 }
+
+val DownloadState.isActive: Boolean
+    get() = this is DownloadState.Loading || this is DownloadState.Extracting || this is DownloadState.Success

app/src/main/java/com/example/research/feature/download/repository/DictionaryDownloader.kt

@@ -15,8 +15,11 @@ import com.example.research.feature.download.config.DictionaryConfig
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.async
 import kotlinx.coroutines.awaitAll
+import kotlinx.coroutines.NonCancellable
+import kotlinx.coroutines.currentCoroutineContext
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.ensureActive
+import kotlinx.coroutines.isActive
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlinx.coroutines.withContext
 import kotlinx.coroutines.yield
@@ -58,6 +61,7 @@ class DictionaryDownloader(
     ) {
         if (fileUri == null) return
 
+        withContext(NonCancellable) {
             runCatching {
                 val fileToDelete = fileStorageManager.getDocumentFile(fileUri)
                 if (fileToDelete != null && fileToDelete.exists()) {
@@ -75,6 +79,7 @@ class DictionaryDownloader(
                 }
             }
         }
+    }
     suspend fun downloadDictionaries(
         folderUri: Uri,
         sources: List<DictionarySource>,
@@ -169,7 +174,7 @@ class DictionaryDownloader(
     }
 
     private suspend fun deletePartialFileIfExists(folderUri: Uri, fileName: String) {
-        withContext(Dispatchers.IO) {
+        withContext(Dispatchers.IO + NonCancellable) {
             runCatching {
                 val existingFile = fileStorageManager.findFile(folderUri, fileName)
                 if (existingFile != null && existingFile.exists()) {
@@ -313,7 +318,7 @@ class DictionaryDownloader(
             call?.cancel()
             response?.close()
             outputStream?.close()
-            if (e is CancellationException) {
+            if (e is CancellationException || !currentCoroutineContext().isActive) {
                 deletePartialFileIfExists(folderUri, fileName)
                 deletePartialFileSafely(fileUri, folderUri, fileName)
                 throw e

app/src/main/java/com/example/research/feature/download/repository/DictionaryExtractor.kt

@@ -9,7 +9,9 @@ import com.example.research.common.util.FileStorageManager
 import com.example.research.data.dictzip.DictZipRandomAccessFile
 import com.example.research.data.dictzip.DictZipWriter
 import com.example.research.feature.download.config.DictionaryConfig
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.NonCancellable
 import kotlinx.coroutines.withContext
 
 class DictionaryExtractor(
@@ -138,11 +140,39 @@ class DictionaryExtractor(
 
             onProgress?.invoke(1f)
             Result.success(Unit)
+        } catch (e: CancellationException) {
+            deleteOrphanedFiles(folderUri)
+            throw e
         } catch (e: Exception) {
             Result.failure(e)
         }
     }
 
+    private suspend fun deleteOrphanedFiles(folderUri: Uri) {
+        try {
+            withContext(Dispatchers.IO + NonCancellable) {
+                val files = fileStorageManager.listFilesInFolder(folderUri)
+                for (file in files) {
+                    val n = file.name.lowercase()
+                    val isRawDsl = n.endsWith(DictionaryConfig.DSL_EXTENSION) &&
+                        !n.endsWith(DictionaryConfig.DICTZIP_EXTENSION) &&
+                        !n.endsWith(".dsl.gz")
+                    val isBareDz = n.endsWith(".dz") && !n.endsWith(DictionaryConfig.DICTZIP_EXTENSION)
+                    when {
+                        isBareDz -> ArchiveUtils.deleteFile(context, file.uri)
+                        isRawDsl -> {
+                            val pair = fileStorageManager.findFile(folderUri, file.name + ".dz")
+                            if (pair == null || !pair.exists()) {
+                                ArchiveUtils.deleteFile(context, file.uri)
+                            }
+                        }
+                    }
+                }
+            }
+        } catch (_: Exception) {
+        }
+    }
+
     private suspend fun ensureDslDictZip(
         dslUri: Uri,
         dslFileName: String,

app/src/main/java/com/example/research/feature/download/service/DictionaryForegroundService.kt

@@ -3,19 +3,19 @@ package com.example.research.feature.download.service
 import android.app.Service
 import android.content.Intent
 import android.os.IBinder
-import android.util.Log
 import androidx.core.app.ServiceCompat
 import com.example.research.ReSearchApplication
-import com.example.research.common.progress.renderTitle
+import com.example.research.common.progress.DictionaryPipelineCoordinator
+import com.example.research.common.progress.DictionaryProgressPresenter
 import com.example.research.common.util.NotificationHelper
-import com.example.research.core.util.OperationResult
 import com.example.research.data.repository.LocalDictionaryRepository
 import com.example.research.feature.download.DownloadManager
-import com.example.research.feature.download.model.DownloadState
-import kotlinx.coroutines.*
-import kotlinx.coroutines.flow.*
-import kotlin.time.Duration.Companion.milliseconds
-import kotlin.time.Duration.Companion.seconds
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.cancelChildren
+import kotlinx.coroutines.Job
 
 class DictionaryForegroundService : Service() {
 
@@ -23,21 +23,21 @@ class DictionaryForegroundService : Service() {
         const val ACTION_START = "com.example.research.START_DOWNLOAD"
         const val ACTION_STOP = "com.example.research.STOP_DOWNLOAD"
         const val ACTION_IMPORT = "com.example.research.START_IMPORT"
+        const val ACTION_FINISH = "com.example.research.FINISH_PIPELINE"
         private const val NOTIFICATION_ID = NotificationHelper.NOTIFICATION_ID
     }
 
     private lateinit var downloadManager: DownloadManager
     private lateinit var localDictionaryRepository: LocalDictionaryRepository
     private lateinit var dictionaryImportManager: com.example.research.feature.import.DictionaryImportManager
-    private lateinit var progressStateHolder: com.example.research.common.progress.DictionaryProgressStateHolder
+    private lateinit var pipelineCoordinator: DictionaryPipelineCoordinator
+    private lateinit var presenter: DictionaryProgressPresenter
     private val notificationHelper by lazy {
         NotificationHelper(this)
     }
 
     private val serviceScope = CoroutineScope(SupervisorJob() + Dispatchers.Main)
     @Volatile
-    private var isHandlingSuccess = false
-    @Volatile
     private var latestStartId = 0
 
     override fun onCreate() {
@@ -47,164 +47,8 @@ class DictionaryForegroundService : Service() {
         downloadManager = app.downloadManager
         localDictionaryRepository = app.localDictionaryRepository
         dictionaryImportManager = app.dictionaryImportManager
-        progressStateHolder = app.dictionaryProgressStateHolder
-        observeDownloadState()
-        observeImportState()
-        observeUnifiedProgress()
-    }
-
-    private fun observeDownloadState() {
-        serviceScope.launch {
-            downloadManager.downloadState.collect { state ->
-                when (state) {
-                    is DownloadState.Success -> handleSuccess()
-                    is DownloadState.Error -> {
-                        notificationHelper.showErrorNotification()
-                        stopForegroundService(removeNotification = false)
-                    }
-                    is DownloadState.Cancelled -> {
-                        notificationHelper.cancelNotification()
-                        stopForegroundService()
-                    }
-                    else -> {}
-                }
-            }
-        }
-    }
-
-    private fun observeImportState() {
-        serviceScope.launch {
-            dictionaryImportManager.importState.collect { state ->
-                when (state) {
-                    is com.example.research.ui.settings.ImportState.Success -> handleSuccess()
-                    is com.example.research.ui.settings.ImportState.Error -> {
-                        notificationHelper.showErrorNotification()
-                        stopForegroundService(removeNotification = false)
-                    }
-                    else -> {}
-                }
-            }
-        }
-    }
-
-    private fun observeUnifiedProgress() {
-        serviceScope.launch {
-            progressStateHolder.progressSnapshot
-                .collect { snapshot ->
-                    if (snapshot != null) {
-                        notificationHelper.showUnifiedProgressNotification(
-                            title = snapshot.renderTitle(this@DictionaryForegroundService),
-                            contentText = "${snapshot.percent}%",
-                            progressPercent = snapshot.percent,
-                        )
-                    }
-                }
-        }
-    }
-
-    private suspend fun triggerReindexing(isImportFlow: Boolean) = withContext(Dispatchers.IO) {
-        try {
-            waitForIndexingCompletion()
-            delay(1.seconds)
-
-            val app = application as? ReSearchApplication
-                ?: return@withContext
-            val path = app.preferencesManager.dictionaryPath
-            if (isImportFlow) {
-                dictionaryImportManager.updateExtractionProgress(0f)
-            }
-            app.downloadDictionaryRepository.extractArchives(onProgress = { progress ->
-                if (isImportFlow) {
-                    dictionaryImportManager.updateExtractionProgress(progress)
-                }
-            })
-            val result = localDictionaryRepository.scanDirectory(path)
-            if (result is OperationResult.Success && result.data > 0) {
-                localDictionaryRepository.warmupIndexes()
-                app.downloadDictionaryRepository.performAllCleanup()
-            }
-            if (isImportFlow) {
-                dictionaryImportManager.markImportPipelineSuccess()
-            }
-        } catch (e: CancellationException) {
-            throw e
-        } catch (e: Exception) {
-            Log.e("DictionaryForegroundService", "triggerReindexing() failed: ${e.message}", e)
-        }
-    }
-
-    private suspend fun waitForIndexingCompletion(): Boolean {
-        val isIndexing = localDictionaryRepository.indexingProgress.first().isIndexing
-
-        if (!isIndexing) {
-            return true
-        }
-
-        var waitCount = 0
-        while (localDictionaryRepository.indexingProgress.first().isIndexing && waitCount < 100) {
-            delay(200.milliseconds)
-            waitCount++
-        }
-
-        return waitCount < 100
-    }
-
-    private fun handleSuccess() {
-        if (isHandlingSuccess) return
-        isHandlingSuccess = true
-        serviceScope.launch {
-            try {
-                val isImportFlow = dictionaryImportManager.importState.value !is com.example.research.ui.settings.ImportState.Idle
-
-                if (isImportFlow) {
-                    val app = application as? ReSearchApplication
-                    val path = app?.preferencesManager?.dictionaryPath
-                    val dictionariesDir = path?.let { java.io.File(it) }
-                    val filesBeforeReindex = dictionariesDir?.listFiles()?.map { it.name }?.toSet() ?: emptySet()
-
-                    try {
-                        triggerReindexing(true)
-                        dictionaryImportManager.getAndClearImportedFiles()
-                    } catch (e: CancellationException) {
-                        val filesToCleanup = dictionaryImportManager.getAndClearImportedFiles()
-                        filesToCleanup.forEach { file ->
-                            try { if (file.exists()) file.delete() } catch (_: Exception) { /* Ignore cleanup failure */ }
-                        }
-                        if (dictionariesDir != null) {
-                            cleanupNewFiles(dictionariesDir, filesBeforeReindex)
-                        }
-                        throw e
-                    }
-                } else {
-                    triggerReindexing(false)
-                }
-
-                if (isImportFlow) {
-                    notificationHelper.showImportSuccessNotification()
-                    dictionaryImportManager.clearImportState()
-                } else {
-                    notificationHelper.showSuccessNotification()
-                }
-            } catch (e: Exception) {
-                if (e !is CancellationException) {
-                    Log.e("DownloadForegroundService", "handleSuccess() failed: ${e.message}", e)
-                    notificationHelper.showErrorNotification()
-                }
-            } finally {
-                isHandlingSuccess = false
-                stopForegroundService(removeNotification = false)
-            }
-        }
-    }
-
-    private fun cleanupNewFiles(dir: java.io.File, filesBeforeSnapshot: Set<String>) {
-        try {
-            dir.listFiles()?.forEach { file ->
-                if (file.name !in filesBeforeSnapshot) {
-                    try { file.delete() } catch (_: Exception) { /* Ignore delete failure */ }
-                }
-            }
-        } catch (_: Exception) { /* Ignore directory listing failure */ }
+        pipelineCoordinator = app.dictionaryPipelineCoordinator
+        presenter = app.dictionaryProgressPresenter
     }
 
     private fun startForegroundService() {
@@ -249,15 +93,20 @@ class DictionaryForegroundService : Service() {
     }
 
     private fun stopForTimeout(startId: Int) {
+        cancelAllWork()
+        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
+        stopSelfResult(startId)
+    }
+
+    private fun cancelAllWork() {
         serviceScope.coroutineContext[Job]?.cancelChildren()
+        pipelineCoordinator.cancelPipeline()
         if (localDictionaryRepository.isIndexingInProgress()) {
             localDictionaryRepository.cancelIndexing()
         }
         downloadManager.cancelDownload()
         dictionaryImportManager.cancelImport()
-        notificationHelper.cancelNotification()
-        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
-        stopSelfResult(startId)
+        presenter.cancelProgress()
     }
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
@@ -275,21 +124,16 @@ class DictionaryForegroundService : Service() {
             ACTION_IMPORT -> {
                 startForegroundService()
             }
+            ACTION_FINISH -> {
+                stopForegroundService(removeNotification = false)
+            }
             ACTION_STOP -> {
                 try {
                     startForegroundService()
                 } catch (_: Exception) {
                     // Service may already be stopped
                 }
-                serviceScope.coroutineContext[Job]?.cancelChildren()
-
-                if (localDictionaryRepository.isIndexingInProgress()) {
-                    localDictionaryRepository.cancelIndexing()
-                }
-
-                downloadManager.cancelDownload()
-                dictionaryImportManager.cancelImport()
-                notificationHelper.cancelNotification()
+                cancelAllWork()
                 stopForegroundService()
             }
         }

app/src/main/java/com/example/research/feature/import/DictionaryImportManager.kt

@@ -3,6 +3,7 @@ package com.example.research.feature.import
 import android.app.Application
 import android.net.Uri
 import com.example.research.R
+import com.example.research.common.progress.ImportFlowOperations
 import com.example.research.common.util.SafeFileName
 import com.example.research.core.performance.ReSearchTrace
 import com.example.research.ui.settings.ImportState
@@ -14,16 +15,19 @@ import java.util.Collections
 
 class DictionaryImportManager(
     private val application: Application
-) {
+) : ImportFlowOperations {
     private val mutableImportState = MutableStateFlow<ImportState>(ImportState.Idle)
     val importState: StateFlow<ImportState> = mutableImportState.asStateFlow()
 
     private val managerScope = CoroutineScope(SupervisorJob() + Dispatchers.Main)
     private var importJob: Job? = null
     private val importedFiles = Collections.synchronizedList(mutableListOf<File>())
+    var onFlowStarted: (() -> Unit)? = null
+    var onTerminal: ((ImportState) -> Unit)? = null
 
     fun importDictionaries(uris: List<Uri>) {
         importJob?.cancel()
+        onFlowStarted?.invoke()
         importJob = managerScope.launch {
             mutableImportState.value = ImportState.Idle
             performImport(uris)
@@ -36,6 +40,8 @@ class DictionaryImportManager(
         val dictionariesDir = File(context.getExternalFilesDir(null), "dictionaries")
         val totalFiles = uris.size.coerceAtLeast(1)
         importedFiles.clear()
+        val skippedNames = mutableListOf<String>()
+        val deferredErrors = mutableListOf<String>()
 
         if (!dictionariesDir.exists()) {
             dictionariesDir.mkdirs()
@@ -46,9 +52,7 @@ class DictionaryImportManager(
                 currentCoroutineContext().ensureActive()
                 val fileName = getFileName(uri) ?: continue
                 if (SafeFileName.validate(fileName) == null) {
-                    mutableImportState.value = ImportState.Error(
-                        context.getString(R.string.import_invalid_file_name, fileName)
-                    )
+                    deferredErrors += context.getString(R.string.import_invalid_file_name, fileName)
                     continue
                 }
                 val lowerFileName = fileName.lowercase()
@@ -65,9 +69,7 @@ class DictionaryImportManager(
                 val destFile = File(dictionariesDir, fileName)
 
                 if (destFile.exists()) {
-                    mutableImportState.value = ImportState.Error(
-                        context.getString(R.string.import_file_exists, fileName)
-                    )
+                    skippedNames += fileName
                     continue
                 }
 
@@ -115,16 +117,30 @@ class DictionaryImportManager(
 
             currentCoroutineContext().ensureActive()
 
-            mutableImportState.value = ImportState.Success
+            val terminalState = resolveImportOutcome(
+                importedCount = importedFiles.size,
+                skippedNames = skippedNames,
+                deferredErrors = deferredErrors,
+            ).toImportState(
+                existsMessage = { names ->
+                    context.getString(R.string.import_file_exists, names.joinToString(separator = ", "))
+                },
+                invalidMessage = { message -> message },
+                nothingImportedMessage = { context.getString(R.string.import_nothing_imported) },
+            )
+            mutableImportState.value = terminalState
+            onTerminal?.invoke(terminalState)
 
         } catch (e: CancellationException) {
             cleanupImportedFiles()
             mutableImportState.value = ImportState.Idle
             throw e
         } catch (e: Exception) {
-            mutableImportState.value = ImportState.Error(
+            val errorState = ImportState.Error(
                 context.getString(R.string.import_error, e.message ?: "Unknown error")
             )
+            mutableImportState.value = errorState
+            onTerminal?.invoke(errorState)
         }
         }
 
@@ -154,18 +170,18 @@ class DictionaryImportManager(
         return size
     }
 
-    fun clearImportState() {
+    override fun clearImportState() {
         mutableImportState.value = ImportState.Idle
     }
 
-    fun updateExtractionProgress(progress: Float) {
+    override fun updateExtractionProgress(progress: Float) {
         mutableImportState.update { current ->
             if (current is ImportState.Idle || current is ImportState.Error) current
             else ImportState.Extracting(progress.coerceIn(0f, 1f))
         }
     }
 
-    fun markImportPipelineSuccess() {
+    override fun markImportPipelineSuccess() {
         mutableImportState.update { current ->
             if (current is ImportState.Idle || current is ImportState.Error) current
             else ImportState.Success
@@ -179,7 +195,7 @@ class DictionaryImportManager(
         mutableImportState.value = ImportState.Idle
     }
 
-    fun getAndClearImportedFiles(): List<File> {
+    override fun getAndClearImportedFiles(): List<File> {
         val files = importedFiles.toList()
         importedFiles.clear()
         return files

app/src/main/java/com/example/research/feature/import/ImportOutcome.kt

@@ -0,0 +1,32 @@
+package com.example.research.feature.import
+
+import com.example.research.ui.settings.ImportState
+
+internal sealed interface ImportOutcome {
+    data object Imported : ImportOutcome
+    data class AlreadyExists(val names: List<String>) : ImportOutcome
+    data class InvalidFile(val message: String) : ImportOutcome
+    data object NothingImported : ImportOutcome
+}
+
+internal fun resolveImportOutcome(
+    importedCount: Int,
+    skippedNames: List<String>,
+    deferredErrors: List<String>,
+): ImportOutcome = when {
+    importedCount > 0 -> ImportOutcome.Imported
+    skippedNames.isNotEmpty() -> ImportOutcome.AlreadyExists(skippedNames)
+    deferredErrors.isNotEmpty() -> ImportOutcome.InvalidFile(deferredErrors.first())
+    else -> ImportOutcome.NothingImported
+}
+
+internal fun ImportOutcome.toImportState(
+    existsMessage: (List<String>) -> String,
+    invalidMessage: (String) -> String,
+    nothingImportedMessage: () -> String,
+): ImportState = when (this) {
+    ImportOutcome.Imported -> ImportState.Success
+    is ImportOutcome.AlreadyExists -> ImportState.Error(existsMessage(names))
+    is ImportOutcome.InvalidFile -> ImportState.Error(invalidMessage(message))
+    ImportOutcome.NothingImported -> ImportState.Error(nothingImportedMessage())
+}

app/src/main/java/com/example/research/ui/about/AboutScreen.kt

@@ -1,6 +1,5 @@
 package com.example.research.ui.about
 
-import androidx.compose.animation.animateContentSize
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.ExperimentalLayoutApi
@@ -27,6 +26,7 @@ import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
@@ -43,6 +43,8 @@ import androidx.compose.ui.unit.dp
 import com.example.research.R
 import com.example.research.common.ui.components.OutlinedChoiceButton
 import com.example.research.ui.theme.AppWindowInsets
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 
 @OptIn(ExperimentalMaterial3Api::class, ExperimentalLayoutApi::class)
 @Composable
@@ -57,9 +59,11 @@ fun AboutScreen(
     }
     val versionName = packageInfo?.versionName ?: stringResource(R.string.version_unknown)
     val uriHandler = LocalUriHandler.current
-    val librariesData = remember(context) {
+    val librariesData by produceState<AboutLibrariesData?>(initialValue = null, context) {
+        value = withContext(Dispatchers.IO) {
             AboutLibrariesParser.read(context, R.raw.aboutlibraries)
         }
+    }
     var expandedLibraryId by remember { mutableStateOf<String?>(null) }
     var dialogLicense by remember { mutableStateOf<AboutLicense?>(null) }
 
@@ -93,12 +97,12 @@ fun AboutScreen(
                 AboutHeader(versionName = versionName)
             }
             items(
-                items = librariesData.libraries,
+                items = librariesData?.libraries.orEmpty(),
                 key = AboutLibrary::uniqueId,
             ) { library ->
                 AboutLibraryRow(
                     library = library,
-                    licenses = librariesData.licenses,
+                    licenses = librariesData?.licenses.orEmpty(),
                     expanded = expandedLibraryId == library.uniqueId,
                     onToggle = {
                         expandedLibraryId = if (expandedLibraryId == library.uniqueId) {
@@ -191,8 +195,7 @@ private fun AboutLibraryRow(
     ) {
         Column(
             modifier = Modifier
-                .padding(horizontal = 16.dp, vertical = 12.dp)
-                .animateContentSize(),
+                .padding(horizontal = 16.dp, vertical = 12.dp),
             verticalArrangement = Arrangement.spacedBy(5.dp)
         ) {
             Row(

app/src/main/java/com/example/research/ui/main/components/SearchResultsList.kt

@@ -41,6 +41,7 @@ fun SearchResultsList(
     ) {
         items(
             count = results.itemCount,
+            key = results.itemKey { "${it.dictionaryPath}:${it.offset.value}:${it.word}" },
             contentType = results.itemContentType { "search_result" }
         ) { index ->
             results[index]?.let { entry ->

app/src/main/java/com/example/research/ui/navigation/AppNavigation.kt

@@ -9,15 +9,11 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.window.core.layout.WindowSizeClass.Companion.WIDTH_DP_MEDIUM_LOWER_BOUND
 import com.example.research.feature.search.SearchAction
 import com.example.research.feature.search.SearchViewModel
-import com.example.research.feature.download.model.DownloadState
 import com.example.research.ui.about.AboutScreen
 import com.example.research.ui.article.ArticleRoute
 import com.example.research.ui.main.MainRoute
-import com.example.research.ui.settings.ImportState
 import com.example.research.ui.settings.SettingsRoute
 import com.example.research.ui.settings.SettingsViewModel
-import kotlinx.coroutines.delay
-import kotlin.time.Duration.Companion.milliseconds
 
 private data class NavigationState(
     val shouldShowSettings: Boolean,
@@ -33,7 +29,8 @@ enum class Screen {
 @Composable
 fun AppNavigation(
     searchViewModel: SearchViewModel,
-    settingsViewModel: SettingsViewModel
+    settingsViewModel: SettingsViewModel,
+    seedNoDictionaries: Boolean = false
 ) {
     val screenStack = rememberSaveable(
         saver = listSaver(
@@ -53,39 +50,15 @@ fun AppNavigation(
     val currentScreen = screenStack.lastOrNull() ?: Screen.Home
 
     val settingsState by settingsViewModel.uiState.collectAsStateWithLifecycle()
-    val progressSnapshot by settingsViewModel.progressSnapshot.collectAsStateWithLifecycle()
-    val isPipelineActiveByState = remember(
-        progressSnapshot,
-        settingsState.indexingProgress.isIndexing,
-        settingsState.downloadState,
-        settingsState.importState,
-    ) {
-        progressSnapshot != null ||
-            settingsState.indexingProgress.isIndexing ||
-            settingsState.downloadState is DownloadState.Loading ||
-            settingsState.downloadState is DownloadState.Extracting ||
-            settingsState.downloadState is DownloadState.Success ||
-            settingsState.importState is ImportState.Importing ||
-            settingsState.importState is ImportState.Extracting ||
-            settingsState.importState is ImportState.Success
-    }
-    var stickyPipelineActive by rememberSaveable { mutableStateOf(false) }
-    LaunchedEffect(isPipelineActiveByState) {
-        if (isPipelineActiveByState) {
-            stickyPipelineActive = true
-        } else {
-            delay(1500.milliseconds)
-            stickyPipelineActive = false
-        }
-    }
 
     val navState by remember {
         derivedStateOf {
-            val isOperationActive = stickyPipelineActive
+            val isOperationActive = !settingsState.pipelineIdle
             val hasConfirmedNoDictionaries =
                 settingsState.hasCompletedStartupScan && settingsState.dictionaries.isEmpty()
+            val hasSeededNoDictionaries = seedNoDictionaries && !settingsState.hasCompletedStartupScan
             NavigationState(
-                shouldShowSettings = hasConfirmedNoDictionaries || isOperationActive,
+                shouldShowSettings = hasConfirmedNoDictionaries || hasSeededNoDictionaries || isOperationActive,
                 showBackButtonInSettings = settingsState.dictionaries.isNotEmpty() && !isOperationActive,
                 isOperationActive = isOperationActive,
             )

app/src/main/java/com/example/research/ui/settings/ImportState.kt

@@ -10,3 +10,6 @@ sealed interface ImportState {
     data object Success : ImportState
     data class Error(val message: String) : ImportState
 }
+
+val ImportState.isActive: Boolean
+    get() = this is ImportState.Importing || this is ImportState.Extracting || this is ImportState.Success

app/src/main/java/com/example/research/ui/settings/SettingsUiState.kt

@@ -23,6 +23,7 @@ data class SettingsUiState(
     val importState: ImportState = ImportState.Idle,
     val dictionarySources: List<DictionarySource> = emptyList(),
     val hasCompletedStartupScan: Boolean = false,
+    val pipelineIdle: Boolean = true,
     val appVersion: String = "1.0",
 )
 

app/src/main/java/com/example/research/ui/settings/SettingsViewModel.kt

@@ -19,6 +19,7 @@ import com.example.research.data.local.preferences.PreferencesManager
 import com.example.research.data.repository.LocalDictionaryRepository
 import com.example.research.feature.download.DownloadManager
 import com.example.research.feature.download.model.DownloadState
+import com.example.research.feature.download.model.isActive
 import com.example.research.feature.download.repository.DictionaryRepository
 import com.example.research.feature.import.DictionaryImportManager
 import kotlinx.coroutines.Dispatchers
@@ -89,9 +90,20 @@ class SettingsViewModel(
 
     init {
         setupStateObservation()
+        observeDictionariesForSeedFlag()
         initialize()
     }
 
+    private fun observeDictionariesForSeedFlag() {
+        viewModelScope.launch {
+            localDictionaryRepository.dictionaries.collect { dictionaries ->
+                if (hasCompletedStartupScan.value) {
+                    preferencesManager.setHadNoDictionaries(dictionaries.isEmpty())
+                }
+            }
+        }
+    }
+
     private fun setupStateObservation() {
         viewModelScope.launch {
             var wasIndexing = false
@@ -214,6 +226,9 @@ class SettingsViewModel(
                     importState = operationState.importState,
                     dictionaryStatus = operationState.dictionaryStatus,
                     hasCompletedStartupScan = operationState.hasCompletedStartupScan,
+                    pipelineIdle = !isIndexing &&
+                        !operationState.downloadState.isActive &&
+                        !operationState.importState.isActive,
                     isThemeExpanded = operationState.isThemeExpanded,
                     isLanguageExpanded = operationState.isLanguageExpanded,
                     isDictionariesExpanded = operationState.isDictionariesExpanded,
@@ -245,6 +260,9 @@ class SettingsViewModel(
                     android.util.Log.w("SettingsViewModel", "Failed to load language preference: ${e.message}")
                 }
                 hasCompletedStartupScan.value = true
+                preferencesManager.setHadNoDictionaries(
+                    localDictionaryRepository.dictionaries.value.isEmpty()
+                )
             }
         }
     }

app/src/main/java/com/example/research/ui/settings/components/DictionaryProgressSection.kt

@@ -1,8 +1,8 @@
 package com.example.research.ui.settings.components
 
 import androidx.compose.animation.AnimatedVisibility
-import androidx.compose.animation.core.FastOutSlowInEasing
-import androidx.compose.animation.core.animateFloatAsState
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.expandVertically
 import androidx.compose.animation.fadeIn
@@ -19,6 +19,10 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import com.example.research.R
 
+private const val MILLIS_PER_PROGRESS_UNIT = 10_000
+private const val MIN_PROGRESS_MOTION_MS = 50
+private const val MAX_PROGRESS_MOTION_MS = 650
+
 @Composable
 fun DictionaryProgressSection(
     visible: Boolean,
@@ -58,11 +62,21 @@ fun DictionaryProgressSection(
                 displayedTestTag = testTag
             }
         }
-        val animatedProgress by animateFloatAsState(
+        val animatedState = remember { Animatable(0f) }
+        LaunchedEffect(monotonicTargetProgress) {
+            val delta = monotonicTargetProgress - animatedState.value
+            if (delta > 0f) {
+                animatedState.animateTo(
                     targetValue = monotonicTargetProgress,
-            animationSpec = tween(durationMillis = 650, easing = FastOutSlowInEasing),
-            label = "dictionary-progress"
+                    animationSpec = tween(
+                        durationMillis = (delta * MILLIS_PER_PROGRESS_UNIT).toInt()
+                            .coerceIn(MIN_PROGRESS_MOTION_MS, MAX_PROGRESS_MOTION_MS),
+                        easing = LinearEasing,
+                    ),
                 )
+            }
+        }
+        val animatedProgress = animatedState.value
 
         Column(modifier = Modifier.testTag(displayedTestTag)) {
             Row(

app/src/main/res/values-ru/strings.xml

@@ -12,7 +12,6 @@
     <string name="language_english">Английский</string>
     <string name="language_russian">Русский</string>
     <string name="language_system">Системный</string>
-    <string name="indexing_label">Индексация словарей</string>
     <string name="clear_search">Очистить поиск</string>
     <string name="article_no_selected">Статья не выбрана</string>
     <string name="article_return_to_search">Вернуться к поиску</string>
@@ -68,8 +67,9 @@
     <string name="dictionary_management_title">Словари</string>
     <string name="import_dictionary_button">Выбрать файлы</string>
     <string name="import_error">Не удалось импортировать словарь: %1$s</string>
-    <string name="import_file_exists">Файл уже существует: %1$s</string>
+    <string name="import_file_exists">Словарь уже добавлен: %1$s</string>
     <string name="import_invalid_file_name">Недопустимое имя файла: %1$s</string>
+    <string name="import_nothing_imported">В выбранном нет поддерживаемых файлов словарей</string>
     <string name="dictionary_source_url_hint">URL</string>
     <string name="dictionary_source_add_button">Добавить источник</string>
     <string name="dictionary_source_duplicate">Этот URL уже существует</string>

app/src/main/res/values/strings.xml

@@ -12,7 +12,6 @@
     <string name="language_english">English</string>
     <string name="language_russian">Russian</string>
     <string name="language_system">System</string>
-    <string name="indexing_label">Indexing dictionaries</string>
     <string name="clear_search">Clear search</string>
     <string name="article_no_selected">No article selected</string>
     <string name="article_return_to_search">Return to search</string>
@@ -66,8 +65,9 @@
     <string name="dictionary_management_title">Dictionaries</string>
     <string name="import_dictionary_button">Select files</string>
     <string name="import_error">Failed to import dictionary: %1$s</string>
-    <string name="import_file_exists">File already exists: %1$s</string>
+    <string name="import_file_exists">Dictionary already added: %1$s</string>
     <string name="import_invalid_file_name">Invalid file name: %1$s</string>
+    <string name="import_nothing_imported">No supported dictionary files were found in the selection</string>
     <string name="dictionary_source_url_hint">URL</string>
     <string name="dictionary_source_add_button">Add source</string>
     <string name="dictionary_source_duplicate">This URL already exists</string>

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-aboutlibraries = "15.0.4"
+aboutlibraries = "15.2.0"
 activity_compose = "1.13.0"
 agp = "9.3.1"
 compose_bom = "2026.08.00"