Collecting reading stats

app/src/main/kotlin/org/koitharu/kotatsu/core/backup/JsonDeserializer.kt

@@ -54,6 +54,7 @@ class JsonDeserializer(private val json: JSONObject) {
 		page = json.getInt("page"),
 		scroll = json.getDouble("scroll").toFloat(),
 		percent = json.getFloatOrDefault("percent", -1f),
+		chaptersCount = json.getIntOrDefault("chapters", -1),
 		deletedAt = 0L,
 	)
 

app/src/main/kotlin/org/koitharu/kotatsu/core/backup/JsonSerializer.kt

@@ -41,6 +41,7 @@ class JsonSerializer private constructor(private val json: JSONObject) {
 			put("page", e.page)
 			put("scroll", e.scroll)
 			put("percent", e.percent)
+			put("chapters", e.chaptersCount)
 		},
 	)
 

app/src/main/kotlin/org/koitharu/kotatsu/core/db/MangaDatabase.kt

@@ -30,6 +30,7 @@ import org.koitharu.kotatsu.core.db.migrations.Migration14To15
 import org.koitharu.kotatsu.core.db.migrations.Migration15To16
 import org.koitharu.kotatsu.core.db.migrations.Migration16To17
 import org.koitharu.kotatsu.core.db.migrations.Migration17To18
+import org.koitharu.kotatsu.core.db.migrations.Migration18To19
 import org.koitharu.kotatsu.core.db.migrations.Migration1To2
 import org.koitharu.kotatsu.core.db.migrations.Migration2To3
 import org.koitharu.kotatsu.core.db.migrations.Migration3To4
@@ -48,20 +49,22 @@ import org.koitharu.kotatsu.history.data.HistoryDao
 import org.koitharu.kotatsu.history.data.HistoryEntity
 import org.koitharu.kotatsu.scrobbling.common.data.ScrobblingDao
 import org.koitharu.kotatsu.scrobbling.common.data.ScrobblingEntity
+import org.koitharu.kotatsu.stats.data.StatsDao
+import org.koitharu.kotatsu.stats.data.StatsEntity
 import org.koitharu.kotatsu.suggestions.data.SuggestionDao
 import org.koitharu.kotatsu.suggestions.data.SuggestionEntity
 import org.koitharu.kotatsu.tracker.data.TrackEntity
 import org.koitharu.kotatsu.tracker.data.TrackLogEntity
 import org.koitharu.kotatsu.tracker.data.TracksDao
 
-const val DATABASE_VERSION = 18
+const val DATABASE_VERSION = 19
 
 @Database(
 	entities = [
 		MangaEntity::class, TagEntity::class, HistoryEntity::class, MangaTagsEntity::class,
 		FavouriteCategoryEntity::class, FavouriteEntity::class, MangaPrefsEntity::class,
 		TrackEntity::class, TrackLogEntity::class, SuggestionEntity::class, BookmarkEntity::class,
-		ScrobblingEntity::class, MangaSourceEntity::class,
+		ScrobblingEntity::class, MangaSourceEntity::class, StatsEntity::class,
 	],
 	version = DATABASE_VERSION,
 )
@@ -90,6 +93,8 @@ abstract class MangaDatabase : RoomDatabase() {
 	abstract fun getScrobblingDao(): ScrobblingDao
 
 	abstract fun getSourcesDao(): MangaSourcesDao
+
+	abstract fun getStatsDao(): StatsDao
 }
 
 fun getDatabaseMigrations(context: Context): Array<Migration> = arrayOf(
@@ -110,6 +115,7 @@ fun getDatabaseMigrations(context: Context): Array<Migration> = arrayOf(
 	Migration15To16(),
 	Migration16To17(context),
 	Migration17To18(),
+	Migration18To19(),
 )
 
 fun MangaDatabase(context: Context): MangaDatabase = Room

app/src/main/kotlin/org/koitharu/kotatsu/core/db/migrations/Migration18To19.kt

@@ -0,0 +1,12 @@
+package org.koitharu.kotatsu.core.db.migrations
+
+import androidx.room.migration.Migration
+import androidx.sqlite.db.SupportSQLiteDatabase
+
+class Migration18To19 : Migration(18, 19) {
+
+	override fun migrate(db: SupportSQLiteDatabase) {
+		db.execSQL("ALTER TABLE history ADD COLUMN `chapters` INTEGER NOT NULL DEFAULT -1")
+		db.execSQL("CREATE TABLE IF NOT EXISTS `stats` (`manga_id` INTEGER NOT NULL, `started_at` INTEGER NOT NULL, `duration` INTEGER NOT NULL, `pages` INTEGER NOT NULL, PRIMARY KEY(`manga_id`, `started_at`), FOREIGN KEY(`manga_id`) REFERENCES `manga`(`manga_id`) ON UPDATE NO ACTION ON DELETE CASCADE )")
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/core/prefs/AppSettings.kt

@@ -416,6 +416,9 @@ class AppSettings @Inject constructor(@ApplicationContext context: Context) {
 	val isPagesSavingAskEnabled: Boolean
 		get() = prefs.getBoolean(KEY_PAGES_SAVE_ASK, true)
 
+	val isStatsEnabled: Boolean
+		get() = prefs.getBoolean(KEY_STATS_ENABLED, false)
+
 	fun isTipEnabled(tip: String): Boolean {
 		return prefs.getStringSet(KEY_TIPS_CLOSED, emptySet())?.contains(tip) != true
 	}
@@ -606,8 +609,7 @@ class AppSettings @Inject constructor(@ApplicationContext context: Context) {
 		const val KEY_READING_TIME = "reading_time"
 		const val KEY_PAGES_SAVE_DIR = "pages_dir"
 		const val KEY_PAGES_SAVE_ASK = "pages_dir_ask"
-
-		// About
+		const val KEY_STATS_ENABLED = "stats_on"
 		const val KEY_APP_UPDATE = "app_update"
 		const val KEY_APP_TRANSLATION = "about_app_translation"
 	}

app/src/main/kotlin/org/koitharu/kotatsu/history/data/HistoryEntity.kt

@@ -15,8 +15,8 @@ import org.koitharu.kotatsu.core.db.entity.MangaEntity
 			parentColumns = ["manga_id"],
 			childColumns = ["manga_id"],
 			onDelete = ForeignKey.CASCADE,
-		)
-	]
+		),
+	],
 )
 data class HistoryEntity(
 	@PrimaryKey(autoGenerate = false)
@@ -28,4 +28,5 @@ data class HistoryEntity(
 	@ColumnInfo(name = "scroll") val scroll: Float,
 	@ColumnInfo(name = "percent") val percent: Float,
 	@ColumnInfo(name = "deleted_at") val deletedAt: Long,
+	@ColumnInfo(name = "chapters") val chaptersCount: Int,
 )

app/src/main/kotlin/org/koitharu/kotatsu/history/data/HistoryRepository.kt

@@ -94,6 +94,7 @@ class HistoryRepository @Inject constructor(
 		if (shouldSkip(manga)) {
 			return
 		}
+		assert(manga.chapters != null)
 		db.withTransaction {
 			mangaRepository.storeManga(manga)
 			db.getHistoryDao().upsert(
@@ -105,6 +106,7 @@ class HistoryRepository @Inject constructor(
 					page = page,
 					scroll = scroll.toFloat(), // we migrate to int, but decide to not update database
 					percent = percent,
+					chaptersCount = manga.chapters?.size ?: -1,
 					deletedAt = 0L,
 				),
 			)

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/ReaderViewModel.kt

@@ -58,6 +58,7 @@ import org.koitharu.kotatsu.reader.domain.DetectReaderModeUseCase
 import org.koitharu.kotatsu.reader.domain.PageLoader
 import org.koitharu.kotatsu.reader.ui.config.ReaderSettings
 import org.koitharu.kotatsu.reader.ui.pager.ReaderUiState
+import org.koitharu.kotatsu.stats.domain.StatsCollector
 import java.time.Instant
 import javax.inject.Inject
 
@@ -78,11 +79,11 @@ class ReaderViewModel @Inject constructor(
 	private val detailsLoadUseCase: DetailsLoadUseCase,
 	private val historyUpdateUseCase: HistoryUpdateUseCase,
 	private val detectReaderModeUseCase: DetectReaderModeUseCase,
+	private val statsCollector: StatsCollector,
 ) : BaseViewModel() {
 
 	private val intent = MangaIntent(savedStateHandle)
 	private val preselectedBranch = savedStateHandle.get<String>(ReaderActivity.EXTRA_BRANCH)
-	private val isIncognito = savedStateHandle.get<Boolean>(ReaderActivity.EXTRA_INCOGNITO) ?: false
 
 	private var loadingJob: Job? = null
 	private var pageSaveJob: Job? = null
@@ -98,7 +99,7 @@ class ReaderViewModel @Inject constructor(
 	val onShowToast = MutableEventFlow<Int>()
 	val uiState = MutableStateFlow<ReaderUiState?>(null)
 
-	val incognitoMode = if (isIncognito) {
+	val incognitoMode = if (savedStateHandle.get<Boolean>(ReaderActivity.EXTRA_INCOGNITO) == true) {
 		MutableStateFlow(true)
 	} else mangaFlow.map {
 		it != null && historyRepository.shouldSkip(it)
@@ -208,7 +209,7 @@ class ReaderViewModel @Inject constructor(
 		if (state != null) {
 			currentState.value = state
 		}
-		if (isIncognito) {
+		if (incognitoMode.value) {
 			return
 		}
 		val readerState = state ?: currentState.value ?: return
@@ -377,7 +378,7 @@ class ReaderViewModel @Inject constructor(
 
 			chaptersLoader.loadSingleChapter(requireNotNull(currentState.value).chapterId)
 			// save state
-			if (!isIncognito) {
+			if (!incognitoMode.value) {
 				currentState.value?.let {
 					val percent = computePercent(it.chapterId, it.page)
 					historyUpdateUseCase.invoke(manga, it, percent)
@@ -426,6 +427,9 @@ class ReaderViewModel @Inject constructor(
 			percent = computePercent(state.chapterId, state.page),
 		)
 		uiState.value = newState
+		if (!incognitoMode.value) {
+			statsCollector.onStateChanged(m.id, state)
+		}
 	}
 
 	private fun computePercent(chapterId: Long, pageIndex: Int): Float {

app/src/main/kotlin/org/koitharu/kotatsu/stats/data/StatsDao.kt

@@ -0,0 +1,11 @@
+package org.koitharu.kotatsu.stats.data
+
+import androidx.room.Dao
+import androidx.room.Upsert
+
+@Dao
+abstract class StatsDao {
+
+	@Upsert
+	abstract suspend fun upsert(entity: StatsEntity)
+}

app/src/main/kotlin/org/koitharu/kotatsu/stats/data/StatsEntity.kt

@@ -0,0 +1,25 @@
+package org.koitharu.kotatsu.stats.data
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.ForeignKey
+import org.koitharu.kotatsu.core.db.entity.MangaEntity
+
+@Entity(
+	tableName = "stats",
+	primaryKeys = ["manga_id", "started_at"],
+	foreignKeys = [
+		ForeignKey(
+			entity = MangaEntity::class,
+			parentColumns = ["manga_id"],
+			childColumns = ["manga_id"],
+			onDelete = ForeignKey.CASCADE,
+		),
+	],
+)
+data class StatsEntity(
+	@ColumnInfo(name = "manga_id") val mangaId: Long,
+	@ColumnInfo(name = "started_at") val startedAt: Long,
+	@ColumnInfo(name = "duration") val duration: Long,
+	@ColumnInfo(name = "pages") val pages: Int,
+)

app/src/main/kotlin/org/koitharu/kotatsu/stats/domain/StatsCollector.kt

@@ -0,0 +1,68 @@
+package org.koitharu.kotatsu.stats.domain
+
+import androidx.collection.LongSparseArray
+import androidx.collection.set
+import dagger.hilt.android.ViewModelLifecycle
+import dagger.hilt.android.scopes.ViewModelScoped
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import org.koitharu.kotatsu.core.db.MangaDatabase
+import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.util.RetainedLifecycleCoroutineScope
+import org.koitharu.kotatsu.reader.ui.ReaderState
+import org.koitharu.kotatsu.stats.data.StatsEntity
+import javax.inject.Inject
+
+@ViewModelScoped
+class StatsCollector @Inject constructor(
+	private val db: MangaDatabase,
+	private val settings: AppSettings,
+	lifecycle: ViewModelLifecycle,
+) {
+
+	private val viewModelScope = RetainedLifecycleCoroutineScope(lifecycle)
+	private val stats = LongSparseArray<Entry>(1)
+
+	@Synchronized
+	fun onStateChanged(mangaId: Long, state: ReaderState) {
+		if (!settings.isStatsEnabled) {
+			return
+		}
+		val now = System.currentTimeMillis()
+		val entry = stats[mangaId]
+		if (entry == null) {
+			stats[mangaId] = Entry(
+				state = state,
+				stats = StatsEntity(
+					mangaId = mangaId,
+					startedAt = now,
+					duration = 0,
+					pages = 0,
+				),
+			)
+			return
+		}
+		val pagesDelta = if (entry.state.page != state.page || entry.state.chapterId != state.chapterId) 1 else 0
+		val newEntry = entry.copy(
+			stats = StatsEntity(
+				mangaId = mangaId,
+				startedAt = entry.stats.startedAt,
+				duration = now - entry.stats.startedAt,
+				pages = entry.stats.pages + pagesDelta,
+			),
+		)
+		stats[mangaId] = newEntry
+		commit(newEntry.stats)
+	}
+
+	private fun commit(entity: StatsEntity) {
+		viewModelScope.launch(Dispatchers.Default) {
+			db.getStatsDao().upsert(entity)
+		}
+	}
+
+	private data class Entry(
+		val state: ReaderState,
+		val stats: StatsEntity,
+	)
+}