Use stats for reading time estimation

app/src/main/kotlin/org/koitharu/kotatsu/details/domain/ReadingTimeUseCase.kt

@@ -5,25 +5,27 @@ import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.details.data.MangaDetails
 import org.koitharu.kotatsu.details.data.ReadingTime
+import org.koitharu.kotatsu.stats.data.StatsRepository
+import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 import kotlin.math.roundToInt
 
 class ReadingTimeUseCase @Inject constructor(
 	private val settings: AppSettings,
+	private val statsRepository: StatsRepository,
 ) {
 
-	fun invoke(manga: MangaDetails?, branch: String?, history: MangaHistory?): ReadingTime? {
+	suspend fun invoke(manga: MangaDetails?, branch: String?, history: MangaHistory?): ReadingTime? {
 		if (!settings.isReadingTimeEstimationEnabled) {
 			return null
 		}
-		// FIXME MAXIMUM HARDCODE!!! To do calculation with user's page read speed and his favourites/history mangas average pages in chapter
 		val chapters = manga?.chapters?.get(branch)
 		if (chapters.isNullOrEmpty()) {
 			return null
 		}
 		val isOnHistoryBranch = history != null && chapters.findById(history.chapterId) != null
 		// Impossible task, I guess. Good luck on this.
-		var averageTimeSec: Int = 20 * 10 * chapters.size // 20 pages, 10 seconds per page
+		var averageTimeSec: Int = 20 /* pages */ * getSecondsPerPage(manga.id) * chapters.size
 		if (isOnHistoryBranch) {
 			averageTimeSec = (averageTimeSec * (1f - checkNotNull(history).percent)).roundToInt()
 		}
@@ -36,4 +38,16 @@ class ReadingTimeUseCase @Inject constructor(
 			isContinue = isOnHistoryBranch,
 		)
 	}
+
+	private suspend fun getSecondsPerPage(mangaId: Long): Int {
+		var time = if (settings.isStatsEnabled) {
+			TimeUnit.MILLISECONDS.toSeconds(statsRepository.getTimePerPage(mangaId)).toInt()
+		} else {
+			0
+		}
+		if (time == 0) {
+			time = 10 // default
+		}
+		return time
+	}
 }

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

@@ -23,4 +23,15 @@ class StatsRepository @Inject constructor(
 		}
 		result
 	}
+
+	suspend fun getTimePerPage(mangaId: Long): Long = db.withTransaction {
+		val dao = db.getStatsDao()
+		val pages = dao.getReadPagesCount(mangaId)
+		val time = if (pages >= 10) {
+			dao.getAverageTimePerPage(mangaId)
+		} else {
+			dao.getAverageTimePerPage()
+		}
+		time
+	}
 }

app/src/main/res/xml/pref_appearance.xml

@@ -48,12 +48,6 @@
 
 	<PreferenceCategory android:title="@string/details">
 
-		<SwitchPreferenceCompat
-			android:defaultValue="true"
-			android:key="reading_time"
-			android:summary="@string/reading_time_estimation_summary"
-			android:title="@string/reading_time_estimation" />
-
 		<ListPreference
 			android:defaultValue="0"
 			android:entries="@array/details_tabs"

app/src/main/res/xml/pref_services.xml

@@ -34,6 +34,12 @@
 		android:title="@string/reading_stats"
 		app:allowDividerAbove="true" />
 
+	<SwitchPreferenceCompat
+		android:defaultValue="true"
+		android:key="reading_time"
+		android:summary="@string/reading_time_estimation_summary"
+		android:title="@string/reading_time_estimation" />
+
 	<PreferenceCategory android:title="@string/tracking">
 
 		<Preference