Improved last_read sorting (#576)

app/src/main/java/eu/kanade/tachiyomi/data/database/queries/HistoryQueries.kt

@@ -40,16 +40,6 @@ interface HistoryQueries : DbProvider {
                     .build())
             .prepare()
 
-    fun getLastHistoryByMangaId(mangaId: Long) = db.get()
-            .`object`(History::class.java)
-            .withQuery(RawQuery.builder()
-                    .query(getLastHistoryByMangaId())
-                    .args(mangaId)
-                    .observesTables(HistoryTable.TABLE)
-                    .build())
-            .prepare()
-
-
     /**
      * Updates the history last read.
      * Inserts history object if not yet in database

app/src/main/java/eu/kanade/tachiyomi/data/database/queries/MangaQueries.kt

@@ -84,4 +84,11 @@ interface MangaQueries : DbProvider {
                     .build())
             .prepare()
 
+    fun getLastReadManga() = db.get()
+            .listOfObjects(Manga::class.java)
+            .withQuery(RawQuery.builder()
+                    .query(getLastReadMangaQuery())
+                    .observesTables(MangaTable.TABLE)
+                    .build())
+            .prepare()
 }

app/src/main/java/eu/kanade/tachiyomi/data/database/queries/RawQueries.kt

@@ -73,17 +73,16 @@ fun getHistoryByMangaId() = """
     WHERE ${Chapter.TABLE}.${Chapter.COL_MANGA_ID} = ? AND ${History.TABLE}.${History.COL_CHAPTER_ID} = ${Chapter.TABLE}.${Chapter.COL_ID}
 """
 
-fun getLastHistoryByMangaId() = """
-    SELECT ${History.TABLE}.*
-    FROM ${History.TABLE}
+fun getLastReadMangaQuery() = """
+    SELECT ${Manga.TABLE}.*, MAX(${History.TABLE}.${History.COL_LAST_READ}) AS max
+    FROM ${Manga.TABLE}
     JOIN ${Chapter.TABLE}
-    ON ${History.TABLE}.${History.COL_CHAPTER_ID} = ${Chapter.TABLE}.${Chapter.COL_ID}
-     LEFT JOIN (
-            SELECT MAX(${History.TABLE}.${History.COL_LAST_READ}) AS max
-            FROM ${History.TABLE}
-            GROUP BY ${History.COL_LAST_READ}
-        ) AS M
-    WHERE ${Chapter.TABLE}.${Chapter.COL_MANGA_ID} = ? AND M.max = ${History.TABLE}.${History.COL_LAST_READ}
+    ON ${Manga.TABLE}.${Manga.COL_ID} = ${Chapter.TABLE}.${Chapter.COL_MANGA_ID}
+    JOIN ${History.TABLE}
+    ON ${Chapter.TABLE}.${Chapter.COL_ID} = ${History.TABLE}.${History.COL_CHAPTER_ID}
+    WHERE ${Manga.TABLE}.${Manga.COL_FAVORITE} = 1
+    GROUP BY ${Manga.TABLE}.${Manga.COL_ID}
+    ORDER BY max DESC
 """
 
 /**

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt

@@ -85,6 +85,11 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
      */
     private val updateTriggerRelay = BehaviorRelay.create(Unit)
 
+    /**
+     * Value that contains library sorted by last read
+     */
+    private lateinit var lastReadManga: Map<Long, Int>
+
     /**
      * Library subscription.
      */
@@ -136,7 +141,7 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
 
                 val mangaDirName = downloadManager.getMangaDirName(manga)
                 val mangaDir = mangaDirs.find { it.name == mangaDirName }
-                
+
                 return@f if (mangaDir == null) {
                     false
                 } else {
@@ -149,14 +154,22 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
         }
 
         // Sorting
+        val sortingMode = preferences.librarySortingMode().getOrDefault()
+        if (sortingMode == LibrarySort.LAST_READ) {
+            var counter = 0
+            lastReadManga = db.getLastReadManga().executeAsBlocking()
+                    .associate { it.id!! to counter++ }
+        }
+
         val comparator: Comparator<Manga> = if (preferences.librarySortingAscending().getOrDefault())
-            Comparator { m1, m2 -> sortManga(m1, m2) }
+            Comparator { m1, m2 -> sortManga(sortingMode, m1, m2) }
         else
-            Comparator { m1, m2 -> sortManga(m2, m1) }
+            Comparator { m1, m2 -> sortManga(sortingMode, m2, m1) }
 
-        return map.mapValues { entry -> entry.value
-                .filter(filterFn)
-                .sortedWith(comparator)
+        return map.mapValues { entry ->
+            entry.value
+                    .filter(filterFn)
+                    .sortedWith(comparator)
         }
     }
 
@@ -210,18 +223,18 @@ class LibraryPresenter : BasePresenter<LibraryFragment>() {
      * Returns zero if this object is equal to the specified other object,
      * a negative number if it's less than other, or a positive number if it's greater than other.
      *
+     * @param sortingMode current sorting mode
      * @param manga1 first manga to compare
      * @param manga2 second manga to compare
      */
-    fun sortManga(manga1: Manga, manga2: Manga): Int {
-        when (preferences.librarySortingMode().getOrDefault()) {
+    fun sortManga(sortingMode: Int, manga1: Manga, manga2: Manga): Int {
+        when (sortingMode) {
             LibrarySort.ALPHA -> return manga1.title.compareTo(manga2.title)
             LibrarySort.LAST_READ -> {
-                var a = 0L
-                var b = 0L
-                db.getLastHistoryByMangaId(manga1.id!!).executeAsBlocking()?.let { a = it.last_read }
-                db.getLastHistoryByMangaId(manga2.id!!).executeAsBlocking()?.let { b = it.last_read }
-                return b.compareTo(a)
+                // Get index of manga, set equal to list if size unknown.
+                val manga1LastRead = lastReadManga.getOrElse(manga1.id!!, { lastReadManga.size })
+                val manga2LastRead = lastReadManga.getOrElse(manga2.id!!, { lastReadManga.size })
+                return manga1LastRead.compareTo(manga2LastRead)
             }
             LibrarySort.LAST_UPDATED -> return manga2.last_update.compareTo(manga1.last_update)
             else -> return manga1.title.compareTo(manga2.title)