Convert new and important files to Kotlin and optimize

app/src/main/java/org/schabi/newpipe/database/LocalItem.kt

@@ -0,0 +1,18 @@
+package org.schabi.newpipe.database
+
+/**
+ * Represents a generic item that can be stored locally. This can be a playlist, a stream, etc.
+ */
+interface LocalItem {
+    /**
+     * The type of local item. Can be null if the type is unknown or not applicable.
+     */
+    val localItemType: LocalItemType?
+
+    enum class LocalItemType {
+        PLAYLIST_LOCAL_ITEM,
+        PLAYLIST_REMOTE_ITEM,
+        PLAYLIST_STREAM_ITEM,
+        STATISTIC_STREAM_ITEM,
+    }
+}

app/src/main/java/org/schabi/newpipe/database/history/model/StreamHistoryEntry.kt

@@ -30,18 +30,16 @@ data class StreamHistoryEntry(
             accessDate.isEqual(other.accessDate)
     }
 
-    fun toStreamInfoItem(): StreamInfoItem {
-        val item = StreamInfoItem(
+    fun toStreamInfoItem(): StreamInfoItem =
+        StreamInfoItem(
             streamEntity.serviceId,
             streamEntity.url,
             streamEntity.title,
-            streamEntity.streamType
-        )
-        item.duration = streamEntity.duration
-        item.uploaderName = streamEntity.uploader
-        item.uploaderUrl = streamEntity.uploaderUrl
-        item.thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
-
-        return item
-    }
+            streamEntity.streamType,
+        ).apply {
+            duration = streamEntity.duration
+            uploaderName = streamEntity.uploader
+            uploaderUrl = streamEntity.uploaderUrl
+            thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
+        }
 }

app/src/main/java/org/schabi/newpipe/database/playlist/PlaylistLocalItem.kt

@@ -0,0 +1,28 @@
+package org.schabi.newpipe.database.playlist
+
+import org.schabi.newpipe.database.LocalItem
+
+/**
+ * Represents a playlist item stored locally.
+ */
+interface PlaylistLocalItem : LocalItem {
+    /**
+     * The name used for ordering this item within the playlist. Can be null.
+     */
+    val orderingName: String?
+
+    /**
+     * The index used to display this item within the playlist.
+     */
+    var displayIndex: Long
+
+    /**
+     * The unique identifier for this playlist item.
+     */
+    val uid: Long
+
+    /**
+     * The URL of the thumbnail image for this playlist item. Can be null.
+     */
+    val thumbnailUrl: String?
+}

app/src/main/java/org/schabi/newpipe/database/playlist/PlaylistStreamEntry.kt

@@ -22,19 +22,20 @@ data class PlaylistStreamEntry(
     @ColumnInfo(name = PlaylistStreamEntity.JOIN_INDEX)
     val joinIndex: Int
 ) : LocalItem {
-
     @Throws(IllegalArgumentException::class)
-    fun toStreamInfoItem(): StreamInfoItem {
-        val item = StreamInfoItem(streamEntity.serviceId, streamEntity.url, streamEntity.title, streamEntity.streamType)
-        item.duration = streamEntity.duration
-        item.uploaderName = streamEntity.uploader
-        item.uploaderUrl = streamEntity.uploaderUrl
-        item.thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
-
-        return item
-    }
-
-    override fun getLocalItemType(): LocalItem.LocalItemType {
-        return LocalItem.LocalItemType.PLAYLIST_STREAM_ITEM
-    }
+    fun toStreamInfoItem() =
+        StreamInfoItem(
+            streamEntity.serviceId,
+            streamEntity.url,
+            streamEntity.title,
+            streamEntity.streamType,
+        ).apply {
+            duration = streamEntity.duration
+            uploaderName = streamEntity.uploader
+            uploaderUrl = streamEntity.uploaderUrl
+            thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
+        }
+
+    override val localItemType: LocalItem.LocalItemType
+        get() = LocalItem.LocalItemType.PLAYLIST_STREAM_ITEM
 }

app/src/main/java/org/schabi/newpipe/database/stream/StreamStatisticsEntry.kt

@@ -26,19 +26,21 @@ class StreamStatisticsEntry(
     @ColumnInfo(name = STREAM_WATCH_COUNT)
     val watchCount: Long
 ) : LocalItem {
-    fun toStreamInfoItem(): StreamInfoItem {
-        val item = StreamInfoItem(streamEntity.serviceId, streamEntity.url, streamEntity.title, streamEntity.streamType)
-        item.duration = streamEntity.duration
-        item.uploaderName = streamEntity.uploader
-        item.uploaderUrl = streamEntity.uploaderUrl
-        item.thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
-
-        return item
-    }
-
-    override fun getLocalItemType(): LocalItem.LocalItemType {
-        return LocalItem.LocalItemType.STATISTIC_STREAM_ITEM
-    }
+    fun toStreamInfoItem() =
+        StreamInfoItem(
+            streamEntity.serviceId,
+            streamEntity.url,
+            streamEntity.title,
+            streamEntity.streamType,
+        ).apply {
+            duration = streamEntity.duration
+            uploaderName = streamEntity.uploader
+            uploaderUrl = streamEntity.uploaderUrl
+            thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
+        }
+
+    override val localItemType: LocalItem.LocalItemType
+        get() = LocalItem.LocalItemType.STATISTIC_STREAM_ITEM
 
     companion object {
         const val STREAM_LATEST_DATE = "latestAccess"

app/src/main/java/org/schabi/newpipe/player/Player.java

@@ -45,6 +45,7 @@
 import static org.schabi.newpipe.util.ListHelper.getPopupResolutionIndex;
 import static org.schabi.newpipe.util.ListHelper.getResolutionIndex;
 import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+import static java.util.Objects.requireNonNull;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
 import android.content.BroadcastReceiver;
@@ -417,7 +418,7 @@ public void handleIntent(@NonNull final Intent intent) {
             }
             if (playQueue.getIndex() != newQueue.getIndex()) {
                 simpleExoPlayer.seekTo(newQueue.getIndex(),
-                        newQueue.getItem().getRecoveryPosition());
+                        requireNonNull(newQueue.getItem()).getRecoveryPosition());
             }
             simpleExoPlayer.setPlayWhenReady(playWhenReady);