VE-93 - add reset player API (kaltura#188)

* add reset API to player so app can reset player state before change media

* add reset to player API
so  app that wants to change media can call reset before so player state will be in the initial state

* codacy

* change API to be called stop
add stopped event to this operation

playkit/src/androidTest/java/com/kaltura/playkit/plugins/MockPlayer.java

@@ -53,6 +53,11 @@ public void destroy() {
 
     }
 
+    @Override
+    public void stop() {
+       // stop player
+    }
+
     @Override
     public void play() {
         isPlaying = true;

playkit/src/main/java/com/kaltura/playkit/Player.java

@@ -46,6 +46,12 @@ public interface Player {
      * Should be called when you want to destroy the player.
      */
     void destroy();
+
+    /**
+     * stop player and back to initial playback state.
+     */
+    void stop();
+
     /**
      * Start playback of the media.
      */

playkit/src/main/java/com/kaltura/playkit/PlayerDecoratorBase.java

@@ -73,6 +73,11 @@ public void destroy() {
         player.destroy();
     }
 
+    @Override
+    public void stop() {
+        player.stop();
+    }
+
     @Override
     public PlayerView getView() {
         return player.getView();

playkit/src/main/java/com/kaltura/playkit/PlayerEvent.java

@@ -118,7 +118,8 @@ public enum Type {
         TRACKS_AVAILABLE, // Sent when track info is available.
         REPLAY, //Sent when replay happened.
         PLAYBACK_PARAMS_UPDATED, // Sent event that notify about changes in the playback parameters. When bitrate of the video or audio track changes or new media loaded. Holds the PlaybackParamsInfo.java object with relevant data.
-        VOLUME_CHANGED // Sent when volume is changed.
+        VOLUME_CHANGED, // Sent when volume is changed.
+        STOPPED // sent when stop player api is called
     }
 
     @Override

playkit/src/main/java/com/kaltura/playkit/player/ExoPlayerWrapper.java

@@ -560,6 +560,16 @@ public PlayerEvent.ExceptionInfo getCurrentException() {
         return new PlayerEvent.ExceptionInfo(currentException, sameErrorOccurrenceCounter);
     }
 
+    @Override
+    public void stop() {
+        if (player != null) {
+            player.setPlayWhenReady(false);
+            player.seekTo(0);
+            player.stop();
+            sendDistinctEvent(PlayerEvent.Type.STOPPED);
+        }
+    }
+
     void savePlayerPosition() {
         if (player == null) {
             log.e("Attempt to invoke 'savePlayerPosition()' on null instance of the exoplayer");

playkit/src/main/java/com/kaltura/playkit/player/MediaPlayerWrapper.java

@@ -353,6 +353,16 @@ public PlayerEvent.ExceptionInfo getCurrentException() {
         return null;
     }
 
+    @Override
+    public void stop() {
+        if (player != null) {
+            player.pause();
+            player.seekTo(0);
+            player.reset();
+            sendDistinctEvent(PlayerEvent.Type.STOPPED);
+        }
+    }
+
     public static String getWidevineAssetPlaybackUri(String assetUri) {
         String assetUriForPlayback = assetUri;
         if (assetUri.startsWith("file:")) {

playkit/src/main/java/com/kaltura/playkit/player/PlayerController.java

@@ -218,6 +218,11 @@ public void destroy() {
         eventListener = null;
     }
 
+    @Override
+    public void stop() {
+        player.stop();
+    }
+
     private void startPlaybackFrom(long startPosition) {
         if (player == null) {
             log.e("Attempt to invoke 'startPlaybackFrom()' on null instance of the player engine");

playkit/src/main/java/com/kaltura/playkit/player/PlayerEngine.java

@@ -167,4 +167,11 @@ interface PlayerEngine {
      * @return - the last {@link PlayerEvent.ExceptionInfo} that happened.
      */
     PlayerEvent.ExceptionInfo getCurrentException();
+
+
+    /**
+     * Stop player executing the {@link PlayerEngine} implementation.
+     * stop the player and seek to start position.
+     */
+    void stop();
 }