[Jetcaster] Allow Slider seeking player

Jetcaster/core/src/main/java/com/example/jetcaster/core/player/EpisodePlayer.kt

@@ -103,6 +103,16 @@ interface EpisodePlayer {
      */
     fun rewindBy(duration: Duration)
 
+    /**
+     * Signal that user started seeking.
+     */
+    fun onSeekingStarted()
+
+    /**
+     * Seeks to a given time interval specified in [duration].
+     */
+    fun onSeekingFinished(duration: Duration)
+
     /**
      * Increases the speed of Player playback by a given time specified in [duration].
      */

Jetcaster/core/src/main/java/com/example/jetcaster/core/player/MockEpisodePlayer.kt

@@ -173,6 +173,17 @@ class MockEpisodePlayer(
         }
     }
 
+    override fun onSeekingStarted() {
+        // Need to pause the player so that it doesn't compete with timeline progression.
+        pause()
+    }
+
+    override fun onSeekingFinished(duration: Duration) {
+        val currentEpisodeDuration = _currentEpisode.value?.duration ?: return
+        timeElapsed.update { duration.coerceIn(Duration.ZERO, currentEpisodeDuration) }
+        play()
+    }
+
     override fun increaseSpeed(speed: Duration) {
         _playerSpeed.value += speed
     }