From 3799c7828ad8ef2968f39e4044db36885aec1ab4 Mon Sep 17 00:00:00 2001
From: Brandon <bwaggone@umich.edu>
Date: Sat, 7 Apr 2018 15:55:32 -0400
Subject: Initial commit

---
 src/main/java/soundbot/TrackScheduler.java | 56 ++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 src/main/java/soundbot/TrackScheduler.java

(limited to 'src/main/java/soundbot/TrackScheduler.java')

diff --git a/src/main/java/soundbot/TrackScheduler.java b/src/main/java/soundbot/TrackScheduler.java
new file mode 100644
index 0000000..4cbda71
--- /dev/null
+++ b/src/main/java/soundbot/TrackScheduler.java
@@ -0,0 +1,56 @@
+package soundbot;
+
+import com.sedmelluq.discord.lavaplayer.player.AudioPlayer;
+import com.sedmelluq.discord.lavaplayer.player.event.AudioEventAdapter;
+import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
+import com.sedmelluq.discord.lavaplayer.track.AudioTrackEndReason;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+/**
+ * This class schedules tracks for the audio player. It contains the queue of tracks.
+ */
+public class TrackScheduler extends AudioEventAdapter {
+  private final AudioPlayer player;
+  private final BlockingQueue<AudioTrack> queue;
+
+  /**
+   * @param player The audio player this scheduler uses
+   */
+  public TrackScheduler(AudioPlayer player) {
+    this.player = player;
+    this.queue = new LinkedBlockingQueue<>();
+  }
+
+  /**
+   * Add the next track to queue or play right away if nothing is in the queue.
+   *
+   * @param track The track to play or add to queue.
+   */
+  public void queue(AudioTrack track) {
+    // Calling startTrack with the noInterrupt set to true will start the track only if nothing is currently playing. If
+    // something is playing, it returns false and does nothing. In that case the player was already playing so this
+    // track goes to the queue instead.
+    if (!player.startTrack(track, true)) {
+      queue.offer(track);
+    }
+  }
+
+  /**
+   * Start the next track, stopping the current one if it is playing.
+   */
+  public void nextTrack() {
+    // Start the next track, regardless of if something is already playing or not. In case queue was empty, we are
+    // giving null to startTrack, which is a valid argument and will simply stop the player.
+    player.startTrack(queue.poll(), false);
+  }
+
+  @Override
+  public void onTrackEnd(AudioPlayer player, AudioTrack track, AudioTrackEndReason endReason) {
+    // Only start the next track if the end reason is suitable for it (FINISHED or LOAD_FAILED)
+    if (endReason.mayStartNext) {
+      nextTrack();
+    }
+  }
+}
-- 
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