From 5ba964d130fd51e56a8db66239c4d51d45315bdf Mon Sep 17 00:00:00 2001
From: carlos-aurelio <github@carlosaurelio.net>
Date: Fri, 21 Dec 2018 16:29:14 -0200
Subject: [PATCH] Support player control through headset hook button

Allow controlling the player and playlist by pressing the headset hook
button one or more times in a short interval:

1: play/pause
2: skip to next track
3: skip to beginning of current track/previous track

Signed-off-by: Carlos Aurelio <github@carlosaurelio.net>
---
 .../receiver/MediaButtonsReceiver.java        | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/app/src/main/java/org/helllabs/android/xmp/service/receiver/MediaButtonsReceiver.java b/app/src/main/java/org/helllabs/android/xmp/service/receiver/MediaButtonsReceiver.java
index 10c50661..0d4dd6ec 100644
--- a/app/src/main/java/org/helllabs/android/xmp/service/receiver/MediaButtonsReceiver.java
+++ b/app/src/main/java/org/helllabs/android/xmp/service/receiver/MediaButtonsReceiver.java
@@ -7,12 +7,53 @@
 import android.content.Intent;
 import android.view.KeyEvent;
 
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
 
 public class MediaButtonsReceiver extends BroadcastReceiver {
 	private static final String TAG = "MediaButtonsReceiver";
 	public static final int NO_KEY = -1;
 	private static int keyCode = NO_KEY;
+	private static long smartKeyPressMaxDelayMs = 500;
 	protected boolean ordered = true;
+	protected static final Semaphore smartButtonSem = new Semaphore(0);
+
+	protected static Thread smartKeyThread = new Thread(new Runnable() {
+		public void run() {
+			Log.i(TAG, "Started smart button thread");
+			try {
+				while (true) {
+					smartButtonSem.acquire();
+					int pressCount = 1;
+					Log.i(TAG, "First smart button press, waiting next presses...");
+					while (smartButtonSem.tryAcquire(smartKeyPressMaxDelayMs, TimeUnit.MILLISECONDS)) {
+						pressCount++;
+						Log.i(TAG, "Smart button press #" + pressCount + ", waiting next presses...");
+					}
+					Log.i(TAG, "Total smart button key presses: " + pressCount);
+					switch (pressCount) {
+						case 1: //play/pause
+							keyCode = KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE;
+							break;
+						case 2: // next
+							keyCode = KeyEvent.KEYCODE_MEDIA_NEXT;
+							break;
+						default: // previous
+							keyCode = KeyEvent.KEYCODE_MEDIA_PREVIOUS;
+							break;
+					}
+				}
+			} catch (InterruptedException ex) {
+				Log.e(TAG, ex.getMessage());
+			}
+		}
+	});
+
+	public MediaButtonsReceiver() {
+		if (!smartKeyThread.isAlive()) {
+			smartKeyThread.start();
+		}
+	}
 
 	@Override
 	public void onReceive(final Context context, final Intent intent) {
@@ -36,6 +77,10 @@ public void onReceive(final Context context, final Intent intent) {
 				Log.i(TAG, "Key code " + code);
 				keyCode = code;
 				break;
+			case KeyEvent.KEYCODE_HEADSETHOOK:
+				Log.i(TAG, "Smart key pressed");
+				smartButtonSem.release();
+				break;
 			default:
 				Log.i(TAG, "Unhandled key code " + code);
 			}