1 files changed, 148 insertions, 0 deletions
diff --git a/app/src/main/java/github/daneren2005/dsub/util/ArtistRadioBuffer.java b/app/src/main/java/github/daneren2005/dsub/util/ArtistRadioBuffer.java
new file mode 100644
index 00000000..6e9b8309
--- /dev/null
+++ b/app/src/main/java/github/daneren2005/dsub/util/ArtistRadioBuffer.java
@@ -0,0 +1,148 @@
+/*
+  This file is part of Subsonic.
+	Subsonic is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	Subsonic is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+	You should have received a copy of the GNU General Public License
+	along with Subsonic. If not, see <http://www.gnu.org/licenses/>.
+	Copyright 2014 (C) Scott Jackson
+*/
+
+package github.daneren2005.dsub.util;
+
+import android.util.Log;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import github.daneren2005.dsub.domain.MusicDirectory;
+import github.daneren2005.dsub.service.DownloadService;
+import github.daneren2005.dsub.service.MusicService;
+import github.daneren2005.dsub.service.MusicServiceFactory;
+
+public class ArtistRadioBuffer {
+	private static final String TAG = ArtistRadioBuffer.class.getSimpleName();
+
+	private ScheduledExecutorService executorService;
+	private Runnable runnable;
+	private final ArrayList<MusicDirectory.Entry> buffer = new ArrayList<MusicDirectory.Entry>();
+	private int lastCount = -1;
+	private DownloadService context;
+	private boolean awaitingResults = false;
+	private int capacity;
+	private int refillThreshold;
+
+	private String artistId;
+
+	public ArtistRadioBuffer(DownloadService context) {
+		this.context = context;
+		runnable = new Runnable() {
+			@Override
+			public void run() {
+				refill();
+			}
+		};
+		
+		// Calculate out the capacity and refill threshold based on the user's random size preference
+		int shuffleListSize = Integer.parseInt(Util.getPreferences(context).getString(Constants.PREFERENCES_KEY_RANDOM_SIZE, "20"));
+		// ex: default 20 -> 50
+		capacity = shuffleListSize * 5 / 2;
+		capacity = Math.min(500, capacity);
+		
+		// ex: default 20 -> 40
+		refillThreshold = capacity * 4 / 5;
+	}
+
+	public void setArtist(String artistId) {
+		if(!Util.equals(this.artistId, artistId)) {
+			buffer.clear();
+		}
+
+		context.clear();
+		this.artistId = artistId;
+		awaitingResults = true;
+		refill();
+	}
+	public void restoreArtist(String artistId) {
+		this.artistId = artistId;
+		awaitingResults = false;
+		restart();
+	}
+
+	public List<MusicDirectory.Entry> get(int size) {
+		// Make sure fetcher is running if needed
+		restart();
+
+		List<MusicDirectory.Entry> result = new ArrayList<MusicDirectory.Entry>(size);
+		synchronized (buffer) {
+			while (!buffer.isEmpty() && result.size() < size) {
+				result.add(buffer.remove(buffer.size() - 1));
+			}
+		}
+		Log.i(TAG, "Taking " + result.size() + " songs from artist radio buffer. " + buffer.size() + " remaining.");
+		if(result.isEmpty()) {
+			awaitingResults = true;
+		}
+		return result;
+	}
+
+	public void shutdown() {
+		executorService.shutdown();
+	}
+
+	private void restart() {
+		synchronized(buffer) {
+			if(buffer.size() <= refillThreshold && lastCount != 0 && (executorService == null || executorService.isShutdown())) {
+				executorService = Executors.newSingleThreadScheduledExecutor();
+				executorService.scheduleWithFixedDelay(runnable, 0, 10, TimeUnit.SECONDS);
+			}
+		}
+	}
+
+	private void refill() {
+		if (buffer != null && (buffer.size() > refillThreshold || (!Util.isNetworkConnected(context) && !Util.isOffline(context)) || lastCount == 0)) {
+			executorService.shutdown();
+			return;
+		}
+
+		try {
+			MusicService service = MusicServiceFactory.getMusicService(context);
+			
+			// Get capacity based 
+			int n = capacity - buffer.size();
+			MusicDirectory songs = service.getRandomSongs(n, artistId, context, null);
+
+			synchronized (buffer) {
+				lastCount = 0;
+				for(MusicDirectory.Entry entry: songs.getChildren()) {
+					if(!buffer.contains(entry) && entry.getRating() != 1) {
+						buffer.add(entry);
+						lastCount++;
+					}
+				}
+				Log.i(TAG, "Refilled artist radio buffer with " + lastCount + " songs.");
+			}
+		} catch (Exception x) {
+			// Give it one more try before quitting
+			if(lastCount != -2) {
+				lastCount = -2;
+			} else if(lastCount == -2) {
+				lastCount = 0;
+			}
+			Log.w(TAG, "Failed to refill artist radio buffer.", x);
+		}
+		
+		if(awaitingResults) {
+			awaitingResults = false;
+			context.checkDownloads();
+		}
+	}
+}