/*
  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 net.nullsum.audinaut.fragments;

import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import android.annotation.TargetApi;
import android.support.v7.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.view.MenuItemCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.util.Log;
import android.view.Display;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.view.animation.AnimationUtils;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.PopupMenu;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.ViewFlipper;
import net.nullsum.audinaut.R;
import net.nullsum.audinaut.activity.SubsonicFragmentActivity;
import net.nullsum.audinaut.adapter.SectionAdapter;
import net.nullsum.audinaut.audiofx.EqualizerController;
import net.nullsum.audinaut.domain.PlayerState;
import net.nullsum.audinaut.domain.RepeatMode;
import net.nullsum.audinaut.service.DownloadFile;
import net.nullsum.audinaut.service.DownloadService;
import net.nullsum.audinaut.service.DownloadService.OnSongChangedListener;
import net.nullsum.audinaut.service.MusicService;
import net.nullsum.audinaut.service.MusicServiceFactory;
import net.nullsum.audinaut.service.OfflineException;
import net.nullsum.audinaut.util.Constants;
import net.nullsum.audinaut.util.SilentBackgroundTask;
import net.nullsum.audinaut.adapter.DownloadFileAdapter;
import net.nullsum.audinaut.view.FadeOutAnimation;
import net.nullsum.audinaut.view.FastScroller;
import net.nullsum.audinaut.view.UpdateView;
import net.nullsum.audinaut.util.Util;

import static net.nullsum.audinaut.domain.MusicDirectory.Entry;
import static net.nullsum.audinaut.domain.PlayerState.*;
import net.nullsum.audinaut.util.*;
import net.nullsum.audinaut.view.AutoRepeatButton;
import java.util.ArrayList;
import java.util.concurrent.ScheduledFuture;

public class NowPlayingFragment extends SubsonicFragment implements OnGestureListener, SectionAdapter.OnItemClickedListener<DownloadFile>, OnSongChangedListener {
	private static final String TAG = NowPlayingFragment.class.getSimpleName();
	private static final int PERCENTAGE_OF_SCREEN_FOR_SWIPE = 10;

	private static final int ACTION_PREVIOUS = 1;
	private static final int ACTION_NEXT = 2;
	private static final int ACTION_REWIND = 3;
	private static final int ACTION_FORWARD = 4;

	private ViewFlipper playlistFlipper;
	private TextView emptyTextView;
	private TextView songTitleTextView;
	private ImageView albumArtImageView;
	private RecyclerView playlistView;
	private TextView positionTextView;
	private TextView durationTextView;
	private TextView statusTextView;
	private SeekBar progressBar;
	private AutoRepeatButton previousButton;
	private AutoRepeatButton nextButton;
	private AutoRepeatButton rewindButton;
	private AutoRepeatButton fastforwardButton;
	private View pauseButton;
	private View stopButton;
	private View startButton;
	private ImageButton repeatButton;
	private View toggleListButton;

	private ScheduledExecutorService executorService;
	private DownloadFile currentPlaying;
	private int swipeDistance;
	private int swipeVelocity;
	private ScheduledFuture<?> hideControlsFuture;
	private List<DownloadFile> songList;
	private DownloadFileAdapter songListAdapter;
	private boolean seekInProgress = false;
	private boolean startFlipped = false;
	private boolean scrollWhenLoaded = false;
	private int lastY = 0;
	private int currentPlayingSize = 0;

	/**
	 * Called when the activity is first created.
	 */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		if(savedInstanceState != null) {
			if(savedInstanceState.getInt(Constants.FRAGMENT_DOWNLOAD_FLIPPER) == 1) {
				startFlipped = true;
			}
		}
		primaryFragment = false;
	}

	@Override
	public void onSaveInstanceState(Bundle outState) {
		super.onSaveInstanceState(outState);
		outState.putInt(Constants.FRAGMENT_DOWNLOAD_FLIPPER, playlistFlipper.getDisplayedChild());
	}

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle bundle) {
		rootView = inflater.inflate(R.layout.download, container, false);
		setTitle(R.string.button_bar_now_playing);

		WindowManager w = context.getWindowManager();
		Display d = w.getDefaultDisplay();
		swipeDistance = (d.getWidth() + d.getHeight()) * PERCENTAGE_OF_SCREEN_FOR_SWIPE / 100;
		swipeVelocity = (d.getWidth() + d.getHeight()) * PERCENTAGE_OF_SCREEN_FOR_SWIPE / 100;
		gestureScanner = new GestureDetector(this);

		playlistFlipper = (ViewFlipper)rootView.findViewById(R.id.download_playlist_flipper);
		emptyTextView = (TextView)rootView.findViewById(R.id.download_empty);
		songTitleTextView = (TextView)rootView.findViewById(R.id.download_song_title);
		albumArtImageView = (ImageView)rootView.findViewById(R.id.download_album_art_image);
		positionTextView = (TextView)rootView.findViewById(R.id.download_position);
		durationTextView = (TextView)rootView.findViewById(R.id.download_duration);
		statusTextView = (TextView)rootView.findViewById(R.id.download_status);
		progressBar = (SeekBar)rootView.findViewById(R.id.download_progress_bar);
		previousButton = (AutoRepeatButton)rootView.findViewById(R.id.download_previous);
		nextButton = (AutoRepeatButton)rootView.findViewById(R.id.download_next);
		rewindButton = (AutoRepeatButton) rootView.findViewById(R.id.download_rewind);
		fastforwardButton = (AutoRepeatButton) rootView.findViewById(R.id.download_fastforward);
		pauseButton =rootView.findViewById(R.id.download_pause);
		stopButton =rootView.findViewById(R.id.download_stop);
		startButton =rootView.findViewById(R.id.download_start);
		repeatButton = (ImageButton)rootView.findViewById(R.id.download_repeat);
		toggleListButton =rootView.findViewById(R.id.download_toggle_list);

		playlistView = (RecyclerView)rootView.findViewById(R.id.download_list);
		FastScroller fastScroller = (FastScroller) rootView.findViewById(R.id.download_fast_scroller);
		fastScroller.attachRecyclerView(playlistView);
		setupLayoutManager(playlistView, false);
		ItemTouchHelper touchHelper = new ItemTouchHelper(new DownloadFileItemHelperCallback(this, true));
		touchHelper.attachToRecyclerView(playlistView);

		View.OnTouchListener touchListener = new View.OnTouchListener() {
			@Override
			public boolean onTouch(View v, MotionEvent me) {
				return gestureScanner.onTouchEvent(me);
			}
		};
		pauseButton.setOnTouchListener(touchListener);
		stopButton.setOnTouchListener(touchListener);
		startButton.setOnTouchListener(touchListener);
		emptyTextView.setOnTouchListener(touchListener);
		albumArtImageView.setOnTouchListener(new View.OnTouchListener() {
			@Override
			public boolean onTouch(View v, MotionEvent me) {
				if (me.getAction() == MotionEvent.ACTION_DOWN) {
					lastY = (int) me.getRawY();
				}
				return gestureScanner.onTouchEvent(me);
			}
		});

		previousButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				warnIfStorageUnavailable();
				new SilentBackgroundTask<Void>(context) {
					@Override
					protected Void doInBackground() throws Throwable {
						getDownloadService().previous();
						return null;
					}
				}.execute();
				setControlsVisible(true);
			}
		});
		previousButton.setOnRepeatListener(new Runnable() {
			public void run() {
				changeProgress(true);
			}
		});

		nextButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				warnIfStorageUnavailable();
				new SilentBackgroundTask<Boolean>(context) {
					@Override
					protected Boolean doInBackground() throws Throwable {
						getDownloadService().next();
						return true;
					}
				}.execute();
				setControlsVisible(true);
			}
		});
		nextButton.setOnRepeatListener(new Runnable() {
			public void run() {
				changeProgress(false);
			}
		});

		rewindButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				changeProgress(true);
			}
		});
		rewindButton.setOnRepeatListener(new Runnable() {
			public void run() {
				changeProgress(true);
			}
		});

		fastforwardButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				changeProgress(false);
			}
		});
		fastforwardButton.setOnRepeatListener(new Runnable() {
			public void run() {
				changeProgress(false);
			}
		});


		pauseButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				new SilentBackgroundTask<Void>(context) {
					@Override
					protected Void doInBackground() throws Throwable {
						getDownloadService().pause();
						return null;
					}
				}.execute();
			}
		});

		stopButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				new SilentBackgroundTask<Void>(context) {
					@Override
					protected Void doInBackground() throws Throwable {
						getDownloadService().reset();
						return null;
					}
				}.execute();
			}
		});

		startButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				warnIfStorageUnavailable();
				new SilentBackgroundTask<Void>(context) {
					@Override
					protected Void doInBackground() throws Throwable {
						start();
						return null;
					}
				}.execute();
			}
		});

		repeatButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				RepeatMode repeatMode = getDownloadService().getRepeatMode().next();
				getDownloadService().setRepeatMode(repeatMode);
				switch (repeatMode) {
					case OFF:
						Util.toast(context, R.string.download_repeat_off);
						break;
					case ALL:
						Util.toast(context, R.string.download_repeat_all);
						break;
					case SINGLE:
						Util.toast(context, R.string.download_repeat_single);
						break;
					default:
						break;
				}
				updateRepeatButton();
				setControlsVisible(true);
			}
		});

		toggleListButton.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				toggleFullscreenAlbumArt();
				setControlsVisible(true);
			}
		});

		View overlay = rootView.findViewById(R.id.download_overlay_buttons);
		final int overlayHeight = overlay != null ? overlay.getHeight() : -1;
		albumArtImageView.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View view) {
				if (overlayHeight == -1 || lastY < (view.getBottom() - overlayHeight)) {
					toggleFullscreenAlbumArt();
					setControlsVisible(true);
				}
			}
		});

		progressBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
			@Override
			public void onStopTrackingTouch(final SeekBar seekBar) {
				new SilentBackgroundTask<Void>(context) {
					@Override
					protected Void doInBackground() throws Throwable {
						getDownloadService().seekTo(progressBar.getProgress());
						return null;
					}

					@Override
					protected void done(Void result) {
						seekInProgress = false;
					}
				}.execute();
			}

			@Override
			public void onStartTrackingTouch(final SeekBar seekBar) {
				seekInProgress = true;
			}

			@Override
			public void onProgressChanged(final SeekBar seekBar, final int position, final boolean fromUser) {
				if (fromUser) {
					positionTextView.setText(Util.formatDuration(position / 1000));
					setControlsVisible(true);
				}
			}
		});

		return rootView;
	}

	@Override
	public void onCreateOptionsMenu(Menu menu, MenuInflater menuInflater) {
		DownloadService downloadService = getDownloadService();
		if(Util.isOffline(context)) {
			menuInflater.inflate(R.menu.nowplaying_offline, menu);
		} else {
			menuInflater.inflate(R.menu.nowplaying, menu);
		}
		if(downloadService != null && downloadService.isRemovePlayed()) {
			menu.findItem(R.id.menu_remove_played).setChecked(true);
		}

		boolean equalizerAvailable = downloadService != null && downloadService.getEqualizerAvailable();
		if(equalizerAvailable) {
			SharedPreferences prefs = Util.getPreferences(context);
			boolean equalizerOn = prefs.getBoolean(Constants.PREFERENCES_EQUALIZER_ON, false);
			if (equalizerOn && downloadService != null) {
				if(downloadService.getEqualizerController() != null && downloadService.getEqualizerController().isEnabled()) {
					menu.findItem(R.id.menu_equalizer).setChecked(true);
				}
			}
		} else {
			menu.removeItem(R.id.menu_equalizer);
		}

		if(Util.getPreferences(context).getBoolean(Constants.PREFERENCES_KEY_BATCH_MODE, false)) {
			menu.findItem(R.id.menu_batch_mode).setChecked(true);
		}
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem menuItem) {
		if(menuItemSelected(menuItem.getItemId(), null)) {
			return true;
		}

		return super.onOptionsItemSelected(menuItem);
	}

	@Override
	public void onCreateContextMenu(Menu menu, MenuInflater menuInflater, UpdateView<DownloadFile> updateView, DownloadFile downloadFile) {
		if(Util.isOffline(context)) {
			menuInflater.inflate(R.menu.nowplaying_context_offline, menu);
		} else {
			menuInflater.inflate(R.menu.nowplaying_context, menu);
		}

		if (downloadFile.getSong().getParent() == null) {
			menu.findItem(R.id.menu_show_album).setVisible(false);
			menu.findItem(R.id.menu_show_artist).setVisible(false);
		}

		MenuUtil.hideMenuItems(context, menu, updateView);
	}

	@Override
	public boolean onContextItemSelected(MenuItem menuItem, UpdateView<DownloadFile> updateView, DownloadFile downloadFile) {
		if(onContextItemSelected(menuItem, downloadFile.getSong())) {
			return true;
		}

		return menuItemSelected(menuItem.getItemId(), downloadFile);
	}

	private boolean menuItemSelected(int menuItemId, final DownloadFile song) {
		List<Entry> songs;
		switch (menuItemId) {
			case R.id.menu_show_album: case R.id.menu_show_artist:
				Entry entry = song.getSong();

				Intent intent = new Intent(context, SubsonicFragmentActivity.class);
				intent.putExtra(Constants.INTENT_EXTRA_VIEW_ALBUM, true);
				String albumId;
				String albumName;
				if(menuItemId == R.id.menu_show_album) {
					if(Util.isTagBrowsing(context)) {
						albumId = entry.getAlbumId();
					} else {
						albumId = entry.getParent();
					}
					albumName = entry.getAlbum();
				} else {
					if(Util.isTagBrowsing(context)) {
						albumId = entry.getArtistId();
					} else {
						albumId = entry.getGrandParent();
						if(albumId == null) {
							intent.putExtra(Constants.INTENT_EXTRA_NAME_CHILD_ID, entry.getParent());
						}
					}
					albumName = entry.getArtist();
					intent.putExtra(Constants.INTENT_EXTRA_NAME_ARTIST, true);
				}
				intent.putExtra(Constants.INTENT_EXTRA_NAME_ID, albumId);
				intent.putExtra(Constants.INTENT_EXTRA_NAME_NAME, albumName);
				intent.putExtra(Constants.INTENT_EXTRA_FRAGMENT_TYPE, "Artist");

				if(Util.isOffline(context)) {
					try {
						// This should only be successful if this is a online song in offline mode
						Integer.parseInt(entry.getParent());
						String root = FileUtil.getMusicDirectory(context).getPath();
						String id = root + "/" + entry.getPath();
						id = id.substring(0, id.lastIndexOf("/"));
						if(menuItemId == R.id.menu_show_album) {
							intent.putExtra(Constants.INTENT_EXTRA_NAME_ID, id);
						}
						id = id.substring(0, id.lastIndexOf("/"));
						if(menuItemId != R.id.menu_show_album) {
							intent.putExtra(Constants.INTENT_EXTRA_NAME_ID, id);
							intent.putExtra(Constants.INTENT_EXTRA_NAME_NAME, entry.getArtist());
							intent.removeExtra(Constants.INTENT_EXTRA_NAME_CHILD_ID);
						}
					} catch(Exception e) {
						// Do nothing, entry.getParent() is fine
					}
				}

				intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
				Util.startActivityWithoutTransition(context, intent);
				return true;
			case R.id.menu_remove_all:
				Util.confirmDialog(context, R.string.download_menu_remove_all, "", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						new SilentBackgroundTask<Void>(context) {
							@Override
							protected Void doInBackground() throws Throwable {
								getDownloadService().setShufflePlayEnabled(false);
								getDownloadService().clear();
								return null;
							}

							@Override
							protected void done(Void result) {
								context.closeNowPlaying();
							}
						}.execute();
					}
				});
				return true;
			case R.id.menu_remove_played:
				if (getDownloadService().isRemovePlayed()) {
					getDownloadService().setRemovePlayed(false);
				} else {
					getDownloadService().setRemovePlayed(true);
				}
				context.supportInvalidateOptionsMenu();
				return true;
			case R.id.menu_shuffle:
				new SilentBackgroundTask<Void>(context) {
					@Override
					protected Void doInBackground() throws Throwable {
						getDownloadService().shuffle();
						return null;
					}

					@Override
					protected void done(Void result) {
						Util.toast(context, R.string.download_menu_shuffle_notification);
					}
				}.execute();
				return true;
			case R.id.menu_save_playlist:
				List<Entry> entries = new LinkedList<Entry>();
				for (DownloadFile downloadFile : getDownloadService().getSongs()) {
					entries.add(downloadFile.getSong());
				}
				createNewPlaylist(entries, true);
				return true;
			case R.id.menu_info:
				displaySongInfo(song.getSong());
				return true;
			case R.id.menu_equalizer: {
				DownloadService downloadService = getDownloadService();
				if (downloadService != null) {
					EqualizerController controller = downloadService.getEqualizerController();
					if(controller != null) {
						SubsonicFragment fragment = new EqualizerFragment();
						replaceFragment(fragment);
						setControlsVisible(true);

						return true;
					}
				}

				// Any failed condition will get here
				Util.toast(context, "Failed to start equalizer.  Try restarting.");
				return true;
			}case R.id.menu_batch_mode:
				if(Util.isBatchMode(context)) {
					Util.setBatchMode(context, false);
					songListAdapter.notifyDataSetChanged();
				} else {
					Util.setBatchMode(context, true);
					songListAdapter.notifyDataSetChanged();
				}
				context.supportInvalidateOptionsMenu();

				return true;
			default:
				return false;
		}
	}

	@Override
	public void onResume() {
		super.onResume();
		if(this.primaryFragment) {
			onResumeHandlers();
		} else {
			update();
		}
	}
	private void onResumeHandlers() {
		executorService = Executors.newSingleThreadScheduledExecutor();
		setControlsVisible(true);

		final DownloadService downloadService = getDownloadService();
		if (downloadService == null || downloadService.getCurrentPlaying() == null || startFlipped) {
			playlistFlipper.setDisplayedChild(1);
			startFlipped = false;
		}

		updateButtons();

		if(currentPlaying == null && downloadService != null && currentPlaying == downloadService.getCurrentPlaying()) {
			getImageLoader().loadImage(albumArtImageView, (Entry) null, true, false);
		}

		context.runWhenServiceAvailable(new Runnable() {
			@Override
			public void run() {
				if (primaryFragment) {
					DownloadService downloadService = getDownloadService();
					downloadService.addOnSongChangedListener(NowPlayingFragment.this, true);
				}
				updateRepeatButton();
				updateTitle();
			}
		});
	}

	@Override
	public void onPause() {
		super.onPause();
		onPauseHandlers();
	}
	private void onPauseHandlers() {
		if(executorService != null) {
			DownloadService downloadService = getDownloadService();
			if (downloadService != null) {
				downloadService.removeOnSongChangeListener(this);
			}
			playlistFlipper.setDisplayedChild(0);
		}
	}

	@Override
	public void setPrimaryFragment(boolean primary) {
		super.setPrimaryFragment(primary);
		if(rootView != null) {
			if(primary) {
				onResumeHandlers();
			} else {
				onPauseHandlers();
			}
		}
	}

	@Override
	public void setTitle(int title) {
		this.title = context.getResources().getString(title);
		if(this.primaryFragment) {
			context.setTitle(this.title);
		}
	}
	@Override
	public void setSubtitle(CharSequence title) {
		this.subtitle = title;
		if(this.primaryFragment) {
			context.setSubtitle(title);
		}
	}

	@Override
	public SectionAdapter getCurrentAdapter() {
		return songListAdapter;
	}

	private void scheduleHideControls() {
		if (hideControlsFuture != null) {
			hideControlsFuture.cancel(false);
		}

		final Handler handler = new Handler();
		Runnable runnable = new Runnable() {
			@Override
			public void run() {
				handler.post(new Runnable() {
					@Override
					public void run() {
						setControlsVisible(false);
					}
				});
			}
		};
		hideControlsFuture = executorService.schedule(runnable, 3000L, TimeUnit.MILLISECONDS);
	}

	private void setControlsVisible(boolean visible) {
		DownloadService downloadService = getDownloadService();
		try {
			long duration = 1700L;
			FadeOutAnimation.createAndStart(rootView.findViewById(R.id.download_overlay_buttons), !visible, duration);

			if (visible) {
				scheduleHideControls();
			}
		} catch(Exception e) {

		}
	}

	private void updateButtons() {
		if(context == null) {
			return;
		}
	}

	// Scroll to current playing/downloading.
	@TargetApi(Build.VERSION_CODES.LOLLIPOP)
	private void scrollToCurrent() {
		if (getDownloadService() == null || songListAdapter == null) {
			scrollWhenLoaded = true;
			return;
		}

		// Try to get position of current playing/downloading
		int position = songListAdapter.getItemPosition(currentPlaying);
		if(position == -1) {
			DownloadFile currentDownloading = getDownloadService().getCurrentDownloading();
			position = songListAdapter.getItemPosition(currentDownloading);
		}

		// If found, scroll to it
		if(position != -1) {
			// RecyclerView.scrollToPosition just puts it on the screen (ie: bottom if scrolled below it)
			LinearLayoutManager layoutManager = (LinearLayoutManager) playlistView.getLayoutManager();
			layoutManager.scrollToPositionWithOffset(position, 0);
		}
	}

	private void update() {
		if(startFlipped) {
			startFlipped = false;
			scrollToCurrent();
		}
	}

	private int getMinutes(int progress) {
		if(progress < 30) {
			return progress + 1;
		} else if(progress < 49) {
			return (progress - 30) * 5 + getMinutes(29);
		} else if(progress < 57) {
			return (progress - 48) * 30 + getMinutes(48);
		} else if(progress < 81) {
			return (progress - 56) * 60 + getMinutes(56);
		} else {
			return (progress - 80) * 150 + getMinutes(80);
		}
	}

	private void toggleFullscreenAlbumArt() {
		if (playlistFlipper.getDisplayedChild() == 1) {
			playlistFlipper.setInAnimation(AnimationUtils.loadAnimation(context, R.anim.push_down_in));
			playlistFlipper.setOutAnimation(AnimationUtils.loadAnimation(context, R.anim.push_down_out));
			playlistFlipper.setDisplayedChild(0);
		} else {
			scrollToCurrent();
			playlistFlipper.setInAnimation(AnimationUtils.loadAnimation(context, R.anim.push_up_in));
			playlistFlipper.setOutAnimation(AnimationUtils.loadAnimation(context, R.anim.push_up_out));
			playlistFlipper.setDisplayedChild(1);

			UpdateView.triggerUpdate();
		}
	}

	private void start() {
		DownloadService service = getDownloadService();
		PlayerState state = service.getPlayerState();
		if (state == PAUSED || state == COMPLETED || state == STOPPED) {
			service.start();
		} else if (state == STOPPED || state == IDLE) {
			warnIfStorageUnavailable();
			int current = service.getCurrentPlayingIndex();
			// TODO: Use play() method.
			if (current == -1) {
				service.play(0);
			} else {
				service.play(current);
			}
		}
	}

	private void changeProgress(final boolean rewind) {
		final DownloadService downloadService = getDownloadService();
		if(downloadService == null) {
			return;
		}

		new SilentBackgroundTask<Void>(context) {
			int seekTo;

			@Override
			protected Void doInBackground() throws Throwable {
				if(rewind) {
					seekTo = downloadService.rewind();
				} else {
					seekTo = downloadService.fastForward();
				}
				return null;
			}

			@Override
			protected void done(Void result) {
				progressBar.setProgress(seekTo);
			}
		}.execute();
	}

	@Override
	public boolean onDown(MotionEvent me) {
		setControlsVisible(true);
		return false;
	}

	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
		final DownloadService downloadService = getDownloadService();
		if (downloadService == null || e1 == null || e2 == null) {
			return false;
		}

		// Right to Left swipe
		int action = 0;
		if (e1.getX() - e2.getX() > swipeDistance && Math.abs(velocityX) > swipeVelocity) {
			action = ACTION_NEXT;
		}
		// Left to Right swipe
		else if (e2.getX() - e1.getX() > swipeDistance && Math.abs(velocityX) > swipeVelocity) {
			action = ACTION_PREVIOUS;
		}
		// Top to Bottom swipe
		else if (e2.getY() - e1.getY() > swipeDistance && Math.abs(velocityY) > swipeVelocity) {
			action = ACTION_FORWARD;
		}
		// Bottom to Top swipe
		else if (e1.getY() - e2.getY() > swipeDistance && Math.abs(velocityY) > swipeVelocity) {
			action = ACTION_REWIND;
		}

		if(action > 0) {
			final int performAction = action;
			warnIfStorageUnavailable();
			new SilentBackgroundTask<Void>(context) {
				@Override
				protected Void doInBackground() throws Throwable {
					switch(performAction) {
						case ACTION_NEXT:
							downloadService.next();
							break;
						case ACTION_PREVIOUS:
							downloadService.previous();
							break;
						case ACTION_FORWARD:
							downloadService.seekTo(downloadService.getPlayerPosition() + DownloadService.FAST_FORWARD);
							break;
						case ACTION_REWIND:
							downloadService.seekTo(downloadService.getPlayerPosition() - DownloadService.REWIND);
							break;
					}
					return null;
				}
			}.execute();

			return true;
		} else {
			return false;
		}
	}

	@Override
	public void onLongPress(MotionEvent e) {
	}

	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
		return false;
	}

	@Override
	public void onShowPress(MotionEvent e) {
	}

	@Override
	public boolean onSingleTapUp(MotionEvent e) {
		return false;
	}

	@Override
	public void onItemClicked(UpdateView<DownloadFile> updateView, final DownloadFile item) {
		warnIfStorageUnavailable();
		new SilentBackgroundTask<Void>(context) {
			@Override
			protected Void doInBackground() throws Throwable {
				getDownloadService().play(item);
				return null;
			}
		}.execute();
	}

	@Override
	public void onSongChanged(DownloadFile currentPlaying, int currentPlayingIndex) {
		this.currentPlaying = currentPlaying;
		setupSubtitle(currentPlayingIndex);

        if (currentPlaying != null && !currentPlaying.isSong()) {
            previousButton.setVisibility(View.GONE);
            nextButton.setVisibility(View.GONE);

            rewindButton.setVisibility(View.VISIBLE);
            fastforwardButton.setVisibility(View.VISIBLE);
        } else {
            previousButton.setVisibility(View.VISIBLE);
            nextButton.setVisibility(View.VISIBLE);

            rewindButton.setVisibility(View.GONE);
            fastforwardButton.setVisibility(View.GONE);
		}
		updateTitle();
	}

	private void setupSubtitle(int currentPlayingIndex) {
		if (currentPlaying != null) {
			Entry song = currentPlaying.getSong();
			songTitleTextView.setText(song.getTitle());
			getImageLoader().loadImage(albumArtImageView, song, true, true);

			DownloadService downloadService = getDownloadService();
			if(downloadService.isShufflePlayEnabled()) {
				setSubtitle(context.getResources().getString(R.string.download_playerstate_playing_shuffle));
			} else {
				setSubtitle(context.getResources().getString(R.string.download_playing_out_of, currentPlayingIndex + 1, currentPlayingSize));
			}
		} else {
			songTitleTextView.setText(null);
			getImageLoader().loadImage(albumArtImageView, (Entry) null, true, false);
			setSubtitle(null);
		}
	}

	@Override
	public void onSongsChanged(List<DownloadFile> songs, DownloadFile currentPlaying, int currentPlayingIndex) {
		currentPlayingSize = songs.size();

		DownloadService downloadService = getDownloadService();
		if(downloadService.isShufflePlayEnabled()) {
			emptyTextView.setText(R.string.download_shuffle_loading);
		}
		else {
			emptyTextView.setText(R.string.download_empty);
		}

		if(songListAdapter == null) {
			songList = new ArrayList<>();
			songList.addAll(songs);
			playlistView.setAdapter(songListAdapter = new DownloadFileAdapter(context, songList, NowPlayingFragment.this));
		} else {
			songList.clear();
			songList.addAll(songs);
			songListAdapter.notifyDataSetChanged();
		}

		emptyTextView.setVisibility(songs.isEmpty() ? View.VISIBLE : View.GONE);

		if(scrollWhenLoaded) {
			scrollToCurrent();
			scrollWhenLoaded = false;
		}

		if(this.currentPlaying != currentPlaying) {
			onSongChanged(currentPlaying, currentPlayingIndex);
			onMetadataUpdate(currentPlaying != null ? currentPlaying.getSong() : null, DownloadService.METADATA_UPDATED_ALL);
		} else {
			setupSubtitle(currentPlayingIndex);
		}

        toggleListButton.setVisibility(View.VISIBLE);
        repeatButton.setVisibility(View.VISIBLE);
	}

	@Override
	public void onSongProgress(DownloadFile currentPlaying, int millisPlayed, Integer duration, boolean isSeekable) {
		if (currentPlaying != null) {
			int millisTotal = duration == null ? 0 : duration;

			positionTextView.setText(Util.formatDuration(millisPlayed / 1000));
			if(millisTotal > 0) {
				durationTextView.setText(Util.formatDuration(millisTotal / 1000));
			} else {
				durationTextView.setText("-:--");
			}
			progressBar.setMax(millisTotal == 0 ? 100 : millisTotal); // Work-around for apparent bug.
			if(!seekInProgress) {
				progressBar.setProgress(millisPlayed);
			}
			progressBar.setEnabled(isSeekable);
		} else {
			positionTextView.setText("0:00");
			durationTextView.setText("-:--");
			progressBar.setProgress(0);
			progressBar.setEnabled(false);
		}
	}

	@Override
	public void onStateUpdate(DownloadFile downloadFile, PlayerState playerState) {
		switch (playerState) {
			case DOWNLOADING:
				if(currentPlaying != null) {
					if(Util.isWifiRequiredForDownload(context)) {
						statusTextView.setText(context.getResources().getString(R.string.download_playerstate_mobile_disabled));
					} else {
						long bytes = currentPlaying.getPartialFile().length();
						statusTextView.setText(context.getResources().getString(R.string.download_playerstate_downloading, Util.formatLocalizedBytes(bytes, context)));
					}
				}
				break;
			case PREPARING:
				statusTextView.setText(R.string.download_playerstate_buffering);
				break;
			default:
				if(currentPlaying != null) {
					Entry entry = currentPlaying.getSong();
					if(entry.getAlbum() != null) {
						String artist = "";
						if (entry.getArtist() != null) {
							artist = currentPlaying.getSong().getArtist() + " - ";
						}
						statusTextView.setText(artist + entry.getAlbum());
					} else {
						statusTextView.setText(null);
					}
				} else {
					statusTextView.setText(null);
				}
				break;
		}

		switch (playerState) {
			case STARTED:
				pauseButton.setVisibility(View.VISIBLE);
				stopButton.setVisibility(View.INVISIBLE);
				startButton.setVisibility(View.INVISIBLE);
				break;
			case DOWNLOADING:
			case PREPARING:
				pauseButton.setVisibility(View.INVISIBLE);
				stopButton.setVisibility(View.VISIBLE);
				startButton.setVisibility(View.INVISIBLE);
				break;
			default:
				pauseButton.setVisibility(View.INVISIBLE);
				stopButton.setVisibility(View.INVISIBLE);
				startButton.setVisibility(View.VISIBLE);
				break;
		}
	}

	@Override
	public void onMetadataUpdate(Entry song, int fieldChange) {
		if(song != null && albumArtImageView != null && fieldChange == DownloadService.METADATA_UPDATED_COVER_ART) {
			getImageLoader().loadImage(albumArtImageView, song, true, true);
		}
	}

	public void updateRepeatButton() {
		DownloadService downloadService = getDownloadService();
		switch (downloadService.getRepeatMode()) {
			case OFF:
				repeatButton.setImageResource(DrawableTint.getDrawableRes(context, R.attr.media_button_repeat_off));
				break;
			case ALL:
				repeatButton.setImageResource(DrawableTint.getDrawableRes(context, R.attr.media_button_repeat_all));
				break;
			case SINGLE:
				repeatButton.setImageResource(DrawableTint.getDrawableRes(context, R.attr.media_button_repeat_single));
				break;
			default:
				break;
		}
	}
	private void updateTitle() {
		DownloadService downloadService = getDownloadService();

		String title = context.getResources().getString(R.string.button_bar_now_playing);

		setTitle(title);
	}

	@Override
	protected List<Entry> getSelectedEntries() {
		List<DownloadFile> selected = getCurrentAdapter().getSelected();
		List<Entry> entries = new ArrayList<>();

		for(DownloadFile downloadFile: selected) {
			if(downloadFile.getSong() != null) {
				entries.add(downloadFile.getSong());
			}
		}

		return entries;
	}
}
