/*
 *	Copyright © Jordan Lee, Dave Perrett and Malcolm Jarvis
 *	This code is licensed under the GPL version 2.
 *	For details, see http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 *
 *	Class Torrent
 */


function Torrent(data)
{
	this.initialize(data);
}

/***
****
****  Constants
****
***/

// Torrent.fields.status
Torrent._StatusStopped         = 0;
Torrent._StatusCheckWait       = 1;
Torrent._StatusCheck           = 2;
Torrent._StatusDownloadWait    = 3;
Torrent._StatusDownload        = 4;
Torrent._StatusSeedWait        = 5;
Torrent._StatusSeed            = 6;

// Torrent.fields.seedRatioMode
Torrent._RatioUseGlobal        = 0;
Torrent._RatioUseLocal         = 1;
Torrent._RatioUnlimited        = 2;

// Torrent.fields.error
Torrent._ErrNone               = 0;
Torrent._ErrTrackerWarning     = 1;
Torrent._ErrTrackerError       = 2;
Torrent._ErrLocalError         = 3;

// TrackerStats' announceState
Torrent._TrackerInactive       = 0;
Torrent._TrackerWaiting        = 1;
Torrent._TrackerQueued         = 2;
Torrent._TrackerActive         = 3;


// fields whose values never change and are always known
Torrent._StaticFields = [
	'hashString', 'id' ];

// fields whose values never change and are known upon constructon OR
// when a magnet torrent finishes downloading its metadata
Torrent._MetaDataFields = [
	'addedDate', 'comment', 'creator', 'dateCreated',
	'isPrivate', 'name', 'totalSize', 'pieceCount', 'pieceSize' ];

// torrent fields whose values change all the time
Torrent._DynamicFields = [
	'desiredAvailable', 'downloadDir', 'downloadedEver', 'error',
	'errorString', 'eta', 'haveUnchecked', 'haveValid', 'isFinished',
	'leftUntilDone', 'metadataPercentComplete', 'peers', 'peersConnected',
	'peersGettingFromUs', 'peersSendingToUs', 'queuePosition',
	'rateDownload', 'rateUpload', 'recheckProgress', 'seedRatioLimit',
	'seedRatioMode', 'sizeWhenDone', 'status', 'trackerStats',
	'uploadedEver', 'uploadRatio', 'webseedsSendingToUs' ];

/***
****
****  Methods
****
***/

Torrent.prototype =
{
	initialize: function(data)
	{
		this.fields = {};
		this._files = [];

		// these fields are set in the ctor and never change
		for (var i=0, key; key=Torrent._StaticFields[i]; ++i) {
			if (key in data) {
				this.fields[key] = data[key];
			}
		}

		this.initMetaData(data);
		this._trackerStats = this.buildTrackerStats(data.trackerStats);
		this.refresh(data);
	},

	buildTrackerStats: function(trackerStats) {
		var announce = [];
		var result = [];
		for (var i=0, tracker; tracker=trackerStats[i]; ++i) {
			var tier = result[tracker.tier] || [];
			tier.push(tracker);
			result[tracker.tier] = tier;
			announce.push(tracker.announce);
		}
		this.fields.collatedTrackers = announce.join('\t');
		return result;
	},

	initMetaData: function(data) {

		var f = this.fields;
		var changed = false;

		// populate the metadata fields
		for (var i=0, key; key=Torrent._MetaDataFields[i]; ++i) {
			if (key in data) {
				if (f[key] !== data[key]) {
					f[key] = data[key];
					if (key === 'name')
						f.collatedName = data.name.toLowerCase();
					changed = true;
				}
			}
		}

		// populate the files array
		if (data.files) {
			for (var i=0, row; row=data.files[i]; ++i) {
				this._files[i] = {
					'index': i,
					'length': row.length,
					'name': row.name
				};
			}
		}

		return changed;
	},

	refreshMetaData: function(data)
	{
		var changed = this.initMetaData(data);
		if (changed)
			this.fireDataChanged();
		return changed;
	},

	refresh: function(data)
	{
		var changed = false;

		// FIXME: unnecessary coupling... this should be handled by transmission.js
		if (this.needsMetaData() && (data.metadataPercentComplete >= 1))
			changed |= transmission.refreshMetaData([ this.getId() ]);

		var f = this.fields;

		// refresh the dynamic fields
		for (var i=0, key; key=Torrent._DynamicFields[i]; ++i) {
			if (key in data) {
				if (f[key] !== data[key]) {
					f[key] = data[key];
					changed = true;
				}
			}
		}

		this._trackerStats = this.buildTrackerStats(data.trackerStats);

		if (data.fileStats)
			changed |= this.refreshFiles(data);

		if (changed)
			this.fireDataChanged();
	},

	refreshFiles: function(data) {
		var changed = false;
		for (var i=0; i<data.fileStats.length; ++i) {
			var src = data.fileStats[i];
			var tgt = this._files[i];
			if (!tgt) {
				changed = true;
				tgt = this._files[i] = { };
			}
			if (tgt.wanted !== src.wanted) {
				tgt.wanted = src.wanted;
				changed = true;
			}
			if (tgt.priority !== src.priority) {
				tgt.priority = src.priority;
				changed = true;
			}
			if (tgt.bytesCompleted !== src.bytesCompleted) {
				tgt.bytesCompleted = src.bytesCompleted;
				changed = true;
			}
		}
		return changed;
	},

	fireDataChanged: function()
	{
		$(this).trigger('dataChanged');
	},

	/****
	*****
	****/

	// simple accessors
	getCollatedName: function() { return this.fields.collatedName; },
	getCollatedTrackers: function() { return this.fields.collatedTrackers; },
	getComment: function() { return this.fields.comment; },
	getCreator: function() { return this.fields.creator; },
	getDateAdded: function() { return this.fields.addedDate; },
	getDateCreated: function() { return this.fields.dateCreated; },
	getDesiredAvailable: function() { return this.fields.desiredAvailable; },
	getDownloadDir: function() { return this.fields.downloadDir; },
	getDownloadSpeed: function() { return this.fields.rateDownload; },
	getDownloadedEver: function() { return this.fields.downloadedEver; },
	getError: function() { return this.fields.error; },
	getErrorString: function() { return this.fields.errorString; },
	getETA: function() { return this.fields.eta; },
	getHashString: function() { return this.fields.hashString; },
	getHaveValid: function() { return this.fields.haveValid; },
	getHave: function() { return this.getHaveValid() + this.fields.haveUnchecked; },
	getId: function() { return this.fields.id; },
	getLeftUntilDone: function() { return this.fields.leftUntilDone; },
	getMetadataPercentComplete: function() { return this.fields.metadataPercentComplete; },
	getName: function() { return this.fields.name; },
	getPeers: function() { return this.fields.peers; },
	getPeersConnected: function() { return this.fields.peersConnected; },
	getPeersGettingFromUs: function() { return this.fields.peersGettingFromUs; },
	getPeersSendingToUs: function() { return this.fields.peersSendingToUs; },
	getPieceCount: function() { return this.fields.pieceCount; },
	getPieceCount: function() { return this.fields.pieceCount; },
	getPieceSize: function() { return this.fields.pieceSize; },
	getPrivateFlag: function() { return this.fields.isPrivate; },
	getQueuePosition: function() { return this.fields.queuePosition; },
	getRecheckProgress: function() { return this.fields.recheckProgress; },
	getSeedRatioLimit: function() { return this.fields.seedRatioLimit; },
	getSeedRatioMode: function() { return this.fields.seedRatioMode; },
	getSizeWhenDone: function() { return this.fields.sizeWhenDone; },
	getStatus: function() { return this.fields.status; },
	getTotalSize: function() { return this.fields.totalSize; },
	getUploadSpeed: function() { return this.fields.rateUpload; },
	getUploadRatio: function() { return this.fields.uploadRatio; },
	getUploadedEver: function() { return this.fields.uploadedEver; },
	getWebseedsSendingToUs: function() { return this.fields.webseedsSendingToUs; },
	isFinished: function() { return this.fields.isFinished; },

	// derived accessors
	isSeeding: function() { return this.getStatus() === Torrent._StatusSeed; },
	isStopped: function() { return this.getStatus() === Torrent._StatusStopped; },
	isChecking: function() { return this.getStatus() === Torrent._StatusCheck; },
	isDownloading: function() { return this.getStatus() === Torrent._StatusDownload; },
	isDone: function() { return this.getLeftUntilDone() < 1; },
	needsMetaData: function(){ return this.getMetadataPercentComplete() < 1; },
	getActivity: function() { return this.getDownloadSpeed() + this.getUploadSpeed(); },
	getPercentDoneStr: function() { return Transmission.fmt.percentString(100*this.getPercentDone()); },
	getPercentDone: function() {
		var finalSize = this.getSizeWhenDone();
		if (!finalSize) return 1.0;
		var left = this.getLeftUntilDone();
		if (!left) return 1.0;
		return (finalSize - left) / finalSize;
	},
	getStateString: function() {
		switch(this.getStatus()) {
			case Torrent._StatusStopped:        return this.isFinished() ? 'Seeding complete' : 'Paused';
			case Torrent._StatusCheckWait:      return 'Queued for verification';
			case Torrent._StatusCheck:          return 'Verifying local data';
			case Torrent._StatusDownloadWait:   return 'Queued for download';
			case Torrent._StatusDownload:       return 'Downloading';
			case Torrent._StatusSeedWait:       return 'Queued for seeding';
			case Torrent._StatusSeed:           return 'Seeding';
			default:                            return 'error';
		}
	},
	trackerStats: function() { return this._trackerStats; },
	seedRatioLimit: function(controller){
		switch(this.getSeedRatioMode()) {
			case Torrent._RatioUseGlobal: return controller.seedRatioLimit();
			case Torrent._RatioUseLocal:  return this.getSeedRatioLimit();
			default:                      return -1;
		}
	},
        getErrorMessage: function() {
		var str = this.getErrorString();
		switch(this.getError()) {
			case Torrent._ErrTrackerWarning:
				return 'Tracker returned a warning: ' + str;
			case Torrent._ErrTrackerError:
				return 'Tracker returned an error: ' + str;
			case Torrent._ErrLocalError:
				return 'Error: ' + str;
			default:
				return null;
		}
	},

	/****
	*****
	****/

	testState: function(state)
	{
		var s = this.getStatus();

		switch(state)
		{
			case Prefs._FilterActive:
				return this.getPeersGettingFromUs() > 0
				    || this.getPeersSendingToUs() > 0
				    || this.getWebseedsSendingToUs() > 0
				    || this.isChecking();
			case Prefs._FilterSeeding:
				return (s === Torrent._StatusSeed)
				    || (s === Torrent._StatusSeedWait);
			case Prefs._FilterDownloading:
				return (s === Torrent._StatusDownload)
				    || (s === Torrent._StatusDownloadWait);
			case Prefs._FilterPaused:
				return this.isStopped();
			case Prefs._FilterFinished:
				return this.isFinished();
			default:
				return true;
		}
	},

	/**
	 * @param filter one of Prefs._Filter*
	 * @param search substring to look for, or null
	 * @return true if it passes the test, false if it fails
	 */
	test: function(state, search, tracker)
	{
		// flter by state...
		var pass = this.testState(state);

		// maybe filter by text...
		if (pass && search && search.length)
			pass = this.getCollatedName().indexOf(search.toLowerCase()) !== -1;

		// maybe filter by tracker...
		if (pass && tracker && tracker.length)
			pass = this.getCollatedTrackers().indexOf(tracker) !== -1;

		return pass;
	}
};


/***
****
****  SORTING
****
***/

Torrent.compareById = function(ta, tb)
{
	return ta.getId() - tb.getId();
};
Torrent.compareByName = function(ta, tb)
{
	return ta.getCollatedName().compareTo(tb.getCollatedName())
	    || Torrent.compareById(ta, tb);
};
Torrent.compareByQueue = function(ta, tb)
{
	return ta.getQueuePosition() - tb.getQueuePosition();
};
Torrent.compareByAge = function(ta, tb)
{
	var a = ta.getDateAdded();
	var b = tb.getDateAdded();
	return (b - a) || Torrent.compareByQueue(ta, tb);
};
Torrent.compareByState = function(ta, tb)
{
	var a = ta.getStatus();
	var b = tb.getStatus();
	return (b - a) || Torrent.compareByQueue(ta, tb);
};
Torrent.compareByActivity = function(ta, tb)
{
	var a = ta.getActivity();
	var b = tb.getActivity();
	return (b - a) || Torrent.compareByState(ta, tb);
};
Torrent.compareByRatio = function(ta, tb)
{
	var a = ta.getUploadRatio();
	var b = tb.getUploadRatio();
	if (a < b) return 1;
	if (a > b) return -1;
	return Torrent.compareByState(ta, tb);
};
Torrent.compareByProgress = function(ta, tb)
{
	var a = ta.getPercentDone();
	var b = tb.getPercentDone();
	return (a - b) || Torrent.compareByRatio(ta, tb);
};

/**
 * @param torrents an array of Torrent objects
 * @param sortMethod one of Prefs._SortBy*
 * @param sortDirection Prefs._SortAscending or Prefs._SortDescending
 */
Torrent.sortTorrents = function(torrents, sortMethod, sortDirection)
{
	switch(sortMethod)
	{
		case Prefs._SortByActivity:
			torrents.sort(this.compareByActivity);
			break;
		case Prefs._SortByAge:
			torrents.sort(this.compareByAge);
			break;
		case Prefs._SortByQueue:
			torrents.sort(this.compareByQueue);
			break;
		case Prefs._SortByProgress:
			torrents.sort(this.compareByProgress);
			break;
		case Prefs._SortByState:
			torrents.sort(this.compareByState);
			break;
		case Prefs._SortByRatio:
			torrents.sort(this.compareByRatio);
			break;
		default:
			torrents.sort(this.compareByName);
			break;
	}

	if (sortDirection === Prefs._SortDescending)
		torrents.reverse();

	return torrents;
};