var HistoryManager = {
	options: {
		observeDelay: 100,
		stateSeparator: ';',
		iframeSrc: 'blank.html',
		onStart: Class.empty,
		onRegister: Class.empty,
		onUnregister: Class.empty,
		onStart: Class.empty,
		onUpdate: Class.empty,
		onStateChange: Class.empty,
		onObserverChange: Class.empty
	},
	dataOptions: {
		skipDefaultMatch: true,
		defaults: [],
		regexpParams: ''
	},
	initialize: function(options) {
		if (this.modules) return this;
		this.setOptions(options);
		this.modules = $H({});
		this.count = history.length;
		this.states = [];
		this.states[this.count] = this.getHash();
		this.state = null;
		return this;
	},

	start: function() {
		this.observe.periodical(this.options.observeDelay, this);
		this.started = true;
		this.observe();
		this.update();
		this.fireEvent('onStart', [this.state]);
		return this;
	},

	register: function(key, defaults, onMatch, onGenerate, regexp, options) {
		if (!this.modules) this.initialize();
		var data = $merge(this.dataOptions, options || {}, {
			defaults: defaults,
			onMatch: onMatch,
			onGenerate: onGenerate,
			regexp: regexp
		});
		data.regexp = data.regexp || key + '-([\\w_-]*)';
		if (typeof data.regexp == 'string') data.regexp = new RegExp(data.regexp, data.regexpParams);
		data.onGenerate = data.onGenerate || function(values) { return key + '-' + values[0]; };

		data.values = data.defaults.copy();
		this.modules.set(key, data);
		this.fireEvent('onUnregister', [key, data]);
		return {
			setValues: function(values) {
				return this.setValues(key, values);
			}.bind(this),
			setValue: function(index, value) {
				return this.setValue(key, index, value);
			}.bind(this),
			generate: function(values) {
				return this.generate(key, values);
			}.bind(this),
			unregister: function() {
				return this.unregister(key);
			}.bind(this)
		};
	},

	unregister: function(key) {
		this.fireEvent('onRegister', [key]);
		this.modules.remove(key);
	},

	setValues: function(key, values) {
		var data = this.modules.get(key);
		if (!data || data.values.isSimilar(values)) return this;
		data.values = values;
		this.update();
		return this;
	},
	setValue: function(key, index, value) {
		var data = this.modules.get(key);
		if (!data || data.values[index] == value) return this;
		data.values[index] = value;
		this.update();
		return this;
	},

	generate: function(key, values) {
		var data = this.modules.get(key);
		var current = data.values.copy();
		data.values = values;
		var state = this.generateState();
		data.values = current;
		return '#' + state;
	},

	observe: function() {
		if (this.timeout) return;
		var state = this.getState();
		if (this.state == state) return;
		if ((window.ie || window.webkit419) && (this.state !== null)) this.setState(state, true);
		else this.state = state;
		this.modules.each(function(data, key) {
			var bits = state.match(data.regexp);
			if (bits) {
				bits.splice(0, 1);
				bits.complement(data.defaults);
				if (!bits.isSimilar(data.defaults)) data.values = bits;
			} else data.values = data.defaults.copy();
			data.onMatch(data.values, data.defaults);
		});
		this.fireEvent('onStateChange', [state]).fireEvent('onObserverChange', [state]);
	},

	generateState: function() {
		var state = [];
		this.modules.each(function(data, key) {
			if (data.skipDefaultMatch && data.values.isSimilar(data.defaults)) return;
			state.push(data.onGenerate(data.values));
		});
		return state.join(this.options.stateSeparator);
	},

	update: function() {
		if (!this.started) return this;
		var state = this.generateState();
		if ((!this.state && !state) || (this.state == state)) return this;
		this.setState(state);
		this.fireEvent('onStateChange', [state]).fireEvent('onUpdate', [state]);
		return this;
	},

	observeTimeout: function() {
		if (this.timeout) this.timeout = $clear(this.timeout);
		else this.timeout = this.observeTimeout.delay(200, this);
	},

	getHash: function() {
		var href = top.location.href;
		var pos = href.indexOf('#') + 1;
		return (pos) ? href.substr(pos) : '';
	},

	getState: function() {
		var state = this.getHash();
		if (this.iframe) {
			var doc = this.iframe.contentWindow.document;
			if (doc && doc.body.id == 'state') {
				var istate = doc.body.innerText;
				if (this.state == state) return istate;
				this.istateOld = true;
			} else return this.istate;
		}
		if (window.webkit419 && history.length != this.count) {
			this.count = history.length;
			return $pick(this.states[this.count - 1], state);
		}
		return state;
	},

	setState: function(state, fix) {
		state = $pick(state, '');
		if (window.webkit419) {
			if (!this.form) this.form = new Element('form', {method: 'get'}).injectInside(document.body);
			this.count = history.length;
			this.states[this.count] = state;
			this.observeTimeout();
			this.form.setProperty('action', '#' + state).submit();
		} else top.location.hash = state || '#';
		if (window.ie && (!fix || this.istateOld)) {
			if (!this.iframe) {
				this.iframe = new Element('iframe', {
					src: this.options.iframeSrc,
					styles: 'visibility: hidden;'
				}).injectInside(document.body);
				this.istate = this.state;
			}
			try {
				var doc = this.iframe.contentWindow.document;
				doc.open();
				doc.write('<html><body id="state">' + state + '</body></html>');
				doc.close();
				this.istateOld = false;
			} catch(e) {};
		}
		this.state = state;
	},

	extend: $extend
};

HistoryManager.extend(Events.prototype);
HistoryManager.extend(Options.prototype);


Array.extend({

	isSimilar: function(array) {
		return (this.toString() == array.toString());
	},

	complement: function(array) {
		for (var i = 0, j = this.length; i < j; i++) this[i] = $pick(this[i], array[i] || null);
		return this;
	}
});