/*
 *
 *  Ajax Autocomplete for Prototype, version 1.0.3
 *  (c) 2008 Tomas Kirda
 *
 *  Ajax Autocomplete for Prototype is freely distributable under the terms of an MIT-style license.
 *  For details, see the web site: http://www.devbridge.com/projects/autocomplete/
 *
 */

var Autocomplete = function(el, options){
	this.el = $(el);
	this.id = this.el.identify();
	this.el.setAttribute('autocomplete','off');
	this.suggestions = [];
	this.data = [];
	this.badQueries = [];
	this.selectedIndex = -1;
	this.currentValue = this.el.value;
	this.intervalId = 0;
	this.cachedResponse = [];
	this.instanceId = null;
	this.onChangeInterval = null;
	this.ignoreValueChange = false;
	this.serviceUrl = options.serviceUrl;
	this.options = {
		autoSubmit:false,
		minChars:1,
		maxHeight:300,
		deferRequestBy:0,
		width:0,
		container:null
	};
	if(options){
		Object.extend(this.options, options);
	}
	if(Autocomplete.isDomLoaded){
		this.initialize();
	}else{
		Event.observe(document, 'dom:loaded', this.initialize.bind(this), false);
	}
};

Autocomplete.instances = [];
Autocomplete.isDomLoaded = false;

Autocomplete.getInstance = function(id){
	var instances = Autocomplete.instances;
	var i = instances.length;
	while(i--){
		if(instances[i].id === id){
			return instances[i];
		}
	}
};

Autocomplete.highlight = function(value, re){
	return value.replace(re, function(match){
		return '<strong>' + match + '<\/strong>'
	});
};

Autocomplete.prototype = {

	killerFn: null,

	initialize: function() {
		var me = this;
		this.killerFn = function(e) {
			if (!$(Event.element(e)).up('.autocomplete')) {
				me.killSuggestions();
				me.disableKillerFn();
			}
		} .bindAsEventListener(this);

		if (!this.options.width) {
			this.options.width = this.el.getWidth();
		}

		var div = new Element('div', {
			style: 'position:absolute;'
		});
		div.update('<div class="autocomplete-w1"><div class="autocomplete-w2"><div class="autocomplete" id="Autocomplete_' + this.id + '" style="display:none; width:' + this.options.width + 'px;"></div></div></div>');

		this.options.container = $(this.options.container);
		if (this.options.container) {
			this.options.container.appendChild(div);
			this.fixPosition = function() { };
		} else {
			document.body.appendChild(div);
		}

		this.mainContainerId = div.identify();
		this.container = $('Autocomplete_' + this.id);
		this.fixPosition();
    
		Event.observe(this.el, window.opera ? 'keypress':'keydown', this.onKeyPress.bind(this));
		Event.observe(this.el, 'keyup', this.onKeyUp.bind(this));
		Event.observe(this.el, 'blur', this.enableKillerFn.bind(this));
		Event.observe(this.el, 'focus', this.fixPosition.bind(this));
		this.container.setStyle({
			maxHeight: this.options.maxHeight + 'px'
		});
		this.instanceId = Autocomplete.instances.push(this) - 1;
	},

	fixPosition: function() {
		var offset = this.el.cumulativeOffset();
		offset.left = 18;
		$(this.mainContainerId).setStyle({
			top: (offset.top + this.el.getHeight()) + 'px',
			left: offset.left + 'px'
		});
	},

	enableKillerFn: function() {
		Event.observe(document.body, 'click', this.killerFn);
	},

	disableKillerFn: function() {
		Event.stopObserving(document.body, 'click', this.killerFn);
	},

	killSuggestions: function() {
		this.stopKillSuggestions();
		this.intervalId = window.setInterval(function() {
			this.hide();
			this.stopKillSuggestions();
		} .bind(this), 300);
	},

	stopKillSuggestions: function() {
		window.clearInterval(this.intervalId);
	},

	onKeyPress: function(e) {
		if (!this.enabled) {
			return;
		}
		// return will exit the function
		// and event will not fire
		switch (e.keyCode) {
			case Event.KEY_ESC:
				this.el.value = this.currentValue;
				this.hide();
				break;
			case Event.KEY_TAB:
			case Event.KEY_RETURN:
				if (this.selectedIndex === -1) {
					this.hide();
					return;
				}
				this.select(this.selectedIndex);
				if (e.keyCode === Event.KEY_TAB) {
					return;
				}
				break;
			case Event.KEY_UP:
				this.moveUp();
				break;
			case Event.KEY_DOWN:
				this.moveDown();
				break;
			default:
				return;
		}
		Event.stop(e);
	},

	onKeyUp: function(e) {
		switch (e.keyCode) {
			case Event.KEY_UP:
			case Event.KEY_DOWN:
				return;
		}
		clearInterval(this.onChangeInterval);
		if (this.currentValue !== this.el.value) {
			if (this.options.deferRequestBy > 0) {
				// Defer lookup in case when value changes very quickly:
				this.onChangeInterval = setInterval((function() {
					this.onValueChange();
				}).bind(this), this.options.deferRequestBy);
			} else {
				this.onValueChange();
			}
		}
	},

	onValueChange: function() {
		clearInterval(this.onChangeInterval);
		this.currentValue = this.el.value;
		this.selectedIndex = -1;
		if (this.ignoreValueChange) {
			this.ignoreValueChange = false;
			return;
		}
		if (this.currentValue === '' || this.currentValue.length < this.options.minChars) {
			this.hide();
		} else {
			this.getSuggestions();
		}
	},

	getSuggestions: function() {
		var cr = this.cachedResponse[this.currentValue];
		if (cr && Object.isArray(cr.suggestions)) {
			this.suggestions = cr.suggestions;
			this.data = cr.data;
			this.suggest();
		} else if (!this.isBadQuery(this.currentValue)) {
			new Ajax.Request(this.serviceUrl, {
				parameters: {
					query: this.currentValue
				},
				onComplete: this.processResponse.bind(this),
				method: 'get'
			});
		}
	},

	isBadQuery: function(q) {
		var i = this.badQueries.length;
		while (i--) {
			if (q.indexOf(this.badQueries[i]) === 0) {
				return true;
			}
		}
		return false;
	},

	hide: function() {
		this.enabled = false;
		this.selectedIndex = -1;
		this.container.hide();
	},

	suggest: function() {
		if (this.suggestions.length === 0) {
			this.hide();
			return;
		}
		var content = [];
		var re = new RegExp('\\b' + this.currentValue.match(/\w+/g).join('|\\b'), 'gi');
		this.suggestions.each(function(value, i) {
			content.push((this.selectedIndex === i ? '<div class="selected"' : '<div'), ' title="', value, '" onclick="Autocomplete.instances[', this.instanceId, '].select(', i, ');" onmouseover="Autocomplete.instances[', this.instanceId, '].activate(', i, ');">', Autocomplete.highlight(value, re), '</div>');
		} .bind(this));
		this.enabled = true;
		this.container.update(content.join('')).show();
	},

	processResponse: function(xhr) {
		var response;
		try {
			response = xhr.responseText.evalJSON();
			if (!Object.isArray(response.data)) {
				response.data = [];
			}
		} catch (err) {
			return;
		}
		this.suggestions = response.suggestions;
		this.data = response.data;
		this.cachedResponse[response.query] = response;
		if (response.suggestions.length === 0) {
			this.badQueries.push(response.query);
		}
		if (response.query === this.currentValue) {
			this.suggest();
		}
	},

	activate: function(index) {
		var divs = this.container.childNodes;
		var activeItem;
		// Clear previous selection:
		if (this.selectedIndex !== -1 && divs.length > this.selectedIndex) {
			divs[this.selectedIndex].className = '';
		}
		this.selectedIndex = index;
		if (this.selectedIndex !== -1 && divs.length > this.selectedIndex) {
			activeItem = divs[this.selectedIndex]
			activeItem.className = 'selected';
		}
		return activeItem;
	},

	deactivate: function(div, index) {
		div.className = '';
		if (this.selectedIndex === index) {
			this.selectedIndex = -1;
		}
	},

	select: function(i) {
		var selectedValue = this.suggestions[i];
		if (selectedValue) {
			this.el.value = selectedValue;
			if (this.options.autoSubmit && this.el.form) {
				this.el.form.submit();
			}
			this.ignoreValueChange = true;
			this.hide();
			this.onSelect(i);
		}
	},

	moveUp: function() {
		if (this.selectedIndex === -1) {
			return;
		}
		if (this.selectedIndex === 0) {
			this.container.childNodes[0].className = '';
			this.selectedIndex = -1;
			this.el.value = this.currentValue;
			return;
		}
		this.adjustScroll(this.selectedIndex - 1);
	},

	moveDown: function() {
		if (this.selectedIndex === (this.suggestions.length - 1)) {
			return;
		}
		this.adjustScroll(this.selectedIndex + 1);
	},

	adjustScroll: function(i) {
		var container = this.container;
		var activeItem = this.activate(i);
		var offsetTop = activeItem.offsetTop;
		var upperBound = container.scrollTop;
		var lowerBound = upperBound + this.options.maxHeight - 25;
		if (offsetTop < upperBound) {
			container.scrollTop = offsetTop;
		} else if (offsetTop > lowerBound) {
			container.scrollTop = offsetTop - this.options.maxHeight + 25;
		}
		this.el.value = this.suggestions[i];
	},

	onSelect: function(i) {
		(this.options.onSelect || Prototype.emptyFunction)(this.suggestions[i], this.data[i]);
	}

};

Event.observe(document, 'dom:loaded', function(){
	Autocomplete.isDomLoaded = true;
}, false);