/**
 * Autocomplete plugin
 *
 * @example $([field]).autocomplete([params]);
 * @desc Generate a list of Autocomplete suggestions
 *
 * @param Object of parameters for the autocomplete
 *		minlen			integer		minimum string length to reach before returning suggestions
 *		maxResults		integer		maximum suggestions to return
 *		processUrl			string		path to the processing file
 *		dropdownAlign	string		alignment of dropdown in relation to the field
 *										Pass left ("l"), right ("r"), or center ("c")
 * @return jQuery element object
 *
 * @name Autocomplete
 * @cat Plugins/Search
 * @author Greg Wardwell
 */
(function($) {

$.AutoC = {
	nameSpace: '.AutoC',
	opts: {
		minlen: 2,
		maxResults: 20,
		processUrl: '/include/search/autocomplete.php',
		dropdownAlign: 'l',
		disableOnHttps: true
	}
};

var methods = {
	/**
	 * init function.
	 * Initialize the Autocomplete plugin.
	 * @param object this is the input(s) that will make autocomplete suggestions when typing.
	 * @param object options is the object of optional parameters that will be cached on the passed field(s).
	 * @return object this is the input field(s) (for chaining)
	 */
	init: function( options )
	{
		// Extend the default parameters
		$.extend( $.AutoC.opts, options );
		
		// Disable the plugin on secure pages (unless otherwise noted)
		if ( $.AutoC.opts.disableOnHttps === true && location.href.match(/^(https)/i) ) {
			return false;
		}
		
		// Attach an event listenr to the HTML tag to detect field blurring
		
		// Check if the HTML element already has our event listener
		var html = $('html'),
			eventExists = false,
			checkEvent = $('html').click,
			nameSpace = $.AutoC.nameSpace.replace('.', '');
		jQuery.each(checkEvent, function(key, handlerObj) {
		    if (handlerObj.namespace === nameSpace) {
		    	eventExists = true;
		    }
		});
		
		if (!eventExists) {
			html.bind('click' + $.AutoC.nameSpace, methods.htmlClick);
		}
		
		// Loop over the elements, returning each one for chaining
		return this.each(function() {
			// Cache variables
			var $this = $(this),
				data = $this.data(),
				dropDown;
									
			// If we haven't already initialized on this object...
			if ( methods.isEmpty(data) ) {
				// Define some parameters
				var maxlen = ( $this.attr('maxlength') != undefined && parseInt($this.attr('maxlength'), 10) > 0 ? parseInt($this.attr('maxlength'), 10) : 30 ),
					lastTerm = ( $this.val() != undefined ? jQuery.trim($this.val()).toLowerCase() : '' );
					
				// Create and insert the dropdown
				dropDown = $(jQuery('<ul class="autocomplete"></ul>'));
				$('body').append(dropDown);

				// Add events
				$this
					.bind('keyup' + $.AutoC.nameSpace, methods.fieldKeyup)
					.bind('keydown' + $.AutoC.nameSpace, methods.fieldKeydown)
					.bind('focus' + $.AutoC.nameSpace, methods.fieldFocus)
					.bind('click' + $.AutoC.nameSpace, methods.fieldClick);
				
				// Cache the parameters for this field
				$this.data({
					target: $this,
					dropDown: dropDown,
					maxlen: maxlen,
					cache: [],
					cacheCount: 0,
					active: -1,
					dbResultsLength: 0,
					dbMaxResults: $.AutoC.maxResults,
					lastTerm: lastTerm,
					redirecting: false,
					opts: $.AutoC.opts
				});
				$this = data = dropDown = null;
			}
		});
	},
	
	/**
	 * destroy function.
	 * Destroy an instance of the autocomplete jQuery plugin.
	 * @param object this is the input(s)
	 */
	destroy: function()
	{
		return this.each(function() {
			var $this = $(this),
				data = $this.data();
			data.dropDown.remove();
			$this
				// Remove the Autocomplete data
				.removeData()
				// Add dropdown's li children
				.add($('li', data.dropDown))
				// Unbind Autocomplete events
				.unbind($.AutoC.nameSpace);
			$this = data = null;
		});
	},
	
	/**
	 * constructAc function.
	 * construct the autocomplete HTML.
	 * @param object this is the autocomplete input field
	 * @param object results is the results used to populate the dropdown
	 * @return object this
	 */
	constructAc: function(results)
	{
		// Cache variables
		var $this = $(this),
			data = $this.data(),
			allText = '',
			thispos = $this.offset(),
			pos = { top: 0, left: 0 },
			lis;
		
		data.active = -1;
		
		// Remove the dropdown
		methods.removeDropdown.apply($this[0]);
		
		// If we have results...
		if (results.length > 0)
		{
			// Bold the typed term
			var testingTerm = results[0].substr( 0, data.lastTerm.length ),
				i;
			
			// Remove the "empty" styling from the dropdown
			data.dropDown.removeClass('empty');
			
			// loop through the results, building our list
			for (i in results) {
				if (i > data.opts.maxResults - 1 || i > 200) {
					break;
				}
				// Add the li
				data.dropDown.append('<li class="acNavLi acSuggestion'+ (i === 0 ? ' first' : '') +'">' + ( testingTerm.toLowerCase() === data.lastTerm.toLowerCase() ? '<span>' + results[i].substring( 0, data.lastTerm.length) + '</span>' + results[i].substring(data.lastTerm.length) : results[i]) + '</li>' );
			}
			// Define the "All Results" button text
			allText = 'View results for <em>'+ data.lastTerm +'</em>.';
			testingTerm = i = null;
		}
		else
		{
			// Add the "empty" styling to the dropdown.
			data.dropDown.addClass('empty');
			// Redefine "All Results" button text
			allText = 'No suggestions found.<br /> View results for <em>'+ data.lastTerm +'</em>.';
		}
		
		// Add in the "All Results" button
		data.dropDown.css('display', 'none').append('<li class="ac_view_all acNavLi">'+ allText +'</li>');
		
		// Set the display properties for the dropdown
		if (data.opts.dropdownalign === 'r') {
			pos.left = thispos.left + $this.outerWidth() - data.dropDown.outerWidth();
		} else if (data.opts.dropdownalign === 'c') {
			pos.left = thispos.left + ( ($this.outerWidth() - data.dropDown.outerWidth) / 2 );
		} else {
			pos.left = thispos.left;
		}
		pos.left = parseInt(pos.left, 10);
		pos.top = parseInt(thispos.top + $(this).outerHeight(), 10);
		data.dropDown.css({
			display: 'block',
			top: pos.top + 'px',
			left: pos.left + 'px',
			position: 'absolute'
		});
		
		// Set up hover events on dropdown list
		lis = $('li', data.dropDown)
			.data('target', $this)
			.bind('mouseover' + $.AutoC.nameSpace, methods.mouseoverSuggestion)
			.bind('mouseout' + $.AutoC.nameSpace, methods.mouseoutSuggestion)
			.bind('click' + $.AutoC.nameSpace, methods.liClick);
		
		// Return  this
		$this = data = allText = thispos = pos = null;
		return this;
	},
	
	/**
	 * fieldClick function.
	 * Intercept the click event on an autocomplete field and stop event propagation.
	 * @param object this is the field clicked.
	 * @param object e is the event object.
	 */
	fieldClick: function(e)
	{
		e.stopPropagation();
	},
	
	/**
	 * fieldFocus function.
	 * Intercept the focus event on an autocomplete field and mark the field as focused.
	 * @param object this is the field being brought into focus.
	 * @param object e is the event object.
	 */
	fieldFocus: function(e)
	{
		var $this = $(this).addClass('focus');
		$this = null;
	},
	
	/**
	 * fieldBlur event.
	 * Release focus of an autocomplete field.
	 * @param object this is the field being blurred.
	 * @param object e is the event object.
	 */
	fieldBlur: function(e)
	{
		var $this = $(this),
			data = $this.data();
			
		$this.val(data.lastTerm).removeClass('focus');
		methods.removeDropdown.apply($this[0]);
		$this = data = null;
		return;
	},
	
	/**
	 * fieldKeydown function.
	 * Perform actions when a key is pressed while an autocomplete field is in focus.
	 * @param object this is the input in focus
	 * @param object e the event
	 * @return mixed
	 */
	fieldKeydown: function(e)
	{
		if (e == undefined || e == null) {
			return;
		}
		
		var $this = $(this),
			data = $this.data(),
			keyCode = e.keyCode,
			returnType;
		
		// "Up" arrow
		if (keyCode === 38) {
			methods.highlightLi.apply($this[0], [e]);
			returnType = false;
		}
		// "Down" arrow
		else if (keyCode === 40) {
			methods.highlightLi.apply($this[0], [e]);
			returnType = false;
		}
		// "Enter"
		else if (keyCode === 13) {
			if (data.redirecting !== true) {
				$this.data('redirecting', true);
				methods.selectSuggestion.apply($this[0]);
				returnType = false;
			}
		}
		// "Escape"
		else if (keyCode === 27) {
			$this.val(data.lastTerm);
			methods.removeDropdown.apply($this[0]);
			returnType = false;
		}
		// "Tab"
		else if (keyCode === 9) {
			methods.fieldBlur.apply($this[0], [e]);
		}
		// Return
		$this = data = keyCode = null;
		if (returnType === false) {
			return false;
		}
		return;
	},
	
	/**
	 * fieldKeydown function.
	 * Perform actions on completion of a keypress while an autocomplete field is in focus.
	 * @param object this is the input in focus
	 * @param object e is the event
	 * @return mixed
	 */
	fieldKeyup: function(e)
	{
		var $this = $(this),
			data = $this.data(),
			newTerm = ( $this.val() != undefined ? jQuery.trim($this.val()).toLowerCase() : '' ),
			lastTerm = data.lastTerm,
			killCodes = /^(38|40|13|27|9)$/;
		
		// Escape if newTerm is the same as the last term or if the key pressed in in our kill list
		if ( newTerm === data.lastTerm || $this.hasClass('scrolling') || (e.keyCode + '').match(killCodes) != null) {
			$this.removeClass('scrolling');
			$this = data = newTerm = killCodes = null;
			return;
		}
		killCodes = null;
		
		// Store the new term
		$this.data('lastTerm', newTerm);
		
		// Escape if:
		//		- newterm is shorter than our minlen
		//		- newterm is greater than our maxlen
		//		- we're already searching
		//		- we're submitting
		var newLen = newTerm.length;
		if ( newLen < data.opts.minlen || newLen > data.maxlen || $this.hasClass('searching') || $this.hasClass('submitting') ) {
			if (newLen < data.opts.minlen) {
				methods.removeDropdown.apply($this[0]);
			}
			$this = data = newTerm = null;
			return;
		}
		newLen = null;
		
		// Mark that we're searching
		$this.addClass('searching');
		
		// Check the cache for this exact term
		if (data.cache[newTerm] != undefined) {
			// Construct the dropdown
			methods.constructAc.apply($this[0], [data.cache[newTerm]]);
			$this.data(data).removeClass('searching');
			$this = data = newTerm = null;
			return;
		}
		
		// Check the cache for the first two characters of the term
		var trimTerm = jQuery.trim(newTerm.substr(0, newTerm.length - 1)),
			testingTerm;
		
		// If our trimmed term exists, then try to build our list from that approx. match
		if (data.cache[trimTerm] != undefined) {
				var results = [],
					i;
			// Check for the term in our approx. match
			for ( i in data.cache[trimTerm] ) {
				testingTerm = data.cache[trimTerm][i].substr(0, newTerm.length);
				// Use matching results
				if (testingTerm.toLowerCase() === newTerm.toLowerCase()) {
					results[results.length] = data.cache[trimTerm][i];
				}
			}
			// The logic is...
			//		- If we have more results than the maximum we'll display
			//		- Or the DB returned less than the max that it's set to return
			//		- Or the DB returned less than the maximum we'll display
			if (results.length >= data.opts.maxResults || data.dbResultsLength < data.dbMaxResults || data.dbResultsLength < data.opts.maxResults)
			{
				// Cache the results for this term
				data.cache[newTerm] = results;
				
				// Construct the dropdown
				methods.constructAc.apply($this[0], [results]);
				$this.data(data).removeClass('searching');
				$this = data = newTerm = testingTerm = results = i = null;
				return;	
			}
			testingTerm = results = i = null;
		}
		
		// If:
		//		- the last term was gte our minlen
		//		- AND the DB query returned nothing, quit
		if (lastTerm.length >= data.opts.minlen && data.dbResultsLength === 0) {
			methods.constructAc.apply($this[0], [[]]);
			$this.data(data).removeClass('searching');
			$this = data = newTerm = testingTerm = results = i = null;
			return;
		}
		
		// Query for the term
		$.ajax({
			type: "GET",
			dataType: 'json',
			url: data.opts.processUrl,
			data: "term=" + newTerm,
			cache: false,
			success: function(returnedData)
			{				
				// If we didn't get back any results, remove the dropdown
				if (returnedData.length === 0) {
					methods.removeDropdown.apply($this[0]);
					$this.data(data).removeClass('searching');
					return;
				}
				
				var results = returnedData,
					dbResultsLength = returnedData.length,
					dbMaxResults = dbResultsLength;
				
				// Did we get back a single result object, or a multidimensional object?
				if (returnedData.results != undefined) {
					results = returnedData.results;
					dbResultsLength = results.length;
				}
				if (returnedData.maxresults != undefined) {
					dbMaxResults = returnedData.maxresults;
				}
				
				// Cache DB result info
				data.dbResultsLength = dbResultsLength;
				data.dbMaxResults = dbMaxResults;
				
				// If we didn't get back any results, remove the dropdown
				if (results.length === 0) {
					methods.removeDropdown.apply($this[0]);
					$this.data(data).removeClass('searching');
					return;
				}
				
				// Trim the cache
				var trimTo = 50,
					trimAfter = 100;
				if (data.cacheCount >= trimAfter) {
					data.cacheCount = trimTo;
					var i = 0,
						temp = [],
						key;
					for (key in data.cache) {
						if (i >= trimAfter - trimTo) {
							temp[key] = data.cache[key];
						}
						i++;
					}
					data.cache = temp;
					i = temp = key = null;
				}
				
				// Cache results and current active term
				data.cache[newTerm] = results;
				data.cacheCount++;
				data.active = -1;
				
				// Build the dropdown
				methods.constructAc.apply($this[0], [results]);
				
				// Remove searching marker
				$this.data(data).removeClass('searching');
				$this = data = newTerm = results = trimTo = trimAfter = null;
			}
		});
	},
	
	/**
	 * highlightLi function.
	 * Highlight an LI, marking it as active.
	 * @param object this is the li that should be active
	 * @param object e is the event
	 * @return object this
	 */
	highlightLi: function(e)
	{
		// Cache variables
		var $this = $(this),
			data = $this.data();
		
		// Reset the active field if there are no results
		if ($('li.active', data.dropdown).length === 0) {
			data.active = -1;
		}
		
		// Cache more variables
		var keyCode = e.keyCode,
			indexOffset = 1 + $('.ac_view_all', data.dropDown).length,
			lis = $('li', data.dropDown),
			lisLength = lis.length - indexOffset;
		
		// Going up
		if (keyCode === 38) {
			if (data.active > 0) {
				data.active--;
			} else if (data.active === 0) {
				data.active = -1;
			} else {
				data.active = lisLength;
			}
		}
		// Going down
		else if (keyCode === 40) {
			if (data.active < lisLength) {
				data.active++;
			} else if (data.active === lisLength) {
				data.active = -1;
			} else {
				data.active = 0;
			}
		}
		
		// Update the field data
		$this.data(data);
		
		// Set the active suggestion
		methods.setActive.apply($this[0], [true]);
		
		$this = data = keyCode = indexOffset = lis = lisLength = null;
		return this;
	},
	
	/**
	 * htmlClick function.
	 * Intercept a click event on the HTML tag so we can trigger the input blur event.
	 * @param object this is the html element.
	 * @param object e is the event object.
	 */
	htmlClick: function(e)
	{
		var $this = $('input.focus');
		if ($this.length > 0) {
			methods.fieldBlur.apply($this[0], [e]);
		}
	},
	
	/**
	 * hoverSuggestion function.
	 * Prep the autocomplete data and set an LI as active.
	 * @param object this is the hovered li
	 */
	mouseoverSuggestion: function(e)
	{
		var li = $(this),
			$this = li.data('target'),
			data = $this.data();
		$this.data('active', $('li', data.dropDown).index(li));
		methods.setActive.apply($this[0], [false]);
		li = $this = data = null;
		return;
	},
	
	mouseoutSuggestion: function(e)
	{
		var li = $(this).removeClass('active'),
			$this = li.data('target').data('active', -1);
		li = $this = null;
		return;
	},
	
	/**
	 * isEmpty function.
	 * Check if an object is empty.
	 * @param object obj is the object we're checking.
	 * @return bool
	 */
	isEmpty: function(obj)
	{
		for (var prop in obj) {
			if (obj.hasOwnProperty(prop)) {
				return false;
			}
		}
		return true;
	},
	
	/**
	 * removeDropdown function.
	 * Hide the dropdown of the provided input and remove its contents.
	 * @param object this is the input field
	 * @return object this
	 */
	removeDropdown: function()
	{
		var $this = $(this),
			data = $this.data();
		data.dropDown.css('display','none');
		data.dropDown.contents().remove();
		
		$this = data = null;
		return this;
	},
	
	/**
	 * liClick function.
	 * Select a selection, either via return keypress or via click.
	 * @param object this is the autocomplete input field.
	 */
	liClick: function(e) {
		var li = $(this).addClass('focus'),
			$this = li.data('target');
		
		e.preventDefault();
		e.stopPropagation();		
		methods.selectSuggestion.apply($this[0]);
	},
	
	/**
	 * selectSuggestion function.
	 * Select a selection, either via return keypress or via click.
	 * @param object this is the autocomplete input field.
	 */
	selectSuggestion: function() {
		var $this = $(this).addClass('submitting'),
			data = $this.data(),
			selected = $('li:eq('+ data.active +')', data.dropDown);
		
		// If we clicked the "View All" button
		if (selected.hasClass('ac_view_all')) {
			// Use the last term
			$this.val( data.lastTerm );
		} else if (selected.length > 0) {
			$this.val( jQuery.trim( selected.text() ) );
		}
		
		// Hide the dropdown
		methods.removeDropdown.apply($this[0]);
		
		data = selected = null;
		
		// Submit the form
		$this.closest('form').trigger('submit');
	},
	
	/**
	 * setActive function.
	 * Set an li to it's active state
	 * @param object this is the li.
	 * @param bool updateVal is a flag for whether the value of the input should be changed or not 
	 *		- true: change
	 *		- false: don't change
	 */
	setActive: function(updateVal)
	{
		// Cache variables
		var $this = $(this),
			data = $this.data(),
			activeLi,
			// Clear the active state from the lis
			lis = $('li', data.dropDown).removeClass('active');
		
		// Reset the field value if there is no selected suggestion
		if (data.active === -1) {
			$this.val(data.lastTerm);
			$this = data = lis = activeli = null;
			return false;
		}
		
		activeLi = lis.filter(':eq('+ data.active +')').addClass('active');
		
		// If arrowing up/down, update the value
		if ( updateVal != undefined && updateVal === true ) {
			$this.addClass('scrolling').val( jQuery.trim( activeLi.text() ) );
		}
		$this = data = lis = activeli = null;
		return this;
	}
};

// Instantiate the Social plugin
$.fn.autocomplete = function( method )
{
	// If we passed a method that exists in our methods object, run it
	if ( methods[method] )
	{
		return methods[ method ].apply( this, Array.prototype.slice.call( arguments, 1 ));
	}
	// If we didn't pass a method, or passed an object, run the init method
	else if ( typeof method === 'object' || ! method )
	{
		return methods.init.apply( this, arguments );
	}
	// Otherwise, give up
	else
	{
		return false;
	}
};

})(jQuery);