/**
 * tools.scrollable 1.1.2 - Scroll your HTML with eye candy.
 *
 * Copyright (c) 2009 Tero Piirainen
 * http://flowplayer.org/tools/scrollable.html
 *
 * Dual licensed under MIT and GPL 2+ licenses
 * http://www.opensource.org/licenses
 *
 * Launch  : March 2008
 * Date: ${date}
 * Revision: ${revision}
 */
(function($) {

	// static constructs
	$.tools = $.tools || {};

	$.tools.scrollable = {
		version: '1.1.2',

		conf: {

			// basics
			size: 5,
			vertical: false,
			speed: 400,
			keyboard: true,

			// by default this is the same as size
			keyboardSteps: null,

			// other
			disabledClass: 'disabled',
			hoverClass: null,
			clickable: true,
			activeClass: 'active',
			easing: 'swing',
			loop: false,

			items: '.items',
			item: null,

			// navigational elements
			prev: '.prev',
			next: '.next',
			prevPage: '.prevPage',
			nextPage: '.nextPage',
			api: false

			// CALLBACKS: onBeforeSeek, onSeek, onReload
		}
	};

	var current;

	// constructor
	function Scrollable(root, conf) {

		// current instance
		var self = this, $self = $(this),
			 horizontal = !conf.vertical,
			 wrap = root.children(),
			 index = 0,
			 forward;


		if (!current) { current = self; }

		// bind all callbacks from configuration
		$.each(conf, function(name, fn) {
			if ($.isFunction(fn)) { $self.bind(name, fn); }
		});

		if (wrap.length > 1) { wrap = $(conf.items, root); }

		// navigational items can be anywhere when globalNav = true
		function find(query) {
			var els = $(query);
			return conf.globalNav ? els : root.parent().find(query);
		}

		// to be used by plugins
		root.data("finder", find);

		// get handle to navigational elements
		var prev = find(conf.prev),
			 next = find(conf.next),
			 prevPage = find(conf.prevPage),
			 nextPage = find(conf.nextPage);


		// methods
		$.extend(self, {

			getIndex: function() {
				return index;
			},

			getClickIndex: function() {
				var items = self.getItems();
				return items.index(items.filter("." + conf.activeClass));
			},

			getConf: function() {
				return conf;
			},

			getSize: function() {
				return self.getItems().size();
			},

			getPageAmount: function() {
				return Math.ceil(this.getSize() / conf.size);
			},

			getPageIndex: function() {
				return Math.ceil(index / conf.size);
			},

			getNaviButtons: function() {
				return prev.add(next).add(prevPage).add(nextPage);
			},

			getRoot: function() {
				return root;
			},

			getItemWrap: function() {
				return wrap;
			},

			getItems: function() {
				return wrap.children(conf.item);
			},

			getVisibleItems: function() {
				return self.getItems().slice(index, index + conf.size);
			},

			/* all seeking functions depend on this */
			seekTo: function(i, time, fn) {

				if (i < 0) { i = 0; }

				// nothing happens
				if (index === i) { return self; }

				// function given as second argument
				if ($.isFunction(time)) {
					fn = time;
				}

				// seeking exceeds the end
				if (i > self.getSize() - conf.size) {
					return conf.loop ? self.begin() : this.end();
				}

				var item = self.getItems().eq(i);
				if (!item.length) { return self; }

				// onBeforeSeek
				var e = $.Event("onBeforeSeek");

				$self.trigger(e, [i]);
				if (e.isDefaultPrevented()) { return self; }

				// get the (possibly altered) speed
				if (time === undefined || $.isFunction(time)) { time = conf.speed; }

				function callback() {
					if (fn) { fn.call(self, i); }
					$self.trigger("onSeek", [i]);
				}

				if (horizontal) {
					wrap.animate({left: -item.position().left}, time, conf.easing, callback);
				} else {
					wrap.animate({top: -item.position().top}, time, conf.easing, callback);
				}


				current = self;
				index = i;

				// onStart
				e = $.Event("onStart");
				$self.trigger(e, [i]);
				if (e.isDefaultPrevented()) { return self; }


				/* default behaviour */

				// prev/next buttons disabled flags
				prev.add(prevPage).toggleClass(conf.disabledClass, i === 0);
				next.add(nextPage).toggleClass(conf.disabledClass, i >= self.getSize() - conf.size);

				return self;
			},


			move: function(offset, time, fn) {
				forward = offset > 0;
				return this.seekTo(index + offset, time, fn);
			},

			next: function(time, fn) {
				return this.move(1, time, fn);
			},

			prev: function(time, fn) {
				return this.move(-1, time, fn);
			},

			movePage: function(offset, time, fn) {
				forward = offset > 0;
				var steps = conf.size * offset;

				var i = index % conf.size;
				if (i > 0) {
				 	steps += (offset > 0 ? -i : conf.size - i);
				}

				return this.move(steps, time, fn);
			},

			prevPage: function(time, fn) {
				return this.movePage(-1, time, fn);
			},

			nextPage: function(time, fn) {
				return this.movePage(1, time, fn);
			},

			setPage: function(page, time, fn) {
				return this.seekTo(page * conf.size, time, fn);
			},

			begin: function(time, fn) {
				forward = false;
				return this.seekTo(0, time, fn);
			},

			end: function(time, fn) {
				forward = true;
				var to = this.getSize() - conf.size;
				return to > 0 ? this.seekTo(to, time, fn) : self;
			},

			reload: function() {
				$self.trigger("onReload");
				return self;
			},

			focus: function() {
				current = self;
				return self;
			},

			click: function(i) {

				var item = self.getItems().eq(i),
					 klass = conf.activeClass,
					 size = conf.size;

				// check that i is sane
				if (i < 0 || i >= self.getSize()) { return self; }

				// size == 1
				if (size == 1) {
					if (conf.loop) { return self.next(); }

					if (i === 0 || i == self.getSize() -1)  {
						forward = (forward === undefined) ? true : !forward;
					}
					return forward === false  ? self.prev() : self.next();
				}

				// size == 2
				if (size == 2) {
					if (i == index) { i--; }
					self.getItems().removeClass(klass);
					item.addClass(klass);
					return self.seekTo(i);
				}

				if (!item.hasClass(klass)) {
					self.getItems().removeClass(klass);
					item.addClass(klass);
					var delta = Math.floor(size / 2);
					var to = i - delta;

					// next to last item must work
					if (to > self.getSize() - size) {
						to = self.getSize() - size;
					}

					if (to !== i) {
						return self.seekTo(to);
					}
				}

				return self;
			},

			// bind / unbind
			bind: function(name, fn) {
				$self.bind(name, fn);
				return self;
			},

			unbind: function(name) {
				$self.unbind(name);
				return self;
			}

		});

		// callbacks
		$.each("onBeforeSeek,onStart,onSeek,onReload".split(","), function(i, ev) {
			self[ev] = function(fn) {
				return self.bind(ev, fn);
			};
		});


		// prev button
		prev.addClass(conf.disabledClass).click(function() {
			self.prev();
		});


		// next button
		next.click(function() {
			self.next();
		});

		// prev page button
		nextPage.click(function() {
			self.nextPage();
		});

		if (self.getSize() < conf.size) {
			next.add(nextPage).addClass(conf.disabledClass);
		}


		// next page button
		prevPage.addClass(conf.disabledClass).click(function() {
			self.prevPage();
		});


		// hover
		var hc = conf.hoverClass, keyId = "keydown." + Math.random().toString().substring(10);

		self.onReload(function() {

			// hovering
			if (hc) {
				self.getItems().hover(function()  {
					$(this).addClass(hc);
				}, function() {
					$(this).removeClass(hc);
				});
			}

			// clickable
			if (conf.clickable) {
				self.getItems().each(function(i) {
					$(this).unbind("click.scrollable").bind("click.scrollable", function(e) {
						if ($(e.target).is("a")) { return; }
						return self.click(i);
					});
				});
			}

			// keyboard
			if (conf.keyboard) {

				// keyboard works on one instance at the time. thus we need to unbind first
				$(document).unbind(keyId).bind(keyId, function(evt) {

					// do nothing with CTRL / ALT buttons
					if (evt.altKey || evt.ctrlKey) { return; }

					// do nothing for unstatic and unfocused instances
					if (conf.keyboard != 'static' && current != self) { return; }

					var s = conf.keyboardSteps;

					if (horizontal && (evt.keyCode == 37 || evt.keyCode == 39)) {
						self.move(evt.keyCode == 37 ? -s : s);
						return evt.preventDefault();
					}

					if (!horizontal && (evt.keyCode == 38 || evt.keyCode == 40)) {
						self.move(evt.keyCode == 38 ? -s : s);
						return evt.preventDefault();
					}

					return true;

				});

			} else  {
				$(document).unbind(keyId);
			}

		});

		self.reload();

	}


	// jQuery plugin implementation
	$.fn.scrollable = function(conf) {

		// already constructed --> return API
		var el = this.eq(typeof conf == 'number' ? conf : 0).data("scrollable");
		if (el) { return el; }

		var globals = $.extend({}, $.tools.scrollable.conf);
		conf = $.extend(globals, conf);

		conf.keyboardSteps = conf.keyboardSteps || conf.size;

		this.each(function() {
			el = new Scrollable($(this), conf);
			$(this).data("scrollable", el);
		});

		return conf.api ? el: this;

	};


})(jQuery);