(function($) {
	
	$.entwine('ss', function($) {

		// setup jquery.entwine
		$.entwine.warningLevel = $.entwine.WARN_LEVEL_BESTPRACTISE;

		/**
		 * Horizontal collapsible panel. Generic enough to work with CMS menu as well as various "filter" panels.
		 * 
		 * A panel consists of the following parts:
		 * - Container div: The outer element, with class ".cms-panel"
		 * - Header (optional)
		 * - Content
		 * - Expand and collapse toggle anchors (optional)
		 * 
		 * Sample HTML:
		 * <div class="cms-panel">
		 *  <div class="cms-panel-header">your header</div>
		 * 	<div class="cms-panel-content">your content here</div>
		 *	<div class="cms-panel-toggle">
		 * 		<a href="#" class="toggle-expande">your toggle text</a>
		 * 		<a href="#" class="toggle-collapse">your toggle text</a>
		 *	</div>
		 * </div>
		 */
		$('.cms-panel').entwine({
			
			WidthExpanded: null,
			
			WidthCollapsed: null,

			/**
			 * @func canSetCookie
			 * @return {boolean}
			 * @desc Before trying to set a cookie, make sure $.cookie and the element's id are both defined.
			 */
			canSetCookie: function () {
				return $.cookie !== void 0 && this.attr('id') !== void 0;
			},

			/**
			 * @func getPersistedCollapsedState
			 * @return {boolean|undefined} - Returns true if the panel is collapsed, false if expanded. Returns undefined if there is no cookie set.
			 * @desc Get the collapsed state of the panel according to the cookie.
			 */
			getPersistedCollapsedState: function () {
				var isCollapsed, cookieValue;

				if (this.canSetCookie()) {
					cookieValue = $.cookie('cms-panel-collapsed-' + this.attr('id'));

					if (cookieValue !== void 0 && cookieValue !== null) {
						isCollapsed = cookieValue === 'true';
					}
				}

				return isCollapsed;
			},

			/**
			 * @func setPersistedCollapsedState
			 * @param {boolean} newState - Pass true if you want the panel to be collapsed, false for expanded.
			 * @desc Set the collapsed value of the panel, stored in cookies.
			 */
			setPersistedCollapsedState: function (newState) {
				if (this.canSetCookie()) {
					$.cookie('cms-panel-collapsed-' + this.attr('id'), newState, { path: '/', expires: 31 });
				}
			},

			/**
			 * @func clearPersistedState
			 * @desc Remove the cookie responsible for maintaing the collapsed state.
			 */
			clearPersistedCollapsedState: function () {
				if (this.canSetCookie()) {
					$.cookie('cms-panel-collapsed-' + this.attr('id'), '', { path: '/', expires: -1 });
				}
			},

			/**
			 * @func getInitialCollapsedState
			 * @return {boolean} - Returns true if the the panel is collapsed, false if expanded.
			 * @desc Get the initial collapsed state of the panel. Check if a cookie value is set then fall back to checking CSS classes.
			 */
			getInitialCollapsedState: function () {
				var isCollapsed = this.getPersistedCollapsedState();

				// Fallback to getting the state from the default CSS class
				if (isCollapsed === void 0) {
					isCollapsed = this.hasClass('collapsed');
				}

				return isCollapsed;
			},

			onadd: function() {
				var collapsedContent, container;

				if(!this.find('.cms-panel-content').length) throw new Exception('Content panel for ".cms-panel" not found');
				
				// Create default controls unless they already exist.
				if(!this.find('.cms-panel-toggle').length) {
					container = $("<div class='cms-panel-toggle south'></div>")
						.append('<a class="toggle-expand" href="#"><span>&raquo;</span></a>')
						.append('<a class="toggle-collapse" href="#"><span>&laquo;</span></a>');
						
					this.append(container);
				}
				
				// Set panel width same as the content panel it contains. Assumes the panel has overflow: hidden.
				this.setWidthExpanded(this.find('.cms-panel-content').innerWidth());
				
				// Assumes the collapsed width is indicated by the toggle, or by an optionally collapsed view
				collapsedContent = this.find('.cms-panel-content-collapsed');
				this.setWidthCollapsed(collapsedContent.length ? collapsedContent.innerWidth() : this.find('.toggle-expand').innerWidth());

				// Toggle visibility
				this.togglePanel(!this.getInitialCollapsedState(), true, false);
				
				this._super();
			},

			/**
			 * @func togglePanel
			 * @param doExpand {boolean} - true to expand, false to collapse.
			 * @param silent {boolean} - true means that events won't be fired, which is useful for the component initialization phase.
			 * @param doSaveState - if false, the panel's state will not be persisted via cookies.
			 * @desc Toggle the expanded / collapsed state of the panel.
			 */
			togglePanel: function(doExpand, silent, doSaveState) {
				var newWidth, collapsedContent;

				if(!silent) {
					this.trigger('beforetoggle.sspanel', doExpand);
					this.trigger(doExpand ? 'beforeexpand' : 'beforecollapse');
				}

				this.toggleClass('collapsed', !doExpand);
				newWidth = doExpand ? this.getWidthExpanded() : this.getWidthCollapsed();
				
				this.width(newWidth); // the content panel width always stays in "expanded state" to avoid floating elements
				
				// If an alternative collapsed view exists, toggle it as well
				collapsedContent = this.find('.cms-panel-content-collapsed');
				if(collapsedContent.length) {
					this.find('.cms-panel-content')[doExpand ? 'show' : 'hide']();
					this.find('.cms-panel-content-collapsed')[doExpand ? 'hide' : 'show']();
				}

				if (doSaveState !== false) {
					this.setPersistedCollapsedState(!doExpand);
				}

				// TODO Fix redraw order (inner to outer), and re-enable silent flag
				// to avoid multiple expensive redraws on a single load.
				// if(!silent) {
					this.trigger('toggle', doExpand);
					this.trigger(doExpand ? 'expand' : 'collapse');
				// }
			},
			
			expandPanel: function(force) {
				if(!force && !this.hasClass('collapsed')) return;

				this.togglePanel(true);
			},
			
			collapsePanel: function(force) {
				if(!force && this.hasClass('collapsed')) return;

				this.togglePanel(false);
			}
		});

		$('.cms-panel.collapsed .cms-panel-toggle').entwine({
			onclick: function(e) {
				this.expandPanel();
				e.preventDefault();
			}
		});
		
		$('.cms-panel *').entwine({
			getPanel: function() {
				return this.parents('.cms-panel:first');
			}
		});
				
		$('.cms-panel .toggle-expand').entwine({
			onclick: function(e) {
				e.preventDefault();
				e.stopPropagation();

				this.getPanel().expandPanel();

				this._super(e);
			}
		});
		
		$('.cms-panel .toggle-collapse').entwine({
			onclick: function(e) {
				e.preventDefault();
				e.stopPropagation();

				this.getPanel().collapsePanel();

				this._super(e);
			}
		});

		$('.cms-content-tools.collapsed').entwine({
			// Expand CMS' centre pane, when the pane itself is clicked somewhere
			onclick: function(e) {
				this.getPanel().expandPanel();

				this._super(e);
			}
		});
	});
}(jQuery));