/* toc-plugin.js is part of Aloha Editor project http://aloha-editor.org
 *
 * Aloha Editor is a WYSIWYG HTML5 inline editing library and editor. 
 * Copyright (c) 2010-2012 Gentics Software GmbH, Vienna, Austria.
 * Contributors http://aloha-editor.org/contribution.php 
 * 
 * Aloha Editor is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * Aloha Editor is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * 
 * As an additional permission to the GNU GPL version 2, you may distribute
 * non-source (e.g., minimized or compacted) forms of the Aloha-Editor
 * source code without the copy of the GNU GPL normally required,
 * provided you include this license notice and a URL through which
 * recipients can access the Corresponding Source.
 */
define([
	'aloha', 
	'aloha/plugin', 
	'jquery', 
	'ui/ui', 
	'ui/button',
	'i18n!toc/nls/i18n', 
	'i18n!aloha/nls/i18n', 
	'aloha/console'
], function(
	Aloha,
    Plugin,
	jQuery,
	Ui,
	Button,
	i18n,
	i18nCore,
	console
) {
	'use strict';

	var GENTICS = window.GENTICS,
	    namespace = 'toc',
	    $containers = null,
	    allTocs = [];

	/* helper functions */
	function last(a) { return a[a.length - 1]; }
	function head(a) { return a[0]; }
	function tail(a) { return a.slice(1); }
	function indexOf(a, item) {
		return detect(a, function(cmp){
			return cmp === item;
		});
	}
	function detect(a, f) {
		for (var i = 0; i < a.length; i++) {
			if (f(a[i])) {
				return a[i];
			}
		}
		return null;
	}
	function map(a, f) {
		var result = [];
		for (var i = 0; i < a.length; i++) {
			result.push(f(a[i]));
		}
		return result;
	}
	function each(a, f) {
		map(a, f);
	}

	/**
	 * register the plugin with unique name
	 */
	return Plugin.create(namespace, {
		minEntries: 0,
		updateInterval: 5000,
		config: ['toc'],

		init: function () {
			var that = this;

			if ( typeof this.settings.minEntries === 'undefined' ) {
				this.settings.minEntries = this.minEntries;
			}
			if ( typeof this.settings.updateInterval === 'undefined' ) {
				this.settings.updateInterval = this.updateInterval;
			}

			Aloha.bind( 'aloha-editable-activated', function ( event, rangeObject ) {
				if (Aloha.activeEditable) {
					that.cfg = that.getEditableConfig( Aloha.activeEditable.obj );

					if ( jQuery.inArray( 'toc', that.cfg ) != -1 ) {
						that._insertTocButton.show(true);
		        	} else {
						that._insertTocButton.show(false);
		        		return;
		        	}
				}
			});

	        this.initButtons();
			jQuery(document).ready(function(){
				that.spawn();
			});
			
			
	    },
	
		initButtons: function () {
			var that = this;
			
			this._insertTocButton = Ui.adopt("insertToc", Button, {
		        tooltip: i18n.t('button.addtoc.tooltip'),
		        icon: 'aloha-icon aloha-icon-orderedlist',
				scope: 'Aloha.continuoustext',
		        click: function () { that.insertAtSelection($containers); }
			});
	    },
	
		register: function ($c) {
			$containers = $c;
		},
	
	    /**
	     * inserts a new TOC at the current selection
	     */
	    insertAtSelection: function($containers){
		    $containers = $containers || editableContainers();
			var id = generateId('toc');

	        // we start out with an empty ordered list
	        var $tocElement = jQuery("<ol class='toc_root'></ol>").
				attr('id', id).attr('contentEditable', 'false');
		    var range = Aloha.Selection.getRangeObject();
	        var tocEditable = Aloha.activeEditable;
	        var $tocContainer = jQuery(document.getElementById(tocEditable.getId()));
		    GENTICS.Utils.Dom.insertIntoDOM($tocElement, range, $tocContainer);

		    this.create(id).register($containers).update().tickTock();
	    },
	
		/**
		 * Spawn containers for all ols with the toc_root class.
		 */
		spawn: function ($ctx, $containers) {

			$ctx        = $ctx        || jQuery('body');
			$containers = $containers || editableContainers();
			$ctx.find('ol.toc_root').each(function(){
				var id = jQuery(this).attr('id');
				if (!id) {
					id = generateId('toc');
					jQuery(this).attr('id', id);
				}
				that.create(id).register($containers).tickTock();
			});
		},

	    create: function (id) {
			allTocs.push(this);
			
	        return {
	            'id': id,
	            '$containers': jQuery(),
				'settings': this.settings,
	        /**
	         * find the TOC root element for this instance
	         */
	        root: function(){
	            return jQuery(document.getElementById(this.id));
	        },
	        /**
	         * registers the given containers with the TOC. a
	         * container is an element that may begin or contain
	         * sections. Note: use .live on all [contenteditable=true]
			 * to catch dynamically added editables.
			 * the same containers can be passed in multiple times. they will
			 * be registered only once.
	         */
	        register: function ($containers){
				var self = this;
				// the .add() method ensures that the $containers will be in
				// document order (required for correct TOC order)
				
	            self.$containers = self.$containers.add($containers);
	            self.$containers.filter(function(){
					return !jQuery(this).data(namespace + '.' + self.id + '.listening');
				}).each(function(){
		            var $container = jQuery(this);
					$container.data(namespace + '.' + self.id + '.listening', true);
		            $container.bind('blur', function(){
				        self.cleanupIds($container.get(0));
				        self.update($container);
		            });
	            });
				return self;
	        },
			tickTock: function (interval) {
				var self = this;
				interval = interval || this.settings.updateInterval;
				if (!interval) {
					return;
				}
				window.setInterval(function(){
					self.register(editableContainers());
					// TODO: use the active editable instead of rebuilding
					// the entire TOC
					self.update();
				}, interval);
				return self;
			},
	        /**
	         * there are various ways which can cause duplicate ids on targets
	         * (e.g. pressing enter in a heading and writing in a new line, or
	         * copy&pasting). Passing a ctx updates only those elements
	         * either inside or equal to it.
	         * TODO: to be correct this should do
	         *  a $.contains(documentElement...
	         */
	        cleanupIds: function (ctx) {
	            var ids = [],
					that = this;
	            this.headings(this.$containers).each(function(){
	                var id = jQuery(this).attr('id');
	                if (   (id && -1 != jQuery.inArray(id, ids))
	                    || (   ctx
	                        && (jQuery.contains(ctx, this) || ctx === this)))
	                {
	                    jQuery(this).attr('id', generateId(this));
	                }
	                ids.push(id);
	            });
				return this;
	        },
	        /**
	         * Updates the TOC from the sections in the given context, or in
	         * all containers that have been registered with this TOC, if no
	         * context is given.
	         */
	        update: function ($ctx) {
	            var self = this;
	            $ctx = $ctx || self.$containers;
	            var outline = this.outline(self.$containers);
	            var ancestors = [self.root()];
	            var prevSiblings = [];
				//TODO: handle TOC rebuilding more intelligently. currently,
				//the TOC is always rebuilt from scratch.
				last(ancestors).empty();
	            (function descend(outline) {
					var prevSiblings = [];
	                each(outline, function (node) {
			            var $section = head(node);
	                    var $entry = self.linkSection($section, ancestors, prevSiblings);
	                    ancestors.push($entry);
	                    descend(tail(node));
	                    ancestors.pop();
	                    prevSiblings.push($entry);
	                });
	            })(tail(outline));

	            // count number of li's in the TOC, if less than minEntries, hide the TOC
	            var minEntries = self.root().attr('data-TOC-minEntries') || this.settings.minEntries;
	            if (self.root().find('li').length >= minEntries) {
	            	self.root().show();
	            } else {
	            	self.root().hide();
	            }

				return this;
	        },
	        /**
	         * updates or creates an entry in the TOC for the given section.
	         */
	        linkSection: function ($section, ancestors, prevSiblings) {
	            var linkId = $section.eq(0).attr('id');
	            if (!linkId) {
	                linkId = generateId($section.get(0));
	                $section.eq(0).attr('id', linkId);
	            }
				var $root = this.root();
	            var $entry = anchorFromLinkId($root, linkId);
				if (!$entry.length) {
					$entry = jQuery('<li><a/></li>');
				}
	            $entry.find('a').
	                attr('href', '#' + linkId).
	                text($section.eq(0).text());
				if (last(prevSiblings)) {
					last(prevSiblings).after($entry);
				}
				else {
					if (last(ancestors).get(0) == $root.get(0)) {
						$root.append($entry);
					}
					else {
						var $subToc = jQuery('<ol/>').append($entry);
						last(ancestors).append($subToc);
					}
				}
	            return $entry;
	        },

		    /**
		     * returns a tree of sections in the given context. if the context
		     * element(s) begin a section, they will be included. First element
		     * of each branch in the tree is a $(section) or $() for the
		     * root node.
		     * TODO: http://www.w3.org/TR/html5/sections.html#outline
		     */
		    outline: function (ctx) {
		        var rootNode = [jQuery()];
		        var potentialParents = [rootNode];
		        this.headings(ctx).each(function(){
		            var $heading = jQuery(this);
		            var nodeName = this.nodeName.toLowerCase();
		            var hLevels = ['h6', 'h5', 'h4', 'h3', 'h2', 'h1'];
		            var currLevel = jQuery.inArray(nodeName, hLevels);
		            var higherEq = hLevels.slice(currLevel).join(',');
		            var $section = $heading.nextUntil(higherEq).andSelf();
		            var node = [$section];

		            var parent = detect(potentialParents, function (parent) {
		                var parentSection = parent[0];
		                return !parentSection.length || //top-level contains everything
		                    detect(parentSection, function (sectionElem) {
		                        return $heading.get(0) === sectionElem ||
								       jQuery.contains(sectionElem, $heading.get(0));
			                });
		            });
		            parent.push(node);
		            potentialParents.splice(0, indexOf(potentialParents, parent), node);
		        });
		        return rootNode;
		    },

		    headings: function ($ctx) {
			    return $ctx.find(':header').add($ctx.filter(':header'));
		    }



		}
		}

	});
	
	//-------------- module methods -----------------

    function editableContainers () {
	    return jQuery(map(Aloha.editables, function (editable) {
				    return document.getElementById(editable.getId());
			    }));
    }

    function anchorFromLinkId ($ctx, linkId) {
        return linkId ? $ctx.find('a[href $= "#' + linkId + '"]') : jQuery();
    }

    function linkIdFromAnchor ($anchor){
        var href = $anchor.attr('href');
        return href ? href.match(/#(.*?)$/)[1] : null;
    }

	function generateId (elemOrText) {
	    var validId;
	    if (typeof elemOrText == "object") {
	        validId = jQuery(elemOrText).text().
	            replace(/[^a-zA-Z-]+/g, '-').
	            replace(/^[^a-zA-Z]+/, '');
	    } else if (elemOrText) {
	        validId = elemOrText;
	    }
	    for (var uniquifier = 0;; uniquifier++) {
	        var uniqueId = validId;
	        if (uniquifier) {
	            uniqueId += '-' + uniquifier;
	        }
	        var conflict = document.getElementById(uniqueId);
	        if (   !conflict
	            || (   typeof elemOrText == "object"
	                && conflict === elemOrText))
	        {
				return uniqueId;
	        }
	    }
		//unreachable
	}
});