/* 	Author : Mike @ moretechtips.net
	Blog : http://www.moretechtips.net
	Project: http://code.google.com/p/blogger-related-posts
	Copyright 2009 [Mike@moretechtips.net] 
	Licensed under the Apache License, Version 2.0 
	(the "License"); you may not use this file except in compliance with the License. 
	You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 
	Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. 
*/
function relatedPostsWidget(userOp){
    var self = this;
    var op = {
        'blogURL':''
        ,'maxPosts':8
        ,'maxTags':8
        ,'maxPostsPerTag':8
        ,'containerSelector':''
        ,'tags':null
        ,'loadingText':''
        ,'loadingClass':''
        ,'relevantTip':''
        ,'relatedTitle':'Related Posts'
        ,'recentTitle':'Recent Posts'
        ,'postScoreClass':''
        ,'onLoad':false
    };
    op = $.extend({}, op, userOp);
    var tagsLoaded = 0,div= null,ul=null;
    // If no contianer selected , will create div in place of script call
    if (!op.containerSelector) {
        document.write('<div id="related-posts" />');
        op.containerSelector = '#related-posts';
    }
    // Tag json posts are loaded
    var tagLoaded = function(json,status){
        tagsLoaded++;
        if(json.feed.entry) {
            for (var i=0; i<json.feed.entry.length; i++) {
                var entry = json.feed.entry[i];
                var url='';
                for (var k=0; k<entry.link.length; k++) {
                    if(entry.link[k].rel=='alternate') {
                        url = entry.link[k].href;
                        break;
                    }
                }
                var title = entry.title.$t;
                //Ignore current url
                if(location.href.toLowerCase()!= url.toLowerCase()) addPost(url,title);
            }
        } 
        // Loading posts of all tags is done
        if(tagsLoaded>=op.tags.length) {
             ul.attr('class','');
             $('#related-posts-loadingtext',div).remove();
             // Hide extra posts if maxPosts >0
             if(op.maxPosts>0) $('li:gt('+ (op.maxPosts-1) +')',ul).remove();
        }    
    }
    // Add post and re-order
    var addPost = function(url,title) {
        //current LI items inside of UL
        var list = $('li',ul);
        for(var i=0; i<list.length; i++) {
            //get score
            var a= $('a', list.eq(i) );
            var sc = getScore(a);
            //Post exists ?
            if(a.attr('href')==url) {
                //Yes : Then increment score
                setScore(a,++sc);
                //Re-order : compare with prevoius li items
                for(var j=i-1; j>=0; j--){
                    // find the item with higher score than current
                    var jA= $('a', list.eq(j) );
                    if (getScore(jA)>sc) {
                        // re-order if only there are items in the middle to appear before
                        if(i-j>1) list.eq(j).after(list.eq(i));
                        return;
                    }
                };
                // If no higher item then this one should go first
                if(i>0) list.eq(0).before(list.eq(i));
                return;
            }
        }
        //Add new post
        ul.append('<li><a href="'+url+'" title="'+(op.relevantTip? op.relevantTip.replace('\d',1):'')+'">'+title+'</a></li>');
    }
    // parse score from attribute
    var getScore = function(a){
        var score = parseInt(a.attr('score'));
        return score>0? score : 1;
    }
    // set score from attribute
    var setScore = function(a,sc) {
        a.attr('score',sc);
        if(op.relevantTip) a.attr('title',op.relevantTip.replace('\d',sc)); 
        if(op.postScoreClass) a.attr('class',op.postScoreClass+sc); 
    }
    // init 
    var initRelatedPosts = function() {
        // append my div to user selected container 
        if(op.containerSelector != '#related-posts'){
            var container = $(op.containerSelector);
            // check contianer is there and only one for pages like home
            if (container.length!=1) return;
            div = $('<div id="related-posts"/>').appendTo(container);
        }
        else div = $(op.containerSelector); // div which I wrote on document
        
        // get tags if wasn't preset
        if (!op.tags) {
            op.tags = [];
            $('a[rel="tag"]:lt('+op.maxTags+')').each(function () {
                var tag= $.trim($(this).text().replace(/\n/g,''));
                if($.inArray(tag,op.tags)==-1) op.tags[op.tags.length]=tag;
            });
        }
        // should make recent posts but no recent title :exit
        if(op.tags.length==0 && !op.recentTitle) return;
        
        //add recent posts title
        if(op.tags.length==0) $('<b>'+op.recentTitle+'</b>').appendTo(div);
        //add related posts title if any
        else if(op.relatedTitle) $('<b>'+op.relatedTitle+'</b>').appendTo(div);
        
        //Add loading text if any
        if(op.loadingText) $('<div id="related-posts-loadingtext">'+op.loadingText+'</div>').appendTo(div);
        // Appending UL with loading class if selected
        ul= $('<ul '+(op.loadingClass? 'class="'+ op.loadingClass+'"':'')+'/>').appendTo(div);
        
        //recent posts
        if(op.tags.length==0){
            $.ajax({url:op.blogURL+'/feeds/posts/summary/'
                    ,data:{'max-results':op.maxPostsPerTag,'alt':'json-in-script'}
                    ,success:tagLoaded
                    ,dataType:'jsonp'
                    ,cache:true });
        // Tags found , do related posts widget
        }else{
            // Requesting json feeds for each tag    
            for(var t=0; t<op.tags.length;t++) 
                $.ajax({url:op.blogURL+'/feeds/posts/summary/'
                        ,data:{'category':op.tags[t],'max-results':op.maxPostsPerTag,'alt':'json-in-script'}
                        ,success:tagLoaded
                        ,dataType:'jsonp'
                        ,cache:true });
        }    
    }
    // Call init on document ready
    if(op.onLoad) $(window).load(initRelatedPosts);
    else $(document).ready(initRelatedPosts);
}