/**
 * @author alexander.farkas
 *
 * @version 2.5
 * project site: http://plugins.jquery.com/project/AjaxManager
 */
(function($){

  $.manageAjax = (function(){
    var cache       = {},
      queues      = {},
      presets     = {},
      activeRequest   = {},
      allRequests   = {},
      triggerEndCache = {},
      defaults    = {
            queue: true, //clear
            maxRequests: 1,
            abortOld: false,
            preventDoubbleRequests: true,
            cacheResponse: false,
            complete: function(){},
            error: function(ahr, status){
              var opts = this;
              if(status &&  status.indexOf('error') != -1){
                setTimeout(function(){
                  var errStr = status +': ';
                  if(ahr.status){
                    errStr += 'status: '+ ahr.status +' | ';
                  }
                  errStr += 'URL: '+ opts.url;
                  throw new Error(errStr);
                }, 1);
              }
            },
            success: function(){},
            abort: function(){}
        }
    ;

    function create(name, settings){
      var publicMethods = {};
      presets[name] = presets[name] ||
        {};

      $.extend(true, presets[name], $.ajaxSettings, defaults, settings);
      if(!allRequests[name]){
        allRequests[name]   = {};
        activeRequest[name] = {};
        activeRequest[name].queue = [];
        queues[name]    = [];
        triggerEndCache[name] = [];
      }
      $.each($.manageAjax, function(fnName, fn){
        if($.isFunction(fn) && fnName.indexOf('_') !== 0){
          publicMethods[fnName] = function(param, param2){
            if(param2 && typeof param === 'string'){
              param = param2;
            }
            fn(name, param);
          };
        }
      });
      return publicMethods;
    }

    function complete(opts, args){

      if(args[1] == 'success' || args[1] == 'notmodified'){
        opts.success.apply(opts, [args[0].successData, args[1]]);
        if (opts.global) {
          $.event.trigger("ajaxSuccess", args);
        }
      }

      if(args[1] === 'abort'){
        opts.abort.apply(opts, args);
        if(opts.global){
          $.active--;
          $.event.trigger("ajaxAbort", args);
        }
      }

      opts.complete.apply(opts, args);

      if (opts.global) {
        $.event.trigger("ajaxComplete", args);
      }

      if (opts.global && ! $.active){
        $.event.trigger("ajaxStop");
      }
      //args[0] = null;
    }

    function proxy(oldFn, fn){
      return function(xhr, s, e){
        fn.call(this, xhr, s, e);
        oldFn.call(this, xhr, s, e);
        xhr = null;
        e = null;
      };
    }


    function callQueueFn(name){
      var q = queues[name];
      if(q && q.length){
        var fn = q.shift();
        if(fn){
          fn();
        }
      }
    }


    function add(name, opts){
      if(!presets[name]){
        create(name, opts);
      }
      opts = $.extend({}, presets[name], opts);
      //aliases
      var allR  = allRequests[name],
        activeR = activeRequest[name],
        queue = queues[name];

      var id        = opts.type +'_'+ opts.url.replace(/\./g, '_'),
        triggerStart  = true,
        oldComplete   = opts.complete,
        ajaxFn      = function(){
                  activeR[id] = {
                    xhr: $.ajax(opts),
                    ajaxManagerOpts: opts
                  };
                  activeR.queue.push(id);
                  return id;
                }
        ;

      if(opts.data){
        id += (typeof opts.data == 'string') ? opts.data : $.param(opts.data);
      }

      if(opts.preventDoubbleRequests && allRequests[name][id]){
        return false;
      }

      allR[id] = true;

      opts.complete = function(xhr, s, e){
        var triggerEnd = true;
        if(opts.abortOld){
          $.each(activeR.queue, function(i, activeID){
            if(activeID == id){
              return false;
            }
            abort(name, activeID);
            return activeID;
          });
        }
        oldComplete.call(this, xhr, s, e);
        //stop memory leak
        if(activeRequest[name][id]){
          if(activeRequest[name][id] && activeRequest[name][id].xhr){
            activeRequest[name][id].xhr = null;
          }
          activeRequest[name][id] = null;
        }
        triggerEndCache[name].push({xhr: xhr, status: s});
        xhr = null;
        activeRequest[name].queue = $.grep(activeRequest[name].queue, function(qid){
          return (qid !== id);
        });
        allR[id] = false;

        e = null;

        delete activeRequest[name][id];

        $.each(activeR, function(id, queueRunning){
          if(id !== 'queue' || queueRunning.length){
            triggerEnd = false;
            return false;
          }
        });

        if(triggerEnd){
          $.event.trigger(name +'End', [triggerEndCache[name]]);
          $.each(triggerEndCache[name], function(i, cached){
            cached.xhr = null; //memory leak
          });
          triggerEndCache[name] = [];
        }
      };

      if(cache[id]){
        ajaxFn = function(){
          activeR.queue.push(id);
          complete(opts, cache[id]);
          return id;
        };
      } else if(opts.cacheResponse){
         opts.complete = proxy(opts.complete, function(xhr, s){
          if( s !== "success" && s !== "notmodified" ){
            return false;
          }
          cache[id][0].responseXML  = xhr.responseXML;
          cache[id][0].responseText   = xhr.responseText;
          cache[id][1]        = s;
          //stop memory leak
          xhr = null;
          return id; //strict
        });

        opts.success = proxy(opts.success, function(data, s){
          cache[id] = [{
            successData: data,
            ajaxManagerOpts: opts
          }, s];
          data = null;
        });
      }

      ajaxFn.ajaxID = id;

      $.each(activeR, function(id, queueRunning){
        if(id !== 'queue' || queueRunning.length){
          triggerStart = false;
          return false;
        }
      });

      if(triggerStart){
        $.event.trigger(name +'Start');
      }
      if(opts.queue){
        opts.complete = proxy(opts.complete, function(){

          callQueueFn(name);
        });

        if(opts.queue === 'clear'){
          queue = clear(name);
        }

        queue.push(ajaxFn);

        if(activeR.queue.length < opts.maxRequests){
          callQueueFn(name);
        }
        return id;
      }



      return ajaxFn();
    }

    function clear(name, shouldAbort){
      $.each(queues[name], function(i, fn){
        allRequests[name][fn.ajaxID] = false;
      });
      queues[name] = [];

      if(shouldAbort){
        abort(name);
      }
      return queues[name];
    }

    function getXHR(name, id){
      var ar = activeRequest[name];
      if(!ar || !allRequests[name][id]){
        return false;
      }
      if(ar[id]){
        return ar[id].xhr;
      }
      var queue = queues[name],
        xhrFn;
      $.each(queue, function(i, fn){
        if(fn.ajaxID == id){
          xhrFn = [fn, i];
          return false;
        }
        return xhrFn;
      });
      return xhrFn;
    }

    function abort(name, id){
      var ar = activeRequest[name];
      if(!ar){
        return false;
      }
      function abortID(qid){
        if(qid !== 'queue' && ar[qid] && typeof ar[qid].xhr !== 'unedfiend' && typeof ar[qid].xhr.abort !== 'unedfiend'){
          ar[qid].xhr.abort();
          complete(ar[qid].ajaxManagerOpts, [ar[qid].xhr, 'abort']);
        }
        return null;
      }
      if(id){
        return abortID(id);
      }
      return $.each(ar, abortID);
    }

    function unload(){
      $.each(presets, function(name){
        clear(name, true);
      });
      cache = {};
    }

    return {
      defaults:     defaults,
      add:      add,
      create:     create,
      cache:      cache,
      abort:      abort,
      clear:      clear,
      getXHR:     getXHR,
      _activeRequest: activeRequest,
      _complete:    complete,
      _allRequests:   allRequests,
      _unload:    unload
    };
  })();
  //stop memory leaks
  $(window).unload($.manageAjax._unload);
})(jQuery);