// script.aculo.us is freely distributable under the terms of an MIT-style license.

// For details, see the script.aculo.us web site: http://script.aculo.us/

if(Object.isUndefined(Effect))

  throw("dragdrop.js requires including script.aculo.us' effects.js library");

var Droppables = {

  drops: [],

  remove: function(element) {

    this.drops = this.drops.reject(function(d) { return d.element==$(element) });

  },

  add: function(element) {

    element = $(element);

    var options = Object.extend({

      greedy:     true,

      hoverclass: null,

      tree:       false

    }, arguments[1] || { });

    // cache containers

    if(options.containment) {

      options._containers = [];

      var containment = options.containment;

      if(Object.isArray(containment)) {

        containment.each( function(c) { options._containers.push($(c)) });

      } else {

        options._containers.push($(containment));

      }

    }

    if(options.accept) options.accept = [options.accept].flatten();

    Element.makePositioned(element); // fix IE

    options.element = element;

    this.drops.push(options);

  },

  findDeepestChild: function(drops) {

    deepest = drops[0];

    for (i = 1; i < drops.length; ++i)

      if (Element.isParent(drops[i].element, deepest.element))

        deepest = drops[i];

    return deepest;

  },

  isContained: function(element, drop) {

    var containmentNode;

    if(drop.tree) {

    } else {

      containmentNode = element.parentNode;

    }

    return drop._containers.detect(function(c) { return containmentNode == c });

  },

  isAffected: function(point, element, drop) {

    return (

      (drop.element!=element) &&

      ((!drop._containers) ||

        this.isContained(element, drop)) &&

      ((!drop.accept) ||

          function(v) { return drop.accept.include(v) } ) )) &&

      Position.within(drop.element, point[0], point[1]) );

  },

  deactivate: function(drop) {

    if(drop.hoverclass)

      Element.removeClassName(drop.element, drop.hoverclass);

    this.last_active = null;

  },

  activate: function(drop) {

    if(drop.hoverclass)

      Element.addClassName(drop.element, drop.hoverclass);

    this.last_active = drop;

  },

  show: function(point, element) {

    if(!this.drops.length) return;

    var drop, affected = [];

    this.drops.each( function(drop) {

      if(Droppables.isAffected(point, element, drop))

        affected.push(drop);

    });

    if(affected.length>0)

      drop = Droppables.findDeepestChild(affected);

    if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);

    if (drop) {

      Position.within(drop.element, point[0], point[1]);

      if(drop.onHover)

        drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));

      if (drop != this.last_active) Droppables.activate(drop);

    }

  },

  fire: function(event, element) {

    if(!this.last_active) return;

    Position.prepare();

    if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))

      if (this.last_active.onDrop) {

      }

  },

  reset: function() {

    if(this.last_active)

      this.deactivate(this.last_active);

  }

var Draggables = {

  drags: [],

  observers: [],

  register: function(draggable) {

    if(this.drags.length == 0) {

      this.eventMouseUp   = this.endDrag.bindAsEventListener(this);

      this.eventMouseMove = this.updateDrag.bindAsEventListener(this);

      this.eventKeypress  = this.keyPress.bindAsEventListener(this);

      Event.observe(document, "mouseup", this.eventMouseUp);

      Event.observe(document, "mousemove", this.eventMouseMove);

      Event.observe(document, "keypress", this.eventKeypress);

    }

    this.drags.push(draggable);

  },

  unregister: function(draggable) {

    this.drags = this.drags.reject(function(d) { return d==draggable });

    if(this.drags.length == 0) {

      Event.stopObserving(document, "mouseup", this.eventMouseUp);

      Event.stopObserving(document, "mousemove", this.eventMouseMove);

      Event.stopObserving(document, "keypress", this.eventKeypress);

    }

  },

  activate: function(draggable) {

    } else {

      window.focus(); // allows keypress events if window isn't currently focused, fails for Safari

      this.activeDraggable = draggable;

    }

  },

  deactivate: function() {

    this.activeDraggable = null;

  },

  updateDrag: function(event) {

    if(!this.activeDraggable) return;

    var pointer = [Event.pointerX(event), Event.pointerY(event)];

    // Mozilla-based browsers fire successive mousemove events with

    // the same coordinates, prevent needless redrawing (moz bug?)

    if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;

    this._lastPointer = pointer;

    this.activeDraggable.updateDrag(event, pointer);

  },

  endDrag: function(event) {

    }

    if(!this.activeDraggable) return;

    this._lastPointer = null;

    this.activeDraggable.endDrag(event);

    this.activeDraggable = null;

  },

  keyPress: function(event) {

    if(this.activeDraggable)

      this.activeDraggable.keyPress(event);

  },

  addObserver: function(observer) {

    this.observers.push(observer);

    this._cacheObserverCallbacks();

  },

  removeObserver: function(element) {  // element instead of observer fixes mem leaks

    this.observers = this.observers.reject( function(o) { return o.element==element });

    this._cacheObserverCallbacks();

  },

  notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'

    if(this[eventName+'Count'] > 0)

      this.observers.each( function(o) {

        if(o[eventName]) o[eventName](eventName, draggable, event);

      });

    if(draggable.options[eventName]) draggable.options[eventName](draggable, event);

  },

  _cacheObserverCallbacks: function() {

    ['onStart','onEnd','onDrag'].each( function(eventName) {

      Draggables[eventName+'Count'] = Draggables.observers.select(

        function(o) { return o[eventName]; }

      ).length;

    });

  }

/*--------------------------------------------------------------------------*/

var Draggable = Class.create({

  initialize: function(element) {

    var defaults = {

      handle: false,

      reverteffect: function(element, top_offset, left_offset) {

        var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;

        new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,

          queue: {scope:'_draggable', position:'end'}

        });

      },

      endeffect: function(element) {

        var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;

          queue: {scope:'_draggable', position:'end'},

          }

      },

      zindex: 1000,

      revert: false,

      quiet: false,

      scroll: false,

      scrollSensitivity: 20,

      scrollSpeed: 15,

      snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }

      delay: 0

    };

    if(!arguments[1] || Object.isUndefined(arguments[1].endeffect))

      Object.extend(defaults, {

        starteffect: function(element) {

          element._opacity = Element.getOpacity(element);

          Draggable._dragging[element] = true;

        }

      });

    var options = Object.extend(defaults, arguments[1] || { });

    this.element = $(element);

    if(options.handle && Object.isString(options.handle))

      this.handle = this.element.down('.'+options.handle, 0);

    if(!this.handle) this.handle = $(options.handle);

    if(!this.handle) this.handle = this.element;

    if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {

      options.scroll = $(options.scroll);

      this._isScrollChild = Element.childOf(this.element, options.scroll);

    }

    this.options  = options;

    this.eventMouseDown = this.initDrag.bindAsEventListener(this);

    Event.observe(this.handle, "mousedown", this.eventMouseDown);

    Draggables.register(this);

  },

  destroy: function() {

    Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);

    Draggables.unregister(this);

  },

  currentDelta: function() {

    return([

      parseInt(Element.getStyle(this.element,'left') || '0'),

      parseInt(Element.getStyle(this.element,'top') || '0')]);

  },

  initDrag: function(event) {

    if(!Object.isUndefined(Draggable._dragging[this.element]) &&

      Draggable._dragging[this.element]) return;

      // abort on form elements, fixes a Firefox issue

      var src = Event.element(event);

      if((tag_name = src.tagName.toUpperCase()) && (

        tag_name=='INPUT' ||

        tag_name=='SELECT' ||

        tag_name=='OPTION' ||

        tag_name=='BUTTON' ||

        tag_name=='TEXTAREA')) return;

      var pointer = [Event.pointerX(event), Event.pointerY(event)];

      this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });

      Draggables.activate(this);

      Event.stop(event);

    }

  },

  startDrag: function(event) {

    this.dragging = true;

    if(!this.delta)

      this.delta = this.currentDelta();

    if(this.options.zindex) {

      this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);

      this.element.style.zIndex = this.options.zindex;

    }

    if(this.options.ghosting) {