/*
	Copyright (c) 2004-2008, The Dojo Foundation
	All Rights Reserved.

	Licensed under the Academic Free License version 2.1 or above OR the
	modified BSD license. For more information on Dojo licensing, see:

		http://dojotoolkit.org/book/dojo-book-0-9/introduction/licensing
*/


if(!dojo._hasResource["dojo.dnd.Source"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojo.dnd.Source"] = true;
dojo.provide("dojo.dnd.Source");

dojo.require("dojo.dnd.Selector");
dojo.require("dojo.dnd.Manager");

/*
	Container property:
		"Horizontal"- if this is the horizontal container
	Source states:
		""			- normal state
		"Moved"		- this source is being moved
		"Copied"	- this source is being copied
	Target states:
		""			- normal state
		"Disabled"	- the target cannot accept an avatar
	Target anchor state:
		""			- item is not selected
		"Before"	- insert point is before the anchor
		"After"		- insert point is after the anchor
*/

/*=====
dojo.dnd.__SourceArgs = function(){
	//	summary:
	//		a dict of parameters for DnD Source configuration. Note that any
	//		property on Source elements may be configured, but this is the
	//		short-list
	//	isSource: Boolean?
	//		can be used as a DnD source. Defaults to true.
	//	accept: Array?
	//		list of accepted types (text strings) for a target; defaults to
	//		["text"]
	//	horizontal: Boolean?
	//		a horizontal container, if true, vertical otherwise or when omitted
	//	copyOnly: Boolean?
	//		always copy items, if true, use a state of Ctrl key otherwise
	//	withHandles: Boolean?
	//		allows dragging only by handles
	this.isSource = isSource;
	this.accept = accept;
	this.horizontal = horizontal;
	this.copyOnly = copyOnly;
	this.withHandles = withHandles;
}
=====*/

dojo.declare("dojo.dnd.Source", dojo.dnd.Selector, {
	// summary: a Source object, which can be used as a DnD source, or a DnD target
	
	// object attributes (for markup)
	isSource: true,
	horizontal: false,
	copyOnly: false,
	skipForm: false,
	withHandles: false,
	accept: ["text"],
	
	constructor: function(/*DOMNode|String*/node, /*dojo.dnd.__SourceArgs?*/params){
		// summary: 
		//		a constructor of the Source
		// node:
		//		node or node's id to build the source on
		// params: 
		//		any property of this class may be configured via the params
		//		object which is mixed-in to the `dojo.dnd.Source` instance
		dojo.mixin(this, dojo.mixin({}, params));
		var type = this.accept;
		if(type.length){
			this.accept = {};
			for(var i = 0; i < type.length; ++i){
				this.accept[type[i]] = 1;
			}
		}
		// class-specific variables
		this.isDragging = false;
		this.mouseDown = false;
		this.targetAnchor = null;
		this.targetBox = null;
		this.before = true;
		// states
		this.sourceState  = "";
		if(this.isSource){
			dojo.addClass(this.node, "dojoDndSource");
		}
		this.targetState  = "";
		if(this.accept){
			dojo.addClass(this.node, "dojoDndTarget");
		}
		if(this.horizontal){
			dojo.addClass(this.node, "dojoDndHorizontal");
		}
		// set up events
		this.topics = [
			dojo.subscribe("/dnd/source/over", this, "onDndSourceOver"),
			dojo.subscribe("/dnd/start",  this, "onDndStart"),
			dojo.subscribe("/dnd/drop",   this, "onDndDrop"),
			dojo.subscribe("/dnd/cancel", this, "onDndCancel")
		];
	},
	
	// methods
	checkAcceptance: function(source, nodes){
		// summary: checks, if the target can accept nodes from this source
		// source: Object: the source which provides items
		// nodes: Array: the list of transferred items
		if(this == source){ return true; }
		for(var i = 0; i < nodes.length; ++i){
			var type = source.getItem(nodes[i].id).type;
			// type instanceof Array
			var flag = false;
			for(var j = 0; j < type.length; ++j){
				if(type[j] in this.accept){
					flag = true;
					break;
				}
			}
			if(!flag){
				return false;	// Boolean
			}
		}
		return true;	// Boolean
	},
	copyState: function(keyPressed){
		// summary: Returns true, if we need to copy items, false to move.
		//		It is separated to be overwritten dynamically, if needed.
		// keyPressed: Boolean: the "copy" was pressed
		return this.copyOnly || keyPressed;	// Boolean
	},
	destroy: function(){
		// summary: prepares the object to be garbage-collected
		dojo.dnd.Source.superclass.destroy.call(this);
		dojo.forEach(this.topics, dojo.unsubscribe);
		this.targetAnchor = null;
	},

	// markup methods
	markupFactory: function(params, node){
		params._skipStartup = true;
		return new dojo.dnd.Source(node, params);
	},

	// mouse event processors
	onMouseMove: function(e){
		// summary: event processor for onmousemove
		// e: Event: mouse event
		if(this.isDragging && this.targetState == "Disabled"){ return; }
		dojo.dnd.Source.superclass.onMouseMove.call(this, e);
		var m = dojo.dnd.manager();
		if(this.isDragging){
			// calculate before/after
			var before = false;
			if(this.current){
				if(!this.targetBox || this.targetAnchor != this.current){
					this.targetBox = {
						xy: dojo.coords(this.current, true),
						w: this.current.offsetWidth,
						h: this.current.offsetHeight
					};
				}
				if(this.horizontal){
					before = (e.pageX - this.targetBox.xy.x) < (this.targetBox.w / 2);
				}else{
					before = (e.pageY - this.targetBox.xy.y) < (this.targetBox.h / 2);
				}
			}
			if(this.current != this.targetAnchor || before != this.before){
				this._markTargetAnchor(before);
				m.canDrop(!this.current || m.source != this || !(this.current.id in this.selection));
			}
		}else{
			if(this.mouseDown && this.isSource){
				var nodes = this.getSelectedNodes();
				if(nodes.length){
					m.startDrag(this, nodes, this.copyState(dojo.dnd.getCopyKeyState(e)));
				}
			}
		}
	},
	onMouseDown: function(e){
		// summary: event processor for onmousedown
		// e: Event: mouse event
		if(this._legalMouseDown(e) && (!this.skipForm || !dojo.dnd.isFormElement(e))){
			this.mouseDown = true;
			this.mouseButton = e.button;
			dojo.dnd.Source.superclass.onMouseDown.call(this, e);
		}
	},
	onMouseUp: function(e){
		// summary: event processor for onmouseup
		// e: Event: mouse event
		if(this.mouseDown){
			this.mouseDown = false;
			dojo.dnd.Source.superclass.onMouseUp.call(this, e);
		}
	},
	
	// topic event processors
	onDndSourceOver: function(source){
		// summary: topic event processor for /dnd/source/over, called when detected a current source
		// source: Object: the source which has the mouse over it
		if(this != source){
			this.mouseDown = false;
			if(this.targetAnchor){
				this._unmarkTargetAnchor();
			}
		}else if(this.isDragging){
			var m = dojo.dnd.manager();
			m.canDrop(this.targetState != "Disabled" && (!this.current || m.source != this || !(this.current.id in this.selection)));
		}
	},
	onDndStart: function(source, nodes, copy){
		// summary: topic event processor for /dnd/start, called to initiate the DnD operation
		// source: Object: the source which provides items
		// nodes: Array: the list of transferred items
		// copy: Boolean: copy items, if true, move items otherwise
		if(this.isSource){
			this._changeState("Source", this == source ? (copy ? "Copied" : "Moved") : "");
		}
		var accepted = this.accept && this.checkAcceptance(source, nodes);
		this._changeState("Target", accepted ? "" : "Disabled");
		if(accepted && this == source){
			dojo.dnd.manager().overSource(this);
		}
		this.isDragging = true;
	},
	onDndDrop: function(source, nodes, copy){
		// summary: topic event processor for /dnd/drop, called to finish the DnD operation
		// source: Object: the source which provides items
		// nodes: Array: the list of transferred items
		// copy: Boolean: copy items, if true, move items otherwise
		do{ //break box
			if(this.containerState != "Over"){ break; }
			var oldCreator = this._normalizedCreator;
			if(this != source){
				// transferring nodes from the source to the target
				if(this.creator){
					// use defined creator
					this._normalizedCreator = function(node, hint){
						return oldCreator.call(this, source.getItem(node.id).data, hint);
					};
				}else{
					// we have no creator defined => move/clone nodes
					if(copy){
						// clone nodes
						this._normalizedCreator = function(node, hint){
							var t = source.getItem(node.id);
							var n = node.cloneNode(true);
							n.id = dojo.dnd.getUniqueId();
							return {node: n, data: t.data, type: t.type};
						};
					}else{
						// move nodes
						this._normalizedCreator = function(node, hint){
							var t = source.getItem(node.id);
							source.delItem(node.id);
							return {node: node, data: t.data, type: t.type};
						};
					}
				}
			}else{
				// transferring nodes within the single source
				if(this.current && this.current.id in this.selection){ break; }
				if(this.creator){
					// use defined creator
					if(copy){
						// create new copies of data items
						this._normalizedCreator = function(node, hint){
							return oldCreator.call(this, source.getItem(node.id).data, hint);
						};
					}else{
						// move nodes
						if(!this.current){ break; }
						this._normalizedCreator = function(node, hint){
							var t = source.getItem(node.id);
							return {node: node, data: t.data, type: t.type};
						};
					}
				}else{
					// we have no creator defined => move/clone nodes
					if(copy){
						// clone nodes
						this._normalizedCreator = function(node, hint){
							var t = source.getItem(node.id);
							var n = node.cloneNode(true);
							n.id = dojo.dnd.getUniqueId();
							return {node: n, data: t.data, type: t.type};
						};
					}else{
						// move nodes
						if(!this.current){ break; }
						this._normalizedCreator = function(node, hint){
							var t = source.getItem(node.id);
							return {node: node, data: t.data, type: t.type};
						};
					}
				}
			}
			this._removeSelection();
			if(this != source){
				this._removeAnchor();
			}
			if(this != source && !copy && !this.creator){
				source.selectNone();
			}
			this.insertNodes(true, nodes, this.before, this.current);
			if(this != source && !copy && this.creator){
				source.deleteSelectedNodes();
			}
			this._normalizedCreator = oldCreator;
		}while(false);
		this.onDndCancel();
	},
	onDndCancel: function(){
		// summary: topic event processor for /dnd/cancel, called to cancel the DnD operation
		if(this.targetAnchor){
			this._unmarkTargetAnchor();
			this.targetAnchor = null;
		}
		this.before = true;
		this.isDragging = false;
		this.mouseDown = false;
		delete this.mouseButton;
		this._changeState("Source", "");
		this._changeState("Target", "");
	},
	
	// utilities
	onOverEvent: function(){
		// summary: this function is called once, when mouse is over our container
		dojo.dnd.Source.superclass.onOverEvent.call(this);
		dojo.dnd.manager().overSource(this);
	},
	onOutEvent: function(){
		// summary: this function is called once, when mouse is out of our container
		dojo.dnd.Source.superclass.onOutEvent.call(this);
		dojo.dnd.manager().outSource(this);
	},
	_markTargetAnchor: function(before){
		// summary: assigns a class to the current target anchor based on "before" status
		// before: Boolean: insert before, if true, after otherwise
		if(this.current == this.targetAnchor && this.before == before){ return; }
		if(this.targetAnchor){
			this._removeItemClass(this.targetAnchor, this.before ? "Before" : "After");
		}
		this.targetAnchor = this.current;
		this.targetBox = null;
		this.before = before;
		if(this.targetAnchor){
			this._addItemClass(this.targetAnchor, this.before ? "Before" : "After");
		}
	},
	_unmarkTargetAnchor: function(){
		// summary: removes a class of the current target anchor based on "before" status
		if(!this.targetAnchor){ return; }
		this._removeItemClass(this.targetAnchor, this.before ? "Before" : "After");
		this.targetAnchor = null;
		this.targetBox = null;
		this.before = true;
	},
	_markDndStatus: function(copy){
		// summary: changes source's state based on "copy" status
		this._changeState("Source", copy ? "Copied" : "Moved");
	},
	_legalMouseDown: function(e){
		// summary: checks if user clicked on "approved" items
		// e: Event: mouse event
		if(!this.withHandles){ return true; }
		for(var node = e.target; node && !dojo.hasClass(node, "dojoDndItem"); node = node.parentNode){
			if(dojo.hasClass(node, "dojoDndHandle")){ return true; }
		}
		return false;	// Boolean
	}
});

dojo.declare("dojo.dnd.Target", dojo.dnd.Source, {
	// summary: a Target object, which can be used as a DnD target
	
	constructor: function(node, params){
		// summary: a constructor of the Target --- see the Source constructor for details
		this.isSource = false;
		dojo.removeClass(this.node, "dojoDndSource");
	},

	// markup methods
	markupFactory: function(params, node){
		params._skipStartup = true;
		return new dojo.dnd.Target(node, params);
	}
});

}
