/**
 * Ext.DataView.DragSelector plugin for Ext.DataView
 *
 * @author  Timothy Grant Vogelsang
 * @date    January 1, 2010
 *
 * @class Ext.DataView.DragSelector
 */
Ext.ns('Ext.DataView');

Ext.DataView.DragSelector = function (cfg) {
	cfg = cfg || {};
	var view, regions, proxy, tracker;
	var rs, bodyRegion, dragRegion = new Ext.lib.Region(0,0,0,0);
	var dragSafe = cfg.dragSafe === true;

	this.init = function (dataView) {
		view = dataView;
		view.on('render', onRender);
	};

	function fillRegions() {
		rs = [];
		view.all.each(function (el) {
			rs[rs.length] = el.getRegion();
		});
		bodyRegion = view.el.getRegion();
	}

	function cancelClick() {
		return false;
	}

	function onBeforeStart(e) {
		return !dragSafe || e.target == view.el.dom;
	}

	function onStart(e) {
		view.on('containerclick', cancelClick, view, {single:true});
		if (!proxy) {
			proxy = view.el.createChild({cls:'x-view-selector'});
		}else{
			proxy.setDisplayed('block');
		}
		fillRegions();
		view.clearSelections();
	}

	function onDrag(e) {
		var startXY = tracker.startXY;
		var xy = tracker.getXY();

		var x = Math.min(startXY[0], xy[0]);
		var y = Math.min(startXY[1], xy[1]);
		var w = Math.abs(startXY[0] - xy[0]);
		var h = Math.abs(startXY[1] - xy[1]);

		dragRegion.left = x;
		dragRegion.top = y;
		dragRegion.right = x+w;
		dragRegion.bottom = y+h;

		dragRegion.constrainTo(bodyRegion);
		proxy.setRegion(dragRegion);

		for (var i = 0, len = rs.length; i < len; i++) {
			var r = rs[i], sel = dragRegion.intersect(r);

			if (sel && !r.selected) {
				r.selected = true;
				view.select(i, true);
			}else if (!sel && r.selected) {
				r.selected = false;
				view.deselect(i);
			}
		}
	}

	function onEnd(e) {
		if (proxy) {
			proxy.setDisplayed(false);
		}
	}

	function onRender(view) {
		tracker = new Ext.dd.DragTracker({
			onBeforeStart: onBeforeStart,
			onStart: onStart,
			onDrag: onDrag,
			onEnd: onEnd
		});
		tracker.initEl(view.el);
	}
};