/*
 * positionBy 1.0.7 (2008-01-29)
 *
 * Copyright (c) 2006,2007 Jonathan Sharp (http://jdsharp.us)
 * Dual licensed under the MIT (MIT-LICENSE.txt)
 * and GPL (GPL-LICENSE.txt) licenses.
 *
 * http://jdsharp.us/
 *
 * Built upon jQuery 1.2.2 (http://jquery.com)
 * This also requires the jQuery dimensions plugin
 */
(function($) {
	/**
	* This function centers an absolutely positioned element
	*/
	/*
	$.fn.positionCenter = function(offsetLeft, offsetTop) {
	var offsetLeft 	= offsetLeft || 1;
	var offsetTop 	= offsetTop || 1;

		var ww = $(window).width();
	var wh = $(window).height();
	var sl = $(window).scrollLeft();
	var st = $(window).scrollTop();

		return this.each(function() {
	var $t = $(this);
			
	// If we are not visible we have to display our element (with a negative position offscreen)

			var left = Math.round( ( ww - $t.outerWidth() ) / 2 );
	if ( left < 0 ) {
	left = 0;
	} else {
	left *= offsetLeft;
	}
	left += sl;
	var top  = Math.round( ( wh - $t.outerHeight() ) / 2 );
	if ( top < 0 ) {
	top = 0;
	} else {
	top *= offsetTop;
	}
	top += st;

			$(this).parents().each(function() {
	var $this = $(this);
	if ( $this.css('position') != 'static' ) {
	var o = $this.offset();
	left += -o.left;
	top	 += -o.top;
	return false;
	}
	});

			$t.css({left: left, top: top});
	});
	};
	*/

	// Our range object is used in calculating positions
	var Range = function(x1, y1, x2, y2) {
		this.x1 = x1; this.x2 = x2;
		this.y1 = y1; this.y2 = y2;
	};
	Range.prototype.contains = function(range) {
		return (this.x1 <= range.x1 && range.x2 <= this.x2)
				&&
				(this.y1 <= range.y1 && range.y2 <= this.y2);
	};
	Range.prototype.transform = function(x, y) {
		return new Range(this.x1 + x, this.y1 + y, this.x2 + x, this.y2 + y);
	};

	$.fn.positionBy = function(args) {
		var date1 = new Date();
		if (this.length == 0) {
			return this;
		}

		var args = $.extend({	// The target element to position us relative to
			target: null,
			// The target's corner, possible values 0-3
			targetPos: null,
			// The element's corner, possible values 0-3
			elementPos: null,

			// A raw x,y coordinate
			x: null,
			y: null,

			sx: null,
			sy: null,

			// Pass in an array of positions that are valid 0-15
			positions: null,

			// Add the final position class to the element (eg. positionBy0 through positionBy3, positionBy15)
			addClass: false,

			// Force our element to be at the location we specified (don't try to auto position it)
			force: false,

			// The element that we will make sure our element doesn't go outside of
			container: window,

			// Should the element be hidden after positioning?
			hideAfterPosition: false
		}, args);

		if (args.x != null) {
			var tLeft = args.x;
			var tTop = args.y;
			var tWidth = 0;
			var tHeight = 0;

			// Position in relation to an element
		} else {
			var $target = $($(args.target)[0]);
			var tWidth = $target.outerWidth();
			var tHeight = $target.outerHeight();
			var tOffset = $target.offset();
			var tLeft = tOffset.left + (args.sx ? args.sx : 0);
			var tTop = tOffset.top + (args.sy ? args.sy : 0);
		}

		// Our target right, bottom coord
		var tRight = tLeft + tWidth;
		var tBottom = tTop + tHeight;

		return this.each(function() {
			var $element = $(this);

			// Position our element in the top left so we can grab its width without triggering scrollbars
			if (!$element.is(':visible')) {
				$element.css({ left: -3000,
					top: -3000
				})
								.show();
			}

			var eWidth = $element.outerWidth();
			var eHeight = $element.outerHeight();

			// Holds x1,y1,x2,y2 coordinates for a position in relation to our target element
			var position = [];
			// Holds a list of alternate positions to try if this one is not in the browser viewport
			var next = [];

			// Our Positions via ASCII ART
			/*
			8   9       10   11
			+------------+
			7 | 15      12 | 0
			|            |
			6 | 14      13 | 1
			+------------+ 
			5   4        3   2
	
			 */

			position[0] = new Range(tRight, tTop, tRight + eWidth, tTop + eHeight);
			next[0] = [1, 7, 4];

			position[1] = new Range(tRight, tBottom - eHeight, tRight + eWidth, tBottom);
			next[1] = [0, 6, 4];

			position[2] = new Range(tRight, tBottom, tRight + eWidth, tBottom + eHeight);
			next[2] = [1, 3, 10];

			position[3] = new Range(tRight - eWidth, tBottom, tRight, tBottom + eHeight);
			next[3] = [1, 6, 10];

			position[4] = new Range(tLeft, tBottom, tLeft + eWidth, tBottom + eHeight);
			next[4] = [1, 6, 9];

			position[5] = new Range(tLeft - eWidth, tBottom, tLeft, tBottom + eHeight);
			next[5] = [6, 4, 9];

			position[6] = new Range(tLeft - eWidth, tBottom - eHeight, tLeft, tBottom);
			next[6] = [7, 1, 4];

			position[7] = new Range(tLeft - eWidth, tTop, tLeft, tTop + eHeight);
			next[7] = [6, 0, 4];

			position[8] = new Range(tLeft - eWidth, tTop - eHeight, tLeft, tTop);
			next[8] = [7, 9, 4];

			position[9] = new Range(tLeft, tTop - eHeight, tLeft + eWidth, tTop);
			next[9] = [0, 7, 4];

			position[10] = new Range(tRight - eWidth, tTop - eHeight, tRight, tTop);
			next[10] = [0, 7, 3];

			position[11] = new Range(tRight, tTop - eHeight, tRight + eWidth, tTop);
			next[11] = [0, 10, 3];

			position[12] = new Range(tRight - eWidth, tTop, tRight, tTop + eHeight);
			next[12] = [13, 7, 10];

			position[13] = new Range(tRight - eWidth, tBottom - eHeight, tRight, tBottom);
			next[13] = [12, 6, 3];

			position[14] = new Range(tLeft, tBottom - eHeight, tLeft + eWidth, tBottom);
			next[14] = [15, 1, 4];

			position[15] = new Range(tLeft, tTop, tLeft + eWidth, tTop + eHeight);
			next[15] = [14, 0, 9];

			if (args.positions !== null) {
				var pos = args.positions[0];
			} else if (args.targetPos != null && args.elementPos != null) {
				var pos = [];
				pos[0] = [];
				pos[0][0] = 15;
				pos[0][1] = 7;
				pos[0][2] = 8;
				pos[0][3] = 9;
				pos[1] = [];
				pos[1][0] = 0;
				pos[1][1] = 12;
				pos[1][2] = 10;
				pos[1][3] = 11;
				pos[2] = [];
				pos[2][0] = 2;
				pos[2][1] = 3;
				pos[2][2] = 13;
				pos[2][3] = 1;
				pos[3] = [];
				pos[3][0] = 4;
				pos[3][1] = 5;
				pos[3][2] = 6;
				pos[3][3] = 14;

				var pos = pos[args.targetPos][args.elementPos];
			}
			var ePos = position[pos];
			var fPos = pos;

			if (!args.force) {
				// TODO: Do the args.container
				// window width & scroll offset
				$window = $(window);
				var sx = $window.scrollLeft();
				var sy = $window.scrollTop();

				// TODO: Look at innerWidth & innerHeight
				var container = new Range(sx, sy, sx + $window.width(), sy + $window.height());

				// If we are outside of our viewport, see if we are outside vertically or horizontally and push onto the stack
				var stack;
				if (args.positions) {
					stack = args.positions;
				} else {
					stack = [pos];
				}
				var test = []; 	// Keeps track of our positions we already tried

				while (stack.length > 0) {
					var p = stack.shift();
					if (test[p]) {
						continue;
					}
					test[p] = true;

					// If our current position is not within the viewport (eg. window) 
					// add the next suggested position
					if (!container.contains(position[p])) {
						if (args.positions === null) {
							stack = jQuery.merge(stack, next[p]);
						}
					} else {
						ePos = position[p];
						break;
					}
				}
			}

			// + TODO: Determine if we are going to use absolute left, top, bottom, right 
			// positions relative to our target

			// Take into account any absolute or fixed positioning
			// to 'normalize' our coordinates
			$element.parents().each(function() {
				var $this = $(this);
				if ($this.css('position') != 'static') {
					var abs = $this.offset();
					ePos = ePos.transform(-abs.left, -abs.top);
					return false;
				}
			});

			// Finally position our element
			var css = { left: ePos.x1, top: ePos.y1 };
			if (args.hideAfterPosition) {
				css['display'] = 'none';
			}
			$element.css(css);

			if (args.addClass) {
				$element.removeClass('positionBy0 positionBy1 positionBy2 positionBy3 positionBy4 positionBy5 '
									+ 'positionBy6 positionBy7 positionBy8 positionBy9 positionBy10 positionBy11 '
									+ 'positionBy12 positionBy13 positionBy14 positionBy15')
						.addClass('positionBy' + p);
			}
		});
	};
})(jQuery);