/*
 * jQuery UI Position 1.8rc3
 *
 * Copyright (c) 2010 AUTHORS.txt (http://jqueryui.com/about)
 * Dual licensed under the MIT (MIT-LICENSE.txt)
 * and GPL (GPL-LICENSE.txt) licenses.
 *
 * http://docs.jquery.com/UI/Position
 */
(function( $ ) {

$.ui = $.ui || {};

var horizontalPositions = /left|center|right/,
	horizontalDefault = "center",
	verticalPositions = /top|center|bottom/,
	verticalDefault = "center",
	_position = $.fn.position;

$.fn.position = function( options ) {
	if ( !options || !options.of ) {
		return _position.apply( this, arguments );
	}

	// make a copy, we don't want to modify arguments
	options = $.extend( {}, options );

	var target = $( options.of ),
		collision = ( options.collision || "flip" ).split( " " ),
		offset = options.offset ? options.offset.split( " " ) : [ 0, 0 ],
		targetWidth,
		targetHeight,
		basePosition;

	if ( options.of.nodeType === 9 ) {
		targetWidth = target.width();
		targetHeight = target.height();
		basePosition = { top: 0, left: 0 };
	} else if ( options.of.scrollTo && options.of.document ) {
		targetWidth = target.width();
		targetHeight = target.height();
		basePosition = { top: target.scrollTop(), left: target.scrollLeft() };
	} else if ( options.of.preventDefault ) {
		// force left top to allow flipping
		options.at = "left top";
		targetWidth = targetHeight = 0;
		basePosition = { top: options.of.pageY, left: options.of.pageX };
	} else {
		targetWidth = target.outerWidth();
		targetHeight = target.outerHeight();
		basePosition = target.offset();
	}

	// force my and at to have valid horizontal and veritcal positions
	// if a value is missing or invalid, it will be converted to center 
	$.each( [ "my", "at" ], function() {
		var pos = ( options[this] || "" ).split( " " );
		if ( pos.length === 1) {
			pos = horizontalPositions.test( pos[0] ) ?
				pos.concat( [verticalDefault] ) :
				verticalPositions.test( pos[0] ) ?
					[ horizontalDefault ].concat( pos ) :
					[ horizontalDefault, verticalDefault ];
		}
		pos[ 0 ] = horizontalPositions.test( pos[0] ) ? pos[ 0 ] : horizontalDefault;
		pos[ 1 ] = verticalPositions.test( pos[1] ) ? pos[ 1 ] : verticalDefault;
		options[ this ] = pos;
	});

	// normalize collision option
	if ( collision.length === 1 ) {
		collision[ 1 ] = collision[ 0 ];
	}

	// normalize offset option
	offset[ 0 ] = parseInt( offset[0], 10 ) || 0;
	if ( offset.length === 1 ) {
		offset[ 1 ] = offset[ 0 ];
	}
	offset[ 1 ] = parseInt( offset[1], 10 ) || 0;

	if ( options.at[0] === "right" ) {
		basePosition.left += targetWidth;
	} else if (options.at[0] === horizontalDefault ) {
		basePosition.left += targetWidth / 2;
	}

	if ( options.at[1] === "bottom" ) {
		basePosition.top += targetHeight;
	} else if ( options.at[1] === verticalDefault ) {
		basePosition.top += targetHeight / 2;
	}

	basePosition.left += offset[ 0 ];
	basePosition.top += offset[ 1 ];

	return this.each(function() {
		var elem = $( this ),
			elemWidth = elem.outerWidth(),
			elemHeight = elem.outerHeight(),
			position = $.extend( {}, basePosition ),
			over,
			myOffset,
			atOffset;

		if ( options.my[0] === "right" ) {
			position.left -= elemWidth;
		} else if ( options.my[0] === horizontalDefault ) {
			position.left -= elemWidth / 2;
		}

		if ( options.my[1] === "bottom" ) {
			position.top -= elemHeight;
		} else if ( options.my[1] === verticalDefault ) {
			position.top -= elemHeight / 2;
		}

		$.each( [ "left", "top" ], function( i, dir ) {
			if ( $.ui.position[ collision[i] ] ) {
				$.ui.position[ collision[i] ][ dir ]( position, {
					targetWidth: targetWidth,
					targetHeight: targetHeight,
					elemWidth: elemWidth,
					elemHeight: elemHeight,
					offset: offset,
					my: options.my,
					at: options.at
				});
			}
		});

		if ( $.fn.bgiframe ) {
			elem.bgiframe();
		}
		elem.offset( $.extend( position, { using: options.using } ) );
	});
};

$.ui.position = {
	fit: {
		left: function( position, data ) {
			var win = $( window ),
				over = position.left + data.elemWidth - win.width() - win.scrollLeft();
			position.left = over > 0 ? position.left - over : Math.max( 0, position.left );
		},
		top: function( position, data ) {
			var win = $( window ),
				over = position.top + data.elemHeight - win.height() - win.scrollTop();
			position.top = over > 0 ? position.top - over : Math.max( 0, position.top );
		}
	},

	flip: {
		left: function( position, data ) {
			if ( data.at[0] === "center" ) {
				return;
			}
			var win = $( window ),
				over = position.left + data.elemWidth - win.width() - win.scrollLeft(),
				myOffset = data.my[ 0 ] === "left" ?
					-data.elemWidth :
					data.my[ 0 ] === "right" ?
						data.elemWidth :
						0,
				offset = -2 * data.offset[ 0 ];
			position.left += position.left < 0 ?
				myOffset + data.targetWidth + offset :
				over > 0 ?
					myOffset - data.targetWidth + offset :
					0;
		},
		top: function( position, data ) {
			if ( data.at[1] === "center" ) {
				return;
			}
			var win = $( window ),
				over = position.top + data.elemHeight - win.height() - win.scrollTop(),
				myOffset = data.my[ 1 ] === "top" ?
					-data.elemHeight :
					data.my[ 1 ] === "bottom" ?
						data.elemHeight :
						0,
				atOffset = data.at[ 1 ] === "top" ?
					data.targetHeight :
					-data.targetHeight,
				offset = -2 * data.offset[ 1 ];
			position.top += position.top < 0 ?
				myOffset + data.targetHeight + offset :
				over > 0 ?
					myOffset + atOffset + offset :
					0;
		}
	}
};

// offset setter from jQuery 1.4
if ( !$.offset.setOffset ) {
	$.offset.setOffset = function( elem, options ) {
		// set position first, in-case top/left are set even on static elem
		if ( /static/.test( jQuery.curCSS( elem, "position" ) ) ) {
			elem.style.position = "relative";
		}
		var curElem   = jQuery( elem ),
			curOffset = curElem.offset(),
			curTop    = parseInt( jQuery.curCSS( elem, "top",  true ), 10 ) || 0,
			curLeft   = parseInt( jQuery.curCSS( elem, "left", true ), 10)  || 0,
			props     = {
				top:  (options.top  - curOffset.top)  + curTop,
				left: (options.left - curOffset.left) + curLeft
			};
		
		if ( 'using' in options ) {
			options.using.call( elem, props );
		} else {
			curElem.css( props );
		}
	};

	var _offset = $.fn.offset;
	$.fn.offset = function( options ) {
		var elem = this[ 0 ];
		if ( !elem || !elem.ownerDocument ) { return null; }
		if ( options ) { 
			return this.each(function() {
				$.offset.setOffset( this, options );
			});
		}
		return _offset.call( this );
	};
}

})( jQuery );
