/*
 * jQuery UI Position @VERSION
 *
 * Copyright 2010, AUTHORS.txt (http://jqueryui.com/about)
 * Dual licensed under the MIT or GPL Version 2 licenses.
 * http://jquery.org/license
 *
 * http://docs.jquery.com/UI/Position
 */
(function( $, undefined ) {

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

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

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

  if ( targetElem.nodeType === 9 ) {
    targetWidth = target.width();
    targetHeight = target.height();
    basePosition = { top: 0, left: 0 };
  // TODO: use $.isWindow() in 1.9
  } else if ( targetElem.setTimeout ) {
    targetWidth = target.width();
    targetHeight = target.height();
    basePosition = { top: target.scrollTop(), left: target.scrollLeft() };
  } else if ( targetElem.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( [center] ) :
        verticalPositions.test( pos[0] ) ?
          [ center ].concat( pos ) :
          [ center, center ];
    }
    pos[ 0 ] = horizontalPositions.test( pos[0] ) ? pos[ 0 ] : center;
    pos[ 1 ] = verticalPositions.test( pos[1] ) ? pos[ 1 ] : center;
    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] === center ) {
    basePosition.left += targetWidth / 2;
  }

  if ( options.at[1] === "bottom" ) {
    basePosition.top += targetHeight;
  } else if ( options.at[1] === center ) {
    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(),
      marginLeft = parseInt( $.curCSS( this, "marginLeft", true ) ) || 0,
      marginTop = parseInt( $.curCSS( this, "marginTop", true ) ) || 0,
      collisionWidth = elemWidth + marginLeft +
        parseInt( $.curCSS( this, "marginRight", true ) ) || 0,
      collisionHeight = elemHeight + marginTop +
        parseInt( $.curCSS( this, "marginBottom", true ) ) || 0,
      position = $.extend( {}, basePosition ),
      collisionPosition;

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

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

    // prevent fractions (see #5280)
    position.left = parseInt( position.left );
    position.top = parseInt( position.top );

    collisionPosition = {
      left: position.left - marginLeft,
      top: position.top - marginTop
    };

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

  flip: {
    left: function( position, data ) {
      if ( data.at[0] === center ) {
        return;
      }
      var win = $( window ),
        over = data.collisionPosition.left + data.collisionWidth - win.width() - win.scrollLeft(),
        myOffset = data.my[ 0 ] === "left" ?
          -data.elemWidth :
          data.my[ 0 ] === "right" ?
            data.elemWidth :
            0,
        atOffset = data.at[ 0 ] === "left" ?
          data.targetWidth :
          -data.targetWidth,
        offset = -2 * data.offset[ 0 ];
      position.left += data.collisionPosition.left < 0 ?
        myOffset + atOffset + offset :
        over > 0 ?
          myOffset + atOffset + offset :
          0;
    },
    top: function( position, data ) {
      if ( data.at[1] === center ) {
        return;
      }
      var win = $( window ),
        over = data.collisionPosition.top + data.collisionHeight - 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 += data.collisionPosition.top < 0 ?
        myOffset + atOffset + 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( $.curCSS( elem, "position" ) ) ) {
      elem.style.position = "relative";
    }
    var curElem   = $( elem ),
      curOffset = curElem.offset(),
      curTop    = parseInt( $.curCSS( elem, "top",  true ), 10 ) || 0,
      curLeft   = parseInt( $.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 );
    }
  };

  $.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 ));