/*
    Copyright 2008-2013
        Matthias Ehmann,
        Michael Gerhaeuser,
        Carsten Miller,
        Bianca Valentin,
        Alfred Wassermann,
        Peter Wilfahrt

    This file is part of JSXGraph.

    JSXGraph is free software dual licensed under the GNU LGPL or MIT License.
    
    You can redistribute it and/or modify it under the terms of the
    
      * GNU Lesser General Public License as published by
        the Free Software Foundation, either version 3 of the License, or
        (at your option) any later version
      OR
      * MIT License: https://github.com/jsxgraph/jsxgraph/blob/master/LICENSE.MIT
    
    JSXGraph is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public License and
    the MIT License along with JSXGraph. If not, see <http://www.gnu.org/licenses/>
    and <http://opensource.org/licenses/MIT/>.
 */


/*global JXG: true, define: true*/
/*jslint nomen: true, plusplus: true*/

/* depends:
 jxg
 base/composition
 options
 utils/type
  elements:
   point
   line
 */

define([
    'jxg', 'base/composition', 'options', 'utils/type', 'base/point', 'base/line'
], function (JXG, Composition, Options, Type, Point, Line) {

    "use strict";

    JXG.extend(Options, {
        square: {
            points: {
                withLabel: false,
                visible: false,
                name: ''
            },

            lines: {
                straightFirst: false,
                straightLast: false,
                withLabel: true
            }
        }
    });

    /**
     * @class A square is a rectangle with four sides each of the same length.
     * @pseudo
     * @name Square
     * @augments JXG.Composition
     * @constructor
     * @type JXG.Composition
     * @throws {Error} If the element cannot be constructed with the given parent objects an exception is thrown.
     * @param {JXG.Point_JXG.Point} p1,p2 To build the square two additional points will be created. Those will be placed
     * at a pi/2 rotation of the two given points around the center of the square.
     * @example
     * var p1 = board.create('point', [2.0, 2.0]),
     *     p2 = board.create('point', [1.0, 0.5]),
     *
     *     a = board.create('square', [p1, p2]);
     * </pre><div id="3558cfad-59f0-4385-8602-7ac14cded0df" style="width: 300px; height: 300px;"></div>
     * <script type="text/javascript">
     * (function () {
     *   var board = JXG.JSXGraph.initBoard('3558cfad-59f0-4385-8602-7ac14cded0df', {boundingbox: [-1, 7, 7, -1], axis: true, showcopyright: false, shownavigation: false}),
     *       p1 = board.create('point', [2.0, 2.0]),
     *       p2 = board.create('point', [1.0, 0.5]),
     *
     *       a = board.create('square', [p1, p2]);
     * })();
     * </script><pre>
     */
    JXG.createSquare = function (board, parents, attributes) {
        var p1, p2, p3, p4, l1, l2, l3, l4, ret, i, attr, sq;

        if (Type.isPoint(parents[0]) && Type.isPoint(parents[1])) {
            p1 = parents[0];
            p2 = parents[1];

            attr = Type.copyAttributes(attributes, board.options, 'square', 'points');

            p3 = board.create('point', [
                function () {
                    return (-p1.Y() + (p1.X() + p2.X()) / 2 + (p1.Y() + p2.Y()) / 2);
                },
                function () {
                    return (p1.X() - (p1.X() + p2.X()) / 2 + (p1.Y() + p2.Y()) / 2);
                }
            ], attr);

            p4 = board.create('point', [
                function () {
                    return (-p2.Y() + (p1.X() + p2.X()) / 2 + (p1.Y() + p2.Y()) / 2);
                },
                function () {
                    return (p2.X() - (p1.X() + p2.X()) / 2 + (p1.Y() + p2.Y()) / 2);
                }
            ], attr);

            attr = Type.copyAttributes(attributes, board.options, 'square', 'lines');
            l1 = board.create('line', [p1, p3], attr);
            l2 = board.create('line', [p1, p4], attr);
            l3 = board.create('line', [p2, p3], attr);
            l4 = board.create('line', [p2, p4], attr);

            /** @lends Square.prototype */
            sq = {
                /**
                 * Contains the square's points. The first two points are the ones given as parent elements by the user.
                 * The third and the fourth point are a rotation of pi/2 of the first resp. the second point around the
                 * center of the square.
                 * @type Array
                 */
                points: [p1, p2, p3, p4],

                /**
                 * Contains the square's stroke lines. The first line is the one from the point 1 to point 3, the second line
                 * the one from point 1 to point 4. The same with the third and the fourth line but with point 2 instead of
                 * point 1. The order of the points is the same as in {@link Square#points}.
                 * @type Array
                 */
                lines: [l1, l2, l3, l4]
            };

            ret = new Composition(sq);

            for (i = 1; i <= 4; i++) {
                ret['point' + i] = ret.points[i - 1];
                ret['line' + i] = ret.lines[i - 1];
            }

            return ret;
        }

        throw new Error("JSXGraph: Can't create square with parent types '" + (typeof parents[0]) + "' and '" + (typeof parents[1]) + "'.");
    };

    JXG.registerElement('square', JXG.createSquare);

    return {
        createSquare: JXG.createSquare
    };
});