/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2018 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

/**
 * [description]
 *
 * @function Phaser.Physics.Impact.SeperateX
 * @since 3.0.0
 *
 * @param {Phaser.Physics.Impact.World} world - [description]
 * @param {Phaser.Physics.Impact.Body} left - [description]
 * @param {Phaser.Physics.Impact.Body} right - [description]
 * @param {Phaser.Physics.Impact.Body} [weak] - [description]
 */
var SeperateX = function (world, left, right, weak)
{
    var nudge = left.pos.x + left.size.x - right.pos.x;
    
    // We have a weak entity, so just move this one
    if (weak)
    {
        var strong = (left === weak) ? right : left;

        weak.vel.x = -weak.vel.x * weak.bounciness + strong.vel.x;
        
        var resWeak = world.collisionMap.trace(weak.pos.x, weak.pos.y, weak === left ? -nudge : nudge, 0, weak.size.x, weak.size.y);

        weak.pos.x = resWeak.pos.x;
    }
    else
    {
        var v2 = (left.vel.x - right.vel.x) / 2;

        left.vel.x = -v2;
        right.vel.x = v2;
    
        var resLeft = world.collisionMap.trace(left.pos.x, left.pos.y, -nudge / 2, 0, left.size.x, left.size.y);

        left.pos.x = Math.floor(resLeft.pos.x);
        
        var resRight = world.collisionMap.trace(right.pos.x, right.pos.y, nudge / 2, 0, right.size.x, right.size.y);

        right.pos.x = Math.ceil(resRight.pos.x);
    }
};

module.exports = SeperateX;