(function() {-
"use strict";

var MovementSystem = function() {
    this.initialize();
}
var p = MovementSystem.prototype;

    p.initialize = function() {

    }

    p.process = function(boids, fdelta) {
        for (var i=0; i<boids.length; i++) {
            var b = boids[i];
            var flock = b.getComponent('Flock');
            var norm = norm2d(flock.velocityX, flock.velocityY);

            // if (flock.velocityY != 0 && flock.velocityX != 0) {
            if (norm > 10) {

                var px = b.display.x;
                var py = b.display.y;
                var tx = toCoordX(px);
                var ty = toCoordY(py);
                var slow = registry.map.getLayerByName('area_slow');


                var angle = Math.atan2(flock.velocityY, flock.velocityX)*(180/Math.PI);
                var rot = b.display.rotation;

                if (b.lastAngle < 0 && angle > 0 && angle < 150) {
                    rot -= 360;
                } 
                else if (b.lastAngle > 0 && angle < 0 && angle > -150) {
                    rot += 360;
                }

                b.lastAngle = angle;
                angle += 360;
                angle %= 360;

                var diff = Math.abs(angle-rot);
                if (norm > 15) {
                    rot = angle*SHEEP_ROTATION_SPEED*fdelta + rot*(1.0-SHEEP_ROTATION_SPEED*fdelta);
                }
                b.display.rotation = rot;

                // var rotationEffect = easeInOut(1-diff/180);
                var rotationEffect = (1-diff/180);
                var slowEffect = 1;

                if (getTile(slow, tx, ty)) {
                    slowEffect = SHEEP_SLOW_RATE;
                }

                b.display.x += flock.velocityX*fdelta*rotationEffect*slowEffect;
                b.display.y += flock.velocityY*fdelta*rotationEffect*slowEffect;
            }
        }
    }

window.MovementSystem = MovementSystem;

})();