/**
 * System takes care of updating all the entities (based on their component data)
 * Visualization System takes care of visualizing all objects which are not meshes (like physics data)
 *
 * @param apiSystem GameLib.API.System
 * @param graphics
 * @param physics
 * @constructor
 */
GameLib.System.Visualization = function(
    apiSystem,
    graphics,
    physics
) {

    GameLib.System.call(
        this,
        apiSystem
    );

    this.graphics = graphics;
    this.graphics.isNotThreeThrow();

    this.physics = physics;
    this.physics.isNotCannonThrow();

    this.visualizationSubscription = null;
    this.stopVisualizationSubscription = null;

};

GameLib.System.Visualization.prototype = Object.create(GameLib.System.prototype);
GameLib.System.Visualization.prototype.constructor = GameLib.System.Visualization;

GameLib.System.Visualization.prototype.start = function() {

    this.visualizationSubscription = this.subscribe(
        GameLib.Event.VISUALIZE,
        this.visualize
    );

    this.stopVisualizationSubscription = this.subscribe(
        GameLib.Event.STOP_VISUALIZE,
        this.stopVisualize
    )
};


GameLib.System.Visualization.prototype.visualize = function(data) {

    var shape = data.shape;

    var parentMesh = shape.parentMesh;

    shape.setFromMesh();

    var apiMesh = new GameLib.D3.API.Mesh();

    apiMesh.name = 'Visualization Mesh for Shape ' + shape.name;

    if (shape instanceof GameLib.D3.Shape.HeightMap) {
        var v0 = new CANNON.Vec3();
        var v1 = new CANNON.Vec3();
        var v2 = new CANNON.Vec3();
        for (var xi = 0; xi < shape.heightData.length - 1; xi++) {
            for (var yi = 0; yi < shape.heightData[xi].length - 1; yi++) {
                for (var k = 0; k < 2; k++) {
                    shape.instance.getConvexTrianglePillar(xi, yi, k===0);
                    v0.copy(shape.instance.pillarConvex.vertices[0]);
                    v1.copy(shape.instance.pillarConvex.vertices[1]);
                    v2.copy(shape.instance.pillarConvex.vertices[2]);
                    v0.vadd(shape.instance.pillarOffset, v0);
                    v1.vadd(shape.instance.pillarOffset, v1);
                    v2.vadd(shape.instance.pillarOffset, v2);
                    apiMesh.vertices.push(
                        new GameLib.D3.API.Vertex(
                            new GameLib.API.Vector3(v0.x, v0.y, v0.z)
                        ),
                        new GameLib.D3.API.Vertex(
                            new GameLib.API.Vector3(v1.x, v1.y, v1.z)
                        ),
                        new GameLib.D3.API.Vertex(
                            new GameLib.API.Vector3(v2.x, v2.y, v2.z)
                        )
                    );
                    var i = apiMesh.vertices.length - 3;
                    apiMesh.faces.push(
                        new GameLib.D3.API.Face(
                            null,
                            null,
                            i,
                            i+1,
                            i+2
                        )
                    );
                }
            }
        }
    }

    new GameLib.D3.Mesh(
        this.graphics,
        apiMesh
    );

};

GameLib.System.Visualization.prototype.stopVisualize = function(data) {
};

GameLib.System.Visualization.prototype.stop = function() {

	if (this.visualizationSubscription) {
        this.visualizationSubscription.remove();
    }

    if (this.stopVisualizationSubscription) {
        this.stopVisualizationSubscription.remove();
    }

};