import algebra.*;

/**
 * The Renderer class drives the rendering pipeline: read in a scene, projects
 * the vertices and rasterizes every faces / edges.
 * 
 * @author: cdehais
 */
public class Renderer {

    static Scene scene;
    static Mesh mesh;
    static Rasterizer rasterizer;
    static GraphicsWrapper screen;
    static Shader shader;
    static Transformation xform;
    static Lighting lighting;
    static boolean lightingEnabled;

    static void init(String sceneFilename) throws Exception {
        scene = new Scene(sceneFilename);
        mesh = new Mesh(scene.getMeshFileName());
        screen = new GraphicsWrapper(scene.getScreenW(), scene.getScreenH());
        screen.clearBuffer();
        // shader = new SimpleShader(screen);
        shader = new PainterShader(screen);
        rasterizer = new PerspectiveCorrectRasterizer(shader);
        rasterizer = new Rasterizer(shader);

        xform = new Transformation();
        xform.setLookAt(scene.getCameraPosition(),
                scene.getCameraLookAt(),
                scene.getCameraUp());
        xform.setProjection();
        xform.setCalibration(scene.getCameraFocal(), scene.getScreenW(), scene.getScreenH());

        lighting = new Lighting();
        lighting.addAmbientLight(scene.getAmbientI());
        double[] lightCoord = scene.getSourceCoord();
        lighting.addPointLight(lightCoord[0], lightCoord[1], lightCoord[2], scene.getSourceI());
    }

    static Fragment[] projectVertices() {
        Vector[] vertices = mesh.getVertices();
        Vector3[] normals = mesh.getNormals();
        double[] colors = mesh.getColors();

        Fragment[] fragments = new Fragment[vertices.length];

        try {
            for (int i = 0; i < vertices.length; i++) {
                Vector pVertex = xform.projectPoint(vertices[i]);
                // Vector pNormal = xform.transformVector (normals[i]);
                Vector3 pNormal = normals[i];

                int x = (int) Math.round(pVertex.get(0));
                int y = (int) Math.round(pVertex.get(1));
                fragments[i] = new Fragment(x, y);
                fragments[i].setDepth(pVertex.get(2));
                fragments[i].setNormal(pNormal);

                double[] texCoords = mesh.getTextureCoordinates();
                if (texCoords != null) {
                    fragments[i].setAttribute(7, texCoords[2 * i]);
                    fragments[i].setAttribute(8, texCoords[2 * i + 1]);
                }

                if (!lightingEnabled) {
                    fragments[i].setColor(colors[3 * i], colors[3 * i + 1], colors[3 * i + 2]);
                } else {
                    double[] color = new double[3];
                    color[0] = colors[3 * i];
                    color[1] = colors[3 * i + 1];
                    color[2] = colors[3 * i + 2];
                    double material[] = scene.getMaterial();
                    double[] litColor = lighting.applyLights(new Vector3(vertices[i]), pNormal, color,
                            scene.getCameraPosition(),
                            material[0], material[1], material[2], material[3]);
                    fragments[i].setColor(litColor[0], litColor[1], litColor[2]);
                }
            }
        } catch (SizeMismatchException e) {
            e.printStackTrace();
            /* should not reach */
        } catch (InstantiationException e) {
            e.printStackTrace();
            /* should not reach */
        }

        return fragments;
    }

    static void renderWireframe() {
        Fragment[] fragment = projectVertices();
        int[] faces = mesh.getFaces();

        for (int i = 0; i < 3 * mesh.getNumFaces(); i += 3) {
            for (int j = 0; j < 3; j++) {
                Fragment v1 = fragment[faces[i + j]];
                Fragment v2 = fragment[faces[i + ((j + 1) % 3)]];
                rasterizer.rasterizeEdge(v1, v2);
            }
        }
    }

    static void renderSolid() {
        Fragment[] fragments = projectVertices();
        int[] faces = mesh.getFaces();

        for (int i = 0; i < 3 * mesh.getNumFaces(); i += 3) {
            Fragment v1 = fragments[faces[i]];
            Fragment v2 = fragments[faces[i + 1]];
            Fragment v3 = fragments[faces[i + 2]];

            rasterizer.rasterizeFace(v1, v2, v3);
        }
    }

    public static void setLightingEnabled(boolean enabled) {
        lightingEnabled = enabled;
    }

    public static void wait(int sec) {
        try {
            Thread.sleep(sec * 1000);
        } catch (Exception e) {
            /* nothing */
        }
    }

    public static void main(String[] args) {

        if (args.length == 0) {
            System.out.println("usage: java Renderer <scene_file>");
        } else {
            try {
                init(args[0]);
            } catch (Exception e) {
                System.out.println("Problem initializing Renderer: " + e);
                e.printStackTrace();
                return;
            }
        }

        /* wireframe rendering */
        renderWireframe();
        screen.swapBuffers();
        wait(1);

        /* solid rendering, no lighting */

        screen.clearBuffer();
        shader.reset();
        renderSolid();
        screen.swapBuffers();
        wait(1);

        wait(10);

        /* solid rendering, with lighting */
        /*
         * screen.clearBuffer ();
         * shader.reset ();
         * setLightingEnabled (true);
         * renderSolid ();
         * screen.swapBuffers ();
         * wait (3);
         */

        /* solid rendering, with texture */
        /*
         * screen.clearBuffer ();
         * TextureShader texShader = new TextureShader (screen);
         * texShader.setTexture ("data/brick.jpg");
         * shader = texShader;
         * rasterizer.setShader (texShader);
         * setLightingEnabled (true);
         * renderSolid ();
         * screen.swapBuffers ();
         * wait (3);
         */

        screen.destroy();
        System.exit(0);
    }
}