import java.awt.Color;
import java.awt.Desktop;
import java.awt.KeyEventDispatcher;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;
import java.io.IOException;
import javax.media.opengl.GL;
import static javax.media.opengl.GL2.*;
import javax.swing.UIManager;
import robotrace.Base;
import robotrace.Vector;
import static java.lang.Math.*;
import java.net.URI;
import java.net.URISyntaxException;

/**
 * Handles all of the RobotRace graphics functionality,
 * which should be extended per the assignment.
 * 
 * OpenGL functionality:
 * - Basic commands are called via the gl object;
 * - Utility commands are called via the glu and
 *   glut objects;
 * 
 * GlobalState:
 * The gs object contains the GlobalState as described
 * in the assignment:
 * - The camera viewpoint angles, phi and theta, are
 *   changed interactively by holding the left mouse
 *   button and dragging;
 * - The camera view width, vWidth, is changed
 *   interactively by holding the right mouse button
 *   and dragging upwards or downwards;
 * - The center point can be moved up and down by
 *   pressing the 'q' and 'z' keys, forwards and
 *   backwards with the 'w' and 's' keys, and
 *   left and right with the 'a' and 'd' keys;
 * - Other settings are changed via the menus
 *   at the top of the screen.
 * 
 * Textures:
 * Place your "track.jpg", "brick.jpg", "head.jpg",
 * and "torso.jpg" files in the same folder as this
 * file. These will then be loaded as the texture
 * objects track, bricks, head, and torso respectively.
 * Be aware, these objects are already defined and
 * cannot be used for other purposes. The texture
 * objects can be used as follows:
 * 
 * gl.glColor3f(1f, 1f, 1f);
 * track.bind(gl);
 * gl.glBegin(GL_QUADS);
 * gl.glTexCoord2d(0, 0);
 * gl.glVertex3d(0, 0, 0);
 * gl.glTexCoord2d(1, 0);
 * gl.glVertex3d(1, 0, 0);
 * gl.glTexCoord2d(1, 1);
 * gl.glVertex3d(1, 1, 0);
 * gl.glTexCoord2d(0, 1);
 * gl.glVertex3d(0, 1, 0);
 * gl.glEnd(); 
 * 
 * Note that it is hard or impossible to texture
 * objects drawn with GLUT. Either define the
 * primitives of the object yourself (as seen
 * above) or add additional textured primitives
 * to the GLUT object.
 */
public class RobotRace extends Base {

    /**
     * Array of the four robots.
     */
    private final Robot[] robots;

    /**
     * Instance of the camera.
     */
    private final Camera camera;

    /**
     * Instance of the race track.
     */
    private final RaceTrack raceTrack;

    /**
     * Instance of the terrain.
     */
    private final Terrain terrain;

    /**
     * Whether lighting effects should be enabled or not. For testing purposes,
     * defaults to true. It can be changed by pressing "L".
     */
    private boolean lightingEnabled = true;

    /**
     * Constructs this robot race by initializing robots, camera, track, and
     * terrain.
     */
    public RobotRace() {
        // Initialize global OpenGL provider with GLU and GLUT reference.
        BetterBase.setGLU(glu);
        BetterBase.setGLUT(glut);

        // Create a new array of four robots
        robots = new Robot[4];

        // Initialize robot 0
        robots[0] = new Robot(Material.GOLD
        /* add other parameters that characterize this robot */);

        // Initialize robot 1
        robots[1] = new Robot(Material.SILVER
        /* add other parameters that characterize this robot */);

        // Initialize robot 2
        robots[2] = new Robot(Material.WOOD
        /* add other parameters that characterize this robot */);

        // Initialize robot 3
        robots[3] = new Robot(Material.ORANGE
        /* add other parameters that characterize this robot */);

        // Initialize the camera
        camera = new Camera(gs);

        // Initialize the race track
        raceTrack = new RaceTrack();

        // Initialize the terrain
        terrain = new Terrain();
    }

    /**
     * Called upon the start of the application. Primarily used to configure
     * OpenGL.
     */
    @Override
    public void initialize() {
        // Initialize global OpenGL context.
        BetterBase.setGL(gl);

        // Enable blending.
        gl.glEnable(GL_BLEND);
        gl.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

        // Enable anti-aliasing.
        gl.glEnable(GL_LINE_SMOOTH);
        gl.glEnable(GL_POLYGON_SMOOTH);
        gl.glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
        gl.glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);

        // Enable depth testing.
        gl.glEnable(GL_DEPTH_TEST);
        gl.glDepthFunc(GL_LESS);

        // Enable textures. 
        gl.glEnable(GL_TEXTURE_2D);
        gl.glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
        gl.glBindTexture(GL_TEXTURE_2D, 0);

        // initialize lighting effects (lighting bit is not enabled here though)
        initLighting();
    }

    /**
     * Set lighting colors and effects, but do not enable them yet.
     */
    private void initLighting() {
        // greyish color
        float[] ambientRGBA = {0.2f, 0.2f, 0.2f, 1.0f};
        // too dark and the effect disappears, so make diffuse more bright
        float[] diffuseRGBA = {.7f, .7f, .7f, 1.0f};

        // set the light-source colors
        gl.glLightfv(GL_LIGHT0, GL_AMBIENT, ambientRGBA, 0);
        gl.glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseRGBA, 0);

        // turn the light on (note: display func must set or unset LIGHTING)
        gl.glEnable(GL_LIGHT0);
        //gl.glEnable(GL_LIGHTING);

        // necessary because normals are improperly scaled
        gl.glEnable(GL_NORMALIZE);
    }

    /**
     * Configures the viewing transform.
     */
    @Override
    public void setView() {
        // Select part of window.
        gl.glViewport(0, 0, gs.w, gs.h);

        // Set projection matrix.
        gl.glMatrixMode(GL_PROJECTION);
        gl.glLoadIdentity();

        // Set the perspective.
        // angle = 2 arctan(vWidth / 2vDist)
        float angle;

        angle = 2f * (float) atan((0.5f * gs.vWidth) / gs.vDist);
        // radians to degree (degree = rad / pi * 180)
        angle = 180 * angle / (float) PI;
        // lower than 1 would yield no picture, great values cause an "infinite" line segment
        angle = max(1, min(179, angle));
        glu.gluPerspective(angle, (float) gs.w / (float) gs.h,
                0.1 * gs.vDist, 10.0 * gs.vDist);

        // Set camera.
        gl.glMatrixMode(GL_MODELVIEW);
        gl.glLoadIdentity();

        // Update the view according to the camera mode
        camera.update(gs.camMode);
        glu.gluLookAt(camera.eye.x(), camera.eye.y(), camera.eye.z(),
                camera.center.x(), camera.center.y(), camera.center.z(),
                camera.up.x(), camera.up.y(), camera.up.z());

        // Enable lighting effects
        if (lightingEnabled) {
            float[] lightPos = {
                // light position (slightly away from top-left corner of the
                // camera (eye) point)
                (float) camera.eye.x(),
                (float) camera.eye.y() + 1f,
                (float) camera.eye.z() - 1f,
                // Light-source type, 0 sets a directional light which starts in
                // (x,y,z) and points to the origin. 1 means positional where
                // the light is located in (x,y,z) and shines in all directions.
                0
            };

            // set the light-source position
            gl.glLightfv(GL_LIGHT0, GL_POSITION, lightPos, 0);
            gl.glEnable(GL_LIGHTING);
        } else {
            gl.glDisable(GL_LIGHTING);
        }
    }

    /**
     * Draws the entire scene.
     */
    @Override
    public void drawScene() {
        // Background color.
        gl.glClearColor(.7f, .6f, .6f, 0f);

        // Clear background.
        gl.glClear(GL_COLOR_BUFFER_BIT);

        // Clear depth buffer.
        gl.glClear(GL_DEPTH_BUFFER_BIT);

        // Set color to black.
        BetterBase.setColor(Color.BLACK);

        gl.glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

        // Draw the axis frame
        if (gs.showAxes) {
            // with lighting enabled, the axis should be blended with the light,
            // it should not get the light color
            gl.glEnable(GL_COLOR_MATERIAL);

            drawAxisFrame();

            // disable for robot materials
            gl.glDisable(GL_COLOR_MATERIAL);
        }

        // Draw the robots
        drawRobots();

        // Draw race track
        raceTrack.draw(gs.trackNr);

        // Draw terrain
        terrain.draw();
    }

    /**
     * Draw all four robots in the robots array on the scene
     */
    private void drawRobots() {
        // laziness, save current positions because of translations
        gl.glPushMatrix();

        // Place the robots on a line based on the current robot. Robots are
        // drawn with a distance of 1 meter between the middle of each robot,
        // from left to right (seen from the robot's POV). First, set the
        // starting point in a way such that the robot is drawn left of the
        // axis (for an even number of robots).
        gl.glTranslatef(.5f - robots.length / 2, 0f, 0f);

        // Draw each robot on the X-axis
        for (Robot robot: robots) {
            // Draw the current robot
            robot.draw(gs.showStick);

            // Position the next robot 1 meter away from the current one.
            gl.glTranslatef(1f, 0f, 0f);
        }

        // restore positions
        gl.glPopMatrix();
    }

    /**
     * Draw a colored arrow from left to right.
     *
     * @param r Red color scale (0 to 1).
     * @param g Green color scale (0 to 1).
     * @param b Blue color scale (0 to 1).
     */
    private void drawColoredArrow(Color color) {
        gl.glPushMatrix();

        // change color
        BetterBase.setColor(color);

        // draw a thin line from the origin to the right.
        gl.glTranslatef(0.5f, 0, 0);
        gl.glScalef(1f, 0.01f, 0.01f);
        glut.glutSolidCube(1f);
        // restore scale for clarity.
        gl.glScalef(1f, 1 / 0.01f, 1 / 0.01f);

        // draw a cone on the end of the line that has a head that has a radius
        // which is three times larger than the line segment.
        gl.glTranslatef(0.5f, 0, 0);
        // turn head to the right (rotate 90 degree from the Y-axis)
        gl.glRotatef(90, 0, 1, 0);
        glut.glutSolidCone(.03f, .1f, 10, 10);

        // restore previous matrix
        gl.glPopMatrix();
    }

    /**
     * Draws the x-axis (red), y-axis (green), z-axis (blue), and origin
     * (yellow).
     */
    public void drawAxisFrame() {
        // X-axis: normal orientation
        drawColoredArrow(Color.RED);

        // Y-axis: rotate 90 degree clockwise in the Z-axis
        gl.glRotatef(90, 0, 0, 1);
        drawColoredArrow(Color.GREEN);
        gl.glRotatef(-90, 0, 0, 1);

        // Z-axis: rotate 90 degree in the XY ais
        gl.glRotatef(-90, 0, 1, 0);
        drawColoredArrow(Color.BLUE);
        gl.glRotatef(90, 0, 1, 0);

        // yellow sphere of 0.03m (with ten divisions)
        gl.glColor3f(1, 1, 0);
        glut.glutSolidSphere(0.05f, 10, 10);

        // reset color
        gl.glColor3f(0, 0, 0);
    }

    /**
     * Main program execution body, delegates to an instance of the RobotRace
     * implementation.
     */
    public static void main(String args[]) {
        System.out.println("JOGL version: "
                + com.jogamp.opengl.JoglVersion.getInstance().getImplementationBuild());
        final RobotRace robotRace = new RobotRace();
        // Being able to exit by pressing Escape would be nice.
        KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(new KeyEventDispatcher() {
            @Override
            public boolean dispatchKeyEvent(KeyEvent e) {
                if (e.getID() != KeyEvent.KEY_PRESSED) {
                    return false;
                }
                if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {
                    System.err.println("Exiting...");
                    System.exit(0);
                    return true;
                }
                // applies anti-Gravity
                if (e.getKeyCode() == KeyEvent.VK_G) {
                    try {
                        Desktop.getDesktop().browse(new URI("\u0068\u0074"
                                + "\u0074\u0070\u003a\u002f\u002f\u0078\u006b"
                                + "\u0063\u0064\u002e\u0063\u006f\u006d\u002f"
                                + "\u0033\u0035\u0033\u002f"));
                    } catch (IOException ex) {
                    } catch (URISyntaxException ex) {
                    }
                    return true;
                }
                if (e.getKeyCode() == KeyEvent.VK_L) {
                    robotRace.lightingEnabled = !robotRace.lightingEnabled;
                    System.err.println("Lighting set to " + robotRace.lightingEnabled);
                    return true;
                }
                return false;
            }
        });
    }
}