package p5.test_awt_canvas;

import java.applet.Applet;
import java.awt.Canvas;
import java.awt.Frame;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Insets;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.GL11;

public class MiniPApplet extends Applet {
  private static final long serialVersionUID = 1L;

  /////////////////////////////////////////////////////////////
  //
  // Test parameters

  public int frameRate = 120;
  public boolean resizeableFrame = false;

  /////////////////////////////////////////////////////////////
  //
  // Internal variables

  int width;
  int height;

  private Frame frame;
  private Canvas canvas;

  private long beforeTime;
  private long overSleepTime;
  private long frameRatePeriod = 1000000000L / frameRate;

  private boolean initialized = false;

  private double theta = 0;
  private double s = 0;
  private double c = 0;

  private long millisOffset;
  private int fcount, lastm;
  private float frate;
  private int fint = 3;

  void run() {
    Thread loop = new Thread("Animation Thread") {
      public void run() {
        int frameCount = 0;
        while (true) {
          if (!initialized) {
            setup();
          }

          draw();
          Display.update();

          clock();

          frameCount++;
        }
      }
    };
    loop.start();
  }

  void setup() {
    millisOffset = System.currentTimeMillis();

    // Frame setup ----------------------------------------------------------

    width = 300;
    height = 300;
    MiniPApplet applet = this;

    GraphicsEnvironment environment =
      GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice displayDevice = environment.getDefaultScreenDevice();
    frame = new Frame(displayDevice.getDefaultConfiguration());

    frame.setTitle("MiniPApplet");
    frame.setLayout(null);
    frame.add(applet);
    frame.pack();
    frame.setResizable(resizeableFrame);

    Insets insets = frame.getInsets();

    int windowW = applet.width + insets.left + insets.right;
    int windowH = applet.height + insets.top + insets.bottom;
    int locationX = 100;
    int locationY = 100;

    frame.setSize(windowW, windowH);
    frame.setLocation(locationX, locationY);

    int usableWindowH = windowH - insets.top - insets.bottom;
    applet.setBounds((windowW - applet.width)/2, insets.top + (usableWindowH - applet.height)/2, applet.width, applet.height);

    frame.add(this);
    frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
          System.exit(0);
      }
    });

    frame.setVisible(true);

    // Canvas setup ----------------------------------------------------------

    canvas = new Canvas();
    applet.add(canvas);

    canvas.setBounds(0, 0, applet.width, applet.height);
    canvas.setFocusable(true);
    canvas.requestFocus();
    canvas.setIgnoreRepaint(true);

    try {
      Display.setParent(canvas);
      Display.create();
      Display.setVSyncEnabled(false);
    } catch (LWJGLException e) {
      e.printStackTrace();
    }

    initialized = true;
  }

  void draw() {
    GL11.glClearColor(0, 0, 0, 1);
    GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);

    theta += 0.01;
    s = Math.sin(theta);
    c = Math.cos(theta);

    GL11.glBegin(GL11.GL_TRIANGLES);
    GL11.glColor3f(1, 0, 0);
    GL11.glVertex2d(-c, -c);
    GL11.glColor3f(0, 1, 0);
    GL11.glVertex2d(0, c);
    GL11.glColor3f(0, 0, 1);
    GL11.glVertex2d(s, -s);
    GL11.glEnd();

    GL11.glFlush();

    fcount += 1;
    int m = (int) (System.currentTimeMillis() - millisOffset);
    if (m - lastm > 1000 * fint) {
      frate = (float)(fcount) / fint;
      fcount = 0;
      lastm = m;
      System.out.println("fps: " + frate);
    }
  }

  void clock() {
    long afterTime = System.nanoTime();
    long timeDiff = afterTime - beforeTime;
    long sleepTime = (frameRatePeriod - timeDiff) - overSleepTime;

    if (sleepTime > 0) {  // some time left in this cycle
      try {
        Thread.sleep(sleepTime / 1000000L, (int) (sleepTime % 1000000L));
      } catch (InterruptedException ex) { }

      overSleepTime = (System.nanoTime() - afterTime) - sleepTime;

    } else {    // sleepTime <= 0; the frame took longer than the period
      overSleepTime = 0L;
    }

    beforeTime = System.nanoTime();
  }

  public static void main(String[] args) {
    MiniPApplet mini;
    try {
      Class<?> c = Thread.currentThread().getContextClassLoader().loadClass(MiniPApplet.class.getName());
      mini = (MiniPApplet) c.newInstance();
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
    if (mini != null) {
      mini.run();
    }
  }
}