import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.Timer;

@SuppressWarnings("serial")
public class CopyColors extends JFrame {
  private static final String SOURCE = "mona";
  private static final String PALETTE = "spheres";
  private static final int TRIES_MAX = 5000;
  private static final int COUNT = 100000;
  private static final int DELAY = 20;
  private static final int LUM_WEIGHT = 10;

  private static final double[] F = { 0.114, 0.587, 0.299 };
  private final BufferedImage source;
  protected final BufferedImage dest;
  private final int sw;
  private final int sh;
  private final int n;
  private final Random r = new Random();
  private final JLabel l;

  public CopyColors(final String sourceName, final String paletteName)
      throws IOException {
    super("CopyColors by aditsu");
    source = ImageIO.read(getClass().getResourceAsStream(sourceName + ".png"));
    final BufferedImage palette = ImageIO.read(getClass().getResourceAsStream(
        paletteName + ".png"));
    sw = source.getWidth();
    sh = source.getHeight();
    final int pw = palette.getWidth();
    final int ph = palette.getHeight();
    n = sw * sh;
    if (n != pw * ph) {
      throw new RuntimeException();
    }
    dest = new BufferedImage(sw, sh, BufferedImage.TYPE_INT_RGB);
    for (int i = 0; i < sh; ++i) {
      for (int j = 0; j < sw; ++j) {
        final int x = i * sw + j;
        dest.setRGB(j, i, palette.getRGB(x % pw, x / pw));
      }
    }
    l = new JLabel(new ImageIcon(dest));
    add(l);
    final JButton b = new JButton("Save");
    add(b, BorderLayout.SOUTH);
    b.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(final ActionEvent e) {
        try {
          ImageIO.write(dest, "png", new File(sourceName + "-" + paletteName
              + ".png"));
        } catch (IOException ex) {
          ex.printStackTrace();
        }
      }
    });
  }

  protected double dist(final int x, final int y) {
    double t = 0;
    double lx = 0;
    double ly = 0;
    for (int i = 0; i < 3; ++i) {
      final double xi = ((x >> (i * 8)) & 255) * F[i];
      final double yi = ((y >> (i * 8)) & 255) * F[i];
      final double d = xi - yi;
      t += d * d;
      lx += xi;
      ly += yi;
    }
    double l = lx - ly;
    return t + l * l * LUM_WEIGHT;
  }

  public boolean improve() {
    final int x = r.nextInt(n);
    final int y = r.nextInt(n);
    final int sx = source.getRGB(x % sw, x / sw);
    final int sy = source.getRGB(y % sw, y / sw);
    final int dx = dest.getRGB(x % sw, x / sw);
    final int dy = dest.getRGB(y % sw, y / sw);
    if (dist(sx, dx) + dist(sy, dy) > dist(sx, dy) + dist(sy, dx)) {
      dest.setRGB(x % sw, x / sw, dy);
      dest.setRGB(y % sw, y / sw, dx);
      return true;
    } else {
      return false;
    }
  }

  public void update() {
    l.repaint();
  }

  public static void main(final String... args) throws IOException {
    final CopyColors x = new CopyColors(SOURCE, PALETTE);
    x.setSize(800, 600);
    x.setLocationRelativeTo(null);
    x.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    x.setVisible(true);
    final Timer time = new Timer(DELAY, null);
    final long startTime = System.currentTimeMillis();
    time.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(final ActionEvent e) {
        int swapCounter = 0;
        for (int i = 0; i < COUNT; ++i) {
          if (x.improve()) {
            swapCounter = 0;
          } else {
            swapCounter++;
          }
          if(swapCounter > TRIES_MAX) {
            System.out.println(System.currentTimeMillis() - startTime);
            time.stop();
            break;
          }
        }
        x.update();
      }
    });
    time.start();
  }
}