package graphics;

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.RenderingHints;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JPanel;

import static java.util.Arrays.parallelSetAll;
import static java.util.Arrays.stream;
import static java.util.stream.IntStream.range;

public class Honeycombs extends JFrame {
  HoneycombsPanel panel;

  public static void main(String[] args) {
    JFrame f = new Honeycombs();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
  }

  public Honeycombs() {
    Container content = getContentPane();
    content.setLayout(new BorderLayout());
    panel = new HoneycombsPanel();
    content.add(panel, BorderLayout.CENTER);
    setTitle("Honeycombs");
    setResizable(false);
    pack();
    setLocationRelativeTo(null);
  }
}

class HoneycombsPanel extends JPanel {
  Hexagon[] comb;

  @FunctionalInterface
  private static interface MousePressed extends MouseListener {
    public static MousePressed new_(MousePressed mousePressed) {
      return mousePressed;
    }

    @Override
    public default void mouseClicked(MouseEvent mouseEvent) {}

    @Override
    public default void mouseEntered(MouseEvent mouseEvent) {}

    @Override
    public default void mouseExited(MouseEvent mouseEvent) {}

    @Override
    public default void mouseReleased(MouseEvent mouseEvent) {}
  }

  @FunctionalInterface
  private static interface KeyPressed extends KeyListener {
    public static KeyPressed new_(KeyPressed keyPressed) {
      return keyPressed;
    }

    @Override
    public default void keyReleased(KeyEvent keyEvent) {}

    @Override
    public default void keyTyped(KeyEvent keyEvent) {}
  }

  public HoneycombsPanel() {
    setPreferredSize(new Dimension(600, 500));
    setBackground(Color.white);
    setFocusable(true);

    addMouseListener(MousePressed.new_(e -> {
      stream(comb)
        .filter(hex -> hex.contains(e.getX(), e.getY()))
        .findFirst()
        .ifPresent(hex -> hex.setSelected())
      ;
      repaint();
    }));

    addKeyListener(KeyPressed.new_(e -> {
      stream(comb)
        .filter(hex -> hex.letter == Character.toUpperCase(e.getKeyChar()))
        .findFirst()
        .ifPresent(hex -> hex.setSelected())
      ;
      repaint();
    }));

    char[] letters = "LRDGITPFBVOKANUYCESM".toCharArray();
    comb = new Hexagon[20];

    int x1 = 150, y1 = 100, x2 = 225, y2 = 143, w = 150, h = 87;
    parallelSetAll(comb, i -> {
      int x, y;
      if (i < 12) {
          x = x1 + (i % 3) * w;
          y = y1 + (i / 3) * h;
      } else {
          x = x2 + (i % 2) * w;
          y = y2 + ((i - 12) / 2) * h;
      }
      return new Hexagon(x, y, w / 3, letters[i]);
    });

    requestFocus();
  }

  @Override
  public void paintComponent(Graphics gg) {
    super.paintComponent(gg);
    Graphics2D g = (Graphics2D) gg;
    g.setRenderingHint(
      RenderingHints.KEY_ANTIALIASING,
      RenderingHints.VALUE_ANTIALIAS_ON
    );

    g.setFont(new Font("SansSerif", Font.BOLD, 30));
    g.setStroke(new BasicStroke(3));

    stream(comb)
      .forEach(hex -> hex.draw(g))
    ;
  }
}

class Hexagon extends Polygon {
  final Color baseColor = Color.yellow;
  final Color selectedColor = Color.magenta;
  final char letter;

  private boolean hasBeenSelected;

  Hexagon(int x, int y, int halfWidth, char c) {
    letter = c;
    range(0, 6)
      .forEach(i ->
        addPoint((int) (x + halfWidth * Math.cos(i * Math.PI / 3)),
                 (int) (y + halfWidth * Math.sin(i * Math.PI / 3)))
      )
    ;
    getBounds();
  }

  void setSelected() {
    hasBeenSelected = true;
  }

  void draw(Graphics2D g) {
    g.setColor(hasBeenSelected ? selectedColor : baseColor);
    g.fillPolygon(this);

    g.setColor(Color.black);
    g.drawPolygon(this);

    g.setColor(hasBeenSelected ? Color.black : Color.red);
    drawCenteredString(g, String.valueOf(letter));
  }

  void drawCenteredString(Graphics2D g, String s) {
    FontMetrics fm = g.getFontMetrics();
    int asc = fm.getAscent();
    int dec = fm.getDescent();

    int x = bounds.x + (bounds.width - fm.stringWidth(s)) / 2;
    int y = bounds.y + (asc + (bounds.height - (asc + dec)) / 2);

    g.drawString(s, x, y);
  }
}