package jalview.gui;

import java.awt.*;
import javax.swing.*;

public class ScaleCanvas extends JPanel {

  Image    img;
  Graphics gg;

  int      imgWidth;
  int      imgHeight;
  int      xoffset;

  public static final int HEIGHT = 30;

  boolean paintFlag = false;

  protected AlignViewport av;

  public ScaleCanvas(AlignViewport av) {
    this.av         = av;

  }
  public void paintComponent(Graphics g) {

   double charWidth  = av.getCharWidth();
    int charHeight = av.getCharHeight();

    if (img == null ||
        imgWidth  != getWidth()  ||
        imgHeight != getHeight() ||
        paintFlag == true) {

      imgWidth  = getWidth();
      imgHeight = getHeight();
      img       = createImage(imgWidth,imgHeight);

      gg = img.getGraphics();
      gg.setColor(Color.white);
      gg.fillRect(0,0,imgWidth,imgHeight);



      paintFlag = false;
    }
    gg.setFont(av.getFont());

    //Fill in the background

    gg.setColor(Color.white);
    gg.fillRect(0,0,imgWidth,imgHeight);

    int tickSpace;

    int resWidth = av.getEndRes() - av.getStartRes() + 1;

    // We want roughly one tick every 50 pixels

    double rough = getWidth()/50.0;

    double roughtick = resWidth/rough;

    int   digits  = (int)(Math.log(roughtick)/Math.log(10));
    int   num     = (int)(roughtick/Math.pow(10,digits));

    if (Math.abs(10-num) < 3) {
        num = 10;
    } else if (Math.abs(5-num) <= 2) {
        num = 5;
    } else {
        num = 2;
    }
    //System.out.println("Dig " + digits + " " + rough + " " + roughtick + " " + getWidth() + " " + num);

    int space = (int)(num * Math.pow(10,digits));

    //Set the text font

    gg.setColor(Color.black);

    int startx      = av.getStartRes();
    int endx        = av.getEndRes();
    int scalestartx = startx - startx%space + space;


    //Fill the selected columns
    ColumnSelection cs = av.getColumnSelection();
    int width = (int)charWidth;
    if (width == 0)
      width = 1;

    gg.setColor(new Color(220,0,0));
    for (int i=0; i<cs.size(); i++) {
      int sel  = cs.columnAt(i);
      //      System.out.println("Selection = " + sel);
      if ( sel >= startx  && sel <= endx) {

        gg.fillRect((int)((sel-startx)*charWidth),0,width,getHeight());
      }
    }

    // Draw the scale numbers
    gg.setColor(Color.black);


    for (int i=scalestartx;i < endx;i+= space) {

      String string = String.valueOf(i);

      gg.drawString(string,(int)((i-startx-1)*charWidth),15);
      gg.drawLine( (int)((i-startx-1)*charWidth +charWidth/2), 17, (int)((i-startx-1)*charWidth +charWidth/2), 24);

    }


    g.drawImage(img,0,0,this);

  }

  public Dimension getMinimumSize() {
    return new Dimension(500,HEIGHT);
  }

  public Dimension getPreferredSize() {
    return getMinimumSize();
  }

}