/*
 * Copyright 2009 Jeffrey Palm
 */

import java.awt.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
import java.util.List;
import javax.imageio.*;
import javax.swing.*;

/**
 * Extracts letters from flickr images from <a
 * href="http://www.flickr.com/photos/lwr/">this account</a> of the
 * form:
 * 
 * <pre>
 *   *-*-*-*-*-*-*
 *   | |a|b|c|d| |
 *   *-*-*-*-*-*-*
 *   |e|f|g|h|i|j|
 *   *-*-*-*-*-*-*
 *   |k|l|m|n|o|p|
 *   *-*-*-*-*-*-*
 *   |q|r|s|t|u|v|
 *   *-*-*-*-*-*-*
 *   | |w|x|y|z| |
 *   *-*-*-*-*-*-*
 * </pre>
 * 
 * and then writes an image NAME.jpg to the directory
 * <code>letters/NAME/a.jpg</code> through
 * <code>letters/NAME/z.jpg</code>
 */
public final class AlphaMaker {

  private final File lettersDir = new File("letters");

  public static void main(String[] args) {
    if (args == null || args.length == 0) {
      File testFile = null;
      for (File f : new File(".").listFiles()) {
        if (f.getName().endsWith(".jpg")) {
          testFile = f;
          break;
        }
      }
      args = new String[]{testFile.getAbsolutePath()};
    }
    try {
      new AlphaMaker().realMain(args);
    } catch (Exception e) {e.printStackTrace();}
  }

  void realMain(String[] args) throws Exception {
    if (!lettersDir.exists()) {
      lettersDir.mkdirs();
    }
    for (String arg : args) {
      extract(arg);
    }
  }

  /**
   * Extracts the letters of image (see the header comments) to the
   * subdirectory of the <code>letters</code> directory excluding the
   * image extension.  e.g. an image named <code>foo.jpg</code> will
   * have the letters written to <code>letters/foo/a.jpg</code>
   * through <code>letters/foo/z.jpg</code>.
   *
   * @param image source image
   */
  private void extract(String image) throws Exception {
    note("image: " + image);
    //
    // create the output directory using the input image name
    // also clean it out, if it exists
    //
    String name = new File(image).getName();
    int ilastDot = name.indexOf('.');
    String outputDirName = ilastDot == -1 ? name : name.substring(0,ilastDot);
    File outputDir = new File(lettersDir,outputDirName);
    if (!outputDir.exists()) {
      outputDir.mkdirs();
    } else {
      for (File img : outputDir.listFiles()) {
        img.delete();
      }
    }
    //
    // create an image and get the array of pixels
    //
    Image img = Toolkit.getDefaultToolkit().createImage(image);
    JButton obs = new JButton(new ImageIcon(img));
    int w = img.getWidth(obs);
    int h = img.getHeight(obs);
    note("size: " + w + "x" + h);
    //
    // get the pixels
    //
    int[] pixels = new int[w*h];
    PixelGrabber pg = new PixelGrabber(img,0,0,w,h,pixels,0,w);
    try {pg.grabPixels();} catch (Exception e) {e.printStackTrace();}
    if ((pg.getStatus() & ImageObserver.ABORT) != 0) return;
    //
    // This image is a 6x5 square (probably sized 240x200, but we
    // won't stick to that) with the corners being blank, so we have:
    //
    //   *-*-*-*-*-*-*
    //   | |a|b|c|d| |
    //   *-*-*-*-*-*-*
    //   |e|f|g|h|i|j|
    //   *-*-*-*-*-*-*
    //   |k|l|m|n|o|p|
    //   *-*-*-*-*-*-*
    //   |q|r|s|t|u|v|
    //   *-*-*-*-*-*-*
    //   | |w|x|y|z| |
    //   *-*-*-*-*-*-*
    //
    int letterWidth  = w/6;
    int letterHeight = h/5;
    note("letter width  : " + letterWidth);
    note("letter height : " + letterHeight);
    char c = 'a';

    // top row
    for (int i=1; i<=4; i++) {
      writeLetter(pixels,w,outputDir,c++,i*letterWidth,0*letterHeight,(i+1)*letterWidth,1*letterHeight);
    }

    // middle 3 rows
    for (int j=1; j<=3; j++) {
      for (int i=0; i<=5; i++) {
        writeLetter(pixels,w,outputDir,c++,i*letterWidth,j*letterHeight,(i+1)*letterWidth,(j+1)*letterHeight);
      }
    }

    // bottom row
    for (int i=1; i<=4; i++) {
      writeLetter(pixels,w,outputDir,c++,i*letterWidth,4*letterHeight,(i+1)*letterWidth,5*letterHeight);
    }
  }

  /**
   * Writes out <em>letter</em><code>.jpg</code> to
   * <code>outputDir</code> with upper left coordinates
   * (<code>x0</code>,<code>y0</code>) and lower right coordinates
   * (<code>x1</code>,<code>y1</code>).
   *
   * @param pixel        pixels of the image
   * @param outputDir    output directory
   * @param width        width of passed in image
   * @param letter       letter we're extracting
   * @param x0           upper left x coordinate
   * @param y0           upper left y coordinate
   * @param x1           lower right x coordinate
   * @param y1           lower right y coordinate
   */
  private void writeLetter(int[] pixels, int width,
                           File outputDir, char letter, 
                           int x0, int y0, int x1, int y1) {
    BufferedImage img = new BufferedImage(x1-x0,y1-y0,BufferedImage.TYPE_INT_ARGB);
    for (int i=y0, y=0; i<y1; i++, y++) {
      for (int j=x0, x=0; j<x1; j++, x++) {
        img.setRGB(x,y,pixels[i*width+j]);
      }
    }
    try {
      ImageIO.write(img,"jpg",new File(outputDir,letter + ".jpg"));
    } catch (IOException e) {
      handle(e);
    }
  }

  /**
   * Handles exception in a uniform way.
   *
   * @param e exception to handle
   */
  private void handle(Throwable e) {
    e.printStackTrace();
  }

  /**
   * Outputs to STDOUT.
   *
   * @param msg message to print
   */
  private void out(Object msg) {
    System.out.print(msg);
  }

  /**
   * Returns the hex value of <code>i</code>
   *
   * @param i  integer to convert to hex
   * @return   hex value of <code>i</code>
   */
  private String hex(int i) {
     return Integer.toHexString(i);
  }

  /**
   * Debugging.
   *
   * @param msg message to print for debugging
   */
  protected final void note(Object msg) {
    System.err.println("[" + getClass().getName() + "] " + String.valueOf(msg));
  }

}