/**
 * XKCD is a webcomic by Randall Munroe. It's funny, I swear.
 *
 * @author: Josh Snider
 */

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

public class XKCDImageGetter extends ComicGetter {

  public static void main(String[] args) throws Exception {
    int NewestComic = getNewestComic();
    System.out.println(NewestComic);
    for (int x = 1; x < NewestComic; x++) {
      if (x == 404) {
        x++;
      }
      String fileLoc = getHTML(x);
      System.out.println(x);
      saveImage(fileLoc, x);
      System.out.println(fileLoc);
    }
  }

  /**
   * Get the index of the newest xkcd comic.
   */
  public static int getNewestComic() throws Exception {
    URL xkcd = new URL("http://www.xkcd.com/");
    URLConnection webpage = xkcd.openConnection();
    BufferedReader in = new BufferedReader(
      new InputStreamReader(webpage.getInputStream()));
    String input;
    StringBuffer html = new StringBuffer();
    while ((input =in.readLine()) != null) {
      html.append(input);
    }
    input = html.toString();
    int num = input.indexOf("|&lt");
    num = input.indexOf("href=", num);
    int end = input.indexOf("/", num + 7);
    int comicnumber = Integer.parseInt(input.substring(num + 7, end));
    return comicnumber + 1;
  }

  /**
   * Get the image URL for the given comic number.
   */
  public static String getHTML(int num) throws Exception {
    URL url = new URL("http://www.xkcd.com/" + num);
    URLConnection webpage = url.openConnection();
    BufferedReader in = new BufferedReader(
      new InputStreamReader(webpage.getInputStream()));
    String input;
    StringBuffer html = new StringBuffer();
    while ((input = in.readLine()) != null) {
      html.append(input);
    }
    input = html.toString();
    int start = input.indexOf("http://imgs.xkcd.com/comics");
    int end = input.indexOf('<', start);
    String fileLoc = input.substring(start, end);
    return fileLoc;
  }

  /**
   * Get the given xkcd comic and save it as the given file.
   */
  public static void saveImage(String fileLoc, int comicnumber) {
    String comicname = fileLoc.substring(28);
    ComicGetter.saveImage(fileLoc, comicnumber + comicname);
  }
}