Daily Programmer 174-Intermediate YuriKahn

package ava;

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Random;

import javax.imageio.ImageIO;

public class AvatarGenerator extends Thread {

    private ArrayList<String> userNames;
    private long seed;

    public static final int AVATAR_XSIZE = 10;
    public static final int AVATAR_YSIZE = 10;

    public AvatarGenerator(String s1, String seedString, boolean multipleFiles) {
        userNames = new ArrayList<String>();
        seed = djb2(seedString);
        if(!multipleFiles) {
            userNames.add(s1);
            return;
        }

        try{
            BufferedReader br = new BufferedReader(new FileReader(s1));
            String currentUserName = null;
            while((currentUserName = br.readLine()) != null) {
                userNames.add(currentUserName);
            }
            br.close();
        }catch(IOException e) {
            System.out.println("Error: Could not read usernames file.");
            System.exit(1);
        }
    }

    public void run() {
        for(int i=0; i<userNames.size(); i++) {
            String userName = userNames.get(i);
            String outputFileName = userName + ".bmp";
            Random random = new Random(seed + djb2(userName));
            float H = Math.abs(random.nextFloat())%1f;
            float S = (Math.abs(random.nextFloat())%0.5f)+0.5f;
            float B = (Math.abs(random.nextFloat())%0.3f)+0.7f;
            int forgroundColor = (new Color(50,50,50)).getRGB();

            int[][] avatar = new int[AVATAR_XSIZE][AVATAR_YSIZE];
            for(int x=0; x<AVATAR_XSIZE/2; x++) {
                for(int y=0; y<AVATAR_YSIZE; y++) {
                    boolean choice = random.nextBoolean();
                    if(choice) {
                        float mod1 = ((Math.abs(random.nextFloat()))%0.1f)-0.05f;
                        avatar[x][y] = Color.HSBtoRGB(H+mod1, S, Math.min(Math.max(B+mod1,0.0f),1.0f));
                        float mod2 = ((Math.abs(random.nextFloat()))%0.1f)-0.05f;
                        avatar[AVATAR_XSIZE-x-1][y] = Color.HSBtoRGB(H+mod2, S, Math.min(Math.max(B+mod2,0.0f),1.0f));
                    }else{
                        avatar[x][y] = forgroundColor;
                        avatar[AVATAR_XSIZE-x-1][y] = forgroundColor;
                    }
                }
            }
            writeImage(outputFileName, avatar);
        }
    }

    private void writeImage(String outputFilename, int[][] avatar) {
        File outputFile = new File(outputFilename);
        int PIXELX = 5;
        int PIXELY = 5;
        BufferedImage theImage = new BufferedImage(AVATAR_XSIZE*PIXELX, AVATAR_YSIZE*PIXELY, BufferedImage.TYPE_INT_RGB);
        for(int x=0; x<AVATAR_XSIZE; x++) {
            for(int y=0; y<AVATAR_YSIZE; y++) {
                for(int px=0; px<PIXELX; px++) {
                    for(int py=0; py<PIXELY; py++) {
                        theImage.setRGB(PIXELX*x + px, PIXELY*y + py, avatar[x][y]);
                    }
                }
            }
        }
        try{
            ImageIO.write(theImage, "BMP", outputFile);
        }catch(IOException e) {
            System.out.println("Error: Could not write file.");
            System.exit(1);
        }
    }

    private long djb2(String stringToHash) {
        long hash = 5381;
        int c;
        for(int i=0; i<Math.max(stringToHash.length(),8); i++) {
            c = stringToHash.charAt(i % stringToHash.length());
            hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
        }
        return hash;
    }

    public static void main(String[] args) {
        if(args.length == 2) {
            AvatarGenerator instance = new AvatarGenerator(args[0], args[1], false);
            instance.start();
        }else if(args.length == 3) {
            if("-m".equals(args[2])) {
                AvatarGenerator instance = new AvatarGenerator(args[0], args[1], true);
                instance.start();
                return;
            }else{
                System.out.println("Error: Unknown flag.");
            }
        }else{
            System.out.println("Usage:\n\t$ AvatarGenerator <username> <seed>");
            System.out.println("OR\n\t$ AvatarGenerator <file with usernames> <seed> -m");
        }
    }
}