import java.awt.*;
import java.awt.image.BufferedImage;

/**
 * Short Assignment 3 (SA-3) provided code
 * Use steganography to hide a message in an image by subtly altering the red component of a pixel.
 * Complete hideMessage and getMessage methods.
 *
 * @author Tim Pierson, Dartmouth CS10, Winter 2025
 */
public class Steganography {
    private Character STOP_CHARACTER = '*'; //this character indicates the end of the message
    private int BITS_PER_CHARACTER = 7; //each character in a message is this many bits long
    private int MAX_COLOR = 255; //max pixel red, green, or blue color value

    /**
     * Hides a message in an image.  First add a stop character to the end of the message so when a message is recovered
     * the recovery operations knows it is at the end of the message when it encounters the stop character.
     * Convert each character in message to "1" and "0" bit.
     * For each bit, alter the red component so that "0" bits result in an even red color, while "1" bits result in an odd
     * red color.  Use Integer.toBinaryString(c) to create a String of "1" and "0" bits from Character c.
     * @param original - BufferedImage holding the image to hide the message in
     * @param message - String message to hide
     * @return - altered BufferedImage result where pixels are even if bit is "0" and odd if bit is "1"
     */
    public BufferedImage hideMessage(BufferedImage original, String message) {
        int x = 0, y = 0;
        message += STOP_CHARACTER;

        //make copy of original image so we don't alter the original image
        BufferedImage result = new BufferedImage(original.getColorModel(), original.copyData(null), original.getColorModel().isAlphaPremultiplied(), null);

        //TODO: Your code here



        return result;
    }


    /**
     * Recover message hidden in image.  Loop until stop character is encountered.
     * @param img - BufferedImage with hidden message
     * @return String with recovered message
     */
    public String getMessage(BufferedImage img) {
        String message;
        //TODO: Your code here

        return message;
    }



    public static void main(String[] args) {
        String originalImageFileName = "pictures/baker.png";
        String hiddenImageFileName = "pictures/hidden.png"; //do not use lossy jpg format, corrupts message, use png
        String message = "Great job on this problem!  Good luck with the rest of the term. Now to make the message really crazy long so the message will have to go beyond a single line of pixels in the image.  This should be about enough. If the picture is only 800 pixels wide, about 115 characters would do the trick";

        //hide message in image
        System.out.println("Hiding message: " + message);
        BufferedImage image = ImageIOLibrary.loadImage(originalImageFileName);
        Steganography s = new Steganography();
        BufferedImage hiddenMessageImage = s.hideMessage(image, message);
        ImageGUI gui = new ImageGUI("SA-3  Can you tell the difference between images?",image, hiddenMessageImage);

        //save image with hidden message to disk
        ImageIOLibrary.saveImage(hiddenMessageImage, hiddenImageFileName,"png");

        //read image from disk and retrieve message from image
        BufferedImage img = ImageIOLibrary.loadImage(hiddenImageFileName);
        String recoveredMessage = s.getMessage(hiddenMessageImage);
        System.out.println("Recovered message: " + recoveredMessage);

    }
}