// Import statements
import javax.swing.JFrame;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.Point;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JLabel;

/** This class allows simple pictures to be manually draw on the screen. */
public class Artist extends JLabel {
	// The number of pixels per inch
	private static final int PIXELS_TO_INCHES = 50;
	// The default width of the frame the Artist object draws on.
	private static final int DEFAULT_WIDTH = 900;
	// The default height of the frame the Artist object draws on.
	private static final int DEFAULT_HEIGHT = 900;
	// The current position of the Artist's "pen"
	private Point currentPosition;
	// An auxiliary image to draw on so that drawing can be done outside of the paintComponent method.
	private Image image;
	
	/** Constructs an Artist object and displays its frame to the screen. */
	public Artist() {
		// Creates the frame
		JFrame frame = new JFrame();
		// Sets the frame up
		frame.setDefaultLookAndFeelDecorated(true);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		frame.setVisible(true);
		frame.getContentPane().add(this);
		// Initializes the current position
		currentPosition = new Point(PIXELS_TO_INCHES, 
					    PIXELS_TO_INCHES);
		// Initializes the auxiliary image
		image = new BufferedImage(DEFAULT_WIDTH, DEFAULT_HEIGHT, BufferedImage.TYPE_INT_RGB);
		// Sets the background color to white
		Graphics g = image.getGraphics();
		g.setColor(Color.white);
		g.fillRect(0, 0, DEFAULT_WIDTH, DEFAULT_HEIGHT);
	}

	/** This method does the actual painting to the screen. */
	protected void paintComponent(Graphics g) {		
		g.drawImage(image, 0, 0, this);
	}

	/** This method draws a line of length <code>length</code> up from the current position,
	  * and sets the current position equal to the end of that line. 
	  * @param length The length of the line to be drawn.
	*/
	public void drawLineUp(int length) {
		Graphics g = image.getGraphics();
		g.setColor(Color.black);
		// Calculates the new position
		int ny = currentPosition.y - (length * PIXELS_TO_INCHES);
		// Draws the line
		g.drawLine(currentPosition.x, currentPosition.y, currentPosition.x, ny);
		// Updates the position
		currentPosition.y = ny;
	}

	/** This method draws a line of length <code>length</code> down from the current position,
	  * and sets the current position equal to the end of that line. 
	  * @param length The length of the line to be drawn.
	*/
	public void drawLineDown(int length) {
		Graphics g = image.getGraphics();
		g.setColor(Color.black);
		// Calculates the new position
		int ny = currentPosition.y + (length * PIXELS_TO_INCHES);
		// Draws the line
		g.drawLine(currentPosition.x, currentPosition.y, currentPosition.x, ny);
		// Updates the position
		currentPosition.y = ny;
	}

	/** This method draws a line of length <code>length</code> left from the current position,
	  * and sets the current position equal to the end of that line. 
	  * @param length The length of the line to be drawn.
	*/
	public void drawLineLeft(int length) {
		Graphics g = image.getGraphics();
		g.setColor(Color.black);
		// Calculates the new position
		int nx = currentPosition.x - (length * PIXELS_TO_INCHES);
		// Draws the line
 		g.drawLine(currentPosition.x, currentPosition.y, nx, currentPosition.y);
		// Updates the position		
		currentPosition.x = nx;
	}

	/** This method draws a line of length <code>length</code> right from the current position,
	  * and sets the current position equal to the end of that line. 
	  * @param length The length of the line to be drawn.
	*/
	public void drawLineRight(int length) {
		Graphics g = image.getGraphics();
		g.setColor(Color.black);
		// Calculates the new position
		int nx = currentPosition.x + (length * PIXELS_TO_INCHES);
		// Draws the line
 		g.drawLine(currentPosition.x, currentPosition.y, nx, currentPosition.y);
		// Updates the position	
		currentPosition.x = nx;
	}
	
	/** Moves the current position <code>d</code> inches right of the current position. 
	  * @param d The number of inches to move the current position.
	*/
	public void moveRight(int d) {
		currentPosition.x += (PIXELS_TO_INCHES * d);
	}
	
	/** Moves the current position <code>d</code> inches left of the current position. 
	  * @param d The number of inches to move the current position.
	*/
	public void moveLeft(int d) {
		currentPosition.x -= (PIXELS_TO_INCHES * d);
	}
	
	/** Moves the current position <code>d</code> inches up from the current position. 
	  * @param d The number of inches to move the current position.
	*/
	public void moveUp(int d) {
		currentPosition.y -= (PIXELS_TO_INCHES * d);
	}
	
	/** Moves the current position <code>d</code> inches down fromthe current position. 
	  * @param d The number of inches to move the current position.
	*/
	public void moveDown(int d) {
		currentPosition.y += (PIXELS_TO_INCHES * d);
	}
}