import java.awt.*;
import javax.swing.*;

/**
 * The drawing surface for a maze.  <p>
 * Modeled on ColonyPanel.java from CS 5 Life lab. 
 * 
 * @author Scot Drysdale 
 */

public class MazePanel extends JPanel {
	private static final long serialVersionUID = 1L;

	private Maze maze;       // The current maze to be drawn.
	
	// Colors for various types of maze cells
	private static final Color BACKGROUND_COLOR = Color.yellow;		
	private static final Color EMPTY_COLOR = Color.white;
	private static final Color EXPLORED_COLOR = Color.gray;
	private static final Color WALL_COLOR = Color.black;
	private static final Color ON_PATH_COLOR = Color.cyan;
	private static final Color START_COLOR = Color.green;
	private static final Color TARGET_COLOR = Color.red;
	private static final Color DEFAULT_COLOR = Color.magenta;
	
	/**
	 * Construct a panel with no maze displayed
	 */
	public MazePanel()	{
		maze = null;           // Will be set later via setMaze
		setBackground(BACKGROUND_COLOR);
	}
	
	/**
	 * Used to update the maze to be displayed
	 * @param aMaze a maze that you want to be displayed
	 */
	public void setMaze(Maze aMaze) {
		maze = aMaze;
	}
	
	/**
	 * Draws the whole panel
	 */
	public void paintComponent(Graphics page)
	{  
		super.paintComponent(page); 
		display(page);
	}

	/**
	 * Does the actual work of drawing the maze
	 * @param page the page to which you want to draw
	 */
	public void display(Graphics page)
	{
		if (maze == null) return;    // Nothing to paint if no maze
		
		// Get dimensions of panel and maze
		int panelWidth = getWidth();
    int panelHeight = getHeight();
    int numRows = maze.numRows();
    int numCols = maze.numCols();
    
    // Based on current panel size, figure maximum square size and
    // where the upper left corner of the maze should be to center it
    int squareSize = Math.min(panelHeight/numRows, panelWidth/numCols);
    int upperLeftX = (panelWidth - numCols*squareSize)/2;
    int upperLeftY = (panelHeight - numRows*squareSize)/2;
    
    // Draw the maze
		for (int row = 0; row < numRows; row++)
			for (int col = 0; col < numCols; col++) 
			{
				Color cellColor;   // Color for this cell
				
				switch (maze.get(row, col)) {
				
				case Maze.EMPTY:
					cellColor = EMPTY_COLOR;
			    break;
				case Maze.WALL:
					cellColor = WALL_COLOR;
			    break;
				case Maze.EXPLORED:
					cellColor = EXPLORED_COLOR;
			    break;
				case Maze.ON_PATH:
					cellColor = ON_PATH_COLOR;
			    break;
				case Maze.TARGET:
					cellColor = TARGET_COLOR;
					break;
				case Maze.START:
					cellColor = START_COLOR;
			    break;				
				default:  // Should never occur
					cellColor = DEFAULT_COLOR;	
				}
				
				page.setColor(cellColor);
				page.fillRect(upperLeftX + col*squareSize, 
						upperLeftY + row*squareSize, squareSize, squareSize);
			}
	}
}