// Author: benson limketkai
// Date: May 22, 2007
// Modified: June 3, 2008

import java.awt.*;

// a robot class -- notice how the robot has no notion of
// world coordinates (i.e. the individual pixel coordinates
// of the drawing panel);  in all computations, it only thinks
// in terms of grid coordinates;  the World class abstracts
// away any details about drawing on the drawing panel
public class Robot {
    private Point location;
    private Direction heading;
    private World grid;
    
    public Robot(World grid) {
        heading = Direction.EAST;
        location = new Point();
        this.grid = grid;
    }

    /////////////////////////////////////////////////////////
    // accessors
    /////////////////////////////////////////////////////////
    public double getX() {
        return location.x;
    }

    public double getY() {
        return location.y;
    }
    
    /////////////////////////////////////////////////////////
    
    // changes the heading of the robot
    public void turn(boolean turnRight) {
        Direction[] dirs = { Direction.NORTH, Direction.EAST, Direction.SOUTH, Direction.WEST };
        for (int i = 0; i < dirs.length; i++) {
            if (heading == dirs[i]) {
                if (turnRight) {
                    heading = dirs[(i+1)%dirs.length];
                } else {
                    heading = dirs[(i+3)%dirs.length];
                }
                return; // heading changed, exit
            }
        }
    }
    
    // move the robot NUM number of steps in the direction of the heading;
    // if the robot exceeds the bounds of the world, put them on the edge
    public void move(int num) {
        if (heading == Direction.NORTH) {
            location.translate(0, num);
            int maxY = grid.getMaxY();
            if (getY() > maxY) {
                location.y = maxY;
            }
        } else if (heading == Direction.SOUTH) {
            location.translate(0, -num);
            int minY = grid.getMinY();
            if (getY() < minY) {
                location.y = minY;
            }
        } else if (heading == Direction.EAST) {
            location.translate(num, 0);
            int maxX = grid.getMaxX();
            if (getX() > maxX) {
                location.x = maxX;
            }
        } else if (heading == Direction.WEST) {
            location.translate(-num, 0);
            int minX = grid.getMinX();
            if (getX() < minX) {
                location.x = minX;
            }
        }
    }
    
    // draws the robot in the grid
    public void draw(World grid) {
        grid.setColor(Color.RED);
        
        // draw body
        grid.fillCircle(getX(), getY(), 0.5);
        
        // draw heading
        double angle;
        if (heading == Direction.NORTH) {
            angle = Math.toRadians(90);
        } else if (heading == Direction.SOUTH) {
            angle = Math.toRadians(-90);
        } else if (heading == Direction.EAST) {
            angle = 0;
        } else { // WEST
            angle = Math.toRadians(180);
        }
        
        // draw arrow
        double endX = getX() + (1.5 * Math.cos(angle));
        double endY = getY() + (1.5 * Math.sin(angle));
        grid.drawLine(getX(), getY(), endX, endY, 0.25);

        // draw endpoint of arrow
        double arrowEnd1X = endX + (0.75 * Math.cos(angle - Math.toRadians(135)));
        double arrowEnd1Y = endY + (0.75 * Math.sin(angle - Math.toRadians(135)));
        grid.drawLine(arrowEnd1X, arrowEnd1Y, endX, endY, 0.25);
        double arrowEnd2X = endX + (0.75 * Math.cos(angle + Math.toRadians(135)));
        double arrowEnd2Y = endY + (0.75 * Math.sin(angle + Math.toRadians(135)));
        grid.drawLine(arrowEnd2X, arrowEnd2Y, endX, endY, 0.25);
    }
}