import java.util.*;
/**
 * LOGO parser.
 * Parses commands and holds the array of turtles.
 */
public class Parser{
	/** the array of turtles */
	private Turtle[] turtles;
	/** the current (active) turtle. If set to null, all turtles are active */
	private Turtle currentTurtle;
	static final int MAX_TURTLES = 20;
	/**
	 * Constructs a new Parser object.
	 * Initializes the turtle array.
	 */
	public Parser(){
		turtles = new Turtle[MAX_TURTLES];
	}
	/**
	 * Gets the turtle array.
	 * @return the turtle array
	 */
	public Turtle[] getTurtles(){
		return turtles;
	}
	/**
	 * Parses each line for commands.
	 * @param line the line to parse
	 */
	public void parseLine(String line){
		Scanner scan = new Scanner(line);
		String cmd = scan.next();
		if(cmd.equalsIgnoreCase("forward") || cmd.equalsIgnoreCase("fwd") || cmd.equalsIgnoreCase("fd"))
			forward(scan.nextInt());
		else if(cmd.equalsIgnoreCase("rotate") || cmd.equalsIgnoreCase("rot"))
			rotate(scan.nextInt());
		else if(cmd.equalsIgnoreCase("left") || cmd.equalsIgnoreCase("lt") || cmd.equalsIgnoreCase("lft"))
			rotate(90);
		else if(cmd.equalsIgnoreCase("right") || cmd.equalsIgnoreCase("rt"))
			rotate(-90);
		else if(cmd.equalsIgnoreCase("back") || cmd.equalsIgnoreCase("bk"))
			forward(-scan.nextInt());
		else if(cmd.equalsIgnoreCase("turtle"))
			newTurtle(scan.next());
		else if(cmd.equalsIgnoreCase("activate"))
			activate(scan.next());
		else if(cmd.equalsIgnoreCase("remove"))
			remove(scan.next());
		else if(cmd.equalsIgnoreCase("quit"))
			System.exit(0);
	}
	/**
	 * Moves the turtle(s) forward.
	 * @param dist the distance to move.
	 */
	public void forward(int dist){
		if(currentTurtle == null){
			for(Turtle turtle : turtles){
				if(turtle != null)
					turtle.move(dist);
			}
		}
		else
			currentTurtle.move(dist);
	}
	/**
	 * Rotates the turtle(s).
	 * @param angle the angle to rotate, in degrees
	 */
	public void rotate(int angle){
		if(currentTurtle == null){
			for(Turtle turtle : turtles){
				if(turtle != null)
					turtle.rotate(angle);
			}
		}
		else
			currentTurtle.rotate(angle);
	}
	/**
	 * Creates a new turtle.
	 * Calls the Turtle constructor, passing the name as a parameter.
	 * @param name the name of the turtle
	 */
	public void newTurtle(String name){
		int sentinel = 0;
		if(!name.equalsIgnoreCase("ALL")){
			for(Turtle turtle : turtles){
				if(turtle != null)
					if(turtle.getName() == name)
						sentinel = 1;
			}
			if(sentinel == 0){
				for(Turtle turtle : turtles){
					if(turtle == null){
						turtle = new Turtle(name);
						System.out.println("Constructed");
						break;
					}
				}
			}
		}
	}
	/**
	 * Activates a turtle.
	 * Activating "ALL" activates all turtles.
	 * @param name the turtle to activate
	 */
	public void activate(String name){
		if(name.equalsIgnoreCase("ALL"))
			currentTurtle = null;
		else
			for(Turtle turtle : turtles){
				if(turtle.getName() == name)
					currentTurtle = turtle;
			}
	}
	/**
	 * Deletes a turtle.
	 * @param name the turtle to delete
	 */
	public void remove(String name){
		for(Turtle turtle : turtles){
			if(turtle.getName() == name)
				turtle = null;
		}
	}
}