/*
 * Code by Curt Clifton, Rose-Hulman Institute of Technology.
 * April 29, 2009.
 * 
 * Specification by YOUR_NAME_HERE.
 */

/**
 * This class models a lift.
 */
public class Lift {
	/* You don't need to specify anything about these constants. */
	public static final int UP = 1;

	public static final int STOP = 0;

	public static final int DOWN = -1;

	
	/* TODO: add JML annotations to the instance fields */
	private int location;

	private boolean[] floorRequestLight;

	private boolean upArrowLight;

	private boolean downArrowLight;

	private int nextDirection;

	private boolean doorsOpen;


	/* TODO: add a class invariant */


	/* TODO: add a specification to this constructor */
	public Lift(int numberOfFloors) {
		this.location = 0;
		this.floorRequestLight = new boolean[numberOfFloors];
		this.upArrowLight = false;
		this.downArrowLight = false;
		this.nextDirection = STOP;
		this.doorsOpen = false;
	}

	/* TODO: add a specification to this method */
	public void buttonPressed(int floor) {
		this.floorRequestLight[floor - 1] = true;
	}

	/* TODO: add a specification to this method */
	public void movedUp() {
		this.location++;
	}

	/* TODO: add a specification to this method */
	public void movedDown() {
		this.location--;
	}

	/* TODO: add a specification to this method */
	public void doorsOpened(int newDirection) {
		this.doorsOpen = true;
		this.nextDirection = newDirection;
		if (newDirection == UP) {
			this.upArrowLight = true;
			this.downArrowLight = false;
		} else if (newDirection == DOWN) {
			this.downArrowLight = true;
			this.upArrowLight = false;
		} else {
			this.downArrowLight = false;
			this.upArrowLight = false;
		}
		this.floorRequestLight[this.location] = false;
	}

	/* TODO: add a specification to this method */
	public void doorsClosed() {
		this.doorsOpen = false;
		this.downArrowLight = false;
		this.upArrowLight = false;
	}
	
	/* TODO: add a specification to this method */
	public int getFloor() {
		return this.location + 1;
	}
	
	/* TODO: add a specification to this method */
	public boolean isFloorRequestLit(int floor) {
		return this.floorRequestLight[floor - 1];
	}

	/* TODO: add a specification to this method */
	public boolean isDownArrowLit() {
		return this.downArrowLight;
	}

	/* TODO: add a specification to this method */
	public boolean isUpArrowLit() {
		return this.upArrowLight;
	}

}