package serie08;

import java.util.Observable;

import util.Contract;

public class StdSpeedometerModel extends Observable implements SpeedometerModel {

	// ATTRIBUTS

	private double step;

	private double maxSpeed;

	private double speed;

	private SpeedUnit unit;

	private boolean isOn;

	// CONSTRUCTEURS

	public StdSpeedometerModel(double step, double max) {
		Contract.checkCondition(1 <= step, "step is too small");
		Contract.checkCondition(step <= max, "step is too big");
		maxSpeed = max;
		this.step = step;
		isOn = false;
		unit = SpeedUnit.KMH;
		speed = 0.0;
	}

	// REQUETES

	@Override
	public double getMaxSpeed() {
		return maxSpeed * unit.getUnitPerKm();
	}

	@Override
	public double getSpeed() {
		return speed * unit.getUnitPerKm();
	}

	@Override
	public double getStep() {
		return step * unit.getUnitPerKm();
	}

	@Override
	public SpeedUnit getUnit() {
		return unit;
	}

	@Override
	public boolean isOn() {
		return isOn ;
	}

	// COMMANDES

	@Override
	public void setUnit(SpeedUnit unit) {
		Contract.checkCondition(unit != null, "null unit");
		this.unit = unit;
	}

	@Override
	public void slowDown() {
		Contract.checkCondition(isOn, "contact is off");
		if(speed < step) {
			speed = 0;
		}
		else {
			speed -= step;
		}

	}

	@Override
	public void speedUp() {
		Contract.checkCondition(isOn, "contact is off");
		if((speed + step ) > maxSpeed) {
			speed = maxSpeed;
		}
		else {
			speed += step;
		}

	}

	@Override
	public void turnOff() {
		Contract.checkCondition(isOn, "contact is already off");
		isOn = false;
		speed = 0;
	}

	@Override
	public void turnOn() {
		Contract.checkCondition(!isOn, "contact is already on");
		isOn = true;
	}

}