package com.itcast.traffic;

/**
 * 每个Lamp元素代表一个方向上的灯，总共有12个方向，所以总共有12个Lamp元素
 * @author Administrator
 *
 */
public enum Lamp {

	//每个枚举元素各表示一个方向的控制灯
	S2N("N2S","S2W",false),S2W("N2E","S2W",false),E2W("W2E","E2S",false),E2S("W2N","S2N",false),
	//下面元素表示与上面的元素相反方向的灯，它们的"相反方向灯"与"下一个灯"应忽略不计
	N2S(null,null,false),N2E(null,null,false),W2E(null,null,false),W2N(null,null,false),
	//右拐方向灯，不受红绿灯控制，所以假设常绿
	S2E(null,null,true),N2W(null,null,true),W2S(null,null,true),E2N(null,null,true);
	
	private Lamp(String oppsite,String next,boolean lighted){
		this.oppsite = oppsite;
		this.next = next;
		this.lighted = lighted;
	}
	
	//与当前灯同时为绿的对应方向
	private String oppsite;
	//当前灯变红时下一个变绿的灯
	private String next;
	//当前灯是否为绿灯
	private boolean lighted;
	
	public boolean isLighted(){
		return lighted;
	}
	
	//某个灯变绿时，它对应方向上的灯也要变绿
	public void light(){
		this.lighted = true;
		if(this.oppsite != null){
			Lamp.valueOf(oppsite).light();
		}
		System.out.println(name() + "Lamp is green,下面总共应该有6个方向能看到汽车通过");
	}
	
	//某个方向上的灯变红时，对应方向的灯也要变红，并且下一个方向的灯要变绿
	public Lamp blackOut(){
		this.lighted = false;
		if(this.oppsite != null){
			Lamp.valueOf(oppsite).blackOut();
		}
		Lamp nextLamp = null;
		if(this.next != null){
			nextLamp = Lamp.valueOf(next);
			System.out.println("绿灯从" + name() + "------------->切换为" + next);
			nextLamp.light();
		}
		
		return nextLamp;
	}
	
}