// 500 元客户订单
var order500 = function (orderType,pay,stock) {
	if(orderType === 1 && pay){
		 console.log('500 rmb deposit, get 100 coupon ')
	} else {
		return 'nextSuccessor'  // unknow the next node but always pass to next.
	}
};

// 200 元客户订单
var order200 = function (orderType,pay,stock) {
	if(orderType === 2 && pay){
		console.log('200 rmb deposit , get 50 coupon')
	} else{
		 return 'nextSuccessor'; 
	}
};

// 无预约客户订单
var orderNormal = function (orderType,pay,stock) {
	if(stock > 0){
		 console.log('normal buy no coupon')
	} else{
		 console.log('the stock lack')
	}
};

// 定制职责链对象（作用是形成订单职责链）
var Chain = function (fn) {
	this.fn = fn;
	this.successor = null;
};
// 设置职责链
Chain.prototype.setNextSuccessor = function (successor) {
	return this.successor = successor;
};
// 设置每个节点的调用方式
Chain.prototype.passRequest = function () {
	var ret = this.fn.apply(this.arguments);
	if(ret === 'nextSuccessor'){
		return this.successor && this.successor.passRequest.apply(this.successor,arguments)
	}
	return ret;
};

// 现在我们把3个订单函数分别包装成职责链的节点
var chainOrder500 = new Chain(order500);
var chainOrder200 = new Chain(order200);
var chainOrderNormal = new Chain(orderNormal);

// 这里我们把上面封装的节点连成一条线，依次判断执行
chainOrder500.setNextSuccessor(chainOrder200)
chainOrder200.setNextSuccessor(chainOrderNormal)

// 测试代码
chainOrder500.passRequest(1,true,6); // 500 rmb deposit, get 100 coupon
chainOrder500.passRequest(2,true,4); // 200 rmb deposit , get 50 coupon