const redis = require("redis"),
 redisClient = redis.createClient,
 REDIS_CFG = {
  host: '127.0.0.1',
  port: 6379
 },
 sub = redisClient(REDIS_CFG),
 pub = redisClient(REDIS_CFG),
 PAY_MQ_CHANNEL = 'pay_mq_channel';

// 監(jiān)聽頻道的消息回調(diào)
sub.on('message', function(channel, message) {
 switch (channle){
  case PAY_MQ_CHANNEL:
   console.log('notification received:', message);

   // 廣播消息到指定socket

   break;
 }
});
// 訂閱頻道
sub.subscribe(PAY_MQ_CHANNEL);

// 當(dāng)接收到支付數(shù)據(jù)時(shí)，推送頻道消息
pub.publish(PAY_MQ_CHANNEL, {id: '01', msg: `hello ${PAY_MQ_CHANNEL}!`});

/*
 * redis 訂閱/發(fā)布
 */
const _ = require('lodash'),
 redis = require("redis"),
 REDIS_CFG = {
  host: '127.0.0.1',
  port: 6379
 },
 sub = redisClient(REDIS_CFG),
 pub = redisClient(REDIS_CFG);

let SubListenerFuns = {}; // channel的回調(diào)函數(shù)列表

let RedisMQProxy = {

 // 訂閱channel
 on(channel, cb, errorCb, once = false) {
  sub.subscribe(channel); // 訂閱channel消息

  // 將回調(diào)函數(shù)存放數(shù)組中
  SubListenerFuns[channel] = _.isEmpty( SubListenerFuns[channel] ) ? [] : SubListenerFuns[channel];
  SubListenerFuns[channel].push({
   once, cb, errorCb
  });
 },

 // 監(jiān)聽一次性的channel回調(diào)函數(shù)
 once(channel, cb, errorCb) {
  this.on(channel, cb, errorCb, true);
 },

 // 發(fā)送channel消息
 emit(channel, message) {
  if(!_.isString(message)) {
   message = JSON.stringify(message);
  }
  pub.publish(channel, message);
 },

 // 移除channel上的監(jiān)聽函數(shù)
 removeListener(channel, func) {
  let channelHandlers = _.isEmpty( SubListenerFuns[channel] ) ? [] : SubListenerFuns[channel];
  for(let i = 0, l = channelHandlers.length; i < l; i++) {
   let handler = channelHandlers[i] || {};
   let cb = handler.cb;
   if(func && func == cb) {
    channelHandlers.splice(i, 1);
    return false;
   }
  }
 }
};

RedisMQProxy.SubListeners = SubListenerFuns;

pub.on('error', onError);
sub.on('error', onError);

// 監(jiān)聽redis的訂閱消息
sub.on("message", function(channel, message) {
 // 遍歷執(zhí)行channel的回調(diào)函數(shù)
 try {
  message = JSON.parse(message);
 } catch(e) {}
 broadcastToChannel(channel, message);
});

// 廣播消息到指定頻道
function broadcastToChannel(channel, message, isError) {
 let channelHandlers = _.isEmpty( SubListenerFuns[channel] ) ? [] : SubListenerFuns[channel];
 for(let i = 0, l = channelHandlers.length; i < l; i++) {
  let handler = channelHandlers[i] || {};
  let isOnce = handler.once || false;
  let func = handler.cb;
  let errorFunc = handler.errorCb;

  _.isFunction(func) && func(message);
  isError && _.isFunction(errorFunc) && errorFunc(message);

  isOnce && channelHandlers.splice(i, 1); // 移除一次性監(jiān)聽的函數(shù)
 }
}

function broadcastToAllChannels(message, isError) {
 for(let channel in SubListenerFuns) {
  broadcastToChannel(channel, message, isError);
 }
}

function onError(err) {
 err = err || {};
 err.msg = err.msg || 'redis sub/pub fail';

 // 通知所有channel執(zhí)行錯(cuò)誤回調(diào)函數(shù)
 broadcastToAllChannels(err, true);
}

module.exports = RedisMQProxy;

const RedisMQProxy = require('./RedisMQProxy'),
 PAY_MQ_CHANNEL = 'pay_mq_channel';

// 訂閱channel
RedisMQ.on(PAY_MQ_CHANNEL, function(message) {
 console.log('notification received:', message);
 // 廣播消息到指定socket
 // ...
});

// 訂閱一次性的channel
RedisMQ.once(PAY_MQ_CHANNEL, function(message) {
 // ...
});

// 當(dāng)接收到支付數(shù)據(jù)時(shí)，推送頻道消息
RedisMQ.emit(PAY_MQ_CHANNEL, {id: '01', msg: `hello ${PAY_MQ_CHANNEL}!`});