/*
  The example consists of 3 files:
  queue.js => implements the plugin
  bar.js => implements a basic service
  foo.js => implements another service which calls bar.js
  You will need redis running on localhost port 6379, or change the configurations
*/

//****************     queue.js

// Fire and forget rpc for Studio.
var localServices ={};
//Using redis as message broker for simplicity
var Redis = require('ioredis');
// Adding a prefix to avoid conflict with other lists on redis
var QUEUE_PREFIX = 'studio_queue_';

/*
	Each service will have their own queue, and will wait for messages
	You can implement any message broker you want,
	doing a naive redis implementation just to keep really simple
*/

module.exports = function(options,Studio){
  	"use strict";
  	var redisSender = new Redis();
  	var sendMessageToQueue = Studio.promise.promisify(redisSender.lpush).bind(redisSender);
    options.onStart(function(serv,ref){
    	var redisClient = new Redis();
        localServices[serv.id] = redisClient;
        /*
        	When you start a new service, makes it listen for a message on his queue, when a message arrives,
        	parse and call the service
        */
        redisClient.blpop(QUEUE_PREFIX+serv.id,0,function(error,message){
        	message = JSON.parse(message[1]);
        	message = Object.keys(message).map(function(key){
        		return message[key];
        	});
        	/*
        		Here we call the service, we shouldnt use serv.fn, because this would bypass the
        		interceptSend of other plugins, so we use ref (which is basically the same thing as Studio(serv.id))
        	*/
        	ref.apply(serv,message);
        });
    });
    options.onStop(function(serv,ref){
    	/*
    		Remove from localServices and disconnect
    	*/
    	if(localServices[serv.id]){
    		localServices[serv.id].disconnect();
    		localServices[serv.id] = null;
    	}
    });
    options.interceptSend(function(send,receiver){
    	// Whenever a service is called, if is local call the local service, if not send message to a queue
    	return function(){
    		if(localServices[receiver]){
        		return send.apply(null,arguments);
	        }else{
	        	return sendMessageToQueue(QUEUE_PREFIX+receiver,JSON.stringify(arguments));
	        }
    	}
    });
};


//****************     foo.js

var Studio = require('studio');
var StudioQueue = require('./queue');
Studio.use(StudioQueue);
Studio(function foo() {
  return Studio('bar')({hello:'Hello World!!!'});
});

Studio('foo')();

//****************     bar.js
var Studio = require('studio');
var StudioQueue = require('./queue');
Studio.use(StudioQueue);
Studio(function bar(message) {
  console.log(message);
});