'use strict';

const amqplib = require('amqplib');

function RabbitMQPrx(conf) {
  this.param = {
    protocol: 'amqp',
    hostname: conf.host,
    port: conf.port,
    username: conf.user,
    password: conf.passwd,
    frameMax: 0,
    heartbeat: 0,
    vhost: conf.vhost
  };

  this.amqp = amqplib.connect(this.param);

  this.produces = {};
  this.consumes = {};
}

RabbitMQPrx.prototype.initProduce = async function(excName, excType, excArgs = {}) {
  let produce = {};
  produce.channel = await this.amqp.then(function (conn) {
    return conn.createChannel().then( function(channel) {
      return channel.assertExchange(excName, excType, excArgs).then(function(){
        return channel;
      });
    });
  });
  this.produces[excName] = produce;
};

RabbitMQPrx.prototype.initConsume = async function(excName, excType, excArgs, queueName, queueArgs, routeKey, cb) {
  let consumer = {};
  consumer.channel = await this.amqp.then(function (conn) {
    return conn.createChannel().then( function(channel) {
      let ret = channel.assertExchange(excName, excType, excArgs);
      ret = ret.then(function () {
        return channel.assertQueue(queueName, queueArgs);
      });
      ret = ret.then(function(qok) {
        for (let n in routeKey) {
          if (routeKey.hasOwnProperty(n))
            channel.bindQueue(qok.queue, excName, routeKey[n]);
        }
        return qok.queue;
      });

      ret = ret.then(function(queue) {
        return channel.consume(queue, cb, {noAck: true});
      });

      return ret.then(function() {
        return channel;
      });
    });
  });
  this.consumes[excName] = consumer;
};

RabbitMQPrx.prototype.publish = function(excName, routeKey, msg) {
  this.produces[excName].channel.publish(excName, routeKey, Buffer.from(msg));
};

module.exports = RabbitMQPrx;