import util = require('util');
import winston = require('winston');
let xtend: any;
xtend = require('xtend');
let mlclElastic;

/**
 * Constructor
 *
 *
 */
let elasticsearch = function elasticsearch(options) {

  options = options || {};

  // Set defaults
  this.level = options.level || 'info';
  this.indexName = options.indexName || 'logs';

  // Only set typeName if provided, otherwise we will use "level" for types.
  this.typeName = options.typeName || null;

  this.source = options.source || 'molecuel';

  // Automatically added entry fields
  this.disable_fields = options.disable_fields || false;

  return this;

};

util.inherits(elasticsearch, winston.Transport);

elasticsearch.prototype.name = 'elasticsearch';

/**
 * Handle Log Entries
 *
 *
 */
elasticsearch.prototype.log = function log(level, msg, meta, callback) {

  let self = this;
  let args = Array.prototype.slice.call(arguments, 0);

  // Not sure if Winston always passed a callback and regulates number of args, but we are on the safe side here
  callback = 'function' === typeof args[args.length - 1] ? args[args.length - 1] : function fallback() { };

  // Using some Logstash naming conventions. (https://gist.github.com/jordansissel/2996677) with some useful variables for debugging.
  let entry = {
    level: level,
    '@source': meta.source || self.source,
    '@timestamp': new Date().toISOString(),
    '@message': msg
  };

  // Add auto-generated fields unless disabled
  if (meta && meta._enableProcess) {
    entry['@fields'] = {
      pid: process.pid,
      path: module.parent.filename,
      user: process.env.USER,
      main: require.main.filename,
      uptime: process.uptime(),
      rss: process.memoryUsage().rss,
      heapTotal: process.memoryUsage().heapTotal,
      heapUsed: process.memoryUsage().heapUsed
    };
  }

  if (meta.source) {
    delete (meta.source);
  }

  // Add tags only if they exist
  if (meta && meta.tags) {
    entry['@tags'] = meta && meta.tags;
  }

  if (meta) {
    entry['@fields'] = xtend(entry['@fields'], meta);
  }

  mlclElastic.index(self.indexName, entry, function(error, res) {
    // If we are ignoring callbacks
    if (callback && self.fireAndForget) {
      return callback(null);
    }

    if (callback) {
      return callback(error, res);
    }

    self.emit('logged');
    if (callback) {
      callback(null, true);
    }
    callback = null;
  });

  return this;
};


let init = function init(elastic: any) {
  mlclElastic = elastic;
  return elasticsearch;
};

export = init;