'use strict';

var serversMap = module.exports._serversMap = {};

module.exports.addTcpListener = function (port, handler) {
  var PromiseA = require('bluebird');

  return new PromiseA(function (resolve, reject) {
    var stat = serversMap[port] || serversMap[port];

    if (stat) {
      if (stat._closing) {
        module.exports.destroyTcpListener(port);
      }
      else if (handler !== stat.handler) {

        // we'll replace the current listener
        stat.handler = handler;
        resolve();
        return;
      }
      else {
        // this exact listener is already open
        resolve();
        return;
      }
    }

    var enableDestroy = require('server-destroy');
    var net = require('net');
    var resolved;
    var server = net.createServer();

    stat = serversMap[port] = {
      server: server
    , handler: handler
    , _closing: false
    };

    server.on('connection', function (conn) {
      conn.__port = port;
      conn.__proto = 'tcp';
      stat.handler(conn);
    });
    server.on('error', function (e) {
      delete serversMap[port];

      if (!resolved) {
        reject(e);
        return;
      }

      if (handler.onError) {
        handler.onError(e);
        return;
      }

      throw e;
    });

    server.listen(port, function () {
      resolved = true;
      resolve();
    });

    enableDestroy(server); // adds .destroy
  });
};
module.exports.closeTcpListener = function (port) {
  var PromiseA = require('bluebird');

  return new PromiseA(function (resolve) {
    var stat = serversMap[port];
    if (!stat) {
      return;
    }
    stat.server.on('close', function () {
      // once the clients close too
      delete serversMap[port];
      if (stat._closing) {
        stat._closing(); // resolve
        stat._closing = null;
      }
      stat = null;
    });
    stat._closing = resolve;
    stat.server.close();
  });
};
module.exports.destroyTcpListener = function (port) {
  var stat = serversMap[port];
  delete serversMap[port];
  stat.server.destroy();
  if (stat._closing) {
    stat._closing();
    stat._closing = null;
  }
  stat = null;
};

module.exports.listeners = {
  tcp: {
    add: module.exports.addTcpListener
  , close: module.exports.closeTcpListener
  , destroy: module.exports.destroyTcpListener
  }
};