"use strict";

function _typeof(obj) { if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }

var is = require('is_js');
/**
 * Parse x-forwarded-for headers.
 *
 * @param {string} value - The value to be parsed.
 * @return {string|null} First known IP address, if any.
 */


function getClientIpFromXForwardedFor(value) {
  if (!is.existy(value)) {
    return null;
  }

  if (is.not.string(value)) {
    throw new TypeError("Expected a string, got \"".concat(_typeof(value), "\""));
  } // x-forwarded-for may return multiple IP addresses in the format:
  // "client IP, proxy 1 IP, proxy 2 IP"
  // Therefore, the right-most IP address is the IP address of the most recent proxy
  // and the left-most IP address is the IP address of the originating client.
  // source: http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/x-forwarded-headers.html
  // Azure Web App's also adds a port for some reason, so we'll only use the first part (the IP)


  var forwardedIps = value.split(',').map(function (e) {
    var ip = e.trim();

    if (ip.includes(':')) {
      var splitted = ip.split(':'); // make sure we only use this if it's ipv4 (ip:port)

      if (splitted.length === 2) {
        return splitted[0];
      }
    }

    return ip;
  }); // Sometimes IP addresses in this header can be 'unknown' (http://stackoverflow.com/a/11285650).
  // Therefore taking the left-most IP address that is not unknown
  // A Squid configuration directive can also set the value to "unknown" (http://www.squid-cache.org/Doc/config/forwarded_for/)

  return forwardedIps.find(is.ip);
}
/**
 * Determine client IP address.
 *
 * @param req
 * @returns {string} ip - The IP address if known, defaulting to empty string if unknown.
 */


function getClientIp(req) {
  // Server is probably behind a proxy.
  if (req.headers) {
    // Standard headers used by Amazon EC2, Heroku, and others.
    if (is.ip(req.headers['x-client-ip'])) {
      return req.headers['x-client-ip'];
    } // Load-balancers (AWS ELB) or proxies.


    var xForwardedFor = getClientIpFromXForwardedFor(req.headers['x-forwarded-for']);

    if (is.ip(xForwardedFor)) {
      return xForwardedFor;
    } // Cloudflare.
    // @see https://support.cloudflare.com/hc/en-us/articles/200170986-How-does-Cloudflare-handle-HTTP-Request-headers-
    // CF-Connecting-IP - applied to every request to the origin.


    if (is.ip(req.headers['cf-connecting-ip'])) {
      return req.headers['cf-connecting-ip'];
    } // Fastly and Firebase hosting header (When forwared to cloud function)


    if (is.ip(req.headers['fastly-client-ip'])) {
      return req.headers['fastly-client-ip'];
    } // Akamai and Cloudflare: True-Client-IP.


    if (is.ip(req.headers['true-client-ip'])) {
      return req.headers['true-client-ip'];
    } // Default nginx proxy/fcgi; alternative to x-forwarded-for, used by some proxies.


    if (is.ip(req.headers['x-real-ip'])) {
      return req.headers['x-real-ip'];
    } // (Rackspace LB and Riverbed's Stingray)
    // http://www.rackspace.com/knowledge_center/article/controlling-access-to-linux-cloud-sites-based-on-the-client-ip-address
    // https://splash.riverbed.com/docs/DOC-1926


    if (is.ip(req.headers['x-cluster-client-ip'])) {
      return req.headers['x-cluster-client-ip'];
    }

    if (is.ip(req.headers['x-forwarded'])) {
      return req.headers['x-forwarded'];
    }

    if (is.ip(req.headers['forwarded-for'])) {
      return req.headers['forwarded-for'];
    }

    if (is.ip(req.headers.forwarded)) {
      return req.headers.forwarded;
    }
  } // Remote address checks.


  if (is.existy(req.connection)) {
    if (is.ip(req.connection.remoteAddress)) {
      return req.connection.remoteAddress;
    }

    if (is.existy(req.connection.socket) && is.ip(req.connection.socket.remoteAddress)) {
      return req.connection.socket.remoteAddress;
    }
  }

  if (is.existy(req.socket) && is.ip(req.socket.remoteAddress)) {
    return req.socket.remoteAddress;
  }

  if (is.existy(req.info) && is.ip(req.info.remoteAddress)) {
    return req.info.remoteAddress;
  } // AWS Api Gateway + Lambda


  if (is.existy(req.requestContext) && is.existy(req.requestContext.identity) && is.ip(req.requestContext.identity.sourceIp)) {
    return req.requestContext.identity.sourceIp;
  }

  return null;
}
/**
 * Expose request IP as a middleware.
 *
 * @param {object} [options] - Configuration.
 * @param {string} [options.attributeName] - Name of attribute to augment request object with.
 * @return {*}
 */


function mw(options) {
  // Defaults.
  var configuration = is.not.existy(options) ? {} : options; // Validation.

  if (is.not.object(configuration)) {
    throw new TypeError('Options must be an object!');
  }

  var attributeName = configuration.attributeName || 'clientIp';
  return function (req, res, next) {
    var ip = getClientIp(req);
    Object.defineProperty(req, attributeName, {
      get: function get() {
        return ip;
      },
      configurable: true
    });
    next();
  };
}

module.exports = {
  getClientIpFromXForwardedFor: getClientIpFromXForwardedFor,
  getClientIp: getClientIp,
  mw: mw
};