'use strict';

/**
 * Functions/constants needed by both the client and server (but only in node).
 * These are separate from common.js so they can be skipped when bundling for the browser.
 */

var Buffer = require('safe-buffer').Buffer;
var querystring = require('querystring');

exports.IPV4_RE = /^[\d.]+$/;
exports.IPV6_RE = /^[\da-fA-F:]+$/;
exports.REMOVE_IPV4_MAPPED_IPV6_RE = /^::ffff:/;

exports.CONNECTION_ID = Buffer.concat([toUInt32(0x417), toUInt32(0x27101980)]);
exports.ACTIONS = {CONNECT: 0, ANNOUNCE: 1, SCRAPE: 2, ERROR: 3};
exports.EVENTS = {update: 0, completed: 1, started: 2, stopped: 3};
exports.EVENT_IDS = {
  0: 'update',
  1: 'completed',
  2: 'started',
  3: 'stopped'
};
exports.EVENT_NAMES = {
  update: 'update',
  completed: 'complete',
  started: 'start',
  stopped: 'stop'
};

/**
 * Client request timeout. How long to wait before considering a request to a
 * tracker server to have timed out.
 */
exports.REQUEST_TIMEOUT = 15000;

/**
 * Client destroy timeout. How long to wait before forcibly cleaning up all
 * pending requests, open sockets, etc.
 */
exports.DESTROY_TIMEOUT = 1000;

function toUInt32(n) {
  var buf = Buffer.allocUnsafe(4);
  buf.writeUInt32BE(n, 0);
  return buf;
}
exports.toUInt32 = toUInt32;

/**
 * `querystring.parse` using `unescape` instead of decodeURIComponent, since bittorrent
 * clients send non-UTF8 querystrings
 * @param  {string} q
 * @return {Object}
 */
exports.querystringParse = function (q) {
  return querystring.parse(q, null, null, {decodeURIComponent: unescape});
};

/**
 * `querystring.stringify` using `escape` instead of encodeURIComponent, since bittorrent
 * clients send non-UTF8 querystrings
 * @param  {Object} obj
 * @return {string}
 */
exports.querystringStringify = function (obj) {
  var ret = querystring.stringify(obj, null, null, {encodeURIComponent: escape});
  ret = ret.replace(/[@*/+]/g, function (char) {
    // `escape` doesn't encode the characters @*/+ so we do it manually
    return '%' + char.charCodeAt(0).toString(16).toUpperCase();
  });
  return ret;
};