/*!
 * cookie-parser
 * Copyright(c) 2014 TJ Holowaychuk
 * Copyright(c) 2015 Douglas Christopher Wilson
 * MIT Licensed
 */

'use strict';

/**
 * Module dependencies.
 * @private
 */

var cookie = require('cookie');
var signature = require('cookie-signature');

/**
 * Module exports.
 * @public
 */

module.exports = cookieParser;
module.exports.JSONCookie = JSONCookie;
module.exports.JSONCookies = JSONCookies;
module.exports.signedCookie = signedCookie;
module.exports.signedCookies = signedCookies;

/**
 * Parse Cookie header and populate `req.cookies`
 * with an object keyed by the cookie names.
 *
 * @param {string|array} [secret] A string (or array of strings) representing cookie signing secret(s).
 * @param {Object} [options]
 * @return {Function}
 * @public
 */

function cookieParser(secret, options) {
 return function cookieParser(req, res, next) {
 if (req.cookies) {
 return next();
 }

 var cookies = req.headers.cookie;
 var secrets = !secret || Array.isArray(secret)
 ? (secret || [])
 : [secret];

 req.secret = secrets[0];
 req.cookies = Object.create(null);
 req.signedCookies = Object.create(null);

 // no cookies
 if (!cookies) {
 return next();
 }

 req.cookies = cookie.parse(cookies, options);

 // parse signed cookies
 if (secrets.length !== 0) {
 req.signedCookies = signedCookies(req.cookies, secrets);
 req.signedCookies = JSONCookies(req.signedCookies);
 }

 // parse JSON cookies
 req.cookies = JSONCookies(req.cookies);

 next();
 };
}

/**
 * Parse JSON cookie string.
 *
 * @param {String} str
 * @return {Object} Parsed object or undefined if not json cookie
 * @public
 */

function JSONCookie(str) {
 if (typeof str !== 'string' || str.substr(0, 2) !== 'j:') {
 return undefined;
 }

 try {
 return JSON.parse(str.slice(2));
 } catch (err) {
 return undefined;
 }
}

/**
 * Parse JSON cookies.
 *
 * @param {Object} obj
 * @return {Object}
 * @public
 */

function JSONCookies(obj) {
 var cookies = Object.keys(obj);
 var key;
 var val;

 for (var i = 0; i < cookies.length; i++) {
 key = cookies[i];
 val = JSONCookie(obj[key]);

 if (val) {
 obj[key] = val;
 }
 }

 return obj;
}

/**
 * Parse a signed cookie string, return the decoded value.
 *
 * @param {String} str signed cookie string
 * @param {string|array} secret
 * @return {String} decoded value
 * @public
 */

function signedCookie(str, secret) {
 if (typeof str !== 'string') {
 return undefined;
 }

 if (str.substr(0, 2) !== 's:') {
 return str;
 }

 var secrets = !secret || Array.isArray(secret)
 ? (secret || [])
 : [secret];

 for (var i = 0; i < secrets.length; i++) {
 var val = signature.unsign(str.slice(2), secrets[i]);

 if (val !== false) {
 return val;
 }
 }

 return false;
}

/**
 * Parse signed cookies, returning an object containing the decoded key/value
 * pairs, while removing the signed key from obj.
 *
 * @param {Object} obj
 * @param {string|array} secret
 * @return {Object}
 * @public
 */

function signedCookies(obj, secret) {
 var cookies = Object.keys(obj);
 var dec;
 var key;
 var ret = Object.create(null);
 var val;

 for (var i = 0; i < cookies.length; i++) {
 key = cookies[i];
 val = obj[key];
 dec = signedCookie(val, secret);

 if (val !== dec) {
 ret[key] = dec;
 delete obj[key];
 }
 }

 return ret;
}