/*

* Copyright 2020 Google LLC

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* https://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

// Included for types only.

// eslint-disable-next-line no-unused-vars

const express = require('express');

const path = require('path');

const fs = require('fs');

/**

* @type {express.RequestHandler}

*/

const notFoundHandler = (req, res, next) => {

res.status(404);

res.setHeader('Cache-Control', 'max-age=0,must-revalidate,public');

const extMatch = /(\.[^.]*)$/.exec(req.url);

if (extMatch && extMatch[1] !== '.html') {

// If this had an extension and it was not ".html", don't send any bytes.

// Pages without extensions don't match here.

return res.end();

}

const locale = req.url.split(path.sep)[1];

// Send the 404 for the current locale, or English if we can't find it.

let root = 'dist/en';

const toSend = path.join('dist', locale, '404', 'index.html');

if (fs.existsSync(toSend)) {

root = path.join('dist', locale);

}

res.sendFile('404/index.html', {root}, err => err && next(err));

};

module.exports = {notFoundHandler};