// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

'use strict';

// this is a simple HTTP server that enables CORS.
// following code is based on https://developer.mozilla.org/en-US/docs/Learn/Server-side/Node_server_without_framework

const http = require('http');
const fs = require('fs');
const path = require('path');

const getRequestData = (url, dir) => {
  const pathname = new URL(url, 'http://localhost').pathname;

  let filepath;
  let mimeType;
  if (pathname.startsWith('/test-wasm-path-override/') || pathname.startsWith('/dist/') ||
      pathname.startsWith('/esm-loaders/')) {
    filepath = path.resolve(dir, pathname.substring(1));
  } else {
    return null;
  }

  if (filepath.endsWith('.wasm')) {
    mimeType = 'application/wasm';
  } else if (filepath.endsWith('.js') || filepath.endsWith('.mjs')) {
    mimeType = 'text/javascript';
  } else {
    return null;
  }

  return [filepath, mimeType];
};

module.exports = function(dir, port) {
  const server = http.createServer(function(request, response) {
                       const url = request.url.replace(/\n|\r/g, '');
                       console.log(`request ${url}`);

                       const requestData = getRequestData(url, dir);
                       if (!request || !requestData) {
                         response.writeHead(404);
                         response.end('404');
                       } else {
                         const [filePath, contentType] = requestData;
                         fs.readFile(path.resolve(dir, filePath), function(error, content) {
                           if (error) {
                             if (error.code == 'ENOENT') {
                               response.writeHead(404);
                               response.end('404');
                             } else {
                               response.writeHead(500);
                               response.end('500');
                             }
                           } else {
                             response.setHeader('access-control-allow-origin', '*');
                             response.writeHead(200, {'Content-Type': contentType});
                             response.end(content, 'utf-8');
                           }
                         });
                       }
                     })
                     .listen(port);
  console.log(`Server running at http://localhost:${port}/`);
  return server;
};