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

/**
 * Load all request handlers in the given folder
 *
 * @param {any} app express app
 * @param {string} modulefolder
 * @param {any} opts object to pass to the handlers (for example database access)
 * @param {string} subdir subdirectory for all requests (app will respond to /subdir/... instead of /...)
 */
module.exports = function (app, modulefolder, opts = {}, subdir = '') {
  for (const f of fs.readdirSync(modulefolder)) {
    const regex = /(.*?)-(.*?)\.js/;
    let [, method, url] = regex.exec(f);
    url = '/' + subdir + '/' + url + '/';
    url = url
      .replace(/^\/[^/]*\/root/i, '/')
      .replace(/\./g, '/')
      .replace(/\/+/g, '/');

    const handler = require(path.join(process.cwd(), modulefolder, f));
    const func = (req, res, next) => {
      handler(req, res, next, opts);
    };

    switch (method) {
      case 'post':
        app.post(url, func);
        break;
      case 'get':
        app.get(url, func);
        break;
      case 'put':
        app.put(url, func);
        break;
      case 'delete':
        app.delete(url, func);
        break;
      case 'all':
        app.all(url, func);
        break;
    }
  }
};