/* eslint-disable no-console */
/* eslint-disable no-sync */

'use strict';

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

/**
 * @typedef {object} options
 * @property {any} [opts] object to pass to the handlers
 * @property {string} [subdir] subdirectory for all requests
 * @property {boolean} [verbose] enable verbose logging
 * @property {boolean} [rethrow] rethrow errors (default: true)
 */

/**
 * @typedef {object} handler_description
 * @property {string} module_folder folder the module file is in
 * @property {string} file name of the module
 * @property {any} opts optional arguments
 * @property {boolean} rethrow should errors be rethrown
 */

/**
 * wrap a requestor handler to be compatible with express
 *
 * @param {handler_description} data handler data
 * @returns {Function} requestor handler
 */
function get_handler ({ module_folder, file, opts, rethrow }) {
  // eslint-disable-next-line global-require
  const handler = require (path.join (process.cwd (), module_folder, file));

  return (req, res, next) => {
    try {
      handler (req, res, next, opts);
    }
    catch (e) {
      if (rethrow)
        throw e;
      else
        console.error (e);
    }
  };
}


/**
 * register a handler to the given app
 *
 * @param {any} app express app
 * @param {handler_description} handler_description data for the used handler
 * @param {string} method method to respond to
 * @param {string} url url to respond to
 * @param {boolean} verbose should verbose logging be enabled
 */
function register_handler (
  app,
  handler_description,
  method,
  url,
  verbose
) {
  const handler = get_handler (handler_description);

  if (verbose)
    console.log (
      `[requestor info] redirecting ${url} to ${handler_description.file}`
    );

  switch (method) {
    case 'post':
      app.post (url, handler);
      break;
    case 'get':
      app.get (url, handler);
      break;
    case 'put':
      app.put (url, handler);
      break;
    case 'delete':
      app.delete (url, handler);
      break;
    case 'all':
      app.all (url, handler);
      break;
    default:
      if (verbose)
        console.warn (
          `'${method}' did not match any request method, ignoring`
        );

      break;
  }
}

/**
 * Load all request handlers in the given folder
 *
 * @param {any} app express app
 * @param {string} module_folder folder that contains all modules
 * @param {options} options additional options
 */
module.exports = function main (
  app,
  module_folder,
  options = { opts: null, subdir: '', verbose: false, rethrow: true }
) {
  const { opts, subdir, verbose, rethrow } = options;

  for (const file of fs.readdirSync (module_folder)) {
    const regex = /(?<method>.*?)-(?<url>.*?)\.js/u;
    const { groups } = regex.exec (file);

    if (typeof subdir === 'undefined')
      groups.url = `/${groups.url}/`;
    else
      groups.url = `/${subdir}/${groups.url}/`;

    groups.url = groups.url
      .replace (/^\/[^/]*\/root/iu, '/')
      .replace (/\./gu, '/')
      .replace (/\/+/gu, '/');

    register_handler (
      app,
      {
        file,
        module_folder,
        opts,
        rethrow
      },
      groups.method,
      groups.url,
      verbose
    );
  }
};