// (c) Copyright 2023 Supertenant Ltd. - all rights reserved.
// See LICENSE file in project root for license terms.

'use strict';

/** @type {import('@supertenant/core/src/logger').GenericLogger} */
let logger;
logger = require('../logger').getLogger('util/uncaughtExceptionHandler', newLogger => {
  logger = newLogger;
});

const unhandledRejectionEventName = 'unhandledRejection';
let unhandledRejectionDeprecationWarningHasBeenEmitted = false;

/** @type {import('../util/normalizeConfig').CollectorConfig} */
let config;

// see
// https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode /
// https://github.com/nodejs/node/pull/26599
let unhandledRejectionsMode = 'warn/default';
for (let i = 0; i < process.execArgv.length; i++) {
  if (process.execArgv[i] === '--unhandled-rejections=none') {
    unhandledRejectionsMode = 'none';
  } else if (process.execArgv[i] === '--unhandled-rejections=strict') {
    unhandledRejectionsMode = 'strict';
  }
}

/**
 * @typedef {Object} SerializedErrorObject
 * @property {string} name
 * @property {string} message
 * @property {string} stack
 */

/**
 * @param {import('../util/normalizeConfig').CollectorConfig} _config
 */
exports.init = function (_config) {
  config = _config;
};

exports.activate = function () {
  activateUnhandledPromiseRejectionHandling();
};

exports.deactivate = function () {
  process.removeListener(unhandledRejectionEventName, onUnhandledRejection);
};

function activateUnhandledPromiseRejectionHandling() {
  if (config.reportUnhandledPromiseRejections) {
    if (unhandledRejectionsMode === 'strict') {
      logger.warn(
        'Node.js has been started with --unhandled-rejections=strict, therefore reporting unhandled promise ' +
          'rejections will not be enabled.'
      );
      return;
    }
    process.on(unhandledRejectionEventName, onUnhandledRejection);
    logger.info('Reporting unhandled promise rejections is enabled.');
  } else {
    logger.info('Reporting unhandled promise rejections is disabled.');
  }
}

/**
 * @param {Error} reason
 */
function onUnhandledRejection(reason) {
  if (unhandledRejectionsMode !== 'none') {
    // Best effort to emit the same log messages that Node.js does by default (when no handler for the
    // unhandledRejection event is installed.
    // eslint-disable-next-line no-console
    console.warn('UnhandledPromiseRejectionWarning:', reason);
    // eslint-disable-next-line no-console
    console.warn(
      'UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing ' +
        'inside of an async function without a catch block, or by rejecting a promise which was not handled with ' +
        '.catch().'
    );
    if (!unhandledRejectionDeprecationWarningHasBeenEmitted) {
      // eslint-disable-next-line no-console
      console.warn(
        '[DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise ' +
          'rejections that are not handled will terminate the Node.js process with a non-zero exit code.'
      );
      unhandledRejectionDeprecationWarningHasBeenEmitted = true;
    }
  }
}