'use strict';

const util = require('util'),
  path = require('path'),
  mailer = require('mailer').default,
  KeyFileStorage = require("key-file-storage").default,
  debug = require('debug')('agm:errHelper');

let logFileName = path.basename(__filename);


/**
 * Report important errors to Admin 
 * @param {*} error Error message in text or the Error object 
 */
async function mailErrorToAdmin(error) {
  const errorMsg = (error && error.message) ? error.message : error;
  const contentOps = {
    subject: '[Agm-Errors] Unexpected Errors',
    body: error && error.stack ? errorMsg + '\n' + error.stack : errorMsg,
    to: process.env.AGM_ADM_EMAIL || '"AgMission Admin" <agm_admin@agnav.com>',
  };
  return await mailer.sendTextMail(contentOps);
}

async function _handleCriticalError(error, message) {
  const exitFunc = (err) => {
    debug(err);
    process.exit(1);
  };
  try {
    const baseFilename = path.basename(logFileName);
    const kfs = KeyFileStorage(path.dirname(logFileName), false);

    let lastReport = await kfs[baseFilename];
    let curDateTime = new Date();

    if (kfs[baseFilename] && (lastReport = kfs[baseFilename])) {
      if (lastReport.when && /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.*$/.test(lastReport.when)) {
        if (curDateTime - new Date(lastReport.when) < 2 * 60 * 1e3
          && ((error.code && lastReport.code === error.code) || lastReport.message == error.message))
          return exitFunc(error); // Reported the same error two shortly, at least 2 minutes => ignore to avoid flooding with the same emails
      }
    }
    const logObj = {
      code: error.code,
      message: error.message,
      when: curDateTime
    };
    await kfs(baseFilename, logObj);
  } catch (err) {
    debug(err);
  }

  try {
    await mailErrorToAdmin(message);
  }
  catch (err) {
    debug(err);
  }
  finally {
    return exitFunc(error);
  }
}

/**
 * Register the process error handlers
 * @param {*} process The process object
 * @param {*} fileName The file name to log the error
 */
function registerUnCaughtProcessErrorsHandler(process, fileName) {
  if (!process) return;

  if (fileName) logFileName = fileName;

  process
    .on('uncaughtException', async (err) => {
      await _handleCriticalError(err, util.format('uncaughtException:', err));
    })
    .on('unhandledRejection', async (reason, p) => {
      await _handleCriticalError(reason, util.format(reason, 'Unhandled Rejection at Promise', p));
    });
}

module.exports = {
  mailErrorToAdmin, registerUnCaughtProcessErrorsHandler
}