import later from '@breejs/later';
import is from '@sindresorhus/is';
import { DateTime } from 'luxon';
import type { RenovateConfig } from '../../config/types';
import { logger } from '../../logger';
import { regEx } from '../../util/regex';

const scheduleMappings: Record<string, string> = {
  'every month': 'before 3am on the first day of the month',
  monthly: 'before 3am on the first day of the month',
};

function fixShortHours(input: string): string {
  return input.replace(regEx(/( \d?\d)((a|p)m)/g), '$1:00$2');
}

export function hasValidTimezone(
  timezone: string
): [boolean] | [boolean, string] {
  if (!DateTime.local().setZone(timezone).isValid) {
    return [false, `Invalid schedule: Unsupported timezone ${timezone}`];
  }
  return [true];
}

export function hasValidSchedule(
  schedule: string[] | null | 'at any time'
): [boolean] | [boolean, string] {
  let message: string;
  if (
    !schedule ||
    schedule === 'at any time' ||
    schedule[0] === 'at any time'
  ) {
    return [true];
  }
  // check if any of the schedules fail to parse
  const hasFailedSchedules = schedule.some((scheduleText) => {
    const massagedText = fixShortHours(
      scheduleMappings[scheduleText] || scheduleText
    );
    const parsedSchedule = later.parse.text(massagedText);
    if (parsedSchedule.error !== -1) {
      message = `Invalid schedule: Failed to parse "${scheduleText}"`;
      // It failed to parse
      return true;
    }
    if (parsedSchedule.schedules.some((s) => s.m)) {
      message = `Invalid schedule: "${scheduleText}" should not specify minutes`;
      return true;
    }
    if (
      !parsedSchedule.schedules.some(
        (s) => s.M || s.d !== undefined || s.D || s.t_a !== undefined || s.t_b
      )
    ) {
      message = `Invalid schedule: "${scheduleText}" has no months, days of week or time of day`;
      return true;
    }
    // It must be OK
    return false;
  });
  if (hasFailedSchedules) {
    // If any fail then we invalidate the whole thing
    return [false, message];
  }
  return [true, ''];
}

export function isScheduledNow(config: RenovateConfig): boolean {
  let configSchedule = config.schedule;
  logger.debug(
    `Checking schedule(${String(configSchedule)}, ${config.timezone})`
  );
  if (
    !configSchedule ||
    configSchedule.length === 0 ||
    configSchedule[0] === '' ||
    configSchedule === ('at any time' as never) ||
    configSchedule[0] === 'at any time'
  ) {
    logger.debug('No schedule defined');
    return true;
  }
  if (!is.array(configSchedule)) {
    logger.warn(
      `config schedule is not an array: ${JSON.stringify(configSchedule)}`
    );
    configSchedule = [configSchedule];
  }
  const [validSchedule, errorMessage] = hasValidSchedule(configSchedule);
  if (!validSchedule) {
    logger.warn(errorMessage);
    return true;
  }
  let now = DateTime.local();
  logger.trace(`now=${now.toISO()}`);
  // Adjust the time if repo is in a different timezone to renovate
  if (config.timezone) {
    logger.debug({ timezone: config.timezone }, 'Found timezone');
    const [validTimezone, error] = hasValidTimezone(config.timezone);
    if (!validTimezone) {
      logger.warn(error);
      return true;
    }
    logger.debug('Adjusting now for timezone');
    now = now.setZone(config.timezone);
    logger.trace(`now=${now.toISO()}`);
  }
  const currentDay = now.weekday;
  logger.trace(`currentDay=${currentDay}`);
  // Get the number of seconds since midnight
  const currentSeconds = now
    .startOf('second')
    .diff(now.startOf('day'), 'seconds').seconds;
  logger.trace(`currentSeconds=${currentSeconds}`);
  // Support a single string but massage to array for processing
  logger.debug(`Checking ${configSchedule.length} schedule(s)`);

  // later is timezone agnostic (as in, it purely relies on the underlying UTC date/time that is stored in the Date),
  // which means we have to pass it a Date that has an underlying UTC date/time in the same timezone as the schedule
  const jsNow = now.setZone('utc', { keepLocalTime: true }).toJSDate();

  // We run if any schedule matches
  const isWithinSchedule = configSchedule.some((scheduleText) => {
    const massagedText = scheduleMappings[scheduleText] || scheduleText;
    const parsedSchedule = later.parse.text(fixShortHours(massagedText));
    logger.debug({ parsedSchedule }, `Checking schedule "${scheduleText}"`);

    if (later.schedule(parsedSchedule).isValid(jsNow)) {
      logger.debug(`Matches schedule ${scheduleText}`);
      return true;
    }

    return false;
  });
  if (!isWithinSchedule) {
    logger.debug('Package not scheduled');
    return false;
  }
  return true;
}