import { parseBBCodeTag } from 'pretty-text/engines/discourse-markdown/bbcode-block';

function addLocalDate(buffer, matches, state) {
  let token;

  let config = {
    date: null,
    time: null,
    format: "YYYY-MM-DD HH:mm",
    timezones: ""
  };

  let parsed = parseBBCodeTag("[date date" + matches[1] + "]", 0, matches[1].length + 11);

  config.date = parsed.attrs.date;
  config.time = parsed.attrs.time;
  config.recurring = parsed.attrs.recurring;
  config.format = parsed.attrs.format || config.format;
  config.timezones = parsed.attrs.timezones || config.timezones;

  token = new state.Token('span_open', 'span', 1);
  token.attrs = [
    ['class', 'discourse-local-date'],
    ['data-date', config.date],
    ['data-time', config.time],
    ['data-format', config.format],
    ['data-timezones', config.timezones],
  ];
  if (config.recurring) {
    token.attrs.push(['data-recurring', config.recurring]);
  }
  buffer.push(token);

  const previews = config.timezones.split("|").filter(t => t).map(timezone => {
    const dateTime = moment
                      .utc(`${config.date} ${config.time}`, "YYYY-MM-DD HH:mm")
                      .tz(timezone)
                      .format(config.format);

    const formattedTimezone = timezone.replace("/", ": ").replace("_", " ");

    if (dateTime.match(/TZ/)) {
      return dateTime.replace("TZ", formattedTimezone);
    } else {
      return `${dateTime} (${formattedTimezone})`;
    }
  });

  token.attrs.push(['data-email-preview', previews[0]]);

  token = new state.Token('text', '', 0);
  token.content = previews.join(", ");
  buffer.push(token);

  token = new state.Token('span_close', 'span', -1);
  buffer.push(token);
}

export function setup(helper) {
  helper.whiteList([
    'span.discourse-local-date',
    'span[data-*]',
    'span[title]'
  ]);

  helper.registerOptions((opts, siteSettings) => {
    opts.features['discourse-local-dates'] = !!siteSettings.discourse_local_dates_enabled;
  });

  helper.registerPlugin(md => {
    const rule = {
      matcher: /\[date(.*?)\]/,
      onMatch: addLocalDate
    };

    md.core.textPostProcess.ruler.push('discourse-local-dates', rule);
  });
}