import url from 'url';
import { IncomingMessage } from 'http';

import fromEntries from 'object.fromentries';
import { match } from 'path-to-regexp';

import { ChannelBot, RequestContext } from '..';

import getChannelBots from './getChannelBots';

function getChannelBotAndRequestContext(req: IncomingMessage):
  | {
      requestContext: RequestContext;
      channelBot: ChannelBot;
    }
  | undefined {
  // TODO: add proxy support in Bottender to apply X-Forwarded-Host and X-Forwarded-Proto
  // conditionally instead of replying on express.
  const hostname = (req as any).hostname || req.headers.host;
  const protocol = (req as any).protocol || 'https';

  const requestUrl = `${protocol}://${hostname}${req.url}`;

  const { pathname, searchParams } = new url.URL(requestUrl);

  const query = fromEntries(searchParams.entries());

  const channelBots = getChannelBots();
  for (let i = 0; i < channelBots.length; i++) {
    const channelBot = channelBots[i];
    const matchPath = match<Record<string, string>>(channelBot.webhookPath);
    const matchResult = matchPath(pathname);

    if (matchResult) {
      return {
        requestContext: {
          id: (req as any).id,
          method: req.method as string,
          path: pathname,
          query,
          headers: req.headers,
          rawBody: (req as any).rawBody,
          body: (req as any).body,
          params: matchResult.params,
          url: requestUrl,
        },
        channelBot,
      };
    }
  }
  return undefined;
}

export default getChannelBotAndRequestContext;