import cache from 'memory-cache';

import getServiceWidget from 'utils/config/service-helpers';
import { formatApiCall } from 'utils/proxy/api-helpers';
import widgets from 'widgets/widgets';
import createLogger from 'utils/logger';
import { httpProxy } from 'utils/proxy/http';

const proxyName = 'pyloadProxyHandler';
const logger = createLogger(proxyName);
const sessionCacheKey = `${proxyName}__sessionId`;
const isNgCacheKey = `${proxyName}__isNg`;

async function fetchFromPyloadAPI(url, sessionId, params, service) {
  const options = {
    body: params
      ? Object.keys(params)
          .map((prop) => `${prop}=${params[prop]}`)
          .join('&')
      : `session=${sessionId}`,
    method: 'POST',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
    },
  };

  // see https://github.com/gethomepage/homepage/issues/517
  const isNg = cache.get(`${isNgCacheKey}.${service}`);
  if (isNg && !params) {
    delete options.body;
    options.headers.Cookie = cache.get(`${sessionCacheKey}.${service}`);
  }

  // eslint-disable-next-line no-unused-vars
  const [status, contentType, data, responseHeaders] = await httpProxy(url, options);
  let returnData;
  try {
    returnData = JSON.parse(Buffer.from(data).toString());
  } catch(e) {
    logger.error(`Error logging into pyload API: ${JSON.stringify(data)}`);
    returnData = data;
  }
  return [status, returnData, responseHeaders];
}

async function login(loginUrl, service, username, password = '') {
  const [status, sessionId, responseHeaders] = await fetchFromPyloadAPI(loginUrl, null, { username, password }, service);
  
  // this API actually returns status 200 even on login failure
  if (status !== 200 || sessionId === false) {
    logger.error(`HTTP ${status} logging into Pyload API, returned: ${JSON.stringify(sessionId)}`);
  } else if (responseHeaders['set-cookie']?.join().includes('pyload_session')) {
    // Support pyload-ng, see https://github.com/gethomepage/homepage/issues/517
    cache.put(`${isNgCacheKey}.${service}`, true);
    const sessionCookie = responseHeaders['set-cookie'][0];
    cache.put(`${sessionCacheKey}.${service}`, sessionCookie, 60 * 60 * 23 * 1000); // cache for 23h
  } else {
    cache.put(`${sessionCacheKey}.${service}`, sessionId);
  }

  return sessionId;
}

export default async function pyloadProxyHandler(req, res) {
  const { group, service, endpoint } = req.query;

  try {
    if (group && service) {
      const widget = await getServiceWidget(group, service);

      if (widget) {
        const url = new URL(formatApiCall(widgets[widget.type].api, { endpoint, ...widget }));
        const loginUrl = `${widget.url}/api/login`;

        let sessionId = cache.get(`${sessionCacheKey}.${service}`) ?? await login(loginUrl, service, widget.username, widget.password);
        let [status, data] = await fetchFromPyloadAPI(url, sessionId, null, service);

        if (status === 403 || status === 401) {
          logger.info('Failed to retrieve data from Pyload API, trying to login again...');
          cache.del(`${sessionCacheKey}.${service}`);
          sessionId = await login(loginUrl, service, widget.username, widget.password);
          [status, data] = await fetchFromPyloadAPI(url, sessionId, null, service);
        }

        if (data?.error || status !== 200) {
          try {
            return res.status(status).send({error: {message: "HTTP error communicating with Pyload API", data: Buffer.from(data).toString()}});
          } catch (e) {
            return res.status(status).send({error: {message: "HTTP error communicating with Pyload API", data}});
          }
        }

        return res.json(data);
      }
    }
  } catch (e) {
    logger.error(e);
    return res.status(500).send({error: {message: `Error communicating with Pyload API: ${e.toString()}`}});
  }

  return res.status(400).json({ error: 'Invalid proxy service type' });
}