/* eslint no-underscore-dangle: ["error", { "allow": ["_text", "_cdata"] }] */

import cache from "memory-cache";
import { xml2json } from "xml-js";

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

const proxyName = "qnapProxyHandler";
const sessionTokenCacheKey = `${proxyName}__sessionToken`;
const logger = createLogger(proxyName);

async function login(widget, service) {
  const endpoint = "{url}/cgi-bin/authLogin.cgi";
  const loginUrl = new URL(formatApiCall(endpoint, widget));
  const headers = { "Content-Type": "application/x-www-form-urlencoded" };

  const [, , data,] = await httpProxy(loginUrl, {
    method: "POST",
    body: new URLSearchParams({
      user: widget.username,
      pwd: Buffer.from(`${widget.password}`).toString("base64")
    }).toString(),
    headers,
  });

  try {
    const dataDecoded = xml2json(data.toString(), { compact: true });
    const jsonData = JSON.parse(dataDecoded);
    const token = jsonData.QDocRoot.authSid._cdata;
    cache.put(`${sessionTokenCacheKey}.${service}`, token);
    return { token };
  } catch (e) {
    logger.error("Unable to login to QNAP API: %s", e);
  }

  return { token: false };
}

async function apiCall(widget, endpoint, service) {
  let key = cache.get(`${sessionTokenCacheKey}.${service}`);

  let apiUrl = new URL(formatApiCall(`${endpoint}&sid=${key}`, widget));
  let [status, contentType, data, responseHeaders] = await httpProxy(apiUrl);

  if (status === 404) {
    logger.error("QNAP API rejected the request, attempting to obtain new session token");
    key = await login(widget, service);
    apiUrl = new URL(formatApiCall(`${endpoint}&sid=${key}`, widget));
    [status, contentType, data, responseHeaders] = await httpProxy(apiUrl);
  }

  if (status !== 200) {
    logger.error("Error getting data from QNAP: %s status %d. Data: %s", apiUrl, status, data);
    return { status, contentType, data: null, responseHeaders };
  }

  let dataDecoded = JSON.parse(xml2json(data.toString(), { compact: true }).toString());

  if (dataDecoded.QDocRoot.authPassed._cdata === '0') {
    logger.error("QNAP API rejected the request, attempting to obtain new session token");
    key = await login(widget, service);
    apiUrl = new URL(formatApiCall(`${endpoint}&sid=${key}`, widget));
    [status, contentType, data, responseHeaders] = await httpProxy(apiUrl);

    if (status !== 200) {
      logger.error("Error getting data from QNAP: %s status %d. Data: %s", apiUrl, status, data);
      return { status, contentType, data: null, responseHeaders };
    }
    
    dataDecoded = JSON.parse(xml2json(data.toString(), { compact: true }).toString());
  }

  return { status, contentType, data: dataDecoded, responseHeaders };
}

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

  if (!group || !service) {
    logger.debug("Invalid or missing service '%s' or group '%s'", service, group);
    return res.status(400).json({ error: "Invalid proxy service type" });
  }

  const widget = await getServiceWidget(group, service);
  if (!widget) {
    logger.debug("Invalid or missing widget for service '%s' in group '%s'", service, group);
    return res.status(400).json({ error: "Invalid proxy service type" });
  }

  if (!cache.get(`${sessionTokenCacheKey}.${service}`)) {
    await login(widget, service);
  }

  const { data: systemStatsData } = await apiCall(widget, "{url}/cgi-bin/management/manaRequest.cgi?subfunc=sysinfo&hd=no&multicpu=1", service);
  const { data: volumeStatsData } = await apiCall(widget, "{url}/cgi-bin/management/chartReq.cgi?chart_func=disk_usage&disk_select=all&include=all", service);

  return res.status(200).send({
    system: systemStatsData.QDocRoot.func.ownContent.root,
    volume: volumeStatsData.QDocRoot
  });
}