const proxy = require("http-proxy-middleware")
const express = require("express")
const jwt = require("jsonwebtoken")

const config = require("../config")

const router = express.Router()

router.post("/", (req, res) => {
  const user = res.locals.user
  const permissions = (req.header("X-Permissions") || "").split(",").filter(t => t != "" && t != "undefined" && t != "null")
  let authorization = req.header("Authorization")
  if (authorization == "null") {
    authorization = ""
  }

  if (!authorization && user.loggedIn) {
    authorization = `Bearer ${generateToken(user.name, permissions)}`
  }

  fetch(config.graphqlEndpoint, {
    method: "POST",
    headers: {
      "Content-Type": req.header("Content-Type"),
      "Authorization": authorization,
    },
    body: req,
    credentials: "include",
  }).then(fetchRes => {
    res.setHeader("Content-Type", fetchRes.headers.get("Content-Type"))
    res.status(fetchRes.status)

    return fetchRes.json()
  }).then(json => {
    res.json(json)
  }).catch(err => {
    res.status(500).text(err)
    return null
  })
})

router.use("/", proxy(config.graphqlEndpoint, {ws: true}))

/**
 * @param {string} user 
 * @param {string[]} permissions 
 */
function generateToken(user) {
  return jwt.sign({user, exp: Math.floor((Date.now() / 1000) + 1200)}, config.backend.secret, {header: {kid: config.backend.kid}})
}

module.exports = {router, generateToken}