import express from 'express'
import bodyParser from 'body-parser'
import * as jwt from 'atlassian-jwt'
import fetch from 'node-fetch'
import fs from 'fs/promises'

import descriptor from './atlassian-connect.json'

const {
  CLIENT_SECRET = '',
  PUBLIC_URL = '',
} = process.env

const app = express()

app.use(bodyParser.json())

app.get('/', (req, res) => {
  console.log('/')
  res.redirect('/atlassian-connect.json')
})

app.post('/uninstalled', (req, res) => {
  console.log('uninstalled')
  console.log(req.body)
  res.sendStatus(200)
})

app.post('/installed', (req, res) => {
  console.log('installed')
  console.log(req.body) // store at least { clientKey }
  res.sendStatus(200)
})

app.get('/atlassian-connect.json', (req, res) => {
  console.log('descriptor')
  descriptor.baseUrl = PUBLIC_URL
  res.json(descriptor)
})

app.listen(3000, () => {
  console.log('listening on port 3000')
})

const qs = (params: Record<string, any>) => {
  const sp = new URLSearchParams(params)
  return sp.toString()
}

const getAccessToken = async (key: string, clientKey: string, secret: string) => {
  const baseUrl = 'https://bitbucket.org'
  const url = 'https://bitbucket.org/site/oauth2/access_token'

  const opts = {
    method: 'post' as 'post',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: {
      grant_type: 'urn:bitbucket:oauth2:jwt',
    },
  }

  const req = jwt.fromMethodAndPathAndBody(opts.method, url, opts.body)
  const qsh = jwt.createQueryStringHash(req, true, baseUrl)

  const now = Math.floor(Date.now() / 1000)
  const exp = now + (3 * 60) // expires in 3 minutes
  const tokenData = {
      iss: key,
      iat: now, // the time the token is generated
      exp, // token expiry time
      sub: clientKey,  // clientKey from /installed
      qsh,
  }
  
  const jwtToken = jwt.encodeSymmetric(tokenData, secret)
  const options = {
    method: opts.method,
    headers: {
      ...opts.headers,
      Authorization: `JWT ${jwtToken}`
    },
    body: qs(opts.body),
  }
  const res = await fetch(url, options)
  if (res.status !== 200) {
    throw new Error(`Failed to get access token: ${res.status}`)
  }
  return res.json()
}

const downloadRepo = async (owner: string, name: string, branch: string, accessToken: string) => {
  const url = `https://bitbucket.org/${owner}/${name}/get/${branch}.zip`
  const res = await fetch(url, {
    headers: {
      Authorization: `Bearer ${accessToken}`,
    },
  })

  if (res.status !== 200) {
    throw new Error(`Failed to download repo: ${res.status}`)
  }

  const zip = await res.buffer()
  return zip
}

const go = async (clientKey: string, repoOwner: string, repoName: string, branchName: string) => {
  const token = await getAccessToken(descriptor.key, clientKey, CLIENT_SECRET)
  const zipBuffer = await downloadRepo(repoOwner, repoName, branchName, token.access_token)
  await fs.writeFile(`${repoOwner}-${repoName}-${branchName}.zip`, zipBuffer)
}

// go().then(console.log).catch(console.error)