import query from 'querystring'
import { OAuth2Error, ServerError } from './error'

function dataRes (req, res, code, data) {
  res.header('Cache-Control', 'no-store')
  res.header('Pragma', 'no-cache')
  res.status(code).send(data)
  console.debug('Response: ', data)
}

function redirect (req, res, redirectUri) {
  res.header('Location', redirectUri)
  res.status(302).end()
  console.debug('Redirecting to ', redirectUri)
}

export function error (req, res, err, redirectUri) {
  // Transform unknown error
  if (!(err instanceof OAuth2Error)) {
    console.error(err.stack)
    err = new ServerError('Uncaught exception')
  } else {
    console.error('Exception caught', err.stack)
  }

  if (redirectUri) {
    const obj = {
      error: err.code,
      error_description: err.message
    }

    if (req.query.state) {
      obj.state = req.query.state
    }

    redirectUri += '?' + query.stringify(obj)
    redirect(req, res, redirectUri)
  } else {
    dataRes(req, res, err.status, { error: err.code, error_description: err.message })
  }
}

export function data (req, res, obj, redirectUri, fragment) {
  if (redirectUri) {
    if (fragment) {
      redirectUri += '#'
    } else {
      redirectUri += (redirectUri.indexOf('?') === -1 ? '?' : '&')
    }

    if (req.query.state) {
      obj.state = req.query.state
    }

    redirectUri += query.stringify(obj)
    redirect(req, res, redirectUri)
  } else {
    dataRes(req, res, 200, obj)
  }
}