module.exports = getPage

const deprecate = require('./deprecate')
const getPageLinks = require('./get-page-links')
const HttpError = require('./http-error')

function getPage (octokit, link, which, headers) {
  deprecate(`octokit.get${which.charAt(0).toUpperCase() + which.slice(1)}Page() – You can use octokit.paginate or async iterators instead: https://github.com/octokit/rest.js#pagination.`)
  const url = getPageLinks(link)[which]

  if (!url) {
    const urlError = new HttpError(`No ${which} page found`, 404)
    return Promise.reject(urlError)
  }

  const requestOptions = {
    url,
    headers: applyAcceptHeader(link, headers)
  }

  const promise = octokit.request(requestOptions)

  return promise
}

function applyAcceptHeader (res, headers) {
  const previous = res.headers && res.headers['x-github-media-type']

  if (!previous || (headers && headers.accept)) {
    return headers
  }
  headers = headers || {}
  headers.accept = 'application/vnd.' + previous
    .replace('; param=', '.')
    .replace('; format=', '+')

  return headers
}