'use strict'

module.exports = restEndpoint

const _ = require('lodash')
const urlTemplate = require('url-template')

const addQueryParameters = require('./add-query-parameters')
const extractUrlVariableNames = require('./extract-url-variable-names')

const DEFAULTS = module.exports.DEFAULTS = require('./defaults')
const NON_PARAMETERS = [
  'request',
  'baseUrl'
]

function restEndpoint (options) {
  options = _.defaultsDeep({}, options, DEFAULTS)
  let method = options.method
  let baseUrl = options.baseUrl
  let url = options.url
  let body = options.body
  let headers = options.headers
  let remainingOptions = _.omit(options, ['method', 'baseUrl', 'url', 'headers'])

  method = method.toLowerCase()
  headers = _.mapKeys(headers, (value, key) => key.toLowerCase())

  // replace :varname with {varname} to make it RFC 6570 compatible
  url = url.replace(/:(\w+)/g, '{+$1}')

  // extract variable names from URL to calculate remaining variables later
  const urlVariableNames = extractUrlVariableNames(url)

  url = urlTemplate.parse(url).expand(remainingOptions)

  if (!/^http/.test(url)) {
    url = (baseUrl) + url
  }

  const requestOptions = remainingOptions.request
  remainingOptions = _.omit(remainingOptions, _.intersection(Object.keys(options), urlVariableNames).concat(NON_PARAMETERS))

  if (method === 'get' || method === 'head') {
    url = addQueryParameters(url, remainingOptions)
  } else {
    if ('input' in remainingOptions) {
      body = remainingOptions.input
    } else {
      body = Object.keys(remainingOptions).length ? remainingOptions : undefined
    }
  }

  return Object.assign(requestOptions, {
    method,
    url,
    headers,
    body
  })
}