import queryString from 'query-string'
import Immutable from 'seamless-immutable'

/**
 * API Client
 * Vision-specific client for interacting directly with the API – via these methods.
 *
 * @type {Object}
 */
const apiClient = {
  get: (...args) => fireRequest('GET', ...args),
  post: (...args) => fireRequest('POST', ...args),
  put: (...args) => fireRequest('PUT', ...args),
  delete: (...args) => fireRequest('DELETE', ...args)
}

/**
 * Base API URL that is set in Webpack as a global variable.
 *
 * @type {String}
 */
const BASE_URL = process.env.API_URL

/**
 * Fire Request
 * Use the redux-api-middleware to make a request to the API and fire all actions.
 * Success and failure actions are generated accordingly.
 *
 * @param  method {String} Restful method.
 * @param  uri    {String} API URL endpoint.
 * @param  data   {Object} Any data to send along.
 * @param  action {Object} Redux action being triggered.
 * @return        {Object} Request config and logic as accepted by the middleware.
 */
function fireRequest(method, uri = '', data = {}, action) {
  let endpoint = `${BASE_URL}/${uri}`
  let headers = {
    'Content-Type': 'application/json',
    'X-Application-Name': 'Vision'
  }
  let body = null

  // Just in case a falsey value gets through
  if (!data) {
    data = {}
  }

  // Convert immutable data to normal JS
  if (Immutable.isImmutable(data)) {
    data = Immutable.asMutable(data)
  }

  // Assign token to auth header
  if (data.token) {
    headers.Authorization = `Bearer ${data.token}`
  }

  Reflect.deleteProperty(data, 'token')

  // Convert data to query string for GET requests
  if (method === 'GET') {
    endpoint += queryString.stringify(data)
  } else {
    body = JSON.stringify(data)
  }

  const options = {
    method,
    body,
    headers
  }

  return fetch(endpoint, options).then(response => {
    const contentType = response.headers.get('Content-Type')

    if (contentType && ~contentType.indexOf('json')) {
      return response.json().then(jsonResponse => {
        if (response.ok) {
          return Immutable(jsonResponse)
        }

        throw Immutable({
          status: response.status,
          message: jsonResponse.error || 'Looks like something went wrong…'
        })
      })
    }
  })
}

export default apiClient