import qs from 'qs';

import { getToken, getClientId } from '../selectors/authSelectors'

class APIClient {

  constructor(baseURL) {

    this.baseURL = baseURL;

  }

  setStore = (store) => {

    this.store = store;

  }

  createRequest = (method, uri, data, headers) => {

    headers = headers || new Headers();

    if(method !== 'HEAD') {

      headers.append("Content-Type", "application/json");

    } else {

      headers.append("Content-Type", "text/plain");

    }

    var options = {

      method: method,

      headers: headers,

    };

    let queryparams = '';

    if (data) {

      if(method !== 'HEAD' && method !== 'GET' && data) {

        options.body = JSON.stringify(data);

      }

      else {

        queryparams = "?"+qs.stringify(data);

      }

    }

    // TODO : use URL-module to build URL

    return new Request(this.baseURL + uri + queryparams, options);

  }

  getToken = () => {

    const state = this.store.getState();

    return getToken(state);

  }

  getClientId = () => {

    const state = this.store.getState();

    return getClientId(state);

  }

  hasToken = () => {

    const token = this.getToken();

    return token !== null && token !== '';

  }

  hasClientId = () => {

    const clientId = this.getClientId();

    return clientId !== null && clientId !== '';

  }

  createAuthorizedHeader = (headers) => {

    const token = this.getToken() || '';

    headers.append("Authorization", "JWT " + token);

    return headers;

  }

  createClientIdHeader = (headers) => {

    const clientId = this.getClientId() || '';

    headers.append("Auditlog-Client", clientId);

    return headers;

  }

  request = (method, uri, data) => {

    var headers = new Headers();

    if(this.hasToken()) {

      headers = this.createAuthorizedHeader(headers);

    }

    if(this.hasClientId()) {

      headers = this.createClientIdHeader(headers);

    }

    var req = this.createRequest(method, uri, data, headers);

    return this.fetch(req, { credentials: 'include' });

  }

  get = (uri, data) => {

    return this.request('GET', uri, data);

  }

  post = (uri, data) => {

    return this.request('POST', uri, data);

  }

  put = (uri, data) => {

    return this.request('PUT', uri, data);

  }

  delete = (uri, data) => {

    return this.request('DELETE', uri, data);

  }

  fetch = (req) => {

    return new Promise((resolve, reject) => {

      fetch(req)

        .then((response) => {

          if (response.ok) {

            let resJsonPromise;

            if(response.status === 204) {

              resJsonPromise = Promise.resolve({});

            } else {

              resJsonPromise = response.text().then(data => {

                if(data.length > 0) {

                  return JSON.parse(data);

                } else {

                  return {};

                }

              });

            }

            return resJsonPromise.then(data => resolve(data));

          } else {

            let errorResp = {

              status: response.status,

              statusText: response.statusText

            }

            return response.json().then(data => reject({...errorResp,data }));

          }

        })

        .catch((error) => {

          reject({error});

        });

    });

  }

}

export default APIClient