/*
 * Copyright (c) 2019 - 2020 Arnaud Vergnet.
 *
 * This file is part of Campus INSAT.
 *
 * Campus INSAT is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Campus INSAT is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Campus INSAT.  If not, see <https://www.gnu.org/licenses/>.
 */

export const ERROR_TYPE = {
  SUCCESS: 0,
  BAD_CREDENTIALS: 1,
  BAD_TOKEN: 2,
  NO_CONSENT: 3,
  TOKEN_SAVE: 4,
  TOKEN_RETRIEVE: 5,
  BAD_INPUT: 400,
  FORBIDDEN: 403,
  CONNECTION_ERROR: 404,
  SERVER_ERROR: 500,
  UNKNOWN: 999,
};

export type ApiDataLoginType = {
  token: string;
};

export type ApiGenericDataType = {[key: string]: any};

type ApiResponseType<T> = {
  error: number;
  data: T;
};

const API_ENDPOINT = 'https://www.amicale-insat.fr/api/';

/**
 * Checks if the given API response is valid.
 *
 * For a request to be valid, it must match the response_format as defined in this file.
 *
 * @param response
 * @returns {boolean}
 */
export function isApiResponseValid<T>(response: ApiResponseType<T>): boolean {
  return (
    response != null &&
    response.error != null &&
    response.data != null &&
    typeof response.data === 'object'
  );
}

/**
 * Sends a request to the Amicale Website backend
 *
 * In case of failure, the promise will be rejected with the error code.
 * In case of success, the promise will return the data object.
 *
 * @param path The API path from the API endpoint
 * @param method The HTTP method to use (GET or POST)
 * @param params The params to use for this request
 * @returns {Promise<ApiGenericDataType>}
 */
export async function apiRequest<T>(
  path: string,
  method: string,
  params?: object,
): Promise<T> {
  return new Promise(
    (resolve: (data: T) => void, reject: (error: number) => void) => {
      let requestParams = {};
      if (params != null) {
        requestParams = {...params};
      }
      fetch(API_ENDPOINT + path, {
        method,
        headers: new Headers({
          Accept: 'application/json',
          'Content-Type': 'application/json',
        }),
        body: JSON.stringify(requestParams),
      })
        .then(
          async (response: Response): Promise<ApiResponseType<T>> =>
            response.json(),
        )
        .then((response: ApiResponseType<T>) => {
          if (isApiResponseValid(response)) {
            if (response.error === ERROR_TYPE.SUCCESS) {
              resolve(response.data);
            } else {
              reject(response.error);
            }
          } else {
            reject(ERROR_TYPE.SERVER_ERROR);
          }
        })
        .catch((): void => reject(ERROR_TYPE.CONNECTION_ERROR));
    },
  );
}

/**
 * Reads data from the given url and returns it.
 *
 * Only use this function for non API calls.
 * For Amicale API calls, please use the apiRequest function.
 *
 * If no data was found, returns an empty object
 *
 * @param url The urls to fetch data from
 * @return Promise<any>
 */
export async function readData(url: string): Promise<any> {
  return new Promise((resolve: (response: any) => void, reject: () => void) => {
    fetch(url)
      .then(async (response: Response): Promise<any> => response.json())
      .then((data: any): void => resolve(data))
      .catch((): void => reject());
  });
}