// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License. See License.txt in the project root for license information.

import { ApplicationTokenCredentialsBase } from "./applicationTokenCredentialsBase";
import { Environment } from "@azure/ms-rest-azure-env";
import { AuthConstants, TokenAudience } from "../util/authConstants";
import { TokenResponse, ErrorResponse, TokenCache } from "adal-node";

export class ApplicationTokenCredentials extends ApplicationTokenCredentialsBase {
  readonly secret: string;

  /**
   * Creates a new ApplicationTokenCredentials object.
   * See {@link https://azure.microsoft.com/en-us/documentation/articles/active-directory-devquickstarts-dotnet/ Active Directory Quickstart for .Net}
   * for detailed instructions on creating an Azure Active Directory application.
   *
   * @param clientId - The active directory application client id.
   * @param domain - The domain or tenant id containing this application.
   * @param secret - The authentication secret for the application.
   * @param tokenAudience - The audience for which the token is requested. Valid values are 'graph', 'batch', or any other resource like 'https://vault.azure.net/'.
   * If tokenAudience is 'graph' then domain should also be provided and its value should not be the default 'common' tenant. It must be a string (preferrably in a guid format).
   * @param environment - The azure environment to authenticate with.
   * @param tokenCache - The token cache. Default value is the MemoryCache object from adal.
   */
  public constructor(
    clientId: string,
    domain: string,
    secret: string,
    tokenAudience?: TokenAudience,
    environment?: Environment,
    tokenCache?: TokenCache
  ) {
    if (!secret || typeof secret.valueOf() !== "string") {
      throw new Error("secret must be a non empty string.");
    }
    super(clientId, domain, tokenAudience, environment, tokenCache);

    this.secret = secret;
  }

  /**
   * Tries to get the token from cache initially. If that is unsuccessfull then it tries to get the token from ADAL.
   * @returns A promise that resolves to TokenResponse and rejects with an Error.
   */
  public async getToken(): Promise<TokenResponse> {
    try {
      return await this.getTokenFromCache();
    } catch (error) {
      if (error.message && error.message.startsWith(AuthConstants.SDK_INTERNAL_ERROR)) {
        throw error;
      }
      const resource = this.getActiveDirectoryResourceId();
      return new Promise((resolve, reject) => {
        this.authContext.acquireTokenWithClientCredentials(
          resource,
          this.clientId,
          this.secret,
          (error: any, tokenResponse: TokenResponse | ErrorResponse) => {
            if (error) {
              return reject(error);
            }
            if (tokenResponse.error || tokenResponse.errorDescription) {
              return reject(tokenResponse);
            }
            return resolve(tokenResponse as TokenResponse);
          }
        );
      });
    }
  }
}