// Copyright (c) Microsoft Corporation. All rights reserved.
   // Licensed under the MIT License.
   
   package com.azure.identity.credential;
   
   import com.azure.core.credentials.AccessToken;
   import com.azure.core.credentials.TokenCredential;
   import com.azure.core.util.configuration.BaseConfigurations;
   import com.azure.core.util.configuration.Configuration;
  import com.azure.core.util.configuration.ConfigurationManager;
  import com.azure.identity.IdentityClient;
  import com.azure.identity.IdentityClientOptions;
  import reactor.core.publisher.Mono;
  
  /**
   * The base class for Managed Service Identity token based credentials.
   */
  public final class ManagedIdentityCredential implements TokenCredential {
      private final AppServiceMSICredential appServiceMSICredential;
      private final VirtualMachineMSICredential virtualMachineMSICredential;
  
      /**
       * Creates an instance of the ManagedIdentityCredential with default identity client options.
       */
      public ManagedIdentityCredential() {
          this(new IdentityClientOptions());
      }
  
      /**
       * Creates an instance of the ManagedIdentityCredential.
       * @param identityClientOptions the options for configuring the identity client.
       */
      public ManagedIdentityCredential(IdentityClientOptions identityClientOptions) {
          IdentityClientityClient">IdentityClient identityClient = new IdentityClient(identityClientOptions);
          Configuration configuration = ConfigurationManager.getConfiguration();
          if (configuration.contains(BaseConfigurations.MSI_ENDPOINT)) {
              appServiceMSICredential = new AppServiceMSICredential(identityClient);
              virtualMachineMSICredential = null;
          } else {
              virtualMachineMSICredential = new VirtualMachineMSICredential(identityClient);
              appServiceMSICredential = null;
          }
      }
  
      /**
       * @return the client id of user assigned or system assigned identity.
       */
      public String clientId() {
          return this.appServiceMSICredential != null ? this.appServiceMSICredential.clientId() : this.virtualMachineMSICredential.clientId();
      }
  
      /**
       * Specifies the client id of user assigned or system assigned identity.
       *
       * @param clientId the client id
       * @return ManagedIdentityCredential
       */
      public ManagedIdentityCredential clientId(String clientId) {
          if (this.appServiceMSICredential != null) {
              this.appServiceMSICredential.clientId(clientId);
          } else {
              this.virtualMachineMSICredential.clientId(clientId);
          }
          return this;
      }
  
      /**
       * @return the endpoint from which token needs to be retrieved.
       */
      public String msiEndpoint() {
          return this.appServiceMSICredential == null ? null : this.appServiceMSICredential.msiEndpoint();
      }
      /**
       * @return the secret to use to retrieve the token.
       */
      public String msiSecret() {
          return this.appServiceMSICredential == null ? null : this.appServiceMSICredential.msiSecret();
      }
  
      @Override
      public Mono<AccessToken> getToken(String... scopes) {
          return (appServiceMSICredential != null
              ? appServiceMSICredential.authenticate(scopes)
              : virtualMachineMSICredential.authenticate(scopes));
      }
  }