//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  
  package org.eclipse.jetty.gcloud.session;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.security.KeyStore;
  import java.security.PrivateKey;
  import java.util.Properties;
  
  import org.eclipse.jetty.util.security.Password;
  
  import com.google.gcloud.AuthCredentials;
  import com.google.gcloud.datastore.DatastoreOptions;
  
  
  
  /**
   * GCloudConfiguration
   *
   *
   */
  public class GCloudConfiguration
  {
      public static final String PROJECT_ID = "projectId";
      public static final String P12 = "p12";
      public static final String PASSWORD = "password";
      public static final String SERVICE_ACCOUNT = "serviceAccount";
      
      private String _projectId;
      private String _p12Filename;
      private File _p12File;
      private String _serviceAccount;
      private String _passwordSet;
      private String _password;
      private AuthCredentials _authCredentials;
      private DatastoreOptions _options;
      
      /**
       * Generate a configuration from a properties file
       * 
       * @param propsFile
       * @return
       * @throws IOException
       */
      public static GCloudConfiguration fromFile(String propsFile)
      throws IOException
      {
          if (propsFile == null)
              throw new IllegalArgumentException ("Null properties file");
          
          File f = new File(propsFile);
          if (!f.exists())
              throw new IllegalArgumentException("No such file "+f.getAbsolutePath());
          Properties props = new Properties();
          try (FileInputStream is=new FileInputStream(f))
          {
              props.load(is);
          }
          
          GCloudConfiguration config = new GCloudConfiguration();
          config.setProjectId(props.getProperty(PROJECT_ID));
          config.setP12File(props.getProperty(P12));
          config.setPassword(props.getProperty(PASSWORD));
          config.setServiceAccount(props.getProperty(SERVICE_ACCOUNT));
          return config;
      }
      
      
      
      public String getProjectId()
      {
          return _projectId;
      }
  
      public File getP12File()
      {
          return _p12File;
      }
  
      public String getServiceAccount()
     {
         return _serviceAccount;
     }
 
 
     public void setProjectId(String projectId)
     {
         checkForModification();
         _projectId = projectId;
     }
 
     public void setP12File (String file)
     {
         checkForModification();
         _p12Filename = file;
 
     }
     
     
     public void setServiceAccount (String serviceAccount)
     {
         checkForModification();
         _serviceAccount = serviceAccount;
     }
     
 
     public void setPassword (String pwd)
     {
         checkForModification();
         _passwordSet = pwd;
 
     }
 
 
     public DatastoreOptions getDatastoreOptions ()
             throws Exception
     {
         if (_options == null)
         {
             if (_passwordSet == null && _p12Filename == null && _serviceAccount == null)
             {
                 //When no values are explicitly presented for auth info, we are either running
                 //1. inside GCE environment, in which case all auth info is derived from the environment
                 //2. outside the GCE environment, but using a local gce dev server, in which case you
                 //   need to set the following 2 environment/system properties
                 //          DATASTORE_HOST: eg http://localhost:9999 - this is the host and port of a local development server
                 //          DATASTORE_DATASET: eg myProj - this is the name of your project          
                 _options = DatastoreOptions.defaultInstance();
             }
             else
             {
                 //When running externally to GCE, you need to provide
                 //explicit auth info. You can either set the projectId explicitly, or you can set the
                 //DATASTORE_DATASET env/system property
                 _p12File = new File(_p12Filename);
                 Password p = new Password(_passwordSet);
                 _password = p.toString();
                 _options = DatastoreOptions.builder()
                         .projectId(_projectId)
                         .authCredentials(getAuthCredentials())
                         .build();
             }
         }
         return _options;
     }
 
     /**
      * @return
      * @throws Exception
      */
     public AuthCredentials getAuthCredentials()
     throws Exception
     {
         if (_authCredentials == null)
         {
             if (_password == null)
                 throw new IllegalStateException("No password");
 
             if (_p12File == null || !_p12File.exists())
                 throw new IllegalStateException("No p12 file: "+(_p12File==null?"null":_p12File.getAbsolutePath()));
 
             if (_serviceAccount == null)
                 throw new IllegalStateException("No service account");
 
             char[] pwdChars = _password.toCharArray();
             KeyStore keystore = KeyStore.getInstance("PKCS12");
             keystore.load(new FileInputStream(getP12File()), pwdChars);
             PrivateKey privateKey = (PrivateKey) keystore.getKey("privatekey", pwdChars);
             _authCredentials = AuthCredentials.createFor(getServiceAccount(), privateKey);
         }
         return _authCredentials;
     }
     
     /**
      * @throws IllegalStateException
      */
     protected void checkForModification () throws IllegalStateException
     {
         if (_authCredentials != null || _options != null)
             throw new IllegalStateException("Cannot modify auth configuration after datastore initialized");     
     }
 }