/*
    * Copyright 2014 Google Inc. All rights reserved.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.simpligility.maven.plugins.android.common;
  
  import com.google.api.client.auth.oauth2.Credential;
  import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
  import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
  import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
  import com.google.api.client.http.HttpTransport;
  import com.google.api.client.json.JsonFactory;
  import com.google.api.client.json.jackson2.JacksonFactory;
  import com.google.api.client.repackaged.com.google.common.base.Preconditions;
  import com.google.api.client.repackaged.com.google.common.base.Strings;
  import com.google.api.services.androidpublisher.AndroidPublisher;
  import com.google.api.services.androidpublisher.AndroidPublisherScopes;
  
  import java.io.File;
  import java.io.IOException;
  import java.security.GeneralSecurityException;
  import java.util.Collections;
  
  import javax.annotation.Nullable;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /**
   * Helper class to initialize the publisher APIs client library.
   * <p>
   * Before making any calls to the API through the client library you need to
   * call the {@link AndroidPublisherHelper#init(String)} method. This will run
   * all precondition checks for for client id and secret setup properly in
   * resources/client_secrets.json and authorize this client against the API.
   * </p>
   */
  public class AndroidPublisherHelper
  {
  
      private static final Log LOG = LogFactory.getLog( AndroidPublisherHelper.class );
  
      public static final String MIME_TYPE_APK = "application/vnd.android.package-archive";
  
      public static final String MIME_TYPE_IMAGE = "image/*";
  
      /** Path to the private key file (only used for Service Account auth). */
      private static final String SRC_RESOURCES_KEY_P12 = "resources/key.p12";
  
      /**
       * Path to the client secrets file (only used for Installed Application
       * auth).
       */
      private static final String RESOURCES_CLIENT_SECRETS_JSON = "/resources/client_secrets.json";
  
      /**
       * Directory to store user credentials (only for Installed Application
       * auth).
       */
      private static final String DATA_STORE_SYSTEM_PROPERTY = "user.home";
      private static final String DATA_STORE_FILE = ".store/android_publisher_api";
      private static final File DATA_STORE_DIR =
              new File( System.getProperty( DATA_STORE_SYSTEM_PROPERTY ), DATA_STORE_FILE );
  
      /** Global instance of the JSON factory. */
      private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
  
      /** Global instance of the HTTP transport. */
      private static HttpTransport httpTransport;
  
      /** Installed application user ID. */
      private static final String INST_APP_USER_ID = "user";
  
      private static Credential authorizeWithServiceAccount( String serviceAccountEmail )
              throws GeneralSecurityException, IOException
      {
          LOG.info( String.format( "Authorizing using Service Account: %s", serviceAccountEmail ) );
  
          return authorizeWithServiceAccount( serviceAccountEmail, null );
      }
  
      private static Credential authorizeWithServiceAccount( String serviceAccountEmail, File pk12File )
              throws GeneralSecurityException, IOException
      {
          LOG.info( String.format( "Authorizing using Service Account: %s", serviceAccountEmail ) );
  
          // Build service account credential.
         GoogleCredential credential = new GoogleCredential.Builder()
                 .setTransport( httpTransport )
                 .setJsonFactory( JSON_FACTORY )
                 .setServiceAccountId( serviceAccountEmail )
                 .setServiceAccountScopes( Collections.singleton( AndroidPublisherScopes.ANDROIDPUBLISHER ) )
                 .setServiceAccountPrivateKeyFromP12File( pk12File == null ? new File( SRC_RESOURCES_KEY_P12 )
                         : pk12File )
                 .build();
         return credential;
     }
 
     /**
      * Ensure the client secrets file has been filled out.
      *
      * @param clientSecrets the GoogleClientSecrets containing data from the
      *            file
      */
     private static void checkClientSecretsFile( GoogleClientSecrets clientSecrets )
     {
         if ( clientSecrets.getDetails().getClientId().startsWith( "[[INSERT" )
                 || clientSecrets.getDetails().getClientSecret().startsWith( "[[INSERT" ) )
         {
             LOG.error( "Enter Client ID and Secret from "
                     + "APIs console into resources/client_secrets.json." );
             System.exit( 1 );
         }
     }
 
     /**
      * Performs all necessary setup steps for running requests against the API
      * using the Installed Application auth method.
      *
      * @param applicationName the name of the application: com.example.app
      * @return the {@Link AndroidPublisher} service
      */
     public static AndroidPublisher init( String applicationName ) throws Exception
     {
         return init( applicationName, null );
     }
 
     /**
      * Performs all necessary setup steps for running requests against the API.
      *
      * @param applicationName the name of the application: com.example.app
      * @param serviceAccountEmail the Service Account Email (empty if using
      *            installed application)
      * @return the {@Link AndroidPublisher} service
      * @throws GeneralSecurityException
      * @throws IOException
      */
     public static AndroidPublisher init( String applicationName,
             @Nullable String serviceAccountEmail ) throws IOException, GeneralSecurityException
     {
         Preconditions.checkArgument( !Strings.isNullOrEmpty( applicationName ),
                 "applicationName cannot be null or empty!" );
 
         // Authorization.
         newTrustedTransport();
         Credential credential;
         credential = authorizeWithServiceAccount( serviceAccountEmail );
 
         // Set up and return API client.
         return new AndroidPublisher.Builder(
                 httpTransport, JSON_FACTORY, credential ).setApplicationName( applicationName )
                 .build();
     }
 
     /**
      * Performs all necessary setup steps for running requests against the API.
      *
      * @param serviceAccountEmail the Service Account Email (empty if using
      *            installed application)
      * @return the {@Link AndroidPublisher} service
      * @throws GeneralSecurityException
      * @throws IOException
      */
     public static AndroidPublisher init( String applicationName, String serviceAccountEmail, File pk12File )
             throws IOException, GeneralSecurityException
     {
 
         // Authorization.
         newTrustedTransport();
         Credential credential = authorizeWithServiceAccount( serviceAccountEmail, pk12File );
 
         // Set up and return API client.
         return new AndroidPublisher.Builder( httpTransport, JSON_FACTORY, credential )
                 .setApplicationName( applicationName )
                 .build();
     }
 
     private static void newTrustedTransport() throws GeneralSecurityException,
             IOException
     {
         if ( null == httpTransport )
         {
             httpTransport = GoogleNetHttpTransport.newTrustedTransport();
         }
     }
 
 }