/*
    * Copyright 2013 smartics, Kronseder & Reiner GmbH
    *
    * 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 de.smartics.properties.admin.domain.model;
  
  import java.io.Serializable;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Set;
  import java.util.TreeSet;
  
  import javax.annotation.CheckForNull;
  
  import de.smartics.properties.admin.domain.service.ApplicationIdConfigurationLoader;
  import de.smartics.properties.admin.domain.service.ConfigurationService;
  import de.smartics.properties.admin.domain.service.RemoteConfigurationPropertiesManagementFactory;
  import de.smartics.properties.api.config.domain.ConfigurationPropertiesManagement;
  import de.smartics.properties.api.config.domain.key.ConfigurationKey;
  import de.smartics.properties.api.core.domain.PropertyDescriptorRegistry;
  import de.smartics.properties.api.core.security.PropertyValueSecurity;
  import de.smartics.properties.impl.config.ds.DataSourceConfiguration;
  import de.smartics.properties.impl.config.ds.DataSourceConfigurationLoader;
  import de.smartics.properties.resource.domain.ArtifactId;
  import de.smartics.properties.spi.config.domain.key.ConfigurationKeyContext;
  import de.smartics.properties.spi.config.domain.key.ConfigurationKeyContextManager;
  
  /**
   * The application, managed by this REST service implementation.
   */
  public class ManagedApplication implements Serializable
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The class version identifier.
     * <p>
     * The value of this constant is {@value}.
     */
    private static final long serialVersionUID = 1L;
  
    // --- members --------------------------------------------------------------
  
    /**
     * The singleton. The REST API is only accessing properties of one
     * application.
     */
    private static ManagedApplication instance;
  
    /**
     * The identifier of the application managed.
     *
     * @serial
     */
    private final ArtifactId applicationId;
  
    /**
     * The data source that contains the property definitions.
     *
     * @serial
     */
    private final DataSourceConfiguration dataSourceConfig;
  
    /**
     * The factory to manage configurations for the application.
     *
     * @serial
     */
    private final RemoteConfigurationPropertiesManagementFactory factory;
  
    /**
     * The set of keys that have been encountered in the applications lifetime.
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    private final Set<ConfigurationKey<?>> configurationKeys = Collections
        .synchronizedSet(new TreeSet());
  
    // ****************************** Initializer *******************************
  
    private static void initialize()
      throws CannotInitializeManagedApplicationException
    {
      try
      {
        final ArtifactId applicationId =
            new ApplicationIdConfigurationLoader().load();
       final DataSourceConfiguration dataSourceConfig =
           loadDataSourceConfiguration();
       final RemoteConfigurationPropertiesManagementFactory factory =
           new ConfigurationService().createFactory(applicationId,
               dataSourceConfig);
       instance =
           new ManagedApplication(applicationId, dataSourceConfig, factory);
     }
     catch (final Exception e)
     {
       throw new CannotInitializeManagedApplicationException(e);
     }
   }
 
   private static DataSourceConfiguration loadDataSourceConfiguration()
   {
     try
     {
       return new DataSourceConfigurationLoader().load();
     }
     catch (final IllegalStateException e)
     {
       return null;
     }
   }
 
   // ****************************** Constructors ******************************
 
   /**
    * Default constructor.
    *
    * @param applicationId the identifier of the application managed.
    * @param dataSourceConfig the data source that contains the property
    *          definitions.
    * @param factory the factory to manage configurations for the application.
    */
   public ManagedApplication(final ArtifactId applicationId,
       final DataSourceConfiguration dataSourceConfig,
       final RemoteConfigurationPropertiesManagementFactory factory)
   {
     this.applicationId = applicationId;
     this.dataSourceConfig = dataSourceConfig;
     this.factory = factory;
     configurationKeys.addAll(factory.getRegisteredConfigurationKeys());
   }
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   /**
    * Returns the identifier of the application managed.
    *
    * @return the identifier of the application managed.
    */
   public ArtifactId getApplicationId()
   {
     return applicationId;
   }
 
   /**
    * Returns the data source that contains the property definitions.
    *
    * @return the data source that contains the property definitions.
    */
   @CheckForNull
   public DataSourceConfiguration getDataSourceConfig()
   {
     return dataSourceConfig;
   }
 
   /**
    * Returns the URL to the remote repository.
    *
    * @return the URL to the remote repository.
    */
   public String getRemoteRepositoryUrl()
   {
     return factory.getRemoteUrl();
   }
 
   /**
    * Returns the security component to encrypt and decrypt values.
    *
    * @return the security component to encrypt and decrypt values.
    */
   public PropertyValueSecurity getSecurity()
   {
     return factory.getFactoryConfiguration().getDecrypter();
   }
 
   /**
    * Returns the registry of known descriptors.
    *
    * @return the registry of known descriptors.
    */
   public PropertyDescriptorRegistry getDescriptorRegistry()
   {
     return factory.getRegistry();
   }
 
   // --- business -------------------------------------------------------------
 
   /**
    * Provides access to the managed application.
    *
    * @return the managed application.
    * @throws CannotInitializeManagedApplicationException if the application was
    *           not and cannot be initialized.
    */
   public static ManagedApplication getApplication()
     throws CannotInitializeManagedApplicationException
   {
     if (instance == null)
     {
       initialize();
     }
     return instance;
   }
 
   /**
    * Provides access to configurations.
    *
    * @param key the key to the requested configuration.
    * @return the requested configuration.
    */
   public ConfigurationPropertiesManagement getConfiguration(
       final ConfigurationKey<?> key)
   {
     final ConfigurationPropertiesManagement config = factory.create(key);
     configurationKeys.add(key);
     return config;
   }
 
   /**
    * Provides access to configurations.
    *
    * @param keyString the string representation of the key to the requested
    *          configuration.
    * @return the requested configuration.
    */
   public ConfigurationPropertiesManagement getConfiguration(
       final String keyString)
   {
     final ConfigurationKeyContext context =
         ConfigurationKeyContextManager.INSTANCE.context();
     final ConfigurationKey<?> key =
         context.configurationKeyFactory().createKeyFromString(keyString);
     final ConfigurationPropertiesManagement config = getConfiguration(key);
     return config;
   }
 
   /**
    * Returns the collection of configuration keys.
    *
    * @return the collection of configuration keys.
    */
   public Collection<ConfigurationKey<?>> getConfigurationKeys()
   {
     return Collections.unmodifiableCollection(configurationKeys);
   }
 
   /**
    * Cleans the definitions from the factory.
    */
   public void clean()
   {
     for (final ConfigurationKey<?> key : factory
         .getRegisteredConfigurationKeys())
     {
       factory.remove(key);
     }
 
     configurationKeys.clear();
 
     factory.release();
 
     instance = null;
   }
   // --- object basics --------------------------------------------------------
 
 }