/*
    * Copyright 2012-2013 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.spi.config.support;
  
  import java.beans.PropertyChangeListener;
  import java.beans.PropertyChangeSupport;
  import java.io.IOException;
  import java.io.ObjectInputStream;
  
  import javax.annotation.concurrent.ThreadSafe;
  
  import org.apache.commons.lang.ObjectUtils;
  
  import de.smartics.properties.api.config.domain.ConfigurationProperties;
  import de.smartics.properties.api.config.domain.ConfigurationValidationException;
  import de.smartics.properties.api.config.domain.DescribedProperty;
  import de.smartics.properties.api.config.domain.SerializableConfigurationProperties;
  import de.smartics.properties.api.config.domain.UnknownPropertyException;
  import de.smartics.properties.api.config.domain.ValidatedProperty;
  import de.smartics.properties.api.config.domain.key.ConfigurationKey;
  import de.smartics.properties.api.core.domain.PropertiesContext;
  import de.smartics.properties.api.core.domain.PropertyContext;
  import de.smartics.properties.api.core.domain.PropertyDescriptor;
  import de.smartics.properties.api.core.domain.PropertyDescriptorRegistry;
  import de.smartics.properties.api.core.domain.PropertyExpression;
  import de.smartics.properties.api.core.domain.PropertyExpressionMessageBean;
  import de.smartics.properties.api.core.domain.PropertyKey;
  import de.smartics.properties.api.core.domain.PropertyValidationException;
  import de.smartics.properties.api.core.domain.PropertyValueConversionException;
  import de.smartics.properties.api.core.domain.PropertyValueResolveException;
  import de.smartics.properties.api.core.security.PropertyValueSecurity;
  import de.smartics.properties.api.core.security.SecurityException;
  import de.smartics.properties.spi.config.proxy.PropertyConfigurationObjectBuilder;
  import de.smartics.properties.spi.config.resolve.PropertyValueResolver;
  import de.smartics.properties.spi.config.resolve.ResolveConfigurationException;
  import de.smartics.properties.spi.config.resolve.SimplePropertyValueResolver;
  import de.smartics.properties.spi.core.context.MandatoryPropertyContext;
  import de.smartics.properties.spi.core.convert.BeanUtilsPropertyValueConverter;
  import de.smartics.properties.spi.core.convert.PropertyValueConverter;
  import de.smartics.properties.spi.core.validate.PropertyValidator;
  import de.smartics.util.lang.Arg;
  import de.smartics.util.lang.BlankArgumentException;
  import de.smartics.util.lang.NullArgumentException;
  
  /**
   * Abstract implementation of the {@link ConfigurationProperties} interface.
   */
  @ThreadSafe
  public abstract class AbstractConfigurationProperties implements
      ConfigurationProperties, ConfigurationPropertiesSpi
  { // NOPMD
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The key that identifies the configuration.
     *
     * @serial
     */
    private final ConfigurationKey<?> key;
  
    /**
     * The registry to resolve property descriptors.
     *
     * @serial
     */
    private final PropertyDescriptorRegistry registry;
  
    /**
     * The helper to decrypt secured property values.
     *
     * @serial
     */
    private final PropertyValueSecurity decrypter;
  
    /**
     * The property value converter to and from Strings.
     *
     * @serial
     */
    private final PropertyValueConverter converter =
        new BeanUtilsPropertyValueConverter();
  
   /**
    * The resolver to resolve property value expressions.
    */
   private transient PropertyValueResolver resolver;
 
   /**
    * Helper to handle property change listeners.
    *
    * @serial
    */
   private final PropertyChangeSupport support = new PropertyChangeSupport(this);
 
   // ****************************** Initializer *******************************
 
   // ****************************** Constructor ******************************
 
   /**
    * Constructor for serializable subclasses.
    */
   protected AbstractConfigurationProperties()
   {
     this.key = null;
     this.registry = null;
     this.resolver = null;
     this.decrypter = null;
   }
 
   /**
    * Default constructor.
    *
    * @param key the key that identifies the configuration.
    * @param registry the registry to resolve property descriptors.
    * @param decrypter the helper to decrypt secured property values.
    * @throws NullArgumentException if {@code key}, {@code registry} or
    *           {@code decrypter} is <code>null</code>.
    */
   protected AbstractConfigurationProperties(final ConfigurationKey<?> key,
       final PropertyDescriptorRegistry registry,
       final PropertyValueSecurity decrypter) throws NullArgumentException
   {
     this.key = Arg.checkNotNull("key", key);
     this.registry = Arg.checkNotNull("registry", registry);
     this.decrypter = Arg.checkNotNull("decrypter", decrypter);
     this.resolver = createResolver();
   }
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   private SimplePropertyValueResolver createResolver()
   {
     return new SimplePropertyValueResolver(registry, this);
   }
 
   // --- get&set --------------------------------------------------------------
 
   @Override
   public final ConfigurationKey<?> getKey()
   {
     return key;
   }
 
   @Override
   public final PropertyContext getContext(final PropertyDescriptor descriptor)
     throws NullPointerException
   {
     Arg.checkNotNull("descriptor", descriptor);
     return new MandatoryPropertyContext(registry.getContext(descriptor),
         descriptor);
   }
 
   @Override
   public final PropertiesContext getContext(final Class<?> declaringType)
     throws NullPointerException
   {
     Arg.checkNotNull("declaringType", declaringType);
     return registry.getContext(declaringType);
   }
 
   /**
    * Returns the registry to resolve property descriptors.
    *
    * @return the registry to resolve property descriptors.
    */
   public final PropertyDescriptorRegistry getRegistry()
   {
     return registry;
   }
 
   /**
    * Returns the property value security helper to en- and decrypt property
    * values.
    *
    * @return the property value security helper to en- and decrypt property
    *         values.
    */
   public final PropertyValueSecurity getPropertyValueSecurity()
   {
     return decrypter;
   }
 
   // --- business -------------------------------------------------------------
 
   @Override
   public final DescribedProperty getProperty(final String key)
     throws IllegalArgumentException, UnknownPropertyException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key);
     return getProperty(descriptor);
   }
 
   @Override
   public DescribedProperty getProperty(final String key,
       final Object defaultValue) throws IllegalArgumentException,
     UnknownPropertyException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key);
     return getProperty(descriptor, defaultValue);
   }
 
   @Override
   public final DescribedProperty getProperty(final PropertyKey key)
     throws IllegalArgumentException, UnknownPropertyException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key.toString());
     return getProperty(descriptor);
   }
 
   @Override
   public final DescribedProperty getProperty(final PropertyDescriptor descriptor)
     throws IllegalArgumentException, UnknownPropertyException
   {
     return getProperty(descriptor, null);
   }
 
   @Override
   public final <T> T getProperties(final Class<T> propertiesInterface)
   {
     return getProperties(propertiesInterface, toSerializable());
   }
 
   @Override
   public final <T> T getProperties(final Class<T> propertiesInterface,
       final SerializableConfigurationProperties configuration)
   {
     final PropertyConfigurationObjectBuilder builder =
         new PropertyConfigurationObjectBuilder();
     return builder.build(propertiesInterface, configuration);
   }
 
   @Override
   public final Object getPropertyValue(final String key)
     throws IllegalArgumentException, UnknownPropertyException,
     PropertyValidationException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key);
     return getPropertyValue(descriptor, null);
   }
 
   @Override
   public final Object getPropertyValue(final PropertyKey key)
     throws IllegalArgumentException, UnknownPropertyException,
     PropertyValidationException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key.toString());
     return getPropertyValue(descriptor, null);
   }
 
   @Override
   public final Object getPropertyValue(final String key,
       final Object defaultValue) throws NullArgumentException,
     PropertyValidationException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key);
     return getPropertyValue(descriptor, defaultValue);
   }
 
   @Override
   public final String getPropertyValueAsString(final String key)
     throws NullArgumentException, PropertyValidationException
   {
     return getPropertyValue(key).toString();
   }
 
   @Override
   public final Object getPropertyValue(final PropertyDescriptor descriptor,
       final Object defaultValue) throws NullPointerException,
     PropertyValueConversionException, PropertyValidationException,
     UnknownPropertyException
   {
     return getValidatedProperty(descriptor, defaultValue).getValidatedValue();
   }
 
   @Override
   public final String getPropertyValueAsString(final String key,
       final Object defaultValue) throws NullArgumentException,
     PropertyValidationException
   {
     return getPropertyValue(key, defaultValue).toString();
   }
 
   @Override
   public final Object getPropertyValue(final PropertyDescriptor descriptor)
     throws NullArgumentException, PropertyValidationException
   {
     return getPropertyValue(descriptor, null);
   }
 
   @Override
   public final String getPropertyValueAsString(
       final PropertyDescriptor descriptor) throws NullArgumentException,
     PropertyValidationException
   {
     return ObjectUtils.toString(getPropertyValue(descriptor, null), null);
   }
 
   @Override
   public final String getPropertyValueAsString(
       final PropertyDescriptor descriptor, final Object defaultValue)
     throws NullArgumentException, PropertyValidationException
   {
     return ObjectUtils.toString(getPropertyValue(descriptor, defaultValue),
         null);
   }
 
   @Override
   public final ValidatedProperty getValidatedProperty(final PropertyKey key,
       final Object defaultValue) throws IllegalArgumentException,
     UnknownPropertyException, PropertyValidationException, SecurityException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key.toString());
     return getValidatedProperty(descriptor, defaultValue);
   }
 
   @Override
   public final ValidatedProperty getValidatedProperty(final String key,
       final Object defaultValue) throws IllegalArgumentException,
     UnknownPropertyException, PropertyValidationException, SecurityException
   {
     final PropertyDescriptor descriptor = getPropertyDescriptor(key);
     return getValidatedProperty(descriptor, defaultValue);
   }
 
   /**
    * Returns the property descriptor for a given key.
    *
    * @param key the key for which the property descriptor is needed.
    * @return the property descriptor for the given key.
    * @throws BlankArgumentException when the key is blank.
    * @throws PropertyValidationException when the configuration is invalid.
    */
   protected final PropertyDescriptor getPropertyDescriptor(final String key)
     throws BlankArgumentException, PropertyValidationException
   {
     Arg.checkNotBlank("key", key);
 
     final PropertyDescriptor descriptor = registry.get(key);
     if (descriptor == null)
     {
       throw new UnknownPropertyException(getKey(), key);
     }
     return descriptor;
   }
 
   /**
    * Resolves, converts and validates the given value.
    *
    * @param descriptor the property descriptor.
    * @param defaultValue the default value to use if {@code value} is
    *          <code>null</code> and there is no default expression.
    * @param value the value to resolve, convert and validate.
    * @return the resolved, converted and validated value.
    * @throws PropertyValueConversionException if the value cannot be converted
    *           from {@link String} to the target type. If the configuration is
    *           set to admin mode, the unresolved {@code value} will be returned.
    *           In this case the type is not of the target type as described by
    *           the descriptor.
    * @throws PropertyValidationException if at least on constraint is not met.
    * @throws SecurityException on any problem decrypting an encrypted value.
    */
   protected final Object resolveAndConvertAndValidate(
       final PropertyDescriptor descriptor, final Object defaultValue,
       final Object value) throws PropertyValueConversionException,
     PropertyValidationException, SecurityException
   {
     try
     {
       final Object convertedValue =
           resolveAndConvert(descriptor, value, defaultValue);
       validate(descriptor, convertedValue);
 
       return convertedValue;
     }
     catch (final PropertyValueConversionException e)
     {
       if (isInAdminMode())
       {
         return value;
       }
       throw e;
     }
     catch (final PropertyValueResolveException e)
     {
       if (isInAdminMode())
       {
         return value;
       }
       throw e;
     }
   }
 
   /**
    * Validates the given value for the given property.
    *
    * @param descriptor the descriptor to the property to use for validation.
    * @param value the property value to validate.
    * @param ifInOneOfTheseGroups the validation groups to consider in the
    *          validation process. The groups will be validated in the given
    *          order. As soon as a validation group fails, the validation process
    *          is aborted without checking the not yet processed groups.
    */
   public void validate(final PropertyDescriptor descriptor, final Object value,
       final Class<?>... ifInOneOfTheseGroups)
   {
     final PropertyValidator validator = new PropertyValidator(isInAdminMode());
     validator.validate(descriptor, value, ifInOneOfTheseGroups);
   }
 
   /**
    * Resolves and converts the given value.
    *
    * @param descriptor the property descriptor.
    * @param value the value to resolve and convert.
    * @param defaultValue the default value to use if {@code value} is
    *          <code>null</code> and there is no default expression.
    * @return the resolved and converted value.
    * @throws PropertyValueResolveException if the value cannot be resolved.
    * @throws PropertyValueConversionException if the value cannot be converted
    *           from {@link String} to the target type.
    * @throws SecurityException on any problem decrypting an encrypted value.
    */
   protected final Object resolveAndConvert(final PropertyDescriptor descriptor,
       final Object value, final Object defaultValue)
     throws PropertyValueResolveException, PropertyValueConversionException,
     SecurityException
   {
     Object currentValue = value;
     if (currentValue == null)
     {
       currentValue = descriptor.getDefaultExpression();
       if (currentValue == null)
       {
         currentValue = defaultValue;
       }
     }
 
     if (currentValue instanceof PropertyExpression)
     {
       final PropertyExpression expression = (PropertyExpression) currentValue;
       currentValue = expression.getExpression();
     }
 
     if (currentValue instanceof String)
     {
       currentValue = resolveValue(descriptor, (String) currentValue);
     }
 
     if (descriptor.isSecured() && currentValue instanceof String)
     {
       currentValue = decrypter.decrypt(descriptor, (String) currentValue);
     }
 
     final Object convertedValue = convert(descriptor, currentValue);
     return convertedValue;
   }
 
   private String resolveValue(final PropertyDescriptor descriptor,
       final String value)
   {
     try
     {
       final String resolvedValue = resolver.resolve((String) value);
       return resolvedValue;
     }
     catch (final ResolveConfigurationException e)
     {
       throw new PropertyValueResolveException(
           new PropertyExpressionMessageBean(e, descriptor, e.getExpression()));
     }
   }
 
   private Object convert(final PropertyDescriptor descriptor,
       final Object currentValue)
   {
     if (currentValue == null)
     {
       return null;
     }
 
     return converter.convert(descriptor, currentValue);
   }
 
   @Override
   public final void validate() throws ConfigurationValidationException
   {
     validate(false);
   }
 
   @Override
   public final void validate(final Class<?>... groups)
     throws ConfigurationValidationException
   {
     validate(false, groups);
   }
 
   // ... change listener support ..............................................
 
   @Override
   public final void addPropertyChangeListener(final PropertyKey name,
       final PropertyChangeListener listener) throws NullPointerException
   {
     support.addPropertyChangeListener(name.toString(), listener);
   }
 
   @Override
   public final void removePropertyChangeListener(final PropertyKey name,
       final PropertyChangeListener listener) throws NullPointerException
   {
     support.removePropertyChangeListener(name.toString(), listener);
   }
 
   @Override
   public final void addPropertyChangeListener(
       final PropertyChangeListener listener) throws NullPointerException
   {
     support.addPropertyChangeListener(listener);
   }
 
   @Override
   public final void removePropertyChangeListener(
       final PropertyChangeListener listener) throws NullPointerException
   {
     support.removePropertyChangeListener(listener);
   }
 
   /**
    * Fires the property change event.
    *
    * @param name the name of the property.
    * @param oldValue the old value of the property that has been changed.
    * @param newValue the new and current value of the property.
    */
   protected final void firePropertyChange(final String name,
       final String oldValue, final String newValue)
   {
     support.firePropertyChange(name, oldValue, newValue);
   }
 
   // --- object basics --------------------------------------------------------
 
   @Override
   public ConfigurationProperties toRepresentative()
   {
     return this;
   }
 
   /**
    * Reads the object from the given stream.
    *
    * @param in the stream to read from.
    * @throws IOException on read problems.
    * @throws ClassNotFoundException if a class cannot be found.
    */
   private void readObject(final ObjectInputStream in) throws IOException,
     ClassNotFoundException
   {
     in.defaultReadObject();
 
     this.resolver = createResolver();
   }
 
   /**
    * Returns the string representation of the object.
    *
    * @return the string representation of the object.
    */
   @Override
   public String toString()
   {
     final StringBuilder buffer = new StringBuilder();
 
     buffer.append(key).append(":\n").append("Registry:\n").append(registry);
 
     return buffer.toString();
   }
 }