/*

  * 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();

   }

 }