/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 javax.faces.validator;
  
  import java.beans.FeatureDescriptor;
  import java.security.AccessController;
  import java.security.PrivilegedActionException;
  import java.security.PrivilegedExceptionAction;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Set;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.el.ELContext;
  import javax.el.ELResolver;
  import javax.el.FunctionMapper;
  import javax.el.ValueExpression;
  import javax.el.VariableMapper;
  import javax.faces.FacesException;
  import javax.faces.application.FacesMessage;
  import javax.faces.component.PartialStateHolder;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.el.CompositeComponentExpressionHolder;
  import javax.validation.ConstraintViolation;
  import javax.validation.MessageInterpolator;
  import javax.validation.Validation;
  import javax.validation.ValidatorFactory;
  import javax.validation.groups.Default;
  import javax.validation.metadata.BeanDescriptor;
  
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFJspProperty;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFProperty;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFValidator;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam;
  
  /**
   * <p>
   * <strong>BeanValidator</strong> is a {@link javax.faces.validator.Validator}
   * that doesn't do any validation itself, but delegates validation logic to
   * Bean Validation.
   * </p>
   *
   * @since 2.0
   */
  @JSFValidator(
          name="f:validateBean",
          bodyContent="empty")
  @JSFJspProperty(
          name = "binding",
          returnType = "javax.faces.validator.BeanValidator",
          longDesc = "A ValueExpression that evaluates to a BeanValidator.")
  public class BeanValidator implements Validator, PartialStateHolder
  {
  
      private static final Logger log = Logger.getLogger(BeanValidator.class.getName());
  
      /**
       * Converter ID, as defined by the JSF 2.0 specification.
       */
      public static final String VALIDATOR_ID = "javax.faces.Bean";
  
      /**
       * The message ID for this Validator in the message bundles.
       */
      public static final String MESSAGE_ID = "javax.faces.validator.BeanValidator.MESSAGE";
  
      /**
       * If this init parameter is present, no Bean Validators should be added to an UIInput by default.
       * Explicitly adding a BeanValidator to an UIInput is possible though.
       */
      @JSFWebConfigParam(defaultValue="true", expectedValues="true, false", since="2.0", group="validation")
      public static final String DISABLE_DEFAULT_BEAN_VALIDATOR_PARAM_NAME
              = "javax.faces.validator.DISABLE_DEFAULT_BEAN_VALIDATOR";
  
      /**
       * The key in the ServletContext where the Bean Validation Factory can be found.
       * In a managed Java EE 6 environment, the container initializes the ValidatorFactory
      * and stores it in the ServletContext under this key.
      * If not present, the manually instantiated ValidatorFactory is stored in the ServletContext
      * under this key for caching purposes.
      */
     public static final String VALIDATOR_FACTORY_KEY = "javax.faces.validator.beanValidator.ValidatorFactory";
 
     /**
      * This is used as a separator so multiple validation groups can be specified in one String.
      */
     public static final String VALIDATION_GROUPS_DELIMITER = ",";
 
     /**
      * This regular expression is used to match for empty validation groups.
      * Currently, a string containing only whitespace is classified as empty.
      */
     public static final String EMPTY_VALIDATION_GROUPS_PATTERN = "^[\\W,]*$";
     
     private static final Class<?>[] DEFAULT_VALIDATION_GROUPS_ARRAY = new Class<?>[] { Default.class };
 
     private static final String DEFAULT_VALIDATION_GROUP_NAME = "javax.validation.groups.Default";
 
     private String validationGroups;
 
     private Class<?>[] validationGroupsArray;
 
     private boolean isTransient = false;
 
     private boolean _initialStateMarked = false;
 
     /**
      * {@inheritDoc}
      */
     public void validate(final FacesContext context, final UIComponent component, final Object value)
             throws ValidatorException
     {
         if (context == null)
         {
             throw new NullPointerException("context");
         }
         if (component == null)
         {
             throw new NullPointerException("component");
         }
 
         ValueExpression valueExpression = component.getValueExpression("value");
         if (valueExpression == null)
         {
             log.warning("cannot validate component with empty value: " 
                     + component.getClientId(context));
             return;
         }
 
         // Obtain a reference to the to-be-validated object and the property name.
         _ValueReferenceWrapper reference = getValueReference(valueExpression, context);
         if (reference == null)
         {
             return;
         }
         Object base = reference.getBase();
         if (base == null)
         {
             return;
         }
         
         Class<?> valueBaseClass = base.getClass();
         if (valueBaseClass == null)
         {
             return;
         }
         
         Object referenceProperty = reference.getProperty();
         if (!(referenceProperty instanceof String))
         {
             // if the property is not a String, the ValueReference does not
             // point to a bean method, but e.g. to a value in a Map, thus we 
             // can exit bean validation here
             return;
         }
         String valueProperty = (String) referenceProperty;
 
         // Initialize Bean Validation.
         ValidatorFactory validatorFactory = createValidatorFactory(context);
         javax.validation.Validator validator = createValidator(validatorFactory, context);
         BeanDescriptor beanDescriptor = validator.getConstraintsForClass(valueBaseClass);
         if (!beanDescriptor.isBeanConstrained())
         {
             return;
         }
         
         // Note that validationGroupsArray was initialized when createValidator was called
         Class[] validationGroupsArray = this.validationGroupsArray;
 
         // Delegate to Bean Validation.
         Set constraintViolations = validator.validateValue(valueBaseClass, valueProperty, value, validationGroupsArray);
         if (!constraintViolations.isEmpty())
         {
             Set<FacesMessage> messages = new LinkedHashSet<FacesMessage>(constraintViolations.size());
             for (Object violation: constraintViolations)
             {
                 ConstraintViolation constraintViolation = (ConstraintViolation) violation;
                 String message = constraintViolation.getMessage();
                 Object[] args = new Object[]{ message, _MessageUtils.getLabel(context, component) };
                 FacesMessage msg = _MessageUtils.getErrorMessage(context, MESSAGE_ID, args);
                 messages.add(msg);
             }
             throw new ValidatorException(messages);
         }
     }
 
     private javax.validation.Validator createValidator(final ValidatorFactory validatorFactory, FacesContext context)
     {
         // Set default validation group when setValidationGroups has not been called.
         // The null check is there to prevent it from happening twice.
         if (validationGroupsArray == null)
         {
             postSetValidationGroups();
         }
 
         return validatorFactory //
                 .usingContext() //
                 .messageInterpolator(new FacesMessageInterpolator(
                         validatorFactory.getMessageInterpolator(), context)) //
                 .getValidator();
 
     }
 
     // This boolean is used to make sure that the log isn't trashed with warnings.
     private static volatile boolean firstValueReferenceWarning = true;
 
     /**
      * Get the ValueReference from the ValueExpression.
      *
      * @param valueExpression The ValueExpression for value.
      * @param context The FacesContext.
      * @return A ValueReferenceWrapper with the necessary information about the ValueReference.
      */
     private _ValueReferenceWrapper getValueReference(
             final ValueExpression valueExpression, final FacesContext context)
     {
         ELContext elCtx = context.getELContext();
         if (_ExternalSpecifications.isUnifiedELAvailable())
         {
             // unified el 2.2 is available --> we can use ValueExpression.getValueReference()
             // we can't access ValueExpression.getValueReference() directly here, because
             // Class loading would fail in applications with el-api versions prior to 2.2
             _ValueReferenceWrapper wrapper = _BeanValidatorUELUtils.getUELValueReferenceWrapper(valueExpression, elCtx);
             if (wrapper != null)
             {
                 if (wrapper.getProperty() == null)
                 {
                     // Fix for issue in Glassfish EL-impl-2.2.3
                     if (firstValueReferenceWarning && log.isLoggable(Level.WARNING))
                     {
                         firstValueReferenceWarning = false;
                         log.warning("ValueReference.getProperty() is null. " +
                                     "Falling back to classic ValueReference resolving. " +
                                     "This fallback may hurt performance. " +
                                     "This may be caused by a bug your EL implementation. " +
                                     "Glassfish EL-impl-2.2.3 is known for this issue. " +
                                     "Try switching to a different EL implementation.");
                     }
                 }
                 else
                 {
                     return wrapper;
                 }
             }
         }
 
         // get base object and property name the "old-fashioned" way
         return _ValueReferenceResolver.resolve(valueExpression, elCtx);
     }
 
     /**
      * This method creates ValidatorFactory instances or retrieves them from the container.
      *
      * Once created, ValidatorFactory instances are stored in the container under the key
      * VALIDATOR_FACTORY_KEY for performance.
      *
      * @param context The FacesContext.
      * @return The ValidatorFactory instance.
      * @throws FacesException if no ValidatorFactory can be obtained because: a) the
      * container is not a Servlet container or b) because Bean Validation is not available.
      */
     private ValidatorFactory createValidatorFactory(FacesContext context)
     {
         Map<String, Object> applicationMap = context.getExternalContext().getApplicationMap();
         Object attr = applicationMap.get(VALIDATOR_FACTORY_KEY);
         if (attr instanceof ValidatorFactory)
         {
             return (ValidatorFactory) attr;
         }
         else
         {
             synchronized (this)
             {
                 if (_ExternalSpecifications.isBeanValidationAvailable())
                 {
                     ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
                     applicationMap.put(VALIDATOR_FACTORY_KEY, factory);
                     return factory;
                 }
                 else
                 {
                     throw new FacesException("Bean Validation is not present");
                 }
             }
         }
     }
 
     /**
      * Fully initialize the validation groups if needed.
      * If no validation groups are specified, the Default validation group is used.
      */
     private void postSetValidationGroups()
     {
         if (this.validationGroups == null || this.validationGroups.matches(EMPTY_VALIDATION_GROUPS_PATTERN))
         {
             this.validationGroupsArray = DEFAULT_VALIDATION_GROUPS_ARRAY;
         }
         else
         {
             String[] classes = this.validationGroups.split(VALIDATION_GROUPS_DELIMITER);
             List<Class<?>> validationGroupsList = new ArrayList<Class<?>>(classes.length);
 
             for (String clazz : classes)
             {
                 clazz = clazz.trim();
                 if (!clazz.equals(""))
                 {
                     Class<?> theClass = null;
                     ClassLoader cl = null;
                     if (System.getSecurityManager() != null) 
                     {
                         try 
                         {
                             cl = AccessController.doPrivileged(new PrivilegedExceptionAction<ClassLoader>()
                                     {
                                         public ClassLoader run() throws PrivilegedActionException
                                         {
                                             return Thread.currentThread().getContextClassLoader();
                                         }
                                     });
                         }
                         catch (PrivilegedActionException pae)
                         {
                             throw new FacesException(pae);
                         }
                     }
                     else
                     {
                         cl = Thread.currentThread().getContextClassLoader();
                     }
                     
                     try
                     {                        
                         // Try WebApp ClassLoader first
                         theClass = Class.forName(clazz,false,cl);
                     }
                     catch (ClassNotFoundException ignore)
                     {
                         try
                         {
                             // fallback: Try ClassLoader for BeanValidator (i.e. the myfaces.jar lib)
                             theClass = Class.forName(clazz,false, BeanValidator.class.getClassLoader());
                         }
                         catch (ClassNotFoundException e)
                         {
                             throw new RuntimeException("Could not load validation group", e);
                         }                        
                     }
                     // the class was found
                     validationGroupsList.add(theClass);
                 }
             }
                     
             this.validationGroupsArray = validationGroupsList.toArray(new Class[validationGroupsList.size()]);
         }
     }
 
     /** {@inheritDoc} */
     public Object saveState(final FacesContext context)
     {
         if (!initialStateMarked())
         {
            //Full state saving.
            return this.validationGroups;
         }
         else if (DEFAULT_VALIDATION_GROUP_NAME.equals(this.validationGroups))
         {
             // default validation groups can be saved as null.
             return null;
         }
         else
         {
             // Save it fully. Remember that by MYFACES-2528
             // validationGroups needs to be stored into the state
             // because this value is often susceptible to use in "combo"
             return this.validationGroups;
         }
     }
 
     /** {@inheritDoc} */
     public void restoreState(final FacesContext context, final Object state)
     {
         if (state != null)
         {
             this.validationGroups = (String) state;
         }
         else
         {
             // When the value is being validated, postSetValidationGroups() sets
             // validationGroups to javax.validation.groups.Default. 
             this.validationGroups = null;
         }
         // Only the String is saved, recalculate the Class[] on state restoration.
         //postSetValidationGroups();
     }
 
     /**
      * Get the Bean Validation validation groups.
      * @return The validation groups String.
      */
     @JSFProperty
     public String getValidationGroups()
     {
         return validationGroups;
     }
 
     /**
      * Set the Bean Validation validation groups.
      * @param validationGroups The validation groups String, separated by
      *                         {@link BeanValidator#VALIDATION_GROUPS_DELIMITER}.
      */
     public void setValidationGroups(final String validationGroups)
     {
         this.validationGroups = validationGroups;
         this.clearInitialState();
         //postSetValidationGroups();
     }
 
     @JSFProperty
     @SuppressWarnings("unused")
     private Boolean isDisabled()
     {
         return null;
     }
     
     @JSFProperty
     @SuppressWarnings("unused")
     private String getFor()
     {
         return null;
     }
 
     /** {@inheritDoc} */
     public boolean isTransient()
     {
         return isTransient;
     }
 
     /** {@inheritDoc} */
     public void setTransient(final boolean isTransient)
     {
         this.isTransient = isTransient;
     }
 
     /** {@inheritDoc} */
     public void clearInitialState()
     {
         _initialStateMarked = false;
     }
 
     /** {@inheritDoc} */
     public boolean initialStateMarked()
     {
         return _initialStateMarked;
     }
 
     /** {@inheritDoc} */
     public void markInitialState()
     {
         _initialStateMarked = true;
     }
     
     /**
      * Note: Before 2.1.5/2.0.11 there was another strategy for this point to minimize
      * the instances used, but after checking this with a profiler, it is more expensive to
      * call FacesContext.getCurrentInstance() than create this object for bean validation.
      * 
      * Standard MessageInterpolator, as described in the JSR-314 spec.
      */
     private static class FacesMessageInterpolator implements MessageInterpolator
     {
         private final FacesContext facesContext;
         private final MessageInterpolator interpolator;
 
         public FacesMessageInterpolator(final MessageInterpolator interpolator, final FacesContext facesContext)
         {
             this.interpolator = interpolator;
             this.facesContext = facesContext;
         }
 
         public String interpolate(final String s, final Context context)
         {
             Locale locale = facesContext.getViewRoot().getLocale();
             return interpolator.interpolate(s, context, locale);
         }
 
         public String interpolate(final String s, final Context context, final Locale locale)
         {
             return interpolator.interpolate(s, context, locale);
         }
     }
 }
 
 /**
  * This class provides access to the object pointed to by the EL expression.
  *
  * It makes the BeanValidator work when Unified EL is not available.
  */
 final class _ValueReferenceWrapper
 {
     private final Object base;
     private final Object property;
 
     /**
      * Full constructor.
      *
      * @param base The object the reference points to.
      * @param property The property the reference points to.
      */
     public _ValueReferenceWrapper(final Object base, final Object property)
     {
         this.base = base;
         this.property = property;
     }
 
     /**
      * The object the reference points to.
      * @return base.
      */
     public Object getBase()
     {
         return base;
     }
 
     /**
      * The property the reference points to.
      * @return property.
      */
     public Object getProperty()
     {
         return property;
     }
 }
 
 /**
  * This class inspects the EL expression and returns a ValueReferenceWrapper
  * when Unified EL is not available.
  */
 final class _ValueReferenceResolver extends ELResolver
 {
     private final ELResolver resolver;
 
     /**
      * This is a simple solution to keep track of the resolved objects,
      * since ELResolver provides no way to know if the current ELResolver
      * is the last one in the chain. By assigning (and effectively overwriting)
      * this field, we know that the value after invoking the chain is always
      * the last one.
      *
      * This solution also deals with nested objects (like: #{myBean.prop.prop.prop}.
      */
     private _ValueReferenceWrapper lastObject;
 
     /**
      * Constructor is only used internally.
      * @param elResolver An ELResolver from the current ELContext.
      */
     _ValueReferenceResolver(final ELResolver elResolver)
     {
         this.resolver = elResolver;
     }
 
     /**
      * This method can be used to extract the ValueReferenceWrapper from the given ValueExpression.
      *
      * @param valueExpression The ValueExpression to resolve.
      * @param elCtx The ELContext, needed to parse and execute the expression.
      * @return The ValueReferenceWrapper.
      */
     public static _ValueReferenceWrapper resolve(ValueExpression valueExpression, final ELContext elCtx)
     {
         _ValueReferenceResolver resolver = new _ValueReferenceResolver(elCtx.getELResolver());
         ELContext elCtxDecorator = new _ELContextDecorator(elCtx, resolver);
         
         valueExpression.getValue(elCtxDecorator);
         
         while (resolver.lastObject.getBase() instanceof CompositeComponentExpressionHolder)
         {
             valueExpression = ((CompositeComponentExpressionHolder) resolver.lastObject.getBase())
                                   .getExpression((String) resolver.lastObject.getProperty());
             valueExpression.getValue(elCtxDecorator);
         }
 
         return resolver.lastObject;
     }
 
     /**
      * This method is the only one that matters. It keeps track of the objects in the EL expression.
      *
      * It creates a new ValueReferenceWrapper and assigns it to lastObject.
      *
      * @param context The ELContext.
      * @param base The base object, may be null.
      * @param property The property, may be null.
      * @return The resolved value
      */
     @Override
     public Object getValue(final ELContext context, final Object base, final Object property)
     {
         lastObject = new _ValueReferenceWrapper(base, property);
         return resolver.getValue(context, base, property);
     }
 
     // ############################ Standard delegating implementations ############################
     public Class<?> getType(final ELContext ctx, final Object base, final Object property)
     {
         return resolver.getType(ctx, base, property);
     }
 
     public void setValue(final ELContext ctx, final Object base, final Object property, final Object value)
     {
         resolver.setValue(ctx, base, property, value);
     }
 
     public boolean isReadOnly(final ELContext ctx, final Object base, final Object property)
     {
         return resolver.isReadOnly(ctx, base, property);
     }
 
     public Iterator<FeatureDescriptor> getFeatureDescriptors(final ELContext ctx, final Object base)
     {
         return resolver.getFeatureDescriptors(ctx, base);
     }
 
     public Class<?> getCommonPropertyType(final ELContext ctx, final Object base)
     {
         return resolver.getCommonPropertyType(ctx, base);
     }
 }
 
 /**
  * This ELContext is used to hook into the EL handling, by decorating the
  * ELResolver chain with a custom ELResolver.
  */
 final class _ELContextDecorator extends ELContext
 {
     private final ELContext ctx;
     private final ELResolver interceptingResolver;
 
     /**
      * Only used by ValueExpressionResolver.
      *
      * @param elContext The standard ELContext. All method calls, except getELResolver, are delegated to it.
      * @param interceptingResolver The ELResolver to be returned by getELResolver.
      */
     _ELContextDecorator(final ELContext elContext, final ELResolver interceptingResolver)
     {
         this.ctx = elContext;
         this.interceptingResolver = interceptingResolver;
     }
 
     /**
      * This is the important one, it returns the passed ELResolver.
      * @return The ELResolver passed into the constructor.
      */
     @Override
     public ELResolver getELResolver()
     {
         return interceptingResolver;
     }
 
     // ############################ Standard delegating implementations ############################
     public FunctionMapper getFunctionMapper()
     {
         return ctx.getFunctionMapper();
     }
 
     public VariableMapper getVariableMapper()
     {
         return ctx.getVariableMapper();
     }
 
     public void setPropertyResolved(final boolean resolved)
     {
         ctx.setPropertyResolved(resolved);
     }
 
     public boolean isPropertyResolved()
     {
         return ctx.isPropertyResolved();
     }
 
     public void putContext(final Class key, Object contextObject)
     {
         ctx.putContext(key, contextObject);
     }
 
     public Object getContext(final Class key)
     {
         return ctx.getContext(key);
     }
 
     public Locale getLocale()
     {
         return ctx.getLocale();
     }
 
     public void setLocale(final Locale locale)
     {
         ctx.setLocale(locale);
     }
 }