/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.metamodel.internal;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.persistence.metamodel.Attribute;
import javax.persistence.metamodel.IdentifiableType;
import javax.persistence.metamodel.MappedSuperclassType;
import javax.persistence.metamodel.SingularAttribute;
import javax.persistence.metamodel.Type;

import org.hibernate.annotations.common.AssertionFailure;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.internal.EntityManagerMessageLogger;
import org.hibernate.internal.HEMLogging;
import org.hibernate.internal.util.ReflectHelper;
import org.hibernate.internal.util.collections.CollectionHelper;
import org.hibernate.mapping.Component;
import org.hibernate.mapping.KeyValue;
import org.hibernate.mapping.MappedSuperclass;
import org.hibernate.mapping.PersistentClass;
import org.hibernate.mapping.Property;

Defines a context for storing information during the building of the MetamodelImpl. 

This contextual information includes data needing to be processed in a second pass as well as
cross-references into the built metamodel classes.
 At the end of the day, clients are interested in the getEntityTypeMap and getEmbeddableTypeMap results, which represent all the registered entities and embeddables respectively. 
Author:
Steve Ebersole, Emmanuel Bernard/**
 * Defines a context for storing information during the building of the {@link MetamodelImpl}.
 * <p/>
 * This contextual information includes data needing to be processed in a second pass as well as
 * cross-references into the built metamodel classes.
 * <p/>
 * At the end of the day, clients are interested in the {@link #getEntityTypeMap} and {@link #getEmbeddableTypeMap}
 * results, which represent all the registered {@linkplain #registerEntityType entities} and
 * {@linkplain #registerEmbeddedableType embeddables} respectively.
 *
 * @author Steve Ebersole
 * @author Emmanuel Bernard
 */
class MetadataContext {
	private static final EntityManagerMessageLogger LOG = HEMLogging.messageLogger( MetadataContext.class );

	private final SessionFactoryImplementor sessionFactory;
	private Set<MappedSuperclass> knownMappedSuperclasses;
	private final boolean ignoreUnsupported;
	private final AttributeFactory attributeFactory = new AttributeFactory( this );

	private Map<Class<?>, EntityTypeImpl<?>> entityTypes = new HashMap<>();
	private Map<String, EntityTypeImpl<?>> entityTypesByEntityName = new HashMap<>();
	private Map<PersistentClass, EntityTypeImpl<?>> entityTypesByPersistentClass = new HashMap<>();
	private Map<Class<?>, EmbeddableTypeImpl<?>> embeddables = new HashMap<>();
	private Map<MappedSuperclass, MappedSuperclassTypeImpl<?>> mappedSuperclassByMappedSuperclassMapping = new HashMap<>();
	//this list contains MappedSuperclass and EntityTypes ordered by superclass first
	private List<Object> orderedMappings = new ArrayList<>();
	
Stack of PersistentClass being process. Last in the list is the highest in the stack.
/**
	 * Stack of PersistentClass being process. Last in the list is the highest in the stack.
	 */
	private List<PersistentClass> stackOfPersistentClassesBeingProcessed = new ArrayList<>();
	private Map<MappedSuperclassTypeImpl<?>, PersistentClass> mappedSuperClassTypeToPersistentClass = new HashMap<>();

	public MetadataContext(
			SessionFactoryImplementor sessionFactory,
			Set<MappedSuperclass> mappedSuperclasses,
			JpaMetaModelPopulationSetting jpaMetaModelPopulationSetting) {
		this.sessionFactory = sessionFactory;
		this.knownMappedSuperclasses = mappedSuperclasses;
		this.ignoreUnsupported = jpaMetaModelPopulationSetting == JpaMetaModelPopulationSetting.IGNORE_UNSUPPORTED;
	}

	/*package*/ SessionFactoryImplementor getSessionFactory() {
		return sessionFactory;
	}

	/*package*/ boolean isIgnoreUnsupported() {
		return ignoreUnsupported;
	}

	
Retrieves the java type to EntityTypeImpl map. 
Returns:
The java type to EntityTypeImpl map./**
	 * Retrieves the {@linkplain Class java type} to {@link EntityTypeImpl} map.
	 *
	 * @return The {@linkplain Class java type} to {@link EntityTypeImpl} map.
	 */
	public Map<Class<?>, EntityTypeImpl<?>> getEntityTypeMap() {
		return Collections.unmodifiableMap( entityTypes );
	}

	public Map<Class<?>, EmbeddableTypeImpl<?>> getEmbeddableTypeMap() {
		return Collections.unmodifiableMap( embeddables );
	}

	public Map<Class<?>, MappedSuperclassType<?>> getMappedSuperclassTypeMap() {
		// we need to actually build this map...
		final Map<Class<?>, MappedSuperclassType<?>> mappedSuperClassTypeMap = CollectionHelper.mapOfSize(
				mappedSuperclassByMappedSuperclassMapping.size()
		);

		for ( MappedSuperclassTypeImpl mappedSuperclassType : mappedSuperclassByMappedSuperclassMapping.values() ) {
			mappedSuperClassTypeMap.put(
					mappedSuperclassType.getJavaType(),
					mappedSuperclassType
			);
		}

		return mappedSuperClassTypeMap;
	}

	/*package*/ void registerEntityType(PersistentClass persistentClass, EntityTypeImpl<?> entityType) {
		if ( entityType.getBindableJavaType() != null ) {
			entityTypes.put( entityType.getBindableJavaType(), entityType );
		}
		entityTypesByEntityName.put( persistentClass.getEntityName(), entityType );
		entityTypesByPersistentClass.put( persistentClass, entityType );
		orderedMappings.add( persistentClass );
	}

	/*package*/ void registerEmbeddedableType(EmbeddableTypeImpl<?> embeddableType) {
		embeddables.put( embeddableType.getJavaType(), embeddableType );
	}

	/*package*/ void registerMappedSuperclassType(
			MappedSuperclass mappedSuperclass,
			MappedSuperclassTypeImpl<?> mappedSuperclassType) {
		mappedSuperclassByMappedSuperclassMapping.put( mappedSuperclass, mappedSuperclassType );
		orderedMappings.add( mappedSuperclass );
		mappedSuperClassTypeToPersistentClass.put( mappedSuperclassType, getEntityWorkedOn() );

		knownMappedSuperclasses.remove( mappedSuperclass );
	}

	
Given a Hibernate PersistentClass, locate the corresponding JPA EntityType implementation. May retur null if the given PersistentClass has not yet been processed. 
Params:
persistentClass – The Hibernate (config time) metamodel instance representing an entity.
Returns:
Tne corresponding JPA EntityType, or null if not yet processed./**
	 * Given a Hibernate {@link PersistentClass}, locate the corresponding JPA {@link org.hibernate.type.EntityType}
	 * implementation.  May retur null if the given {@link PersistentClass} has not yet been processed.
	 *
	 * @param persistentClass The Hibernate (config time) metamodel instance representing an entity.
	 *
	 * @return Tne corresponding JPA {@link org.hibernate.type.EntityType}, or null if not yet processed.
	 */
	public EntityTypeImpl<?> locateEntityType(PersistentClass persistentClass) {
		return entityTypesByPersistentClass.get( persistentClass );
	}

	
Given a Java Class, locate the corresponding JPA EntityType. May return null which could means that no such mapping exists at least at this time. 
Params:
javaType – The java class.
Returns:
The corresponding JPA EntityType, or null./**
	 * Given a Java {@link Class}, locate the corresponding JPA {@link org.hibernate.type.EntityType}.  May
	 * return null which could means that no such mapping exists at least at this time.
	 *
	 * @param javaType The java class.
	 *
	 * @return The corresponding JPA {@link org.hibernate.type.EntityType}, or null.
	 */
	public EntityTypeImpl<?> locateEntityType(Class<?> javaType) {
		return entityTypes.get( javaType );
	}

	
Given an entity-name, locate the corresponding JPA EntityType. May return null which could means that no such mapping exists at least at this time. 
Params:
entityName – The entity-name.
Returns:
The corresponding JPA EntityType, or null./**
	 * Given an entity-name, locate the corresponding JPA {@link org.hibernate.type.EntityType}.  May
	 * return null which could means that no such mapping exists at least at this time.
	 *
	 * @param entityName The entity-name.
	 *
	 * @return The corresponding JPA {@link org.hibernate.type.EntityType}, or null.
	 */
	public EntityTypeImpl<?> locateEntityType(String entityName) {
		return entityTypesByEntityName.get( entityName );
	}

	public Map<String, EntityTypeImpl<?>> getEntityTypesByEntityName() {
		return Collections.unmodifiableMap( entityTypesByEntityName );
	}

	@SuppressWarnings({"unchecked"})
	public void wrapUp() {
		final boolean traceEnabled = LOG.isTraceEnabled();
		if ( traceEnabled ) {
			LOG.trace( "Wrapping up metadata context..." );
		}

		boolean staticMetamodelScanEnabled = JpaStaticMetaModelPopulationSetting
				.determineJpaMetaModelPopulationSetting( sessionFactory.getProperties() ) != JpaStaticMetaModelPopulationSetting.DISABLED;

		//we need to process types from superclasses to subclasses
		for ( Object mapping : orderedMappings ) {
			if ( PersistentClass.class.isAssignableFrom( mapping.getClass() ) ) {
				@SuppressWarnings("unchecked")
				final PersistentClass safeMapping = (PersistentClass) mapping;
				if ( traceEnabled ) {
					LOG.trace( "Starting entity [" + safeMapping.getEntityName() + ']' );
				}
				try {
					final EntityTypeImpl<?> jpa2Mapping = entityTypesByPersistentClass.get( safeMapping );
					applyIdMetadata( safeMapping, jpa2Mapping );
					applyVersionAttribute( safeMapping, jpa2Mapping );
					Iterator<Property> properties = safeMapping.getDeclaredPropertyIterator();
					while ( properties.hasNext() ) {
						final Property property = properties.next();
						if ( property.getValue() == safeMapping.getIdentifierMapper() ) {
							// property represents special handling for id-class mappings but we have already
							// accounted for the embedded property mappings in #applyIdMetadata &&
							// #buildIdClassAttributes
							continue;
						}
						if ( safeMapping.isVersioned() && property == safeMapping.getVersion() ) {
							// skip the version property, it was already handled previously.
							continue;
						}
						final Attribute attribute = attributeFactory.buildAttribute( jpa2Mapping, property );
						if ( attribute != null ) {
							jpa2Mapping.getBuilder().addAttribute( attribute );
						}
					}
					jpa2Mapping.lock();
					if ( staticMetamodelScanEnabled ) {
						populateStaticMetamodel( jpa2Mapping );
					}
				}
				finally {
					if ( traceEnabled ) {
						LOG.trace( "Completed entity [" + safeMapping.getEntityName() + ']' );
					}
				}
			}
			else if ( MappedSuperclass.class.isAssignableFrom( mapping.getClass() ) ) {
				@SuppressWarnings("unchecked")
				final MappedSuperclass safeMapping = (MappedSuperclass) mapping;
				if ( traceEnabled ) {
					LOG.trace( "Starting mapped superclass [" + safeMapping.getMappedClass().getName() + ']' );
				}
				try {
					final MappedSuperclassTypeImpl<?> jpa2Mapping = mappedSuperclassByMappedSuperclassMapping.get(
							safeMapping
					);
					applyIdMetadata( safeMapping, jpa2Mapping );
					applyVersionAttribute( safeMapping, jpa2Mapping );
					Iterator<Property> properties = safeMapping.getDeclaredPropertyIterator();
					while ( properties.hasNext() ) {
						final Property property = properties.next();
						if ( safeMapping.isVersioned() && property == safeMapping.getVersion() ) {
							// skip the version property, it was already handled previously.
							continue;
						}
						final Attribute attribute = attributeFactory.buildAttribute( jpa2Mapping, property );
						if ( attribute != null ) {
							jpa2Mapping.getBuilder().addAttribute( attribute );
						}
					}
					jpa2Mapping.lock();
					if ( staticMetamodelScanEnabled ) {
						populateStaticMetamodel( jpa2Mapping );
					}
				}
				finally {
					if ( traceEnabled ) {
						LOG.trace( "Completed mapped superclass [" + safeMapping.getMappedClass().getName() + ']' );
					}
				}
			}
			else {
				throw new AssertionFailure( "Unexpected mapping type: " + mapping.getClass() );
			}
		}

		if ( staticMetamodelScanEnabled ) {
			for ( EmbeddableTypeImpl embeddable : embeddables.values() ) {
				populateStaticMetamodel( embeddable );
			}
		}
	}


	private <X> void applyIdMetadata(PersistentClass persistentClass, EntityTypeImpl<X> jpaEntityType) {
		if ( persistentClass.hasIdentifierProperty() ) {
			final Property declaredIdentifierProperty = persistentClass.getDeclaredIdentifierProperty();
			if ( declaredIdentifierProperty != null ) {
				jpaEntityType.getBuilder().applyIdAttribute(
						attributeFactory.buildIdAttribute( jpaEntityType, declaredIdentifierProperty )
				);
			}
		}
		else if ( persistentClass.hasIdentifierMapper() ) {
			@SuppressWarnings("unchecked")
			Iterator<Property> propertyIterator = persistentClass.getIdentifierMapper().getPropertyIterator();
			Set<SingularAttribute<? super X, ?>> attributes = buildIdClassAttributes( jpaEntityType, propertyIterator );
			jpaEntityType.getBuilder().applyIdClassAttributes( attributes );
		}
		else {
			final KeyValue value = persistentClass.getIdentifier();
			if ( value instanceof Component ) {
				final Component component = (Component) value;
				if ( component.getPropertySpan() > 1 ) {
					//FIXME we are an Hibernate embedded id (ie not type)
				}
				else {
					//FIXME take care of declared vs non declared property
					jpaEntityType.getBuilder().applyIdAttribute(
							attributeFactory.buildIdAttribute(
									jpaEntityType,
									(Property) component.getPropertyIterator().next()
							)
					);
				}
			}
		}
	}

	private <X> void applyIdMetadata(MappedSuperclass mappingType, MappedSuperclassTypeImpl<X> jpaMappingType) {
		if ( mappingType.hasIdentifierProperty() ) {
			final Property declaredIdentifierProperty = mappingType.getDeclaredIdentifierProperty();
			if ( declaredIdentifierProperty != null ) {
				jpaMappingType.getBuilder().applyIdAttribute(
						attributeFactory.buildIdAttribute( jpaMappingType, declaredIdentifierProperty )
				);
			}
		}
		//a MappedSuperclass can have no identifier if the id is set below in the hierarchy
		else if ( mappingType.getIdentifierMapper() != null ) {
			@SuppressWarnings("unchecked")
			Iterator<Property> propertyIterator = mappingType.getIdentifierMapper().getPropertyIterator();
			Set<SingularAttribute<? super X, ?>> attributes = buildIdClassAttributes(
					jpaMappingType,
					propertyIterator
			);
			jpaMappingType.getBuilder().applyIdClassAttributes( attributes );
		}
	}

	private <X> void applyVersionAttribute(PersistentClass persistentClass, EntityTypeImpl<X> jpaEntityType) {
		final Property declaredVersion = persistentClass.getDeclaredVersion();
		if ( declaredVersion != null ) {
			jpaEntityType.getBuilder().applyVersionAttribute(
					attributeFactory.buildVersionAttribute( jpaEntityType, declaredVersion )
			);
		}
	}

	private <X> void applyVersionAttribute(MappedSuperclass mappingType, MappedSuperclassTypeImpl<X> jpaMappingType) {
		final Property declaredVersion = mappingType.getDeclaredVersion();
		if ( declaredVersion != null ) {
			jpaMappingType.getBuilder().applyVersionAttribute(
					attributeFactory.buildVersionAttribute( jpaMappingType, declaredVersion )
			);
		}
	}

	private <X> Set<SingularAttribute<? super X, ?>> buildIdClassAttributes(
			AbstractIdentifiableType<X> ownerType,
			Iterator<Property> propertyIterator) {
		if ( LOG.isTraceEnabled() ) {
			LOG.trace( "Building old-school composite identifier [" + ownerType.getJavaType().getName() + ']' );
		}
		Set<SingularAttribute<? super X, ?>> attributes = new HashSet<SingularAttribute<? super X, ?>>();
		while ( propertyIterator.hasNext() ) {
			attributes.add( attributeFactory.buildIdAttribute( ownerType, propertyIterator.next() ) );
		}
		return attributes;
	}

	private <X> void populateStaticMetamodel(AbstractManagedType<X> managedType) {
		final Class<X> managedTypeClass = managedType.getJavaType();
		if ( managedTypeClass == null ) {
			// should indicate MAP entity mode, skip...
			return;
		}
		final String metamodelClassName = managedTypeClass.getName() + '_';
		try {
			final Class metamodelClass = Class.forName( metamodelClassName, true, managedTypeClass.getClassLoader() );
			// we found the class; so populate it...
			registerAttributes( metamodelClass, managedType );
		}
		catch (ClassNotFoundException ignore) {
			// nothing to do...
		}

		// todo : this does not account for @MappeSuperclass, mainly because this is not being tracked in our
		// internal metamodel as populated from the annotatios properly
		AbstractManagedType<? super X> superType = managedType.getSupertype();
		if ( superType != null ) {
			populateStaticMetamodel( superType );
		}
	}

	private final Set<Class> processedMetamodelClasses = new HashSet<Class>();

	private <X> void registerAttributes(Class metamodelClass, AbstractManagedType<X> managedType) {
		if ( !processedMetamodelClasses.add( metamodelClass ) ) {
			return;
		}

		// push the attributes on to the metamodel class...
		for ( Attribute<X, ?> attribute : managedType.getDeclaredAttributes() ) {
			registerAttribute( metamodelClass, attribute );
		}

		if ( IdentifiableType.class.isInstance( managedType ) ) {
			final AbstractIdentifiableType<X> entityType = (AbstractIdentifiableType<X>) managedType;

			// handle version
			if ( entityType.hasDeclaredVersionAttribute() ) {
				registerAttribute( metamodelClass, entityType.getDeclaredVersion() );
			}

			// handle id-class mappings specially
			if ( entityType.hasIdClass() ) {
				final Set<SingularAttribute<? super X, ?>> attributes = entityType.getIdClassAttributesSafely();
				if ( attributes != null ) {
					for ( SingularAttribute<? super X, ?> attribute : attributes ) {
						registerAttribute( metamodelClass, attribute );
					}
				}
			}
		}
	}

	private <X> void registerAttribute(Class metamodelClass, Attribute<X, ?> attribute) {
		final String name = attribute.getName();
		try {
			// there is a shortcoming in the existing Hibernate code in terms of the way MappedSuperclass
			// support was bolted on which comes to bear right here when the attribute is an embeddable type
			// defined on a MappedSuperclass.  We do not have the correct information to determine the
			// appropriate attribute declarer in such cases and so the incoming metamodelClass most likely
			// does not represent the declarer in such cases.
			//
			// As a result, in the case of embeddable classes we simply use getField rather than get
			// getDeclaredField
			final boolean allowNonDeclaredFieldReference =
					attribute.getPersistentAttributeType() == Attribute.PersistentAttributeType.EMBEDDED
							|| attribute.getDeclaringType().getPersistenceType() == Type.PersistenceType.EMBEDDABLE;

			final Field field = allowNonDeclaredFieldReference
					? metamodelClass.getField( name )
					: metamodelClass.getDeclaredField( name );
			try {
				// should be public anyway, but to be sure...
				ReflectHelper.ensureAccessibility( field );
				field.set( null, attribute );
			}
			catch (IllegalAccessException e) {
				// todo : exception type?
				throw new AssertionFailure(
						"Unable to inject static metamodel attribute : " + metamodelClass.getName() + '#' + name,
						e
				);
			}
			catch (IllegalArgumentException e) {
				// most likely a mismatch in the type we are injecting and the defined field; this represents a
				// mismatch in how the annotation processor interpretted the attribute and how our metamodel
				// and/or annotation binder did.

//              This is particularly the case as arrays are nto handled propery by the StaticMetamodel generator

//				throw new AssertionFailure(
//						"Illegal argument on static metamodel field injection : " + metamodelClass.getName() + '#' + name
//								+ "; expected type :  " + attribute.getClass().getName()
//								+ "; encountered type : " + field.getType().getName()
//				);
				LOG.illegalArgumentOnStaticMetamodelFieldInjection(
						metamodelClass.getName(),
						name,
						attribute.getClass().getName(),
						field.getType().getName()
				);
			}
		}
		catch (NoSuchFieldException e) {
			LOG.unableToLocateStaticMetamodelField( metamodelClass.getName(), name );
//			throw new AssertionFailure(
//					"Unable to locate static metamodel field : " + metamodelClass.getName() + '#' + name
//			);
		}
	}

	public MappedSuperclassTypeImpl<?> locateMappedSuperclassType(MappedSuperclass mappedSuperclass) {
		return mappedSuperclassByMappedSuperclassMapping.get( mappedSuperclass );
	}

	public void pushEntityWorkedOn(PersistentClass persistentClass) {
		stackOfPersistentClassesBeingProcessed.add( persistentClass );
	}

	public void popEntityWorkedOn(PersistentClass persistentClass) {
		final PersistentClass stackTop = stackOfPersistentClassesBeingProcessed.remove(
				stackOfPersistentClassesBeingProcessed.size() - 1
		);
		if ( stackTop != persistentClass ) {
			throw new AssertionFailure(
					"Inconsistent popping: "
							+ persistentClass.getEntityName() + " instead of " + stackTop.getEntityName()
			);
		}
	}

	private PersistentClass getEntityWorkedOn() {
		return stackOfPersistentClassesBeingProcessed.get(
				stackOfPersistentClassesBeingProcessed.size() - 1
		);
	}

	public PersistentClass getPersistentClassHostingProperties(MappedSuperclassTypeImpl<?> mappedSuperclassType) {
		final PersistentClass persistentClass = mappedSuperClassTypeToPersistentClass.get( mappedSuperclassType );
		if ( persistentClass == null ) {
			throw new AssertionFailure(
					"Could not find PersistentClass for MappedSuperclassType: "
							+ mappedSuperclassType.getJavaType()
			);
		}
		return persistentClass;
	}

	public Set<MappedSuperclass> getUnusedMappedSuperclasses() {
		return new HashSet<MappedSuperclass>( knownMappedSuperclasses );
	}
}