package org.gcube.informationsystem.model.knowledge;

import java.util.AbstractMap.SimpleEntry;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.gcube.informationsystem.base.reference.AccessType;
import org.gcube.informationsystem.base.reference.entities.EntityElement;
import org.gcube.informationsystem.base.reference.relations.RelationElement;
import org.gcube.informationsystem.model.reference.entities.Facet;
import org.gcube.informationsystem.model.reference.entities.Resource;
import org.gcube.informationsystem.model.reference.relations.ConsistsOf;
import org.gcube.informationsystem.model.reference.relations.IsRelatedTo;
import org.gcube.informationsystem.model.reference.relations.Relation;
import org.gcube.informationsystem.tree.Node;
import org.gcube.informationsystem.tree.Tree;
import org.gcube.informationsystem.types.PropertyTypeName;
import org.gcube.informationsystem.types.TypeMapper;
import org.gcube.informationsystem.types.impl.properties.PropertyDefinitionImpl;
import org.gcube.informationsystem.types.reference.Type;
import org.gcube.informationsystem.types.reference.entities.FacetType;
import org.gcube.informationsystem.types.reference.entities.ResourceType;
import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
import org.gcube.informationsystem.types.reference.properties.PropertyDefinition;
import org.gcube.informationsystem.types.reference.relations.ConsistsOfType;
import org.gcube.informationsystem.types.reference.relations.IsRelatedToType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public class ModelKnowledge<T, TI extends TypeInformation<T>> {
	
	private static final Logger logger = LoggerFactory.getLogger(ModelKnowledge.class);
	
	protected TI typeInformation;
	protected Map<AccessType, Tree<T>> trees;
	
	protected UsageKnowledge<Entry<String,PropertyDefinition>> propertyUsage;
	protected Map<AccessType, UsageKnowledge<LinkedEntity>> erTypesUsage;
	
	protected Map<String, AccessType> locate;

	public ModelKnowledge(TI typeInformation) {
		this.typeInformation = typeInformation;
		reset();
	}
	
	protected void reset() {
		
		this.trees = new HashMap<>();
		this.erTypesUsage = new HashMap<>();
		this.locate = new HashMap<>();
		
		AccessType[] modelTypes = AccessType.getModelTypes();
		for(AccessType accessType : modelTypes) {
			
			/*
			 * T t = typeInformation.getRoot(accessType);
			 * Tree<T> tree = new Tree<>(t, typeInformation);
			 */
			
			Tree<T> tree = new Tree<>(typeInformation);
			trees.put(accessType, tree);
			
			if(accessType == AccessType.PROPERTY) {
				/*
				 * In this case we get the type which uses such a property
				 * and the property definition.
				 * In this way we have a complete overview of the usage of the
				 * property type
				 */
				propertyUsage = new UsageKnowledge<>(accessType);
			}else {
				UsageKnowledge<LinkedEntity> usageKnowledge = new UsageKnowledge<LinkedEntity>(accessType);
				erTypesUsage.put(accessType, usageKnowledge);
			}
			
		}
				
	}
	
	protected void addUsage(LinkedEntity linkedEntity, UsageKnowledge<LinkedEntity> relationUsage, UsageKnowledge<LinkedEntity> targetEntityUsage) {
		if (linkedEntity != null) {
			UsageKnowledge<LinkedEntity> resourceUsage = erTypesUsage.get(AccessType.RESOURCE);
			String source = linkedEntity.getSource();
			resourceUsage.add(source, linkedEntity);
			String relation = linkedEntity.getRelation();
			relationUsage.add(relation, linkedEntity);
			String target = linkedEntity.getTarget();
			targetEntityUsage.add(target, linkedEntity);
		}
	}

	protected void addAllUsage(Collection<LinkedEntity> linkedEntities, UsageKnowledge<LinkedEntity> relationUsage, UsageKnowledge<LinkedEntity> targetEntityUsage) {
		if(linkedEntities!=null) {
			for(LinkedEntity le : linkedEntities) {
				addUsage(le, relationUsage, targetEntityUsage);
			}
		}
	}

	protected void addPropertyUsage(T t, Set<PropertyDefinition> properties) {
		if(properties==null || properties.size()==0) {
			return;
		}
		String typeName = typeInformation.getIdentifier(t);
		for(PropertyDefinition propertyDefinition : properties) {
			PropertyTypeName propertyTypeName = ((PropertyDefinitionImpl) propertyDefinition).getPropertyTypeName();
			if(propertyTypeName.isGenericType()) {
				SimpleEntry<String,PropertyDefinition> entry = new SimpleEntry<>(typeName, propertyDefinition);
				propertyUsage.add(propertyTypeName.getGenericClassName(), entry);
			}
		}
	}
	
	protected void addEntityMetadataUsage(T t) {
		Type type = TypeMapper.createTypeDefinition(EntityElement.class);
		addPropertyUsage(t, type.getProperties());
	}
	
	protected void addRelationMetadataUsage(T t) {
		Type type = TypeMapper.createTypeDefinition(RelationElement.class);
		addPropertyUsage(t, type.getProperties());
	}
	
	protected void addPropagationConstraintUsage(T t) {
		Type type = TypeMapper.createTypeDefinition(Relation.class);
		addPropertyUsage(t, type.getProperties());
	}

	public void addAllType(Collection<T> types) {
		Set<T> toRetry = new HashSet<>();
		
		for(T t : types) {
			logger.trace("Going to add {}", typeInformation.getIdentifier(t));
			try {
				addType(t);
			}catch (RuntimeException e) {
				toRetry.add(t);
			}
		}
		
		if(types.size()==toRetry.size()) {
			throw new RuntimeException("Unable to find parent for " + toRetry.toString());
		}
		
		if(toRetry.size()>0) {
			addAllType(toRetry);
		}
	}
	
	public void addType(T t) {
		AccessType accessType = typeInformation.getAccessType(t);
		String typeName = typeInformation.getIdentifier(t);
		
		if(locate.get(typeName)!=null) {
			logger.trace("The type {} was already added to the ModelKnowledge", typeName);
			return;
		}
		
		Tree<T> tree = trees.get(accessType);
		tree.addNode(t);
		locate.put(typeName, accessType);
		
		UsageKnowledge<LinkedEntity> resourceUsage = erTypesUsage.get(AccessType.RESOURCE);
		UsageKnowledge<LinkedEntity> facetUsage = erTypesUsage.get(AccessType.FACET);
		UsageKnowledge<LinkedEntity> isRelatedToUsage = erTypesUsage.get(AccessType.IS_RELATED_TO);
		UsageKnowledge<LinkedEntity> consistsOfUsage = erTypesUsage.get(AccessType.CONSISTS_OF);
		
		switch (accessType) {
			case PROPERTY:
				// Nothing to do
				break;
	
			case RESOURCE:
				ResourceType resourceType = (ResourceType) t;
				addAllUsage(resourceType.getFacets(), consistsOfUsage, facetUsage);
				addAllUsage(resourceType.getResources(), isRelatedToUsage, resourceUsage);
				
				/* 
				 * Metadata is defined in parent type i.e. EntityElement. 
				 * We want to have a reference to all Base type
				 */ 
				if(typeName.compareTo(Resource.NAME)==0) {
					addEntityMetadataUsage(t);
				}
				break;
			
			case FACET:
				FacetType facetType = (FacetType) t;
				/* 
				 * Metadata is defined in parent type i.e. EntityElement. 
				 * We want to have a reference to all Base type
				 */
				if(typeName.compareTo(Facet.NAME)==0) {
					addEntityMetadataUsage(t);
				}
				addPropertyUsage(t, facetType.getProperties());
				
				break;
			
			case IS_RELATED_TO:
				IsRelatedToType isRelatedToType = (IsRelatedToType) t;
				/* 
				 * Metadata is defined in parent type i.e. RelationElement. 
				 * We want to have a reference to all Base type
				 */
				if(typeName.compareTo(IsRelatedTo.NAME)==0) {
					addRelationMetadataUsage(t);
					addPropagationConstraintUsage(t);
				}
				addPropertyUsage(t, isRelatedToType.getProperties());
				break;
			
			case CONSISTS_OF:
				ConsistsOfType consistsOfType = (ConsistsOfType) t;
				/* 
				 * Metadata is defined in parent type i.e. RelationElement. 
				 * We want to have a reference to all Base type
				 */
				if(typeName.compareTo(ConsistsOf.NAME)==0) {
					addRelationMetadataUsage(t);
					addPropagationConstraintUsage(t);
				}
				addPropertyUsage(t, consistsOfType.getProperties());
				break;
			
			default:
				break;
		}
		
		
		
	}
	
	public Tree<T> getTree(AccessType accessType) {
		return trees.get(accessType);
	}
	
	public UsageKnowledge<?> getModelTypesUsage(AccessType accessType) {
		List<AccessType> modelTypes = Arrays.asList(AccessType.getModelTypes());
		if(!modelTypes.contains(accessType)) {
			throw new RuntimeException("Only ModelTypes are allowed, i.e. " + modelTypes.toString());
		}
		if(accessType == AccessType.PROPERTY) {
			return propertyUsage;
		}else {
			return erTypesUsage.get(accessType);
		}
	}
	
	public UsageKnowledge<LinkedEntity> getERTypesUsage(AccessType accessType) {
		List<AccessType> erTypes = Arrays.asList(AccessType.getERTypes());
		if(!erTypes.contains(accessType)) {
			throw new RuntimeException("Only ERTypes are allowed, i.e. " + erTypes.toString());
		}
		return erTypesUsage.get(accessType);
	}
	
	public UsageKnowledge<Entry<String,PropertyDefinition>> getPropertyUsage(){
		return propertyUsage;
	}
	
	public UsageKnowledge<LinkedEntity> getResourceUsage() {
		return erTypesUsage.get(AccessType.RESOURCE);
	}
	
	public UsageKnowledge<LinkedEntity> getFacetUsage() {
		return erTypesUsage.get(AccessType.FACET);
	}
	
	public UsageKnowledge<LinkedEntity> getIsRelatedToUsage() {
		return erTypesUsage.get(AccessType.IS_RELATED_TO);
	}
	
	public UsageKnowledge<LinkedEntity> getConsistsOfUsage() {
		return erTypesUsage.get(AccessType.CONSISTS_OF);
	}
	
	/**
	 * Return the type if it is contained in the Knowledge
	 * @param typeName the type we are looking for
	 * @return the Type
	 * @throws RuntimeException
	 */
	public T getTypeByName(String typeName) throws RuntimeException {
		return getNodeByName(typeName).getNodeElement();
	}
	
	
	/**
	 * Return the node fro the type if it is contained in the Knowledge
	 * @param typeName the type we are looking for
	 * @return the Type
	 * @throws RuntimeException
	 */
	public Node<T> getNodeByName(String typeName) throws RuntimeException {
		AccessType accessType = locate.get(typeName);
		if(accessType==null) {
			throw new RuntimeException("The type " + typeName + " is not contained in the Knowledge");
		}
		
		Tree<T> tree = trees.get(accessType);
		return tree.getNodeByIdentifier(typeName);
	}
	
}