package org.gcube.informationsystem.resourceregistry.instances.model.relations;

import java.util.Iterator;

import org.gcube.informationsystem.base.reference.AccessType;
import org.gcube.informationsystem.model.impl.properties.PropagationConstraintImpl;
import org.gcube.informationsystem.model.reference.entities.Facet;
import org.gcube.informationsystem.model.reference.properties.PropagationConstraint;
import org.gcube.informationsystem.model.reference.properties.PropagationConstraint.AddConstraint;
import org.gcube.informationsystem.model.reference.properties.PropagationConstraint.DeleteConstraint;
import org.gcube.informationsystem.model.reference.properties.PropagationConstraint.RemoveConstraint;
import org.gcube.informationsystem.model.reference.relations.ConsistsOf;
import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.relations.consistsof.ConsistsOfAlreadyPresentException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.relations.consistsof.ConsistsOfAvailableInAnotherContextException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.relations.consistsof.ConsistsOfNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.types.SchemaViolationException;
import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext.PermissionMode;
import org.gcube.informationsystem.resourceregistry.instances.model.Operation;
import org.gcube.informationsystem.resourceregistry.instances.model.entities.FacetManagement;
import org.gcube.informationsystem.resourceregistry.instances.model.entities.ResourceManagement;
import org.gcube.informationsystem.types.reference.entities.FacetType;

import com.arcadedb.graph.Edge;
import com.arcadedb.graph.Vertex;
import com.arcadedb.graph.Vertex.DIRECTION;
import com.arcadedb.remote.RemoteDatabase;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public class ConsistsOfManagement extends RelationManagement<FacetManagement, FacetType> {
	
	public static final PropagationConstraint DEFAULT_CONSISTS_OF_PC;

	static {
		DEFAULT_CONSISTS_OF_PC = new PropagationConstraintImpl();
		DEFAULT_CONSISTS_OF_PC.setDeleteConstraint(DeleteConstraint.cascade);
		DEFAULT_CONSISTS_OF_PC.setRemoveConstraint(RemoveConstraint.cascade);
		DEFAULT_CONSISTS_OF_PC.setAddConstraint(AddConstraint.propagate);
	}
	
	public ConsistsOfManagement() {
		super(AccessType.CONSISTS_OF, Facet.class, DEFAULT_CONSISTS_OF_PC);
	}
	
	@Override
	protected ConsistsOfNotFoundException getSpecificNotFoundException(NotFoundException e) {
		return new ConsistsOfNotFoundException(e.getMessage(), e.getCause());
	}
	
	@Override
	public ConsistsOfAvailableInAnotherContextException getSpecificAvailableInAnotherContextException(
			String message) {
		return new ConsistsOfAvailableInAnotherContextException(message);
	}
	
	@Override
	protected ConsistsOfAlreadyPresentException getSpecificAlreadyPresentException(String message) {
		return new ConsistsOfAlreadyPresentException(message);
	}
	
	@Override
	protected FacetManagement newTargetEntityManagement() throws ResourceRegistryException {
		FacetManagement facetManagement = new FacetManagement();
		facetManagement.setDatabase(database);
		facetManagement.setWorkingContext(getWorkingContext());
		return facetManagement;
	}

	@Override
	protected Edge reallyCreate() throws ResourceRegistryException {
		Edge thisEdge = super.reallyCreate();
		
		Vertex target = (Vertex) getTargetEntityManagement().getElement();
		
		int count = 0;
		Iterable<Edge> iterable = target.getEdges(DIRECTION.IN);
		Iterator<Edge> iterator = iterable.iterator();
		while(iterator.hasNext()) {
			iterator.next();
			++count;
		}
		
		if(count > 1) {
			throw new SchemaViolationException("It is not possible to create multiple " + ConsistsOf.NAME + " between the same " + Facet.NAME);
		}
		
		return thisEdge;
	}
	
	protected void checkResource() throws SchemaViolationException, ResourceRegistryException {
		if(!entryPoint) {
			return;
		}
		
		if(operation.isSafe()) {
			/* 
			 * The sanity check is not required for a safe operation.
			 */
			return;
		}
		
		if(operation == Operation.UPDATE) {
			// an update to the Facet only modify the ConsistsOf properties, no need to check the source resource
			return;
		}
		
		RemoteDatabase targetSecurityContextDatabase = null;
		try {
			ResourceManagement resourceManagement  = getSourceEntityManagement();
			
			switch (operation) {
				case CREATE: case DELETE:
					break;
				
				case ADD_TO_CONTEXT: case REMOVE_FROM_CONTEXT:
					resourceManagement = new ResourceManagement();
					resourceManagement.setElementType(sourceEntityManagement.getTypeName());
					resourceManagement.setUUID(sourceEntityManagement.getUUID());
					if(operation == Operation.ADD_TO_CONTEXT) {
						resourceManagement.setSourceSecurityContext(sourceSecurityContext);
					}
					resourceManagement.setTargetSecurityContext(targetSecurityContext);
					resourceManagement.setWorkingContext(targetSecurityContext);
					targetSecurityContextDatabase = targetSecurityContext.getRemoteDatabase(PermissionMode.READER);
					resourceManagement.setDatabase(targetSecurityContextDatabase);
					break;
					
				default:
					// You should not be here
					return;
			}
			resourceManagement.setOperation(operation);
			resourceManagement.addToRelationManagements(this);
			resourceManagement.sanityCheck();
		}catch (ResourceRegistryException e) {
			throw e;
		}catch (Exception e) {
			throw new ResourceRegistryException(e);
		}finally {
			if(targetSecurityContextDatabase!=null) {
				targetSecurityContextDatabase.close();
//				database.activateOnCurrentThread();
			}
		}
	}
	
	@Override
	public void sanityCheck() throws SchemaViolationException, ResourceRegistryException {
		super.sanityCheck();
		checkResource();
	}
	
}