package org.eclipse.emf.edapt.declaration.replacement;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.emf.ecore.EAttribute;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.emf.edapt.declaration.EdaptConstraint;
import org.eclipse.emf.edapt.declaration.EdaptOperation;
import org.eclipse.emf.edapt.declaration.EdaptParameter;
import org.eclipse.emf.edapt.declaration.OperationImplementation;
import org.eclipse.emf.edapt.internal.common.MetamodelFactory;
import org.eclipse.emf.edapt.spi.migration.Instance;
import org.eclipse.emf.edapt.spi.migration.Metamodel;
import org.eclipse.emf.edapt.spi.migration.Model;

/**
 * {@description}
 *
 * @author herrmama
 * @author $Author$
 * @version $Rev$
 * @levd.rating YELLOW Hash: 71EF4E6C3C56A7C17068FE58DCA3D8F0
 */
@EdaptOperation(identifier = "replaceIdentifierByReference", label = "Identifier to Reference", description = "In the metamodel, an attribute that references elements by identifier is replaced by a reference. In the model, its values are replaced by references to that element.", breaking = true)
public class ReplaceIdentifierByReference extends OperationImplementation {

	/** {@description} */
	@EdaptParameter(main = true, description = "The referencing attribute")
	public EAttribute referencingAttribute;

	/** {@description} */
	@EdaptParameter(description = "The referenced attribute")
	public EAttribute referencedAttribute;

	/** {@description} */
	@EdaptConstraint(description = "Referencing and referenced attribute must be of the same type")
	public boolean checkAttributesSameType() {
		return referencedAttribute == null
			|| referencingAttribute.getEType() == referencedAttribute
				.getEType();
	}

	/** {@inheritDoc} */
	@Override
	public void execute(Metamodel metamodel, Model model) {
		// variables
		final EClass referencedClass = referencedAttribute.getEContainingClass();

		// metamodel adaptation
		final EClass referencingClass = referencingAttribute.getEContainingClass();
		final EReference referencingReference = MetamodelFactory.newEReference(
			referencingClass, referencingAttribute.getName(),
			referencedClass, referencingAttribute.getLowerBound(),
			referencingAttribute.getUpperBound());
		metamodel.delete(referencingAttribute);

		// model migration
		final Map<Object, Instance> referencedElements = new HashMap<Object, Instance>();
		for (final Instance referencedElement : model
			.getAllInstances(referencedClass)) {
			referencedElements.put(referencedElement.get(referencedAttribute),
				referencedElement);
		}
		for (final Instance referencingElement : model
			.getAllInstances(referencingClass)) {
			final Object reference = referencingElement.unset(referencingAttribute);
			referencingElement.set(referencingReference, referencedElements
				.get(reference));
		}
	}
}