/*
 * Copyright (c) 2005, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * IBM Corporation - initial implementation
 *
 */
package org.eclipse.epf.diagramming.edit.policies;

import java.util.Iterator;
import java.util.List;

import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.epf.diagram.core.util.DiagramCoreValidation;
import org.eclipse.epf.diagramming.base.commands.CreateIncomingControlFlowCommand;
import org.eclipse.epf.diagramming.base.commands.CreateOutgoingControlFlowCommand;
import org.eclipse.epf.diagramming.edit.helpers.UMLBaseEditHelper;
import org.eclipse.epf.diagramming.providers.UMLElementTypes;
import org.eclipse.gef.EditPart;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.commands.UnexecutableCommand;
import org.eclipse.gmf.runtime.common.core.command.ICommand;
import org.eclipse.gmf.runtime.diagram.core.commands.DeleteCommand;
import org.eclipse.gmf.runtime.diagram.core.util.ViewUtil;
import org.eclipse.gmf.runtime.diagram.ui.commands.CommandProxy;
import org.eclipse.gmf.runtime.diagram.ui.commands.ICommandProxy;
import org.eclipse.gmf.runtime.diagram.ui.editparts.IGraphicalEditPart;
import org.eclipse.gmf.runtime.diagram.ui.editpolicies.SemanticEditPolicy;
import org.eclipse.gmf.runtime.emf.commands.core.command.CompositeTransactionalCommand;
import org.eclipse.gmf.runtime.emf.type.core.ElementTypeRegistry;
import org.eclipse.gmf.runtime.emf.type.core.IEditHelperContext;
import org.eclipse.gmf.runtime.emf.type.core.IElementType;
import org.eclipse.gmf.runtime.emf.type.core.requests.ConfigureRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.CreateElementRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.CreateRelationshipRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.DestroyElementRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.DestroyReferenceRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.DestroyRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.DuplicateElementsRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.GetEditContextRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.IEditCommandRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.MoveRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.ReorientReferenceRelationshipRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.ReorientRelationshipRequest;
import org.eclipse.gmf.runtime.emf.type.core.requests.SetRequest;
import org.eclipse.gmf.runtime.notation.View;
import org.eclipse.uml2.uml.Activity;
import org.eclipse.uml2.uml.ActivityEdge;
import org.eclipse.uml2.uml.ActivityNode;
import org.eclipse.uml2.uml.UMLPackage;

/**
 * @generated
 */
public class UMLBaseItemSemanticEditPolicy extends SemanticEditPolicy {

	/**
	 * @generated
	 */
	protected Command getSemanticCommand(IEditCommandRequest request) {
		IEditCommandRequest completedRequest = completeRequest(request);
		Object editHelperContext = completedRequest.getEditHelperContext();
		if (editHelperContext instanceof View
				|| (editHelperContext instanceof IEditHelperContext && ((IEditHelperContext) editHelperContext)
						.getEObject() instanceof View)) {
			// no semantic commands are provided for pure design elements
			return null;
		}
		if (editHelperContext == null) {
			editHelperContext = ViewUtil
					.resolveSemanticElement((View) getHost().getModel());
		}
		IElementType elementType = ElementTypeRegistry.getInstance()
				.getElementType(editHelperContext);
		if (elementType == ElementTypeRegistry.getInstance().getType(
				"org.eclipse.gmf.runtime.emf.type.core.default")) { //$NON-NLS-1$ 
			elementType = null;
		}
		Command epCommand = getSemanticCommandSwitch(completedRequest);
		if (epCommand != null) {
			ICommand command = epCommand instanceof ICommandProxy ? ((ICommandProxy) epCommand)
					.getICommand()
					: new CommandProxy(epCommand);
			completedRequest.setParameter(
					UMLBaseEditHelper.EDIT_POLICY_COMMAND, command);
		}
		Command ehCommand = null;
		if (elementType != null) {
			ICommand command = elementType.getEditCommand(completedRequest);
			if (command != null) {
				if (!(command instanceof CompositeTransactionalCommand)) {
					TransactionalEditingDomain editingDomain = ((IGraphicalEditPart) getHost())
							.getEditingDomain();
					command = new CompositeTransactionalCommand(editingDomain,
							null).compose(command);
				}
				ehCommand = new ICommandProxy(command);
			}
		}
		boolean shouldProceed = true;
		if (completedRequest instanceof DestroyRequest) {
			shouldProceed = shouldProceed((DestroyRequest) completedRequest);
		}
		if (shouldProceed) {
			if (completedRequest instanceof DestroyRequest) {
				TransactionalEditingDomain editingDomain = ((IGraphicalEditPart) getHost())
						.getEditingDomain();
				Command deleteViewCommand = new ICommandProxy(
						new DeleteCommand(editingDomain, (View) getHost()
								.getModel()));
				ehCommand = ehCommand == null ? deleteViewCommand : ehCommand
						.chain(deleteViewCommand);
			}
			return ehCommand;
		}
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getSemanticCommandSwitch(IEditCommandRequest req) {
		if (req instanceof CreateRelationshipRequest) {
			return getCreateRelationshipCommand((CreateRelationshipRequest) req);
		} else if (req instanceof CreateElementRequest) {
			return getCreateCommand((CreateElementRequest) req);
		} else if (req instanceof ConfigureRequest) {
			return getConfigureCommand((ConfigureRequest) req);
		} else if (req instanceof DestroyElementRequest) {
			return getDestroyElementCommand((DestroyElementRequest) req);
		} else if (req instanceof DestroyReferenceRequest) {
			return getDestroyReferenceCommand((DestroyReferenceRequest) req);
		} else if (req instanceof DuplicateElementsRequest) {
			return getDuplicateCommand((DuplicateElementsRequest) req);
		} else if (req instanceof GetEditContextRequest) {
			return getEditContextCommand((GetEditContextRequest) req);
		} else if (req instanceof MoveRequest) {
			return getMoveCommand((MoveRequest) req);
		} else if (req instanceof ReorientReferenceRelationshipRequest) {
			return getReorientReferenceRelationshipCommand((ReorientReferenceRelationshipRequest) req);
		} else if (req instanceof ReorientRelationshipRequest) {
			return getReorientRelationshipCommand((ReorientRelationshipRequest) req);
		} else if (req instanceof SetRequest) {
			return getSetCommand((SetRequest) req);
		}
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getConfigureCommand(ConfigureRequest req) {
		return null;
	}

	/**
	 * @modified
	 */
	protected Command getCreateRelationshipCommand(CreateRelationshipRequest req) {
		if (UMLElementTypes.ControlFlow_3001 == req.getElementType()) {
			return req.getTarget() == null ? getCreateOutgoing(req)
					: getCreateIncomingComplete(req);
		}
		return null;
	}

	/**
	 * Children should override this, for any extra validations.
	 * @modified
	 */
	protected Command getCreateIncomingComplete(CreateRelationshipRequest req) {
		Command command;
		if (req.getSource() == req.getTarget()) {
			return new Command() {
			};
		}

		if (!(req.getSource() instanceof ActivityNode)) {
			return UnexecutableCommand.INSTANCE;
		}

		final EObject element = (EObject) req.getSource();
		if (element == null || !(element instanceof ActivityNode)) {
			return UnexecutableCommand.INSTANCE;
		}
		if (isDuplicateRelationship(req.getSource(), req.getTarget())) {
			return UnexecutableCommand.INSTANCE;
		}
		
		if(DiagramCoreValidation.canConnect((EditPart)getHost(), req.getTarget(), req.getSource()) != null)
			return UnexecutableCommand.INSTANCE;
		
		if (element instanceof ActivityNode) {
			if (req.getContainmentFeature() == null) {
				req.setContainmentFeature(UMLPackage.eINSTANCE
						.getActivity_Edge());
			}
			command = getMSLWrapper(new CreateIncomingControlFlowCommand(req,
					element.eContainer()));

			//			if (req.getTarget() != req.getSource()) {
			//				command = command.chain(new CreatePredecessorCommand(req));
			//			}
			return command;

		}
		return null;
	}

	/**
	 * Check  if the link between two ends already exists.
	 * @modified
	 */
	private boolean isDuplicateRelationship(EObject source, EObject target) {
		EObject container = source.eContainer();
		if (container instanceof Activity) {
			Activity activity = (Activity) container;
			List list = activity.getEdges();
			for (Iterator iter = list.iterator(); iter.hasNext();) {
				ActivityEdge element = (ActivityEdge) iter.next();
				if ((element.getSource() == source)
						&& element.getTarget() == target) {
					return true;
				}
			}
		}
		return false;
	}

	/**
	 * @modified
	 */
	protected Command getCreateOutgoing(CreateRelationshipRequest req) {
		if (!(req.getSource() instanceof ActivityNode)) {
			return null;
		}
		final EObject element = (EObject) req.getTarget();
		if (element == null || !(element instanceof ActivityNode)) {
			return new Command() {
			};
		}
		if (element instanceof ActivityNode) {
			// TODO:  check the same type, don't create connection.
			if (req.getContainmentFeature() == null) {
				req.setContainmentFeature(UMLPackage.eINSTANCE
						.getActivity_Edge());
			}
		}
		return getMSLWrapper(new CreateOutgoingControlFlowCommand(req));
	}

	/**
	 * @generated
	 */
	protected Command getCreateCommand(CreateElementRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getSetCommand(SetRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getEditContextCommand(GetEditContextRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getDestroyElementCommand(DestroyElementRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getDestroyReferenceCommand(DestroyReferenceRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getDuplicateCommand(DuplicateElementsRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getMoveCommand(MoveRequest req) {
		return null;
	}

	/**
	 * @generated
	 */
	protected Command getReorientReferenceRelationshipCommand(
			ReorientReferenceRelationshipRequest req) {
		return UnexecutableCommand.INSTANCE;
	}

	/**
	 * @generated
	 */
	protected Command getReorientRelationshipCommand(
			ReorientRelationshipRequest req) {
		return UnexecutableCommand.INSTANCE;
	}

	/**
	 * @generated
	 */
	protected Command getMSLWrapper(ICommand cmd) {
		return new ICommandProxy(cmd);
	}

	/**
	 * @generated
	 */
	protected EObject getSemanticElement() {
		return ViewUtil.resolveSemanticElement((View) getHost().getModel());
	}

	/**
	 * Finds container element for the new relationship of the specified type.
	 * Default implementation goes up by containment hierarchy starting from
	 * the specified element and returns the first element that is instance of
	 * the specified container class.
	 * 
	 * @generated
	 */
	protected EObject getRelationshipContainer(EObject element,
			EClass containerClass, IElementType relationshipType) {
		for (; element != null; element = element.eContainer()) {
			if (containerClass.isSuperTypeOf(element.eClass())) {
				return element;
			}
		}
		return null;
	}

}