/**
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jbpm.bpmn2.xml;

import java.util.HashSet;
import java.util.List;

import org.drools.core.xml.BaseAbstractHandler;
import org.drools.core.xml.ExtensibleXmlParser;
import org.drools.core.xml.Handler;
import org.jbpm.bpmn2.core.Association;
import org.jbpm.bpmn2.core.Lane;
import org.jbpm.bpmn2.core.SequenceFlow;
import org.jbpm.compiler.xml.ProcessBuildData;
import org.jbpm.process.core.ContextContainer;
import org.jbpm.process.core.context.variable.Variable;
import org.jbpm.process.core.context.variable.VariableScope;
import org.jbpm.workflow.core.Node;
import org.jbpm.workflow.core.node.WorkItemNode;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

public class PropertyHandler extends BaseAbstractHandler implements Handler {

	public PropertyHandler() {
        initValidParents();
        initValidPeers();
        this.allowNesting = false;
    }
    
    protected void initValidParents() {
        this.validParents = new HashSet<Class<?>>();
        this.validParents.add(ContextContainer.class);
        this.validParents.add(WorkItemNode.class);
    }
    
    protected void initValidPeers() {
        this.validPeers = new HashSet<Class<?>>();
        this.validPeers.add(null);
        this.validPeers.add(Lane.class);
        this.validPeers.add(Variable.class);
        this.validPeers.add(Node.class);
        this.validPeers.add(SequenceFlow.class);
        this.validPeers.add(Lane.class);
        this.validPeers.add(Association.class);
    }
    
	@SuppressWarnings("unchecked")
	public Object start(final String uri, final String localName,
			            final Attributes attrs, final ExtensibleXmlParser parser)
			throws SAXException {
		parser.startElementBuilder(localName, attrs);

		final String id = attrs.getValue("id");
		final String name = attrs.getValue("name");
		final String itemSubjectRef = attrs.getValue("itemSubjectRef");

		Object parent = parser.getParent();
		if (parent instanceof ContextContainer) {
		    ContextContainer contextContainer = (ContextContainer) parent;
		    VariableScope variableScope = (VariableScope) 
                contextContainer.getDefaultContext(VariableScope.VARIABLE_SCOPE);
			List variables = variableScope.getVariables();
			Variable variable = new Variable();
			// if name is given use it as variable name instead of id
			if (name != null && name.length() > 0) {
			    variable.setName(name);
			} else {
			    variable.setName(id);
			}
			variable.setMetaData("ItemSubjectRef", itemSubjectRef);
			variables.add(variable);
			
			((ProcessBuildData) parser.getData()).setMetaData("Variable", variable);
			return variable;
		}

		return new Variable();
	}

	public Object end(final String uri, final String localName,
			          final ExtensibleXmlParser parser) throws SAXException {
		parser.endElementBuilder();
		return parser.getCurrent();
	}

	public Class<?> generateNodeFor() {
		return Variable.class;
	}

}
