/**
 * 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.process.instance.context.variable;

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

import org.drools.core.event.ProcessEventSupport;
import org.jbpm.process.core.context.variable.Variable;
import org.jbpm.process.core.context.variable.VariableScope;
import org.jbpm.process.instance.ContextInstanceContainer;
import org.jbpm.process.instance.InternalProcessRuntime;
import org.jbpm.process.instance.context.AbstractContextInstance;
import org.jbpm.workflow.core.Node;
import org.jbpm.workflow.instance.node.CompositeContextNodeInstance;

/**
 * 
 * @author <a href="mailto:kris_verlaenen@hotmail.com">Kris Verlaenen</a>
 */
public class VariableScopeInstance extends AbstractContextInstance {

    private static final long serialVersionUID = 510l;
    
    private Map<String, Object> variables = new HashMap<String, Object>();
    private transient String variableIdPrefix = null;
    private transient String variableInstanceIdPrefix = null;

    public String getContextType() {
        return VariableScope.VARIABLE_SCOPE;
    }

    public Object getVariable(String name) {
                
        Object value = variables.get(name);
        if (value != null) {
            return value;
        }

        // support for processInstanceId and parentProcessInstanceId
        if ("processInstanceId".equals(name) && getProcessInstance() != null) {
            return getProcessInstance().getId();
        } else if ("parentProcessInstanceId".equals(name) && getProcessInstance() != null) {
            return getProcessInstance().getParentProcessInstanceId();
        }
        
        // support for globals
        if (getProcessInstance() != null && getProcessInstance().getKnowledgeRuntime() != null) {
            return getProcessInstance().getKnowledgeRuntime().getGlobal(name);
        }        
        return null;
    }

    public Map<String, Object> getVariables() {
        return Collections.unmodifiableMap(variables);
    }

    public void setVariable(String name, Object value) {
        if (name == null) {
            throw new IllegalArgumentException(
                "The name of a variable may not be null!");
        }
        Object oldValue = variables.get(name);
        if (oldValue == null) {
        	if (value == null) {
        		return;
        	}
        } 
        ProcessEventSupport processEventSupport = ((InternalProcessRuntime) getProcessInstance()
    		.getKnowledgeRuntime().getProcessRuntime()).getProcessEventSupport();
    	processEventSupport.fireBeforeVariableChanged(
			(variableIdPrefix == null ? "" : variableIdPrefix + ":") + name,
			(variableInstanceIdPrefix == null? "" : variableInstanceIdPrefix + ":") + name,
			oldValue, value, getProcessInstance(),
			getProcessInstance().getKnowledgeRuntime());
        internalSetVariable(name, value);
        processEventSupport.fireAfterVariableChanged(
			(variableIdPrefix == null ? "" : variableIdPrefix + ":") + name,
			(variableInstanceIdPrefix == null? "" : variableInstanceIdPrefix + ":") + name,
    		oldValue, value, getProcessInstance(),
			getProcessInstance().getKnowledgeRuntime());
    }
    
    public void internalSetVariable(String name, Object value) {
    	variables.put(name, value);
    }
    
    public VariableScope getVariableScope() {
    	return (VariableScope) getContext();
    }
    
    public void setContextInstanceContainer(ContextInstanceContainer contextInstanceContainer) {
    	super.setContextInstanceContainer(contextInstanceContainer);
    	for (Variable variable : getVariableScope().getVariables()) {
            setVariable(variable.getName(), variable.getValue());
        }
    	if (contextInstanceContainer instanceof CompositeContextNodeInstance) {
    		this.variableIdPrefix = ((Node) ((CompositeContextNodeInstance) contextInstanceContainer).getNode()).getUniqueId();
    		this.variableInstanceIdPrefix = ((CompositeContextNodeInstance) contextInstanceContainer).getUniqueId();
    	}
	}

}
