/*
 * Copyright 2015 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.
 * 
 *      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.persistence.processinstance;

import java.util.List;

import org.drools.core.common.InternalKnowledgeRuntime;
import org.jbpm.persistence.api.ProcessPersistenceContext;
import org.jbpm.persistence.api.ProcessPersistenceContextManager;
import org.jbpm.process.core.async.AsyncSignalEventCommand;
import org.jbpm.process.instance.event.DefaultSignalManager;
import org.kie.api.executor.CommandContext;
import org.kie.api.executor.ExecutorService;
import org.kie.api.runtime.EnvironmentName;
import org.kie.api.runtime.manager.RuntimeManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class JPASignalManager extends DefaultSignalManager {
    private static final String ASYNC_SIGNAL_PREFIX = "ASYNC-";
    private static final Logger logger = LoggerFactory.getLogger(JPASignalManager.class);

    public JPASignalManager(InternalKnowledgeRuntime kruntime) {
        super(kruntime);
    }
    
    public void signalEvent(String type, Object event) {
        String actualSignalType = type.replaceFirst(ASYNC_SIGNAL_PREFIX, "");
        
        ProcessPersistenceContextManager contextManager 
            = (ProcessPersistenceContextManager) getKnowledgeRuntime().getEnvironment().get( EnvironmentName.PERSISTENCE_CONTEXT_MANAGER );
        ProcessPersistenceContext context = contextManager.getProcessPersistenceContext();
        List<Long> processInstancesToSignalList = context.getProcessInstancesWaitingForEvent(actualSignalType);
        // handle signal asynchronously
        if (type.startsWith(ASYNC_SIGNAL_PREFIX)) {
            RuntimeManager runtimeManager = ((RuntimeManager)getKnowledgeRuntime().getEnvironment().get("RuntimeManager"));
            ExecutorService executorService = (ExecutorService) getKnowledgeRuntime().getEnvironment().get("ExecutorService");
            if (runtimeManager != null && executorService != null) {
                
                for (Long processInstanceId : processInstancesToSignalList) {
                    CommandContext ctx = new CommandContext();
                    ctx.setData("deploymentId", runtimeManager.getIdentifier());
                    ctx.setData("processInstanceId", processInstanceId);
                    ctx.setData("Signal", actualSignalType);
                    ctx.setData("Event", event);                    
                    
                    executorService.scheduleRequest(AsyncSignalEventCommand.class.getName(), ctx);
                }
                
                return;
            } else {
                logger.warn("Signal should be sent asynchronously but there is no executor service available, continuing sync...");
            }
        }
        
        
        for ( long id : processInstancesToSignalList ) {
            try {
                getKnowledgeRuntime().getProcessInstance( id );
            } catch (IllegalStateException e) {
                // IllegalStateException can be thrown when using RuntimeManager
                // and invalid ksession was used for given context
            } catch (RuntimeException e) {
                logger.warn("Exception when loading process instance for signal '{}', instance with id {} will not be signaled",
                        e.getMessage(), id);
            }
        }
        super.signalEvent( actualSignalType,
                           event );
    }

}