package org.drools.process.instance;



import java.io.Externalizable;

import java.io.IOException;

import java.io.ObjectInput;

import java.io.ObjectOutput;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;



import org.drools.WorkingMemory;

import org.drools.process.instance.impl.WorkItemImpl;



/**

 *

 * @author <a href="mailto:kris_verlaenen@hotmail.com">Kris Verlaenen</a>

 */

public class WorkItemManager implements Externalizable {



    private static final long serialVersionUID = 400L;



    private long workItemCounter;

	private Map<Long, WorkItem> workItems = new HashMap<Long, WorkItem>();

	private WorkingMemory workingMemory;

	private Map<String, WorkItemHandler> workItemHandlers = new HashMap<String, WorkItemHandler>();



    public WorkItemManager() {



    }

    public WorkItemManager(WorkingMemory workingMemory) {

	    this.workingMemory = workingMemory;

	}



    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {

        workItemCounter = in.readLong();

        workItems   = (Map<Long, WorkItem>)in.readObject();

        workingMemory   = (WorkingMemory)in.readObject();

        workItemHandlers   = (Map<String, WorkItemHandler>)in.readObject();

    }



    public void writeExternal(ObjectOutput out) throws IOException {

        out.writeLong(workItemCounter);

        out.writeObject(workItems);

        out.writeObject(workingMemory);

        out.writeObject(workItemHandlers);

    }



	public void internalExecuteWorkItem(WorkItem workItem) {

	    ((WorkItemImpl) workItem).setId(++workItemCounter);

	    internalAddWorkItem(workItem);

	    WorkItemHandler handler = (WorkItemHandler) this.workItemHandlers.get(workItem.getName());

	    if (handler != null) {

	        handler.executeWorkItem(workItem, this);

	    } else {

	        System.err.println("Could not find work item handler for " + workItem.getName());

	    }

	}

	

	public void internalAddWorkItem(WorkItem workItem) {

	    workItems.put(new Long(workItem.getId()), workItem);

	}



    public void internalAbortWorkItem(long id) {

        WorkItemImpl workItem = (WorkItemImpl) workItems.get(new Long(id));

        // work item may have been aborted

        if (workItem != null) {

            WorkItemHandler handler = (WorkItemHandler) this.workItemHandlers.get(workItem.getName());

            if (handler != null) {

                handler.abortWorkItem(workItem, this);

            } else {

                System.err.println("Could not find work item handler for " + workItem.getName());

            }

        }

    }

    

	public Set<WorkItem> getWorkItems() {

	    return new HashSet<WorkItem>(workItems.values());

	}

	

	public WorkItem getWorkItem(long id) {

		return workItems.get(id);

	}



    public void completeWorkItem(long id, Map<String, Object> results) {

        WorkItemImpl workItem = (WorkItemImpl) workItems.get(new Long(id));

        // work item may have been aborted

        if (workItem != null) {

            workItem.setResults(results);

            ProcessInstance processInstance = workingMemory.getProcessInstance(workItem.getProcessInstanceId());

            workItem.setState(WorkItem.COMPLETED);

            // process instance may have finished already

            if (processInstance != null) {

                processInstance.signalEvent("workItemCompleted", workItem);

            }

            workItems.remove(new Long(id));

            workingMemory.fireAllRules();

        }

    }



    public void abortWorkItem(long id) {

        WorkItemImpl workItem = (WorkItemImpl) workItems.get(new Long(id));

        // work item may have been aborted

        if (workItem != null) {

            ProcessInstance processInstance = workingMemory.getProcessInstance(workItem.getProcessInstanceId());

            workItem.setState(WorkItem.ABORTED);

            // process instance may have finished already

            if (processInstance != null) {

                processInstance.signalEvent("workItemAborted", workItem);

            }

            workItems.remove(new Long(id));

            workingMemory.fireAllRules();

        }

    }



    public void registerWorkItemHandler(String workItemName, WorkItemHandler handler) {

        this.workItemHandlers.put(workItemName, handler);

    }



}