package altk.comm.engine;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.time.LocalTime;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Category;
import org.apache.log4j.Logger;
import org.json.simple.JSONObject;

import com.opencsv.CSVWriter;

import altk.comm.engine.Job.CommJobStatus;
import altk.comm.engine.exception.BroadcastError;
import altk.comm.engine.exception.BroadcastException;
import altk.comm.engine.exception.EngineException;
import altk.comm.engine.exception.PlatformError;
import altk.comm.engine.exception.PlatformException;

/**
 * Broadcast class absorbs what was formerly known as Dispatcher class.
 * 
 * @author Yuk-Ming
 * 
 */
public abstract class Broadcast
{
	private static final int SCHEDULER_THREAD_POOL_SIZE = 5;
    private static final String ACTIVITY_RECORD_ID_PARAM_NAME_DEFAULT = "activity_record_id";
    private static final long SLEEP_BETWEEN_JOBS_DEFAULT = 0;
	static final String DAILY_STOP_KEY = "daily_stop";
	static final String DAILY_START_KEY = "daily_start";

	static final String CSV_LOGGER = "csv";
	
    public final String broadcastType;
	private String broadcastId;
	
    private BroadcastState state = BroadcastState.ACCEPTED;
    private Object stateSemaphore = new Object();

    String reason;
    String stateErrorText;
	public CommEngine commEngine;
    public final long receiveTime;
    public long serviceStartTime;
    public long serviceEndTime;
    public long changeStateTime;
    protected String activityRecordIdParamName;
    private String jobReportRootNodeName;

	/**
	 * Set when reading request XML, but never used.
	 */
	private String launchRecordId;

	// protected XPath xpathEngine;
	protected String postbackURL;
	private Postback postback;
	protected String daily_start = ""; 
	protected String daily_stop = "";
	
	/**
	 * Sleep time in milliseconds between consecutive job processing (actualliy batch)
	 */
	protected long sleepBetweenJobs;

	protected static Logger myLogger = Logger.getLogger(Broadcast.class);
    protected List<Service> serviceThreadPool;
	private Object resumeFlag; // Semaphore for dispatcher threads to resume.
    protected List<Recipient> recipientList;
    
    private ScheduledExecutorService scheduler;
	private int jobsTotal;

	/** Queue of jobs ready to be servivced.  Semaphore for next 3 fields */
    private Queue<Job> readyQueue;
    /** Count of items in scheduler */ 
	private int scheduledJobs;
	/** Instantaneous number of jobs being serviced by service provider */
	private int serviceActivityCount;

	
	private Integer transactions;
	
	
	/** Running count of successful jobs */
	private AtomicInteger successCount;
	private int pauseThreshold;
	private int lastPauseCount;
	private Logger csvLogger;

	
    public static enum BroadcastState
    {
    	/** Broadcast request accepted for execution */
        ACCEPTED,
        /** Servicing jobs */
        RUNNING,
        /** User action, causing system to quiesce, i.e. quiet down */
        PAUSING,
        /** System is paused and quiet.  Ready to resume */
        PAUSED,
        /** User action */
        CANCELING,
        /** Ireoverable internal or service provider error */
        ABORTING,
        /** All servicing done, reporting may still be ongoing */
        COMPLETED,
        CANCELED(true),   // Final state
        PURGED(true),     // Final state
        ABORTED(true),    // final state
        /** All servicing and reporting done */
        ALLDONE(true)     // Final state
        ;   
        
        final public boolean isFinal;
        
        private BroadcastState()
        {
            isFinal = false;
        }
        
        private BroadcastState(boolean isFinal)
        {
            this.isFinal = isFinal;
        }
    }
    
    public enum StateChangeStatus
    {
        SUCCESS,
        NO_CHANGE,
        FORBIDDEN
    }
    
    /**
     * When a Broadcast is first created, its state is INSTALLING, during which
     * time, the broadcast request XML is digested.  After this period, the
     * state of the broadcast enters into RUNNING, and it begins with adding
     * all VoiceJobs in the request to the Dispatcher's queues.  During this period
     * calls are dispatched, setup, and terminate.  When the last call is terminated,
     * the broadcast enters into the COMPLETED state.
     * 
     * Transitions from INSTALLING to RUNNING, and from RUNNING to COMPLETED happen
     * automatically without any external influence.
     * 
     * At any time, the broadcast may be canceled by user action, which causes
     * the broadcast to transition from the RUNNING state into the CANCELED state.
     * 
     * Since the RUNNING state may go to the COMLETED or to the CANCELED state,
     * each due to a different thread, there needs to be a mutex to guarantee
     * state and data integrity.
     * 
     * A INSTALLING or RUNNING broadcast may be paused by user action, stopping the
     * Dispatcher from making new calls and causing the broadcast to go to
     * the HALTED state.  Certain error conditions result in the HALTED state.
     * 
     * User may order a broadcast to be removed entirely with a purge command,
     * causing the broadcast to go to the PURGED state.  This state is there so
     * objects, that has reference to a broadcast which has been purged, know
     * what to do in that situation.
     * 
     * We need the pause operation to set a RUNNING machine to be in the PAUSING state,
     * allow ongoing jobs to proceed to normal termination,
     * whereas no new jobs are started.  State goes from PAUSING to HALTED.
     * 
     * Cancel-nice operation is pause, followed by the automatic transition 
     * from HALTED to CANCELED.
     * 
     * Cancel operation forces all jobs to abort, and the state transitions to CANCELED
     * immediately.
     * 
     * Because the Dispatcher and Broadcast is one-to-one, and because they access each other's
     * data, Dispatcher should be combined into Broadcast.
     * 
     * @author Yuk-Ming
     *
     */
    static Map<BroadcastState, List<BroadcastState>> toStates;
    
    static
    {
        // Initialize legal transitions of state machine.
        // For each state, define a list of legal states that this state can transition to
        toStates = new HashMap<BroadcastState, List<BroadcastState>>();

        // Transitions from INSTALLING
        toStates.put(BroadcastState.ACCEPTED, Arrays.asList(
                BroadcastState.RUNNING,    // Normal transition
                BroadcastState.CANCELING,  // User action
                BroadcastState.CANCELED, // User action
                BroadcastState.PAUSING,  // User action
                BroadcastState.PAUSED,     // User action
                BroadcastState.PURGED,     // User action
                BroadcastState.ABORTING,
                BroadcastState.ABORTED,
                BroadcastState.ALLDONE   // When recipient list is empty
            ));
        
        // Transitions from RUNNING
        toStates.put(BroadcastState.RUNNING, Arrays.asList(
        		BroadcastState.COMPLETED,   // after completed all sends
                BroadcastState.CANCELING,  // User action
                BroadcastState.CANCELED, // User action
                BroadcastState.PAUSING,  // User action
                BroadcastState.PAUSED,     // User action
                BroadcastState.PURGED,     // User action
                BroadcastState.ABORTING,
                BroadcastState.ABORTED
            ));
        
        // Transitions from CANCELING
        toStates.put(BroadcastState.CANCELING, Arrays.asList(
                BroadcastState.ABORTING,
                BroadcastState.ABORTED, 
                BroadcastState.COMPLETED,
                BroadcastState.CANCELED, // User action
                BroadcastState.PURGED     // User action
            ));
        
        // Transitions from ABORTING
        toStates.put(BroadcastState.ABORTING, Arrays.asList(
                BroadcastState.ABORTED, 
                BroadcastState.PURGED     // User action
            ));
        
        // Transitions from PAUSING
        toStates.put(BroadcastState.PAUSING, Arrays.asList(
                BroadcastState.RUNNING,    // User action
                BroadcastState.COMPLETED,
                BroadcastState.ABORTING,
                BroadcastState.CANCELING, // User action
                BroadcastState.CANCELED,
                BroadcastState.PAUSED,
                BroadcastState.PURGED     // User action
            ));

        // Transitions from PAUSED
        toStates.put(BroadcastState.PAUSED, Arrays.asList(
                BroadcastState.RUNNING,    // User action
                BroadcastState.CANCELED, // User action
                BroadcastState.CANCELING, // User action
                BroadcastState.ABORTING,
                BroadcastState.ABORTED, 
                BroadcastState.PURGED     // User action
            ));
        toStates.put(BroadcastState.COMPLETED,  Arrays.asList(
        		BroadcastState.ALLDONE  // when all posting back is complete
        		));
    }
    
    public static class StateChangeResult
    {
        public StateChangeStatus stateChangeStatus;
        public BroadcastState currentState;
        public BroadcastState previousState;
        
        public StateChangeResult(StateChangeStatus stateChangeStatus,
                BroadcastState currentState, BroadcastState previousState)
        {
            this.stateChangeStatus = stateChangeStatus;
            this.currentState = currentState;
            this.previousState = previousState;
        }
    }
    
    protected enum PostbackThreadActionOnEmpty
    {
    	CONTINUE,
    	STOP,
    	WAIT
    }
    
    protected class Service extends Thread
    {
        Object serviceProviderPeer;
        
        protected Service(String name) throws BroadcastException
        {
            serviceProviderPeer = getInitializedServiceProviderPeer();
            setName(name);
        }
        
        public void run()
        {
            myLogger.info("Thread starting...");
            for (;;)
            {
                if (serviceThreadsShouldPause())
                {
                    synchronized (resumeFlag)
                    {
                        try
                        {
                        	myLogger.debug("Paused");
                            resumeFlag.wait();
                            myLogger.debug("Pause ended");
                        }
                        catch (InterruptedException e)
                        {
                            myLogger.warn("Dispatcher thread interrupted while waiting to resume");
                        }
                    }
                }
                if (serviceThreadsShouldStop()) break;
                // Get a batch of jobs, if available
    			myLogger.debug("Looking for jobs");
                List<Job> batch =  new ArrayList<Job>();
                int batchSize = getJobBatchSize();
				synchronized(readyQueue)
                {                    
                    // We we are to get a batch of more than one, let us fill in the rest.
 					for (int i = 0; i < batchSize; i++)
                    {
                        Job job = readyQueue.poll();
                        if (job == null) break;
                        batch.add(job);
                    }
	
	                if (batch.size()== 0)
	                {
	                	// wait for jobs	
                		try
                		{
                			myLogger.debug("Waiting for jobs");
                			readyQueue.wait();
                			// go back to look for jobs
                			continue;
                		}
                		catch (Exception e)
                		{
                			// go back to look for jobs
                			continue;
                		}
                	}
                	updateServiceActivityCount(batchSize);
                }

                // Process jobs.
                // Mark start time
                long now = System.currentTimeMillis();
                for (Job job : batch)
                {
                    job.startTime = now;
                }
                
                // Service the jobs
                // But first get dependent resource
                // which includes allocation from capacity.  Only returns when the required allocation
                // is obtained.  Example, RTP port allocation, limit due to total number of allowable calls.
                ServicePrerequisites prerequisites = secureServicePrerequisites();

                try
                {
                    int transactions = processJobs(batch, serviceProviderPeer, prerequisites);
                    incrementTransactions(transactions);
                }
                catch (EngineException e)
                {
                	// Aborting
                    myLogger.error("Caught unexpected Exception", e);
                    setState(BroadcastState.ABORTING, e.errorCodeText, e.errorText);
                    updateServiceActivityCount(-batchSize);
                }
                catch (Throwable t)
                {
                    // This is unexpected. Log stack trace
                    myLogger.error("Caught unexpected Throwable", t);
                    terminate(BroadcastState.ABORTED, t + ": " + t.getMessage());
                    updateServiceActivityCount(-batchSize);
                }
                if (sleepBetweenJobs > 0)
                {
                    try
                    {
                        Thread.sleep(sleepBetweenJobs);
                    }
                    catch (InterruptedException e1)
                    {
                        // Do nothing?
                    }
                }
            }
        	// Exit thread
        	myLogger.info("Thread terminating");
        	synchronized(readyQueue)
        	{
        		readyQueue.notify();
        	}
        	System.out.println(getName() + " terminating");
        	closeServiceProvider(serviceProviderPeer);
        }
    }


    /**
     * 
     * @param broadcastType
     * @param activityRecordIdParamName - if null, default is used.
     * @param jobReportRootNodeName
     */
    protected Broadcast(String broadcastType, String activityRecordIdParamName, String jobReportRootNodeName)
    {
        this.broadcastType = broadcastType;
        this.activityRecordIdParamName = activityRecordIdParamName == null? ACTIVITY_RECORD_ID_PARAM_NAME_DEFAULT : activityRecordIdParamName;
        this.jobReportRootNodeName = jobReportRootNodeName;
        
        postback = null;
        successCount = new AtomicInteger(0);
        sleepBetweenJobs = SLEEP_BETWEEN_JOBS_DEFAULT;
        readyQueue = new LinkedBlockingQueue<Job>();
        serviceThreadPool = new ArrayList<Service>();
        recipientList = new ArrayList<Recipient>();
        scheduler = Executors.newScheduledThreadPool(SCHEDULER_THREAD_POOL_SIZE);
        resumeFlag = new Object();
        
        receiveTime = System.currentTimeMillis();
        serviceActivityCount = Integer.valueOf(0);
        transactions = Integer.valueOf(0);
        lastPauseCount = 0;
        csvLogger = Logger.getLogger(CSV_LOGGER);
    }
    
    private void incrementTransactions(int delta)
    {
    	synchronized (transactions)
    	{
    		transactions += delta;
        	lastPauseCount += delta;
    	}
    	if (pauseThreshold > 0 && lastPauseCount >= pauseThreshold) 
        {
    		pause(null, null);
        }
    }
        
	/**
     * Experimental formulation where it takes over directing
     * the activity of a Broadcast, as it should, instead of relegating
     * it to CommEngine.  This is directly invoked by CommEngine.doPost method,
     * and is much easier to read and comprehend.
     * <p>It is responsible for
     * <ul>
     * <li>Replying with HTTP response, and closing HTTP request and response
     * <li>Does broadcast and posts real-time progress, using post back queues
     * from CommEngine.
     * </ul>
     * Strategy of execution:
     * <ul>
     * <li>Decode xml request
     * <li>Set up Service threads
     * <li> Invite derived class to set up contexts, one for each of the Service threads.
     * <li>Do broadcast.
     * </ul>
     * This method is to be invoked by the CommEngine.doPost method, which fields a HTTP POST.
     * <p>
     * Adopting the use of this method by CommEngine
     * is 100% compatible with derived classes VoiceBroadcast and EmailBroadcast
     * existing today, 6/18/2016.
     * 
     * 
     * @param request
     * @param response
     * @param commEngine
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response,
            CommEngine commEngine)
    {
        myLogger.debug("Entering Broadcast.doPost method");
        BroadcastException myException = null;
        this.commEngine = commEngine;
        pauseThreshold = commEngine.getPauseThreshold();
        try
        {
        	// Check validity of operating hours parameters
        	
            boolean notInService = commEngine.notInService();
            decode(request, notInService);
            // Now that have decoded the id of this broadcast,
            // ask CommEngine to install it with its id.
            commEngine.installBroadcast(this);
        	setOperatingHours(DAILY_START_KEY, daily_start);
        	setOperatingHours(DAILY_STOP_KEY, daily_stop);
            
            if (notInService)
            {
                throw new PlatformException(PlatformError.RUNTIME_ERROR,
                        "Not in service");
            }
            if (recipientList.size() == 0)
            {
                CommonLogger.activity.info("Broadcast " + getBroadcastId() + ": No recipients");
                setState(BroadcastState.ALLDONE, "No recipients", null);
                return;
            }
            initSync(commEngine.getResources());
            for (Recipient recipient : recipientList)
            {
                readyQueue.add(mkJob(recipient));
            }
            if (state == BroadcastState.ALLDONE) return;
        }
        catch (BroadcastException e)
        {
            myException = e;
            setState(BroadcastState.ABORTING, e.errorCodeText, e.errorText);
            CommonLogger.alarm.error("Broadcast aborting: " + e.getMessage());
            myLogger.error("Broadcast aborted", e);
            return;
        }
        catch (Throwable t)
        {
            // Caught stray unexpected runtime problem
            CommonLogger.alarm.error("Broadcast aborted: " + t);
            myLogger.error("Broadcast aborted", t);
            myException = new BroadcastException(BroadcastError.PLATFORM_ERROR, t.getMessage());
            setState(BroadcastState.ABORTED, myException.errorCodeText, myException.errorText);
        }
        finally
        {
            // Return regular or error response
            String responseXML = getResponseXML(myException);
            PrintWriter writer;
            try
            {
                writer = response.getWriter();
                writer.write(responseXML);
                writer.close();
            }
            catch (IOException e)
            {
                myLogger.error("Failed to write reponse to requester.  Aborts broadcast." );
                if (state != BroadcastState.ABORTED)
                {
                    setState(BroadcastState.ABORTED, "Failed to reply to requester", e.getMessage());
                }
                return;
            }
            
            if (myException != null) return;
        }
        // So far so good, we now go ahead with completing
        // initialization.
        try
        {
             
            jobsTotal = recipientList.size();
            postback = new Postback(this,
            		getPostbackMaxQueueSize(),
            		getPostbackSenderPoolSize(),
            		getPostbackMaxBatchSize());
            
            initAsync();
            
           // Create service thread pool to dispatch jobs,
            // at the same time, setting up a list of service thread names
            // for use by derived class to set up contexts in which
            // these threads run.
            int serviceThreadPoolSize = getServiceThreadPoolSize();
            myLogger.debug("At creating service threads, serviceThreadPoolSize = " + serviceThreadPoolSize);
            List<String> serviceThreadNames = new ArrayList<String>();
            for (int i = 0; i < serviceThreadPoolSize; i++)
            {
                String threadName = broadcastId + "-service-thread." + i;
                Service serviceThread = new Service(threadName);
                serviceThreadPool.add(serviceThread);
                serviceThreadNames.add(threadName);
            }

            doBroadcast();
        }
        catch (BroadcastException e)
        {
            setState(BroadcastState.ABORTED, e.errorCodeText, e.errorText);
            CommonLogger.alarm.error("Broadcast aborted: " + e.getMessage());
            myLogger.error("Broadcast aborted", e);
        }
        catch (Exception e)
        {
            setState(BroadcastState.ABORTED, BroadcastError.UNEXPECTED_EXCEPTION.toString(), e.getMessage());
        	CommonLogger.alarm.error("Broadcast aborted: " + e.getMessage());
            myLogger.error("Broadcast aborted", e);
        }
        finally
        {
            destroyResources();
    		if (postback != null)
    		{
    			postback.wrapup();
        	    postback = null;
    		}
    	    CommonLogger.activity.info("Broadcast " + getId() + " terminated");
        }
    }
    
    protected int getPostbackMaxQueueSize()
    {
    	return commEngine.getPostbackMaxQueueSize();
    }
    
    protected int getPostbackMaxBatchSize()
    {
    	return commEngine.getPostbackMaxBatchSize();
    }
    
    protected  int getServiceThreadPoolSize()
    {
    	return commEngine.getServiceThreadPoolSize();
    }
    
    protected  int getPostbackSenderPoolSize()
    {
    	return commEngine.getPostbackSenderPoolSize();
    }
    
    protected abstract void returnPrerequisites(ServicePrerequisites prerequisites);
    
    /**
     * Creates and initializes a service provider, to be used by only one service thread.
     * If service provider is not thread-specific, then this method may return null, and
     * a common service provider is created outside of this method.
     * 
     * @return service provider as a class Object instance.
     * @throws BroadcastException
     */
    protected abstract Object getInitializedServiceProviderPeer() throws BroadcastException;

    /**
     * Obtains the required components to support a service; e.g. RTP port, or a place
     * in maximum total number of calls.  Does not return till the reequired prerequisites are obtained.
     * @return null, if no prerequisite is required, as in the case of email and sms engines.
     */
    abstract protected ServicePrerequisites secureServicePrerequisites();

    abstract public void closeServiceProvider(Object serviceProvider);

    /**
     * Makes a state transition to the given newState if the transition from
     * the current state is legal.  Also posts back a state change notification.
     * @param newState
     * @return StateChangeResult
     */
    public StateChangeResult setState(BroadcastState newState)
    {
        return setState(newState, null, null);
    }
    
    /**
     * Makes a state transition to the given newState if the transition from
     * the current state is legal.  Also posts back a state change notification.
     * @param newState
     * @return StateChangeResult
     */
    public synchronized StateChangeResult setState(BroadcastState newState,
            String reason, String stateErrorText)
    {
        boolean isLegal;
        BroadcastState prev = null;
        if (state == newState)  return new StateChangeResult(StateChangeStatus.NO_CHANGE, state, null);
        synchronized(stateSemaphore)
        {
	        List<BroadcastState> to = toStates.get(state);
	        isLegal = (to == null? false : to.contains(newState));
	        prev = state;
	        if (isLegal)
	        {
	            this.reason = reason;
	            this.stateErrorText = stateErrorText;
	            
	            CommonLogger.activity.info(String.format("Broadcast %s: State transitioned from %s to %s", broadcastId, state, newState));
	            state = newState;
	            changeStateTime = System.currentTimeMillis();
	            if (state == BroadcastState.RUNNING) serviceStartTime = changeStateTime;
	            if (prev == BroadcastState.RUNNING) serviceEndTime = changeStateTime;
	            if (postback != null)
	            {
	            	if (state == BroadcastState.ALLDONE) postback.queueReport(mkStatusReport());
	            	else postback.queueReportFirst(mkStatusReport());
	            }
	            return new StateChangeResult(StateChangeStatus.SUCCESS, newState, prev);
	        }
	        else
	        {
	            // log illegal state transition with call trace
	            Exception e = new Exception(String.format("Broadast %s ignored illegal transition from %s to %s", broadcastId, prev, newState));
	            myLogger.error(e.getMessage());
	            myLogger.debug("This exception is not thrown -- only for debugging information", e);
	            
	            return new StateChangeResult(StateChangeStatus.FORBIDDEN, prev, null);
	        }
        }
    }

	protected void setBroadcastId(String broadcastId)
	{
		if (broadcastId == null)
		    throw new IllegalArgumentException(
		            "Argument broadcastId in Broadcast.setBroadcastId method cannot be null");
		if (this.broadcastId != null)
		    throw new IllegalStateException(
		            "Broadcast.setBroadcastId method cannot be invoked more than once for a Broadcast");
		this.broadcastId = broadcastId;
	}

    protected void setLaunchRecordId(String launchRecordId)
    {
        this.launchRecordId = launchRecordId;
    }

	public String getBroadcastId()
	{
		return broadcastId;
	}

	public String getLaunchRecordId()
    {
        return launchRecordId;
    }

	/**
	 * 
	 * @param e
	 * @return HTTP response for normal case (when exception e is null), or with exception
	 */
	public String getResponseXML(BroadcastException e)
	{
		String tagName = broadcastType + "_response";
		StringBuffer responseXML = new StringBuffer("<" + tagName);
		if (broadcastId != null && broadcastId.length() > 0)
		{
			responseXML.append(" broadcast_id=\"");
			responseXML.append(broadcastId);
			responseXML.append("\"");
		}
		responseXML.append(" accepted='");
		responseXML.append(e != null || state == BroadcastState.COMPLETED ? "FALSE" : "TRUE");
		responseXML.append("'");
		if (e == null)
		{
		    if (reason != null && reason.length() > 0)
		    {
		        responseXML.append(" error='" + reason + "'");
		    }
			responseXML.append('>');
		}
		else
		{
			if (e.errorCode != null)
			{
				responseXML.append(" error='");
				responseXML.append(e.errorCode.toString());
				responseXML.append("'");
			}
			responseXML.append('>');
			if (e.errorText != null)
			{
				responseXML.append("<error_text>");
				responseXML.append(e.errorText);
				responseXML.append("</error_text>");
			}
		}
		responseXML.append("</" + tagName + '>');
		return responseXML.toString();
	}

	public String getPostbackURL()
	{
		return postbackURL;
	}

	protected String mkResponseXML(String errorCode, String errorText)
	{
		String tagName = broadcastType + "_response";
		StringBuffer responseXML = new StringBuffer("<" + tagName);
		String broadcastId = getBroadcastId();
		if (broadcastId != null && broadcastId.length() > 0)
		{
			responseXML.append(" broadcast_id=\"");
			responseXML.append(broadcastId);
			responseXML.append("\"");
		}
		responseXML.append(" accepted='");
		responseXML.append(errorCode == null ? "TRUE" : "FALSE");
		responseXML.append("'");
		if (errorCode == null)
		{
			responseXML.append('>');
		}
		else
		{
			responseXML.append(" error='");
			responseXML.append(errorCode);
			responseXML.append("'");
			responseXML.append('>');
			if (errorText != null)
			{
				responseXML.append("<error_text>");
				responseXML.append(errorText.replaceAll("\\&", "&amp;")
				        .replaceAll("<", "&lt;"));
				responseXML.append("</error_text>");
			}
		}
		responseXML.append("</" + tagName + '>');
		return responseXML.toString();
	}

	/**
	 * If finalState is final, then this state is set, and dispatcher threads are stopped.
	 * Overriding implementation may release all other resources, like timers.
	 * @param finalState
	 */
	public void terminate(BroadcastState finalState, String reason)
	{
	    if (!finalState.isFinal) throw new IllegalArgumentException("Argument finalState " + finalState + " in Broadcast.terminate method is not final");
	    StateChangeResult result = setState(finalState, reason, null);
	    switch (result.stateChangeStatus)
	    {
	    case SUCCESS:
	        break;
	    case NO_CHANGE:
	        return;
	    case FORBIDDEN:
	        myLogger.error("Not allow to terminate broadcast in " + result.currentState + " state");
	        return;
	    default: // Should not happen
	        return;
	    }
	    
	    // Wake up all dispatcher threads waiting on readyQueue so they will all stop
        synchronized(readyQueue)
        {
            readyQueue.notifyAll();
        }
        
        // Wake up all sleeping dispatcher threads for same reason.
        for(Thread t : serviceThreadPool)
        {
            try
            {
                t.interrupt();
            }
            catch (Exception e)
            {
                myLogger.warn("Interrupted while waiting for Thread " + t.getName() + " to terminate");
            }
        }
        
        // Quiesce scheduler, and terminate it.
        scheduler.shutdownNow();
	}
	
	/**
	 * Defaults to current state
	 * @return XML string 
	 */
	protected String mkStatusReport()
    {
        StringBuffer statusBf = new StringBuffer();
		String topLevelTag = broadcastType;
		String broadcastId = getBroadcastId();
		if (broadcastId == null) broadcastId = "";
		statusBf.append("<" + topLevelTag + " broadcast_id='" + broadcastId
		        + "' receive_time='" + receiveTime
		        + "' recipient_count='" + recipientList.size() + "'");
		if (launchRecordId != null)
		{
			statusBf.append(" launch_record_id='" + launchRecordId + "'>");
		}
		statusBf.append("<current_time>" + System.currentTimeMillis() + "</current_time>");
		if (serviceStartTime > 0) statusBf.append("<service_start_time>" + serviceStartTime
				+ "</service_start_time>");
		if (state.isFinal && serviceEndTime > 0) statusBf.append("<service_end_time>" + serviceEndTime
				+ "</service_end_time>");
		statusBf.append("<state>" + state + "</state><state_change_time>" + changeStateTime
		        + "</state_change_time>");
		statusBf.append("<reason>" + (reason == null? "" : Util.xmlEscape(reason))
		        + "</reason>");
		statusBf.append("<error_text>" + (stateErrorText == null? "" : Util.xmlEscape(stateErrorText))
		        + "</error_text>");
		statusBf.append("<transactions>" + transactions + "</transactions>");
		statusBf.append("<success>" + successCount.intValue() + "</success>");
		statusBf.append("<job_summary completed='" + getCompletedJobCount() +
		        "' ready='" + getPendingJobCount() + "'");
		statusBf.append(" active='" + getActiveJobCount() + "'");
		statusBf.append("></job_summary>\n");
		statusBf.append("<daily_stop>" + daily_stop + "</daily_stop>");
		statusBf.append("<daily_start>" + daily_start + "</daily_start>\n");
		statusBf.append(additionalStatusXML());
		statusBf.append("</" + topLevelTag + ">");
		String statusReport = statusBf.toString();
        return statusReport;
    }

	/**
	 * Derived class may add additional status in a broadcast status XML posted back to portal,
	 * by returning an XML tag which will be included immediately in the top-level tag
	 * of the broadcast status.
	 */
	protected String additionalStatusXML() 
	{
		return "";
	}
	
	/**
	 * 
     * @return instantaneous number of jobs being serviced by service provider
     */
	protected int getActiveJobCount()
	{
		return serviceActivityCount;
	}

	/**
	 * Parses broadcastId and return if notInService is true.
	 * Otherwise, continue parsing postBackUrl, recipientList,
	 * and implementation-specific data from request.
	 * Avoid throwing an exception before parsing and setting broadcastId.
	 * @param notInService 
	 * @throws EngineException 
     */
	protected abstract void decode(HttpServletRequest request, boolean notInService)
	        throws EngineException;

    protected abstract void initSync(EngineResources resources) throws BroadcastException;
    
    protected Job mkJob(Recipient recipient)
    {
        return new Job(recipient);
    }

    /**
     * Overriding implementation performs time consuming initialization, after returning
     * POST http status indicating accepting broadcast for processing.
     * 
     * @throws BroadcastException - to abort broadcast
     */
    protected void initAsync() throws BroadcastException
    {
        // Do nothing in base class.
    }
    
	public String getId()
	{
		return broadcastId;
	}

	/**
	 * Sets the stateMachine to CANCEL
	 * @param reasons - may be null.
	 */
	protected void cancel(String reason, PrintWriter out)
	{
	    BroadcastState targetState = getActiveJobCount() == 0?
	            BroadcastState.CANCELED : BroadcastState.CANCELING;
	    StateChangeResult result = setState(targetState, reason, null);
	    String responseContent = null;
	    switch (result.stateChangeStatus)
	    {
	    case SUCCESS:
	        responseContent = "Broadcast is being canceled";
	        break;
	    case NO_CHANGE:
	        responseContent = "Already canceled";
	        break;
	    case FORBIDDEN:
	        responseContent = "Not canceled: Not allowed to cancel a broadcast in " + result.currentState + " state";
	    }
	    out.write(responseContent);

	    wakeUpServiceThreads();
	}

	/**
	 * 
	 * @param reason
	 * @param out
	 */
	protected void pause(String reason, PrintWriter out)
    {
		if (state == BroadcastState.ACCEPTED || state.isFinal) return;

		// Sets state to PAUSING, which is monitored by Broadcast.Service threads.
		// EVentually, when all service activity ends, the state transitions to PAUSED
		StateChangeResult result = setState(BroadcastState.PAUSING, reason, null);
		switch (result.stateChangeStatus)
		{
		case FORBIDDEN:
			if (out != null) out.write("pause not allowed");
			break;
		case SUCCESS:
			lastPauseCount = 0;
			if (out != null) out.write("Broadcast is being PAUSED");
			break;
		case NO_CHANGE:
			if (out != null) out.write("Broadcast is already RUNNING");
		}
    }
	
	protected void resume(String reason, PrintWriter out)
	{
		if (state == BroadcastState.ACCEPTED || state.isFinal) return;
		if (!withinOperatingHours())
		{
			if (out != null) out.write("Cannot resume outside operating hours");
			return;
		}
	    synchronized (resumeFlag)
	    {
			StateChangeResult result = setState(BroadcastState.RUNNING, reason, null);
			switch (result.stateChangeStatus)
			{
			case FORBIDDEN:
				if (out != null) out.write("resume not allowed");
				break;
			case SUCCESS:
				if (out != null) out.write("Broadcast resumed");
				resumeFlag.notifyAll();
				break;
			default:
				break;
			}
	    }
	}
	/**
	 * Derived class may make its own Implementation of JobReport
	 * @return
	 */
    protected JobReport mkJobReport()
    {
        return new JobReport();
    }

	public void addJob(Job job)
	{
	    synchronized(readyQueue)
	    {
	        readyQueue.add(job);
	        readyQueue.notifyAll();
	    }
	}
	
	/**
	 * For use by the new Broadcast.doPost method.
	 * It changes state to RUNNING and waits for all Service threads
	 * to terminate after starting them. 
	 * @throws BroadcastException
	 */
	public void doBroadcast() throws BroadcastException
    {
		changeStateTime = System.currentTimeMillis();
		if (!serviceThreadsShouldStop())
		{
			if (withinOperatingHours())
			{
				setState(BroadcastState.RUNNING);
			}
			else
			{
				setState(BroadcastState.PAUSED, "clock", null);
			}
	
	        // Start the dispatcher threads
	        for (Service thread : serviceThreadPool)
	        {
	            thread.start();
	        }
	        
	        // Wait for them to finish
	        for (Service thread : serviceThreadPool)
	        {
	            try
	            {
	                thread.join();
	            }
	            catch (InterruptedException e)
	            {
	                myLogger.error("Caught exception while waiting for a Service thread to terminate:" + e);
	            }
	        }
	        waitForEndOfService();
		}
    }
	
	private boolean withinOperatingHours() {
		if (daily_start == null || daily_start.trim().length() == 0) return true;
		int dailyStartMin = convert2Min(daily_start);
		if (daily_stop == null || daily_stop.trim().length() == 0) return true;
		int dailyStopMin = convert2Min(daily_stop);
		// Ensure daily stop > daily start
		if (dailyStopMin < dailyStartMin) dailyStopMin += 24 * 60;
		LocalTime now = LocalTime.now();
		int nowMin = now.getHour() * 60 + now.getMinute();
		if (nowMin < dailyStartMin) nowMin += 24 * 60;
		boolean within = nowMin >= dailyStartMin && nowMin < dailyStopMin;
		return within;
	}

	private int convert2Min(String hhmm) {
		String[] parts = hhmm.split(":");
		int hh = Integer.parseInt(parts[0]);
		int mm = Integer.parseInt(parts[1]);
		return hh * 60 + mm;
	}

	/**
	 * Derived class should wait for end of service before returning.
	 * At this point all service threads have already ended.  If the derived
	 * class has other threads still taking part in providing service, wait for
	 * them to terminate.
	 */
	protected void waitForEndOfService() {}

	/**
	 * Derived class destroy resources needed for providing service
	 */
	protected void destroyResources() {}

	/**
	 * Derived may release resources here.
	 */
	protected void close()
	{
		myLogger.debug("In close()");;
		postback.wrapup();
	    postback = null;
	}
	
	/**
	 * Derived class may set up environment before starting Service threads.
	 * @param serviceThreadNames 
	 */
	protected void initServiceThreadContexts()
	{
	    // Do nothing in base class
	}
	
    /**
     * Experimental - needed to go with the also experimental method exec.
     * @param serviceThreadNames
     */
	protected void initServiceThreadContexts(List<String> serviceThreadNames)
    {
        // Do nothing in base class
    }
    
	/**
	 * Examines if service threads should stop running, or even start
	 * 
	 * @return
	 */
	private boolean serviceThreadsShouldStop()
	{
		if (state == BroadcastState.CANCELING ||
				state == BroadcastState.ABORTING ||
				state.isFinal)
		{
			return true;
		}
	    if (getRemainingJobCount() == 0)
		{
	    	wakeUpServiceThreads();
			return true;
		}
	    return false;
	}
	
	private void wakeUpServiceThreads()
	{
		synchronized (readyQueue)
		{
			readyQueue.notifyAll();
		}
		synchronized (resumeFlag)
		{
			resumeFlag.notifyAll();
		}
	}

	private boolean serviceThreadsShouldPause()
	{
		return state == BroadcastState.PAUSED || state == BroadcastState.PAUSING;
	}
	
	/**
	 * job status is reported back to this broadcast, via the logAndQueueForPostBack method.
	 * This method should use the updateServiceActivityCount(+-1) method to allow Broadcast 
	 * to keep track of overall service progress. The serviceActvityCount is used to determine
	 * if all service threads are idle or terminated.
	 * @param batch
	 * @param prerequisites 
	 * @return int - number of transactions employed to service these jobs.
	 * @throw Exception to abort broadcast
	 */
	abstract protected int processJobs(List<Job> batch, Object serviceProvider, ServicePrerequisites prerequisites)
	        throws EngineException;

	/**
	 * Size of a batch of jobs to be processed together.  For email, this may be more than 1,
	 * and this method should be overridden.
	 * @return size of a batch of jobs to be processed together.
	 */
    protected int getJobBatchSize()
    {
        return 1;
    }
    
    protected void updateServiceActivityCount(int increment)
    {
    	synchronized (readyQueue)
    	{
	    	serviceActivityCount += increment;
	    	myLogger.debug("serviceActivityCount = " + serviceActivityCount );
	    	if (increment < 0 && serviceActivityCount <= 0)
	    	{
	    		if (state == BroadcastState.RUNNING
	    		   || state == BroadcastState.PAUSING
	    		   || state == BroadcastState.CANCELING
	    		   ) 
    			{
	    			if (getRemainingJobCount() == 0) {
	    				setState(BroadcastState.COMPLETED);
	    			}
    			}
	    	}
    	}
    }

    /**
     * Sets jobStatus in job, and post job report.
     * If jobStatus is final, and no rescheduling, 
     * then decrement number of remainingJobs,and increment completedJobCount.
     * @param job
     * @param jobStatus
     * @param errorText
     */
    public void postJobStatus(Job job)
    {
    	if (job.isBroadcastFatal()) setState(BroadcastState.ABORTING, job.getErrorText(), null);
        if (job.jobStatus == CommJobStatus.SUCCESS) successCount.incrementAndGet();
        if (postback != null)
        {
           JobReport report = mkJobReport();
           report.initBase(job, broadcastId, launchRecordId, activityRecordIdParamName, jobReportRootNodeName);
           report.init(job);
           postback.queueReport(report.toString());
           if (job.statusIsFinal()) updateServiceActivityCount(-1);
        }
	}
	
	/**
	 * Logs completedJobCount, readyQueue.size(),
	 * active job count, and total.
     * Job statistics are collected by length of readyQueue, completedJobCount,
	 */
	private void logJobCount(String title)
    {
		if (postback == null) {
			myLogger.debug(title + ": postback = null");
	        myLogger.debug(String.format("%s: state %s, completed: %d, active: %d, ready: %d, scheduled: %d, total jobs: %d, remaining: %d, postQueue: ",
	                title,
	                state,
	                getCompletedJobCount(),
	                getActiveJobCount(),
	                readyQueue.size(),
	                scheduledJobs,
	                jobsTotal,
	                getRemainingJobCount()
	                ));
			return;
		}
		if (postback.postQueue == null) {
			myLogger.debug(title + ": postback.postQueue = null");
	        myLogger.debug(String.format("%s: state %s, completed: %d, active: %d, ready: %d, scheduled: %d, total jobs: %d, remaining: %d, postQueue: ",
	                title,
	                state,
	                getCompletedJobCount(),
	                getActiveJobCount(),
	                readyQueue.size(),
	                scheduledJobs,
	                jobsTotal,
	                getRemainingJobCount()
	                ));
			return;
		}
        myLogger.debug(String.format("%s: state %s, completed: %d, active: %d, ready: %d, scheduled %d, total jobs: %d, remaining: %d, postQueue: %d",
                title,
                state,
                getCompletedJobCount(),
                getActiveJobCount(),
                readyQueue.size(),
                scheduledJobs,
                jobsTotal,
                getRemainingJobCount(),
                postback.postQueue.size()
                ));
    }

	/**
	 * Number of jobs to be completed.
	 * @return
	 */
    private int getRemainingJobCount()
    {
    	synchronized(readyQueue) {
    		return readyQueue.size() + scheduledJobs;
    	}
    }

    public ScheduledFuture<?> rescheduleJob(final Job job, long rescheduleTimeMS)
	{
    	if (rescheduleTimeMS < 0) return null;
    	
    	// No more rescheduling on cancel, abort, or alldone
        if (state == BroadcastState.CANCELING
                || state == BroadcastState.CANCELED
                || state == BroadcastState.ABORTED
                || state == BroadcastState.ABORTING
                || state == BroadcastState.ALLDONE
                )  
        {
            return null;
        }
        
    	job.errorText = "";
		if (rescheduleTimeMS == 0)
	    {
	        addJob(job);
            return null;
	    }

    	synchronized(readyQueue) {
    		scheduledJobs++;
    	}
        Runnable r = new Runnable() { public void run() { 
	        	synchronized(readyQueue) {
	        		scheduledJobs--;
		        	addJob(job);
	        	}
        	}
        };
        return scheduler.schedule(r, rescheduleTimeMS, TimeUnit.MILLISECONDS);	    
	}
	
    public BroadcastState getState()
    {
        return state;
    }

    public int getPendingJobCount()
    {
        switch (state)
        {
        case RUNNING:
        case PAUSING:
        case PAUSED:
            return getRemainingJobCount();
        default:
            return 0;    
        }
    }

    public int getCompletedJobCount()
    {
    	synchronized(readyQueue)
    	{
    		return jobsTotal - getRemainingJobCount() - serviceActivityCount;
    	}
    }

	public String getBroadcastType() {
		return broadcastType;
	}

	/**
	 * To be invoked only when postQueue is empty.
	 * Side effect: sets broadcast state from PAUSING to PAUSE 
	 * when there are no active jobs being processed.
	 * Similarly from CANCELING to CANCELED, from ABORTING to ABORTED, from COMPLETED to ALLDONE
	 * @return
	 */
	public PostbackThreadActionOnEmpty getPostbackThreadActionOnEmpty() {
		myLogger.debug(String.format(
				"getPostbackThreadActionOnEmpty(): broadcast state %s, serviceActivityCount %d",
				state, serviceActivityCount));
		if (state.isFinal) return PostbackThreadActionOnEmpty.STOP;
		
		if (serviceActivityCount > 0) {
			return PostbackThreadActionOnEmpty.WAIT;
		}
		
		if (state == BroadcastState.PAUSING) { 
			return setState(BroadcastState.PAUSED, reason, stateErrorText).stateChangeStatus == StateChangeStatus.SUCCESS? 
					PostbackThreadActionOnEmpty.CONTINUE : PostbackThreadActionOnEmpty.WAIT; 
		}
		if (state == BroadcastState.CANCELING) { 
			return setState(BroadcastState.CANCELED, reason, stateErrorText).stateChangeStatus == StateChangeStatus.SUCCESS? 
					PostbackThreadActionOnEmpty.CONTINUE : PostbackThreadActionOnEmpty.STOP; 
		}
		else if (state == BroadcastState.ABORTING) {
			return setState(BroadcastState.ABORTED, reason, stateErrorText).stateChangeStatus == StateChangeStatus.SUCCESS? 
					PostbackThreadActionOnEmpty.CONTINUE : PostbackThreadActionOnEmpty.STOP; 
		}
		else if (state == BroadcastState.COMPLETED && scheduledJobs == 0) {
			return setState(BroadcastState.ALLDONE).stateChangeStatus == StateChangeStatus.SUCCESS? 
					PostbackThreadActionOnEmpty.CONTINUE : PostbackThreadActionOnEmpty.STOP; 
		}
		else {
			return PostbackThreadActionOnEmpty.WAIT;
		}
	}

	/**
	 * @return null or configuration in XML
	 */
	public String getConfigXML() 
	{
		StringBuffer configBuf = new StringBuffer();
		configBuf.append("<broadcast_configuration broadcast_id='" + broadcastId + "'>");
		configBuf.append("<" + DAILY_STOP_KEY + ">" + daily_stop + "</" + DAILY_STOP_KEY + ">");
		configBuf.append("<" + DAILY_START_KEY + ">" + daily_start + "</" + DAILY_START_KEY + ">");
		configBuf.append("</broadcast_configuration>");
		return configBuf.toString();
	}

	public void configure(JSONObject configuration) throws Exception {
		boolean timeChanged = false;
		for (String key : new String[] {DAILY_STOP_KEY, DAILY_START_KEY}) {
			String value = (String)configuration.get(key);
			if (setOperatingHours(key, value)) {
				timeChanged = true;
			}
		}
		if (timeChanged) enforceOperationHours();
	}

	/**
	 * YML:  At this time, we only enforce pause action when a broadcast is
	 * outside its operating hours.  The current design is not satisfactory and needs
	 * a better solution.
	 *  
	 * We are not automatically resuming a paused broadcast because the difference
	 * between intention of an operator-initiated pause and 
	 * that of a clock pause needs clarification in their operation paradigm.
	 * Question is when or if we allow a operator-initiated pause be resumed
	 * when someone changes the operating hours of a broadcast in such a way
	 * that the broadcast is at once within its operasting hours.  it may be 
	 * be counter to the intention of the original operator.
	 * 
	 * On the other hand, if that places the broadcast outside it operating hours,
	 * it is safer to immediately pause it.
	 * 
	 * To add clarity, we may need to separate the PAUSE state into OPERATOR_PAUSE and CLOCK_PAUSE,
	 * and similarly PAUING state.
	 */
	void enforceOperationHours() {
		if (state == BroadcastState.ABORTED) return;
		if (withinOperatingHours()) {
//			resume("clock", null);
		} else {
			pause("clock", null);
		}
	}

	/**
	 * Sets timeParam to value
	 * @param timeParam
	 * @param value
	 * @return false if no change
	 */
	private boolean setOperatingHours(String timeParam, String value) {
		if (value == null || value.trim().length() == 0) return false;
		String timeOfDay = CommEngine.checkTimeOfDay(value);
		if (timeOfDay == null) throw new RuntimeException(String.format("Invalid value for %s: %s", timeParam, value));
		switch (timeParam) {
		case DAILY_STOP_KEY:
			if (timeOfDay.equals(daily_stop)) return false;
			daily_stop = timeOfDay;
			return true;
		case DAILY_START_KEY:
			if (timeOfDay.equals(daily_start)) return false;
			daily_start = timeOfDay;
			return true;
		default:
			throw new RuntimeException("Unknown parameter name: " + timeParam);
		}
	}

	@SuppressWarnings("unchecked")
	public JSONObject getConfigJSON() {
    	JSONObject dataMap = new JSONObject();
    	dataMap.put(DAILY_START_KEY, daily_start);
    	dataMap.put(DAILY_STOP_KEY, daily_stop);
    	childAddConfigJSON(dataMap);
		return dataMap;
	}

    public void logCSV(String[] data)
    {
        StringWriter writer = new StringWriter();
        @SuppressWarnings("resource")
		CSVWriter csvWriter = new CSVWriter(writer);
        csvWriter.writeNext(data);
        csvLogger.info(writer);
    }

	protected void childAddConfigJSON(JSONObject dataMap) {
	}

}