package org.alfresco.repo.activities.feed;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

import org.alfresco.model.ContentModel;
import org.alfresco.query.PagingRequest;
import org.alfresco.query.PagingResults;
import org.alfresco.repo.admin.SysAdminParams;
import org.alfresco.repo.batch.BatchProcessWorkProvider;
import org.alfresco.repo.batch.BatchProcessor;
import org.alfresco.repo.dictionary.RepositoryLocation;
import org.alfresco.repo.lock.JobLockService;
import org.alfresco.repo.lock.LockAcquisitionException;
import org.alfresco.repo.security.authentication.AuthenticationUtil;
import org.alfresco.repo.transaction.RetryingTransactionHelper;
import org.alfresco.service.cmr.admin.RepoAdminService;
import org.alfresco.service.cmr.model.FileFolderService;
import org.alfresco.service.cmr.repository.InvalidNodeRefException;
import org.alfresco.service.cmr.repository.NodeRef;
import org.alfresco.service.cmr.repository.NodeService;
import org.alfresco.service.cmr.repository.StoreRef;
import org.alfresco.service.cmr.search.SearchService;
import org.alfresco.service.cmr.security.PersonService;
import org.alfresco.service.cmr.security.PersonService.PersonInfo;
import org.alfresco.service.namespace.NamespaceService;
import org.alfresco.service.namespace.QName;
import org.alfresco.service.transaction.TransactionService;
import org.alfresco.util.ModelUtil;
import org.alfresco.util.Pair;
import org.alfresco.util.PropertyCheck;
import org.alfresco.util.UrlUtil;
import org.alfresco.util.VmShutdownListener;
import org.alfresco.util.VmShutdownListener.VmShutdownException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.extensions.surf.util.I18NUtil;

/**
 * Implementation of the Activity Feed Notifier component
 * 
 * Note: currently implemented to email activities stored in JSON format
 * 
 * @since 4.0
 */
public class FeedNotifierImpl implements FeedNotifier, ApplicationContextAware
{
    protected static Log logger = LogFactory.getLog(FeedNotifier.class);
    
    private static final QName LOCK_QNAME = QName.createQName(NamespaceService.SYSTEM_MODEL_1_0_URI, "ActivityFeedNotifier");
    private static final long LOCK_TTL = 30000L;
    
    private static VmShutdownListener vmShutdownListener = new VmShutdownListener(FeedNotifierImpl.class.getName());
    
    private static final String MSG_EMAIL_SUBJECT = "activities.feed.notifier.email.subject";
    
    private NamespaceService namespaceService;
    private FileFolderService fileFolderService;
    private SearchService searchService;
    private PersonService personService;
    private NodeService nodeService;
    private JobLockService jobLockService;
    private TransactionService transactionService;
    private SysAdminParams sysAdminParams;
    private RepoAdminService repoAdminService;
    private UserNotifier userNotifier;
    
    private ApplicationContext applicationContext;
    
    private RepositoryLocation feedEmailTemplateLocation;
    
    private int numThreads = 4;
    private int batchSize = 200;
    
    public void setNumThreads(int numThreads)
    {
    	this.numThreads = numThreads;
    }
    
    public void setBatchSize(int batchSize)
    {
    	this.batchSize = batchSize;
    }
    
    public void setUserNotifier(UserNotifier userNotifier)
    {
		this.userNotifier = userNotifier;
	}
    
    public void setFileFolderService(FileFolderService fileFolderService)
    {
		this.fileFolderService = fileFolderService;
	}

	public void setSearchService(SearchService searchService)
	{
		this.searchService = searchService;
	}

	public void setNamespaceService(NamespaceService namespaceService)
	{
		this.namespaceService = namespaceService;
	}

    public void setPersonService(PersonService personService)
    {
        this.personService = personService;
    }
    
    public void setNodeService(NodeService nodeService)
    {
        this.nodeService = nodeService;
    }

    public void setJobLockService(JobLockService jobLockService)
    {
        this.jobLockService = jobLockService;
    }
    
    public void setTransactionService(TransactionService transactionService)
    {
        this.transactionService = transactionService;
    }
    
    public void setSysAdminParams(SysAdminParams sysAdminParams)
    {
        this.sysAdminParams = sysAdminParams;
    }
    
    public void setRepoAdminService(RepoAdminService repoAdminService)
    {
        this.repoAdminService = repoAdminService;
    }
    
    /**
     * Perform basic checks to ensure that the necessary dependencies were injected.
     */
    protected void checkProperties()
    {
        PropertyCheck.mandatory(this, "personService", personService);
        PropertyCheck.mandatory(this, "nodeService", nodeService);
        PropertyCheck.mandatory(this, "jobLockService", jobLockService);
        PropertyCheck.mandatory(this, "transactionService", transactionService);
        PropertyCheck.mandatory(this, "sysAdminParams", sysAdminParams);
    }
    
    public void execute(int repeatIntervalMins)
    {
        checkProperties();
        
        // Bypass if the system is in read-only mode
        if (transactionService.isReadOnly())
        {
            if (logger.isDebugEnabled())
            {
                logger.debug("Activities email notification bypassed; the system is read-only");
            }
            return;
        }

        String lockToken = getLock(LOCK_TTL);

        try
        {
            if (logger.isTraceEnabled())
            {
                logger.trace("Activities email notification started");
            }

            executeInternal(lockToken, repeatIntervalMins);
            
            // Done
            if (logger.isTraceEnabled())
            {
                logger.trace("Activities email notification completed");
            }
        }
        catch (LockAcquisitionException e)
        {
            // Job being done by another process
            if (logger.isDebugEnabled())
            {
                logger.debug("Activities email notification already underway");
            }
        }
        catch (VmShutdownException e)
        {
            // Aborted
            if (logger.isDebugEnabled())
            {
                logger.debug("Activities email notification aborted");
            }
        }
        finally
        {
            releaseLock(lockToken);
        }
    }

    public void setFeedEmailTemplateLocation(RepositoryLocation feedEmailTemplateLocation)
    {
        this.feedEmailTemplateLocation = feedEmailTemplateLocation;
    }
    
    private NodeRef getEmailTemplateRef()
    {
        StoreRef store = feedEmailTemplateLocation.getStoreRef();
        String xpath = feedEmailTemplateLocation.getPath();
        
        if (! feedEmailTemplateLocation.getQueryLanguage().equals(SearchService.LANGUAGE_XPATH))
        {
            logger.warn("Cannot find the activities email template - repository location query language is not 'xpath': "+feedEmailTemplateLocation.getQueryLanguage());
            return null;
        }
        
        List<NodeRef> nodeRefs = searchService.selectNodes(nodeService.getRootNode(store), xpath, null, namespaceService, false);
        if (nodeRefs.size() != 1)
        {
            logger.warn("Cannot find the activities email template: "+xpath);
            return null;
        }

        return fileFolderService.getLocalizedSibling(nodeRefs.get(0));
    }
    
    private void executeInternal(final String lockToken, final int repeatIntervalMins)
    {
        final NodeRef emailTemplateRef = getEmailTemplateRef();
        
        if (emailTemplateRef == null)
        {
            return;
        }

        final String shareUrl = UrlUtil.getShareUrl(sysAdminParams); 

        if (logger.isDebugEnabled())
        {
            logger.debug("Share URL configured as: "+shareUrl);
        }

        final AtomicInteger userCnt = new AtomicInteger(0);
        final AtomicInteger feedEntryCnt = new AtomicInteger(0);

        long startTime = System.currentTimeMillis();

        // local cache for this execution
        final Map<String, String> siteNames = new ConcurrentHashMap<String, String>(10);

        try
        {
            final String subjectText = buildSubjectText(startTime);
            final String currentUser = AuthenticationUtil.getFullyAuthenticatedUser();

            // process the feeds using the batch processor {@link BatchProcessor}
	        BatchProcessor.BatchProcessWorker<PersonInfo> worker = new BatchProcessor.BatchProcessWorker<PersonInfo>()
	        {
	            public String getIdentifier(final PersonInfo person)
	            {
	            	StringBuilder sb = new StringBuilder("Person ");
	                sb.append(person.getUserName());
	                return sb.toString();
	            }

	            public void beforeProcess() throws Throwable
	            {
	                AuthenticationUtil.setRunAsUser(currentUser);

	                refreshLock(lockToken, batchSize * 500L);
	            }

	            public void afterProcess() throws Throwable
	            {
	            }

	            public void process(final PersonInfo person) throws Throwable
	            {
	            	final NodeRef personNodeRef = person.getNodeRef();

	                try
	                {
	                    Pair<Integer, Long> result = userNotifier.notifyUser(personNodeRef, subjectText, siteNames, shareUrl, repeatIntervalMins, emailTemplateRef);
	                    if (result != null)
	                    {
	                        int entryCnt = result.getFirst();
	                        final long maxFeedId = result.getSecond();

	                        Long currentMaxFeedId = (Long)nodeService.getProperty(personNodeRef, ContentModel.PROP_EMAIL_FEED_ID);
	                        if ((currentMaxFeedId == null) || (currentMaxFeedId < maxFeedId))
	                        {
	                        	nodeService.setProperty(personNodeRef, ContentModel.PROP_EMAIL_FEED_ID, maxFeedId);
	                        }

	                        userCnt.incrementAndGet();
	                        feedEntryCnt.addAndGet(entryCnt);
	                    }
	                }
	                catch (InvalidNodeRefException inre)
	                {
	                    // skip this person - eg. no longer exists ?
	                    logger.warn("Skip feed notification for user ("+personNodeRef+"): " + inre.getMessage());
	                }
	            }
	        };

	        // grab people for the batch processor in chunks of size batchSize
	        BatchProcessWorkProvider<PersonInfo> provider = new BatchProcessWorkProvider<PersonInfo>()
			{
	        	private int skip = 0;
	        	private int maxItems = batchSize;

				@Override
				public int getTotalEstimatedWorkSize()
				{
					return personService.countPeople();
				}

				@Override
				public Collection<PersonInfo> getNextWork()
				{
				    PagingResults<PersonInfo> people = personService.getPeople(null, true, null, new PagingRequest(skip, maxItems));
				    skip += maxItems;
				    return people.getPage();
				}
			};

            final RetryingTransactionHelper txHelper = transactionService.getRetryingTransactionHelper();
            txHelper.setMaxRetries(0);

	        new BatchProcessor<PersonInfo>(
	                "FeedNotifier",
	                txHelper,
	                provider,
	                numThreads, batchSize,
	                applicationContext,
	                logger, 100).process(worker, true);
        }
        catch (Throwable e)
        {
            // If the VM is shutting down, then ignore
            if (vmShutdownListener.isVmShuttingDown())
            {
                // Ignore
            }
            else
            {
                logger.error("Exception during notification of feeds", e);
            }
        }
        finally
        {
        	int count = userCnt.get();
        	int entryCount = feedEntryCnt.get();

            // assume sends are synchronous - hence bump up to last max feed id
            if (count > 0)
            {
                if (logger.isInfoEnabled())
                {
                    // TODO i18n of info message
                    StringBuilder sb = new StringBuilder();
                    sb.append("Notified ").append(userCnt).append(" user").append(count != 1 ? "s" : "");
                    sb.append(" of ").append(feedEntryCnt).append(" activity feed entr").append(entryCount != 1 ? "ies" : "y");
                    sb.append(" (in ").append(System.currentTimeMillis()-startTime).append(" msecs)");
                    logger.info(sb.toString());
                }
            }
            else
            {
                if (logger.isTraceEnabled())
                {
                    logger.trace("Nothing to send since no new user activities found");
                }
            }
        }
    }
    
    protected String buildSubjectText(long currentTime)
    {
        return I18NUtil.getMessage(MSG_EMAIL_SUBJECT, ModelUtil.getProductName(repoAdminService));
    }
    
    private String getLock(long time)
    {
        try
        {
            return jobLockService.getLock(LOCK_QNAME, time);
        }
        catch (LockAcquisitionException e)
        {
            return null;
        }
    }
    
    protected void refreshLock(String lockToken, long time)
    {
        if (lockToken == null)
        {
            throw new IllegalArgumentException("Must provide existing lockToken");
        }
        jobLockService.refreshLock(lockToken, LOCK_QNAME, time);
    }
    
    /**
     * Release the lock after the job completes
     */
    private void releaseLock(String lockToken)
    {
	    if (lockToken == null)
	    {
	        throw new IllegalArgumentException("Must provide existing lockToken");
	    }
	    jobLockService.releaseLock(lockToken, LOCK_QNAME);
    }

	@Override
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException
	{
		this.applicationContext = applicationContext;
	}
}