package com.commafeed.backend.services;

import java.util.Date;
import java.util.List;

import javax.ejb.Stateless;
import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.apache.commons.codec.digest.DigestUtils;

import com.commafeed.backend.MetricsBean;
import com.commafeed.backend.cache.CacheService;
import com.commafeed.backend.dao.FeedEntryDAO;
import com.commafeed.backend.dao.FeedEntryStatusDAO;
import com.commafeed.backend.dao.FeedSubscriptionDAO;
import com.commafeed.backend.model.Feed;
import com.commafeed.backend.model.FeedEntry;
import com.commafeed.backend.model.FeedEntryContent;
import com.commafeed.backend.model.FeedSubscription;
import com.commafeed.backend.model.User;
import com.google.common.collect.Lists;

@Stateless
public class FeedUpdateService {

	@PersistenceContext
	protected EntityManager em;

	@Inject
	FeedSubscriptionDAO feedSubscriptionDAO;

	@Inject
	FeedEntryDAO feedEntryDAO;

	@Inject
	FeedEntryStatusDAO feedEntryStatusDAO;

	@Inject
	MetricsBean metricsBean;

	@Inject
	CacheService cache;

	@Inject
	FeedEntryContentService feedEntryContentService;

	/**
	 * this is NOT thread-safe
	 */
	public void updateEntry(Feed feed, FeedEntry entry, List<FeedSubscription> subscriptions) {

		FeedEntry existing = feedEntryDAO.findExisting(entry.getGuid(), entry.getUrl(), feed.getId());
		if (existing != null) {
			return;
		}

		FeedEntryContent content = feedEntryContentService.findOrCreate(entry.getContent(), feed.getLink());
		entry.setGuidHash(DigestUtils.sha1Hex(entry.getGuid()));
		entry.setContent(content);
		entry.setInserted(new Date());
		entry.setFeed(feed);

		List<User> users = Lists.newArrayList();
		for (FeedSubscription sub : subscriptions) {
			User user = sub.getUser();
			users.add(user);
		}
		feedEntryDAO.saveOrUpdate(entry);
		metricsBean.entryInserted();
		cache.invalidateUnreadCount(subscriptions.toArray(new FeedSubscription[0]));
		cache.invalidateUserRootCategory(users.toArray(new User[0]));
	}
}