package org.gcube.portal.social.networking.ws.utils;

import static org.gcube.resources.discovery.icclient.ICFactory.client;

import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.UUID;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.gcube.applicationsupportlayer.social.ApplicationNotificationsManager;
import org.gcube.applicationsupportlayer.social.NotificationsManager;
import org.gcube.applicationsupportlayer.social.ex.ApplicationProfileNotFoundException;
import org.gcube.applicationsupportlayer.social.shared.SocialNetworkingSite;
import org.gcube.applicationsupportlayer.social.shared.SocialNetworkingUser;
import org.gcube.common.authorization.library.utils.Caller;
import org.gcube.common.resources.gcore.utils.XPathHelper;
import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.portal.databook.shared.ApplicationProfile;
import org.gcube.portal.databook.shared.Comment;
import org.gcube.portal.databook.shared.Like;
import org.gcube.portal.databook.shared.Post;
import org.gcube.portal.databook.shared.PostType;
import org.gcube.portal.databook.shared.PrivacyLevel;
import org.gcube.portal.databook.shared.ex.FeedIDNotFoundException;
import org.gcube.portal.notifications.bean.GenericItemBean;
import org.gcube.portal.notifications.thread.CommentNotificationsThread;
import org.gcube.portal.notifications.thread.LikeNotificationsThread;
import org.gcube.portal.notifications.thread.MentionNotificationsThread;
import org.gcube.portal.notifications.thread.PostNotificationsThread;
import org.gcube.portal.social.networking.caches.SocialNetworkingSiteFinder;
import org.gcube.portal.social.networking.liferay.ws.GroupManagerWSBuilder;
import org.gcube.portal.social.networking.liferay.ws.UserManagerWSBuilder;
import org.gcube.portlets.widgets.pickitem.shared.ItemBean;
import org.gcube.resources.discovery.client.api.DiscoveryClient;
import org.gcube.resources.discovery.client.queries.api.Query;
import org.gcube.resources.discovery.client.queries.impl.QueryBox;
import org.gcube.social_networking.socialutillibrary.Utils;
import org.gcube.socialnetworking.socialtoken.SocialMessageParser;
import org.gcube.vomanagement.usermanagement.GroupManager;
import org.gcube.vomanagement.usermanagement.UserManager;
import org.gcube.vomanagement.usermanagement.exception.TeamRetrievalFault;
import org.gcube.vomanagement.usermanagement.exception.UserManagementSystemException;
import org.gcube.vomanagement.usermanagement.exception.UserRetrievalFault;
import org.gcube.vomanagement.usermanagement.impl.LiferayUserManager;
import org.gcube.vomanagement.usermanagement.model.GCubeUser;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;

/**
 * Utility class.
 */
@SuppressWarnings("deprecation")
public class SocialUtils {

	// Logger
	private static final org.slf4j.Logger logger = LoggerFactory.getLogger(SocialUtils.class);

	public final static String NO_TEXT_FILE_SHARE = "_N0_73X7_SH4R3_";
	public final static int CACHING_TIME_TO_EXPIRATION = 2506000;//29 days 6 minutes 40 seconds 
	public final static String DISABLED_USERS_NOTIFICATIONS_NAMESPACE = "dun:";

	// name of the portlet for vre notification
	public static final String NEWS_FEED_PORTLET_CLASSNAME = "org.gcube.portlets.user.newsfeed.server.NewsServiceImpl";

	/**
	 * 
	 * @param mentions the set of string containing the usernames
	 * @return a list of existing usernames associated with their fullnames
	 */
	private static ArrayList<GenericItemBean> getUsersFromUsernames(Set<String> mentions) {
		if (mentions.isEmpty()) 
			return new ArrayList<>();
		ArrayList<GenericItemBean> toReturn = new ArrayList<>();
		UserManager uManager = UserManagerWSBuilder.getInstance().getUserManager();
		for (String username : mentions) {
			try{				
				GCubeUser user = uManager.getUserByUsername(username);
				String fullName = user.getFirstName() + " " + user.getLastName();
				toReturn.add(new GenericItemBean(""+user.getUserId(), username, fullName, ""));
			}catch(Exception e){
				logger.error("Unable to get user informations for username=" + username);
			}			
		}
		return toReturn;
	}

	// utility method
	private static ArrayList<ItemBean> convertToItemBean(Collection<GenericItemBean> items) {
		ArrayList<ItemBean> toReturn = new ArrayList<>(items.size());
		for (GenericItemBean item : items) {
			toReturn.add(new ItemBean(item.getId(), item.getName(), item.getAlternativeName(), item.getThumbnailURL()));
		}
		return toReturn;
	}

	/**
	 * Method used when an application needs to publish something.
	 * @param postText
	 * @param uriParams
	 * @param previewTitle
	 * @param previewDescription
	 * @param httpImageUrl
	 * @return true upon success, false on failure
	 */
	public static Post shareApplicationUpdate(
			String postText, 
			String uriParams, 
			String previewTitle, 
			String previewDescription, 
			String httpImageUrl,
			ApplicationProfile applicationProfile,
			Caller caller,
			boolean notifyGroup
			){

		SocialMessageParser messageParser = new SocialMessageParser(postText);
		String escapedPostText = messageParser.getParsedMessage();
		List<String> hashtags = messageParser.getHashtags();
		ArrayList<GenericItemBean> mentionedUsers = getUsersFromUsernames(Utils.getMentionedUsernames(postText));
		ArrayList<ItemBean> mentionedUsersToConvertInHTML = convertToItemBean(mentionedUsers);

		SocialNetworkingSite site = SocialNetworkingSiteFinder.getSocialNetworkingSiteFromScope(ScopeProvider.instance.get());

		escapedPostText = Utils.convertMentionUsernamesAnchorHTML(escapedPostText, mentionedUsersToConvertInHTML, site.getSiteURL(), site.getSiteLandingPagePath());
		logger.info("*** Escaped post text is " + escapedPostText);

		String scope = ScopeProvider.instance.get();
		String appId = caller.getClient().getId();		

		Post toWrite = 
				buildPost(
						escapedPostText, 
						uriParams == null ? "" : uriParams, 
								previewTitle == null ? "" : previewTitle, 
										previewDescription == null ? "" : previewDescription, 
												httpImageUrl == null ? "" : httpImageUrl, 
														applicationProfile, 
														scope);

		// try to save it
		boolean res = CassandraConnection.getInstance().getDatabookStore().saveAppPost(toWrite);

		if(res){
			logger.info("Feed correctly written by application " + appId);

			// wait a bit before saving hashtags
			if(hashtags != null && !hashtags.isEmpty())
				new Thread(()->{
					try {
						Thread.sleep(1000);
						CassandraConnection.getInstance().getDatabookStore().saveHashTags(toWrite.getKey(), scope, hashtags);
					} catch (Exception e1) {
						logger.error("Failed to save hashtags in Cassandra", e1);
					}
				}).start();


			//  build the notification manager

			SocialNetworkingUser user = new SocialNetworkingUser(appId, "", applicationProfile.getName(), applicationProfile.getImageUrl());
			NotificationsManager nm = new ApplicationNotificationsManager(
					UserManagerWSBuilder.getInstance().getUserManager(),
					site, 
					scope, 
					user, 
					NEWS_FEED_PORTLET_CLASSNAME);

			if (!mentionedUsers.isEmpty())
				new Thread(new MentionNotificationsThread(toWrite.getKey(), toWrite.getDescription(), nm, null, mentionedUsers)).start();

			if(notifyGroup){

				logger.debug("Sending notifications for " + appId + " " + scope);

				try{

					String name = new ScopeBean(scope).name(); // scope such as devVRE

					// retrieve group information
					GroupManager gManager = GroupManagerWSBuilder.getInstance().getGroupManager();

					long groupId = gManager.getGroupId(name);
					String groupName =  gManager.getGroup(groupId).getGroupName();

					logger.debug("Company id and name " + groupId + " " + groupName);

					// start notification thread
					new Thread(new PostNotificationsThread(
							UserManagerWSBuilder.getInstance().getUserManager(),
							toWrite.getKey(), 
							toWrite.getDescription(), 
							""+groupId, 
							nm, 
							new HashSet<String>(hashtags),
							new HashSet<String>())
							).start();
				}catch (Exception e) {
					logger.debug("Feed succesfully created but unable to send notifications.");
				}

			}
			return toWrite;
		}
		else
			return null;

	}

	/**
	 * Build an ApplicationProfile Feed.
	 * 
	 * @param description add a description for the update you are sharing
	 * @param uriParams the additional parameters your applicationProfile needs to open the subject of this update  e.g. id=12345&type=foo
	 * @param previewTitle the title to show in the preview
	 * @param previewDescription the description to show in the preview
	 * @param previewThumbnailUrl the image url to show in the preview
	 * @return a feed instance ready to be written
	 */
	private static Post buildPost(
			String description, 
			String uriParams, 
			String previewTitle, 
			String previewDescription, 
			String previewThumbnailUrl,
			ApplicationProfile applicationProfile,
			String scopeApp) {

		String uri = applicationProfile.getUrl();

		//add the GET params if necessary
		if (uriParams != null && uriParams.compareTo("") != 0)
			uri += "?"+uriParams;		

		Post toReturn = new Post( 
				UUID.randomUUID().toString(), 
				PostType.PUBLISH, 
				applicationProfile.getKey(), 
				new Date(), 
				scopeApp, 
				uri, 
				previewThumbnailUrl, 
				description, 
				PrivacyLevel.SINGLE_VRE, 
				applicationProfile.getName(), 
				"no-email", 
				applicationProfile.getImageUrl(), 
				previewTitle, 
				previewDescription, 
				"", 
				true);

		return toReturn;
	}	

	/**
	 * This method looks up the applicationProfile profile among the ones available in the infrastructure
	 * @param idApp as identifier of your application (as reported in the ApplicationProfile)
	 * @param scopeApp the scope of the application
	 */
	public static ApplicationProfile getProfileFromInfrastrucure(String idApp, String scopeApp) {
		ScopeBean scope =  new ScopeBean(scopeApp);

		logger.debug("Trying to fetch applicationProfile profile from the infrastructure for " + idApp + " scope: " +  scope);

		// set the scope of the root infrastructure
		String rootInfrastructure = scopeApp.split("/")[1];
		ScopeProvider.instance.set("/"+rootInfrastructure);

		try {

			ApplicationProfile toReturn = new ApplicationProfile();
			Query q = new QueryBox("for $profile in collection('/db/Profiles/GenericResource')//Resource " +
					"where $profile/Profile/SecondaryType/string() eq 'ApplicationProfile' and  $profile/Profile/Body/AppId/string() " +
					" eq '" + idApp + "'" +
					"return $profile");


			DiscoveryClient<String> client = client();
			List<String> appProfile = client.submit(q);

			if (appProfile == null || appProfile.size() == 0) 
				throw new Exception("Your applicationProfile is not registered in the infrastructure");

			else {

				String elem = appProfile.get(0);
				DocumentBuilder docBuilder =  DocumentBuilderFactory.newInstance().newDocumentBuilder();
				Node node = docBuilder.parse(new InputSource(new StringReader(elem))).getDocumentElement();
				XPathHelper helper = new XPathHelper(node);

				List<String> currValue = null;
				currValue = helper.evaluate("/Resource/Profile/Name/text()");
				if (currValue != null && currValue.size() > 0) {

					toReturn.setName(currValue.get(0));

				} 
				else throw new ApplicationProfileNotFoundException("Your applicationProfile NAME was not found in the profile");

				currValue = helper.evaluate("/Resource/Profile/Description/text()");
				if (currValue != null && currValue.size() > 0) {

					toReturn.setDescription(currValue.get(0));

				} 
				else logger.warn("No Description exists for " + toReturn.getName());

				currValue = helper.evaluate("/Resource/Profile/Body/AppId/text()");

				if (currValue != null && currValue.size() > 0) {

					toReturn.setKey(currValue.get(0));

				}
				else throw new ApplicationProfileNotFoundException("Your applicationProfile ID n was not found in the profile, consider adding <AppId> element in <Body>");

				currValue = helper.evaluate("/Resource/Profile/Body/ThumbnailURL/text()");
				if (currValue != null && currValue.size() > 0) {

					toReturn.setImageUrl(currValue.get(0));

				}
				else throw new Exception("Your applicationProfile Image Url was not found in the profile, consider adding <ThumbnailURL> element in <Body>");
				currValue = helper.evaluate("/Resource/Profile/Body/EndPoint/Scope/text()");
				if (currValue != null && currValue.size() > 0) {

					List<String> scopes = currValue;
					boolean foundUrl = false;
					for (int i = 0; i < scopes.size(); i++) {
						if (currValue.get(i).trim().compareTo(scope.toString()) == 0) {								
							toReturn.setUrl(helper.evaluate("/Resource/Profile/Body/EndPoint/URL/text()").get(i));
							toReturn.setScope(scope.toString());
							foundUrl = true;
							break;
						}						
					}

					if (! foundUrl)
						throw new ApplicationProfileNotFoundException("Your applicationProfile URL was not found in the profile for Scope: " + scope.toString());
				}

				else throw new ApplicationProfileNotFoundException("Your applicationProfile EndPoint was not found in the profile, consider adding <EndPoint><Scope> element in <Body>");
				logger.debug("Returning " + toReturn);
				return toReturn;
			}

		} catch (Exception e) {

			logger.error("Error while trying to fetch applicationProfile profile from the infrastructure", e);

		} finally{

			// set the scope back
			ScopeProvider.instance.set(scopeApp);

		}

		return null;

	}

	/**
	 * Allows user to post a feed in a certain vre.
	 * @param userId
	 * @param postText
	 * @param vreId
	 * @param previewTitle
	 * @param previewDescription
	 * @param previewHost
	 * @param previewUrl
	 * @param urlThumbnail
	 * @param notifyGroup
	 * @return The written Feed
	 */
	public static Post shareUserUpdate(
			String userId,
			String postText,
			String vreId, 
			String previewTitle, 
			String previewDescription, 
			String previewHost,
			String previewUrl,
			String urlThumbnail, 
			boolean notifyGroup) {

		SocialMessageParser messageParser = new SocialMessageParser(postText);
		String escapedPostText = messageParser.getParsedMessage();
		List<String> hashtags = messageParser.getHashtags();
		//check if any mention exists
		ArrayList<GenericItemBean> mentionedUsers = getUsersFromUsernames(Utils.getMentionedUsernames(postText));
		ArrayList<ItemBean> mentionedUsersToConvertInHTML = convertToItemBean(mentionedUsers);

		SocialNetworkingSite site = SocialNetworkingSiteFinder.getSocialNetworkingSiteFromScope(ScopeProvider.instance.get());

		escapedPostText = Utils.convertMentionUsernamesAnchorHTML(escapedPostText, mentionedUsersToConvertInHTML, site.getSiteURL(), site.getSiteLandingPagePath());

		GCubeUser user;

		// retrieve group information
		UserManager uManager = UserManagerWSBuilder.getInstance().getUserManager();
		try {
			user = uManager.getUserByUsername(userId);
		} catch(Exception e){
			logger.error("Unable to get user informations, post write fails.", e);
			return null;
		}

		String email = user.getEmail();
		String fullName = user.getFirstName() + " " + user.getLastName();
		String thumbnailURL = user.getUserAvatarURL();
		String linkTitle = previewTitle == null ? "" : previewTitle;
		String linkDesc = previewDescription == null ? "" : previewDescription;
		String host = previewHost == null ? "" : previewHost;
		String url = previewUrl == null ? "" : previewUrl;
		if (urlThumbnail == null)
			urlThumbnail = "null";

		//this means the user has shared a file without text in it.
		String textToPost = "";
		if (escapedPostText.trim().compareTo(NO_TEXT_FILE_SHARE) == 0) {
			textToPost = org.gcube.social_networking.socialutillibrary.Utils.convertFileNameAnchorHTML(url);
		} else {
			textToPost = escapedPostText;
		}

		Post toShare = new Post(UUID.randomUUID().toString(), PostType.PUBLISH, userId, new Date(),
				vreId, url, urlThumbnail, textToPost, PrivacyLevel.SINGLE_VRE, fullName, email, thumbnailURL, linkTitle, linkDesc, host);

		logger.info("Attempting to save Post with text: " + textToPost + " Level = " + PrivacyLevel.SINGLE_VRE + " Timeline = " + vreId);

		boolean result = CassandraConnection.getInstance().getDatabookStore().saveUserPost(toShare);

		if(vreId != null && vreId.compareTo("") != 0 && result) {

			logger.trace("Attempting to write onto " + vreId);

			try {

				try{
					logger.info("Sleeping waiting for cassandra's update");
					Thread.sleep(1000);

				}catch(Exception e){

					logger.error(e.toString());

				}
				CassandraConnection.getInstance().getDatabookStore().saveFeedToVRETimeline(toShare.getKey(), vreId);

				if (hashtags != null && !hashtags.isEmpty())
					CassandraConnection.getInstance().getDatabookStore().saveHashTags(toShare.getKey(), vreId, hashtags);

			} catch (FeedIDNotFoundException e) {
				logger.error("Error writing onto VRES Time Line" + vreId);
			}  
			logger.trace("Success writing onto " + vreId);				
		}

		if (!result) 
			return null;

		SocialNetworkingUser socialUser = 
				new SocialNetworkingUser(userId, email, fullName, thumbnailURL);
		NotificationsManager nm = new ApplicationNotificationsManager(UserManagerWSBuilder.getInstance().getUserManager(), site, vreId, socialUser, NEWS_FEED_PORTLET_CLASSNAME);
		if (!mentionedUsers.isEmpty())
			new Thread(new MentionNotificationsThread(toShare.getKey(), toShare.getDescription(), nm, null, mentionedUsers)).start();

		//send the notification about this posts to everyone in the group if notifyGroup is true
		if (vreId != null && vreId.compareTo("") != 0 && notifyGroup) {

			try{		
				// retrieve group information
				GroupManager gManager = GroupManagerWSBuilder.getInstance().getGroupManager();
				// handle the scope
				String name = new ScopeBean(vreId).name(); // scope such as devVR
				long groupId = gManager.getGroupId(name);
				String groupName = gManager.getGroup(groupId).getGroupName();

				logger.debug("Company id and name " + groupId + " " + groupName);
				new Thread(
						new PostNotificationsThread(
								UserManagerWSBuilder.getInstance().getUserManager(),
								toShare.getKey(), 
								toShare.getDescription(), 
								""+groupId, 
								nm, 
								new HashSet<String>(),
								new HashSet<String>(hashtags))
						).start();

				logger.debug("Start sending notifications for post written by " + userId);
			}catch(Exception e){
				logger.error("Unable to notify users", e);
			}
		}
		return toShare;
	}
	/**
	 * Allows to comment post in a certain vre.

	 * @param userid the username
	 * @param time the date and time of the comment
	 * @param postId the key of the post that was commented
	 * @param commentText the text as it is, it will be parsed
	 * @param postOwnerId the username of the user who created the post that was commented
	 * @param context the VRE context
	 * 
	 * @return the Comment instance if ok, null if somwthign went KO
	 * @throws FeedIDNotFoundException 
	 */
	public static Comment commentPost(String userid, Date time, String postId, String commentText, String postOwnerId, String context) throws FeedIDNotFoundException {

		SocialMessageParser messageParser = new SocialMessageParser(commentText);
		String escapedCommentText = messageParser.getParsedMessage();
		//check if any mention exists
		ArrayList<GenericItemBean> mentionedUsers = getUsersFromUsernames(Utils.getMentionedUsernames(commentText));
		ArrayList<ItemBean> mentionedUsersToConvertInHTML = convertToItemBean(mentionedUsers);
		SocialNetworkingSite site = SocialNetworkingSiteFinder.getSocialNetworkingSiteFromScope(ScopeProvider.instance.get());

		escapedCommentText = Utils.convertMentionUsernamesAnchorHTML(escapedCommentText, mentionedUsersToConvertInHTML, site.getSiteURL(), site.getSiteLandingPagePath());

		// retrieve user information
		GCubeUser user;
		UserManager uManager = UserManagerWSBuilder.getInstance().getUserManager();
		try {
			user = uManager.getUserByUsername(userid);
		} catch(Exception e){
			logger.error("Unable to get user informations, comment write fails.", e);
			return null;
		}
		String commentKey = UUID.randomUUID().toString(); // a unique id that goes in the DB
		String email = user.getEmail();
		String fullName = user.getFirstName() + " " + user.getLastName();
		String thumbnailURL = user.getUserAvatarURL();

		Comment theComment = new Comment(commentKey, userid, time, postId, escapedCommentText, fullName, thumbnailURL);		
		logger.info("Attempting to save Comment with text: " + commentText + " postid="+postId);

		boolean result = CassandraConnection.getInstance().getDatabookStore().addComment(theComment);
		logger.info("Added comment? " + theComment.toString() + " Result is " +result);

		if (!result) 
			return null;

		//if the comment was correctly delivered notify users involved
		SocialNetworkingUser socialUser = new SocialNetworkingUser(userid, email, fullName, thumbnailURL);

		NotificationsManager nm = new ApplicationNotificationsManager(uManager, site, context, socialUser, NEWS_FEED_PORTLET_CLASSNAME);

		//if the user who commented this post is not the user who posted it notify the poster user (Post owner) 
		logger.info("The post creator is " + postOwnerId);
		if (! user.getUsername().equals(postOwnerId)) {	
			boolean resultNotifyOwnComment = nm.notifyOwnCommentReply(postOwnerId, postId, escapedCommentText, theComment.getKey());
			logger.info("Comment Notification to post creator added? " + resultNotifyOwnComment);
		} 
		//if there are users who liked this post they get notified, asynchronously with this thread
		ArrayList<Like> likes = getAllLikesByPost(postId);
		Thread likesThread = new Thread(new LikeNotificationsThread(escapedCommentText, nm, likes, postOwnerId, theComment.getKey()));
		likesThread.start();

		//notify the other users who commented this post (excluding the ones above)
		Thread commentsNotificationthread = new Thread(new CommentNotificationsThread(
				CassandraConnection.getInstance().getDatabookStore(),
				uManager, user.getUsername(), theComment.getFeedid(), escapedCommentText, nm, postOwnerId,  theComment.getKey(), likes));
		commentsNotificationthread.start();	

		//send the notification to the mentioned users, if any
		if (mentionedUsers != null && mentionedUsers.size() > 0) {
			ArrayList<GenericItemBean> toPass = new ArrayList<GenericItemBean>();


			// among the mentionedUsers there could be groups of people
			Map<String, ItemBean> uniqueUsersToNotify = new HashMap<>();
			UserManager um = new LiferayUserManager();

			for (ItemBean bean : mentionedUsersToConvertInHTML) {

				if(bean.isItemGroup()){

					// retrieve the users of this group
					try {
						List<GCubeUser> teamUsers = um.listUsersByTeam(Long.parseLong(bean.getId()));

						for (GCubeUser userTeam : teamUsers) {
							if(!uniqueUsersToNotify.containsKey(userTeam.getUsername()))
								uniqueUsersToNotify.put(userTeam.getUsername(), new ItemBean(userTeam.getUserId()+"",
										userTeam.getUsername(), userTeam.getFullname(), userTeam.getUserAvatarURL()));
						}

					} catch (NumberFormatException
							| UserManagementSystemException
							| TeamRetrievalFault | UserRetrievalFault e) {
						logger.error("Unable to retrieve team information", e);
					}

				}else{
					// it is a user, just add to the hashmap
					if(!uniqueUsersToNotify.containsKey(bean.getName()))
						uniqueUsersToNotify.put(bean.getName(), bean);

				}
			}

			// iterate over the hashmap
			Iterator<Entry<String, ItemBean>> userMapIterator = uniqueUsersToNotify.entrySet().iterator();
			while (userMapIterator.hasNext()) {
				Map.Entry<String, ItemBean> userEntry = (Map.Entry<String, ItemBean>) userMapIterator
						.next();
				ItemBean userBean = userEntry.getValue();
				toPass.add(new GenericItemBean(userBean.getId(), userBean.getName(), userBean.getAlternativeName(), userBean.getThumbnailURL()));
			}

			Thread thread = new Thread(new MentionNotificationsThread(theComment.getFeedid(), escapedCommentText, nm, null, toPass));
			thread.start();
		}
		return theComment;
	}

	private static ArrayList<Like> getAllLikesByPost(String postid) {
		ArrayList<Like> toReturn = (ArrayList<Like>) CassandraConnection.getInstance().getDatabookStore().getAllLikesByPost(postid);
		logger.debug("Asking likes for " + postid);
		for (Like like : toReturn) {
			// retrieve user information
			GCubeUser user;
			UserManager uManager = UserManagerWSBuilder.getInstance().getUserManager();
			try {
				user = uManager.getUserByUsername(like.getUserid());
			} catch(Exception e){
				logger.error("Unable to get user informations, comment write fails.", e);
				return null;
			}
			String thumbnailURL = user.getUserAvatarURL();

			like.setThumbnailURL(thumbnailURL == null ? "" : thumbnailURL);
		}
		return toReturn;
	}

	public static boolean like(String username, String postid, String context) {
		boolean likeCommitResult = false;
		// retrieve user information
		GCubeUser user;
		UserManager uManager = UserManagerWSBuilder.getInstance().getUserManager();
		try {
			user = uManager.getUserByUsername(username);
		} catch(Exception e){
			logger.error("Unable to get user informations, like write fails.", e);
			return false;
		}
		String email = user.getEmail();
		String fullName = user.getFirstName() + " " + user.getLastName();
		String thumbnailURL = user.getUserAvatarURL();
		SocialNetworkingUser socialUser = new SocialNetworkingUser(user.getUsername(), email, fullName, thumbnailURL);
	
		Like toLike = new Like(UUID.randomUUID().toString(), user.getUsername(), 
				new Date(), postid, user.getFullname(), user.getUserAvatarURL());
		Post thePost = null;
		try {
			logger.info("Attempting to read post with id: " +postid);
			thePost = CassandraConnection.getInstance().getDatabookStore().readPost(postid);
			likeCommitResult =  CassandraConnection.getInstance().getDatabookStore().like(toLike);
		} catch (Exception e) {
			logger.error("Post not found for this like ot could not like the post " + e.getMessage());
			return false;
		}
		//if the like was correctly delivered notify the user who made the post
		
		boolean resultNotifyLike =false;
		if (likeCommitResult) {
			SocialNetworkingSite site = SocialNetworkingSiteFinder.getSocialNetworkingSiteFromScope(ScopeProvider.instance.get());
			NotificationsManager nm = new ApplicationNotificationsManager(UserManagerWSBuilder.getInstance().getUserManager(), site, context, socialUser, NEWS_FEED_PORTLET_CLASSNAME);
			
			String postText = thePost.getDescription();
			String postOwnerId = thePost.getEntityId();
			SocialMessageParser messageParser = new SocialMessageParser(postText);
			String escapedPostText = messageParser.getParsedMessage();
			
			//if the user who liked this post is not the user who posted it notify the poster user (Post owner) 
			logger.info("The post creator is " + postOwnerId);			
			if (! user.getUsername().equals(postOwnerId)) {	
				resultNotifyLike = nm.notifyLikedPost(postOwnerId, postid, escapedPostText);
				logger.info("Like Notification to post creator added? " + resultNotifyLike);
			} 				
		}
		return likeCommitResult && resultNotifyLike;
	}
	
	public static boolean unlike(String username, String likeid, String postid) {
		boolean unlikeCommitResult = false;
		// retrieve user information
		GCubeUser user;
		UserManager uManager = UserManagerWSBuilder.getInstance().getUserManager();
		try {
			user = uManager.getUserByUsername(username);
		} catch(Exception e){
			logger.error("Unable to get user informations, unlike write fails.", e);
			return false;
		}
		String fullName = user.getFirstName() + " " + user.getLastName();
		String thumbnailURL = user.getUserAvatarURL();
		try {
	
			unlikeCommitResult =  CassandraConnection.getInstance().getDatabookStore().unlike(username, likeid, postid);
		} catch (Exception e) {
			logger.error("Post not Found for this like ot could not unlike the post " + e.getMessage());
			return false;
		}
		
		return unlikeCommitResult;
	}

}