fixed the issue with Topics.markAsRead

src/categories.js

@@ -267,7 +267,26 @@ var	RDB = require('./redis.js'),
 		});
 	}
 
+	Categories.isTopicsRead = function(cid, uid, callback) {
+		RDB.smembers('categories:' + cid + ':tid', function(err, tids) {
 
+			topics.hasReadTopics(tids, uid, function(hasRead) {
+
+				var allread = true;
+				for (var i=0, ii=tids.length; i<ii; i++) {
+					if(hasRead[i] === 0) {
+						allread = false;
+						break;
+					}
+				}
+				callback(allread);				
+			});
+		});
+	}
+
+	Categories.markAsRead = function(cid, uid) {
+		RDB.sadd('cid:' + cid + ':read_by_uid', uid);			
+	}
 
 	Categories.hasReadCategories = function(cids, uid, callback) {
 		var batch = RDB.multi();

src/topics.js

@@ -218,10 +218,16 @@ marked.setOptions({
 	}
 
 	Topics.markAsRead = function(tid, uid) {
-		// there is an issue with this fn. if you read a topic that is previously read you will mark the category as read anyways - there is no check
+		
 		RDB.sadd(schema.topics(tid).read_by_uid, uid);
+		
 		Topics.get_cid_by_tid(tid, function(cid) {
-			RDB.sadd('cid:' + cid + ':read_by_uid', uid);
+					
+			categories.isTopicsRead(cid, uid, function(read) {
+				if(read) {
+					categories.markAsRead(cid, uid);
+				}
+			});
 		});
 	}