fix(matching-service): 🚑 fix some issues with matching algorithm

Fix the matched difficulties and topics so that it will be an OR if either is empty. Also fixes an issue with difficulties matching using wrong variable topics.

apps/matching-service/processes/findmatches.go

@@ -74,18 +74,38 @@ func foundMatch(tx *redis.Tx, ctx context.Context, currentUser *models.MatchRequ
 	}
 
 	var matchedTopics []string
-	for _, topic := range currentUser.Topics {
+	if len(currentUser.Topics) == 0 || len(currentUser.Topics) == 0 {
+		// Ensure that matchedTopics will not be empty unless both users are empty
+		for _, topic := range currentUser.Topics {
+			matchedTopics = append(matchedTopics, topic)
+		}
 		for _, otherTopic := range matchedUser.Topics {
-			if topic == otherTopic {
-				matchedTopics = append(matchedTopics, topic)
+			matchedTopics = append(matchedTopics, otherTopic)
+		}
+	} else {
+		for _, topic := range currentUser.Topics {
+			for _, otherTopic := range matchedUser.Topics {
+				if topic == otherTopic {
+					matchedTopics = append(matchedTopics, topic)
+				}
 			}
 		}
 	}
 	var matchedDifficulties []string
-	for _, topic := range currentUser.Difficulties {
-		for _, otherTopic := range matchedUser.Difficulties {
-			if topic == otherTopic {
-				matchedDifficulties = append(matchedDifficulties, topic)
+	if len(currentUser.Difficulties) == 0 || len(currentUser.Difficulties) == 0 {
+		// Ensure that matchedDifficulties will not be empty unless both users are empty
+		for _, diff := range currentUser.Difficulties {
+			matchedDifficulties = append(matchedDifficulties, diff)
+		}
+		for _, otherDiff := range matchedUser.Difficulties {
+			matchedDifficulties = append(matchedDifficulties, otherDiff)
+		}
+	} else {
+		for _, diff := range currentUser.Difficulties {
+			for _, otherDiff := range matchedUser.Difficulties {
+				if diff == otherDiff {
+					matchedDifficulties = append(matchedDifficulties, diff)
+				}
 			}
 		}
 	}
@@ -200,7 +220,7 @@ func doDifficultyMatching(tx *redis.Tx, ctx context.Context, currentUser *models
 		if err != nil {
 			return nil, err
 		}
-		if len(otherUser.Topics) == 0 {
+		if len(otherUser.Difficulties) == 0 {
 			foundUsers = append(foundUsers, otherUsername)
 		}