added determineWinner Methode zu TournamentService #24

sth-backend/src/main/java/hdm/mi/sthbackend/service/TournamentService.java

 package hdm.mi.sthbackend.service;
 
 import com.mongodb.client.MongoClient;
+import hdm.mi.sthbackend.exeptions.MatchIdNotFoundException;
 import hdm.mi.sthbackend.exeptions.PlayerIdNotFoundException;
 import hdm.mi.sthbackend.exeptions.TeamIdNotFoundException;
 import hdm.mi.sthbackend.exeptions.TournamentIdNotFoundException;
+import hdm.mi.sthbackend.model.Match;
 import hdm.mi.sthbackend.model.Player;
 import hdm.mi.sthbackend.model.Team;
 import hdm.mi.sthbackend.model.Tournament;
@@ -12,12 +14,11 @@ import hdm.mi.sthbackend.repository.MongoManager;
 import lombok.AllArgsConstructor;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.springframework.data.mongodb.core.aggregation.VariableOperators;
 import org.springframework.stereotype.Service;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.Optional;
-import java.util.UUID;
+import javax.swing.text.html.parser.Entity;
+import java.util.*;
 
 @Service
 @AllArgsConstructor
@@ -134,6 +135,26 @@ public class TournamentService {
         return tournament;
     }
 
+    public UUID determineWinner (UUID tournamentId, UUID matchId) throws TournamentIdNotFoundException, MatchIdNotFoundException{
+
+        Tournament tournament = tournamentRepository.findById(tournamentId)
+                .orElseThrow(() -> new TournamentIdNotFoundException(tournamentId));
+
+        Match match = tournament.getMatches().stream()
+                .filter(m -> m.getMatchId().equals(matchId))
+                .findFirst()
+                .orElseThrow(() -> new MatchIdNotFoundException(matchId));
+
+        UUID winnerTeamId = match.getTeamScores().entrySet().stream()
+                .max(Comparator.<Map.Entry<UUID, Number>, Double>comparing(entry -> entry.getValue().doubleValue()))
+                .map(Map.Entry::getKey)
+                .orElse(null);
+
+        match.setWinnerTeamId(winnerTeamId);
+        tournamentRepository.save(tournament);
+        log.debug("The Winner " + winnerTeamId + " is determined for Match " + matchId + " in Tournament " + tournamentId);
+        return winnerTeamId;
+    }
 
     /*
     Weitere Methoden: