Prevent players playing one 1 event from getting drawn out

src/main/java/nl/connectedit/swiss/domain/entity/Tournament.java

@@ -1,7 +1,9 @@
 package nl.connectedit.swiss.domain.entity;
 
 import jakarta.persistence.*;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 import lombok.Getter;
 import lombok.Setter;
 import nl.connectedit.swiss.domain.EventType;
@@ -91,4 +93,18 @@ public class Tournament extends AbstractEntity {
         var drawnOutPlayers = this.getDrawnOutPlayers();
         return drawnOutPlayers.size() == new HashSet<>(drawnOutPlayers).size();
     }
+
+    public List<Player> getPlayersPlayingOnlyOneEvent() {
+        var playerEvents = new HashMap<Player, List<EventType>>();
+        for (var registration : getRegistrations()) {
+            if (!playerEvents.containsKey(registration.getPlayer())) {
+                playerEvents.put(registration.getPlayer(), new ArrayList<>());
+            }
+            playerEvents.get(registration.getPlayer()).add(registration.getEvent().getType());
+        }
+        return playerEvents.entrySet().stream()
+          .filter(entry -> entry.getValue().size() == 1)
+          .map(Map.Entry::getKey)
+          .toList();
+    }
 }

src/main/java/nl/connectedit/swiss/service/TournamentDrawService.java

@@ -25,7 +25,7 @@ public class TournamentDrawService {
         round.setName("Ronde 1");
         round.setGroup(group);
         do {
-          round.setMatches(createMatchList(group, round));
+          round.setMatches(createMatchList(tournament, group, round));
         } while (!tournament.hasPlayersDrawnOutMaxOnce());
         round.setStatus(Status.NOT_STARTED);
       }
@@ -87,7 +87,7 @@ public class TournamentDrawService {
     return tournament;
   }
 
-  private List<Match> createMatchList(Group group, Round round) {
+  private List<Match> createMatchList(Tournament tournament, Group group, Round round) {
     List<Match> matches;
     var drawCounter = 0;
     do {
@@ -112,12 +112,18 @@ public class TournamentDrawService {
         match.setRound(round);
         matches.add(match);
       }
-    } while (!drawIsValid(matches) || drawCounter == 1000);
+    } while (!drawIsValid(tournament, matches, round) || drawCounter == 1000);
 
     return matches;
   }
 
-  private boolean drawIsValid(List<Match> matches) {
+  private boolean drawIsValid(Tournament tournament, List<Match> matches, Round round) {
+    var playersNotToBeDrawnOut = tournament.getPlayersPlayingOnlyOneEvent();
+    if (round.getDrawnOut() != null &&
+         (playersNotToBeDrawnOut.contains(round.getDrawnOut().getPlayer1()) ||
+         (round.getDrawnOut().getPlayer2() != null && playersNotToBeDrawnOut.contains(round.getDrawnOut().getPlayer2())))) {
+      return false;
+    }
     for (var match : matches) {
       var clubs = getClubsFromMatch(match);
       var distinctClubs = new HashSet<>(clubs).size();

src/main/java/nl/connectedit/swiss/service/TournamentPlayService.java

@@ -67,11 +67,12 @@ public class TournamentPlayService {
     round.setStatus(Status.NOT_STARTED);
 
     if (remainingTeams.size() % 2 == 1) {
-      var drawnOutPlayers = tournament.getDrawnOutPlayers();
+      var playersNotToBeDrawnOut = tournament.getDrawnOutPlayers();
+      playersNotToBeDrawnOut.addAll(tournament.getPlayersPlayingOnlyOneEvent());
       var tryPosition = remainingTeams.size() - 1;
       do {
         var tryDrawOutTeam = remainingTeams.get(tryPosition);
-        if (!drawnOutPlayers.contains(tryDrawOutTeam.getPlayer1()) && (tryDrawOutTeam.getPlayer2() == null || !drawnOutPlayers.contains(tryDrawOutTeam.getPlayer2()))) {
+        if (!playersNotToBeDrawnOut.contains(tryDrawOutTeam.getPlayer1()) && (tryDrawOutTeam.getPlayer2() == null || !playersNotToBeDrawnOut.contains(tryDrawOutTeam.getPlayer2()))) {
           remainingTeams.remove(tryDrawOutTeam);
           round.setDrawnOut(tryDrawOutTeam);
           break;