feat: Leaderboard to use Riyadh timezone

backend/src/main/java/online/wesal/wesal/controller/PuzzleController.java

@@ -68,10 +68,11 @@ public class PuzzleController {
     }
     
     @GetMapping("/leaderboard")
-    @Operation(summary = "Get daily leaderboard", description = "Returns leaderboard for today's puzzle ordered by submission time")
+    @Operation(summary = "Get daily leaderboard", description = "Returns leaderboard with 9am cutoff logic (before 9am shows yesterday, from 9am shows today)")
-    public ResponseEntity<ApiResponse<List<LeaderboardEntry>>> getLeaderboard() {
+    public ResponseEntity<ApiResponse<Map<String, Object>>> getLeaderboard() {
         try {
             List<PuzzleAttempt> attempts = puzzleService.getTodaysLeaderboard();
+            String leaderboardInfo = puzzleService.getLeaderboardDateInfo();
             
             List<LeaderboardEntry> leaderboard = attempts.stream()
                 .filter(attempt -> attempt.isSolved())
@@ -85,7 +86,12 @@ public class PuzzleController {
                 ))
                 .collect(Collectors.toList());
             
-            return ResponseEntity.ok(ApiResponse.success(leaderboard));
+            Map<String, Object> response = Map.of(
+                "leaderboard", leaderboard,
+                "dateInfo", leaderboardInfo
+            );
+            
+            return ResponseEntity.ok(ApiResponse.success(response));
         } catch (RuntimeException e) {
             return ResponseEntity.ok(ApiResponse.error(e.getMessage()));
         }

backend/src/main/java/online/wesal/wesal/service/PuzzleService.java

@@ -9,6 +9,10 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
@@ -26,6 +30,9 @@ public class PuzzleService {
     @Autowired
     private UserService userService;
     
+    private static final ZoneId RIYADH_TIMEZONE = ZoneId.of("Asia/Riyadh");
+    private static final LocalTime CUTOFF_TIME = LocalTime.of(9, 0); // 9:00 AM
+    
     private static final List<String> WORD_LIST = Arrays.asList(
         "APPLE", "BEACH", "CHAIN", "DANCE", "EAGLE", "FLAME", "GRAPE", "HOUSE", "IMAGE", "JUDGE",
         "KNIFE", "LIGHT", "MUSIC", "NIGHT", "OCEAN", "PEACE", "QUEEN", "RIVER", "STAGE", "TIGER",
@@ -88,7 +95,7 @@ public class PuzzleService {
     );
     
     public Puzzle getTodaysPuzzle() {
-        LocalDate today = LocalDate.now();
+        LocalDate today = getRiyadhToday();
         Optional<Puzzle> existingPuzzle = puzzleRepository.findByDate(today);
         
         if (existingPuzzle.isPresent()) {
@@ -105,6 +112,26 @@ public class PuzzleService {
         return WORD_LIST.get(random.nextInt(WORD_LIST.size()));
     }
     
+    private LocalDate getRiyadhToday() {
+        return ZonedDateTime.now(RIYADH_TIMEZONE).toLocalDate();
+    }
+    
+    private LocalDateTime getRiyadhNow() {
+        return ZonedDateTime.now(RIYADH_TIMEZONE).toLocalDateTime();
+    }
+    
+    private LocalDate getLeaderboardDate() {
+        LocalDateTime riyadhNow = getRiyadhNow();
+        LocalDate today = riyadhNow.toLocalDate();
+        
+        // If it's before 9 AM, show yesterday's leaderboard
+        if (riyadhNow.toLocalTime().isBefore(CUTOFF_TIME)) {
+            return today.minusDays(1);
+        }
+        // From 9 AM onwards, show today's leaderboard
+        return today;
+    }
+    
     public boolean hasUserSolvedToday() {
         User currentUser = userService.getCurrentUser();
         Puzzle todaysPuzzle = getTodaysPuzzle();
@@ -134,7 +161,26 @@ public class PuzzleService {
     }
     
     public List<PuzzleAttempt> getTodaysLeaderboard() {
-        Puzzle todaysPuzzle = getTodaysPuzzle();
+        LocalDate leaderboardDate = getLeaderboardDate();
-        return puzzleAttemptRepository.findByPuzzleOrderBySubmittedAtAsc(todaysPuzzle);
+        Optional<Puzzle> puzzleOpt = puzzleRepository.findByDate(leaderboardDate);
+        
+        if (puzzleOpt.isEmpty()) {
+            // If no puzzle exists for the leaderboard date, return empty list
+            return Arrays.asList();
+        }
+        
+        return puzzleAttemptRepository.findByPuzzleOrderBySubmittedAtAsc(puzzleOpt.get());
+    }
+    
+    public String getLeaderboardDateInfo() {
+        LocalDateTime riyadhNow = getRiyadhNow();
+        LocalDate leaderboardDate = getLeaderboardDate();
+        LocalDate today = riyadhNow.toLocalDate();
+        
+        if (leaderboardDate.equals(today)) {
+            return "Today's Leaderboard (from 9:00 AM Riyadh time)";
+        } else {
+            return "Yesterday's Leaderboard (before 9:00 AM Riyadh time)";
+        }
     }
 }