feat: add notification system

src/main/java/com/openisle/controller/NotificationController.java

@@ -0,0 +1,62 @@
+package com.openisle.controller;
+
+import com.openisle.model.Notification;
+import com.openisle.model.NotificationType;
+import com.openisle.service.NotificationService;
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.*;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/** Endpoints for user notifications. */
+@RestController
+@RequestMapping("/api/notifications")
+@RequiredArgsConstructor
+public class NotificationController {
+    private final NotificationService notificationService;
+
+    @GetMapping
+    public List<NotificationDto> list(@RequestParam(value = "read", required = false) Boolean read,
+                                      Authentication auth) {
+        return notificationService.listNotifications(auth.getName(), read).stream()
+                .map(this::toDto)
+                .collect(Collectors.toList());
+    }
+
+    @PostMapping("/read")
+    public void markRead(@RequestBody MarkReadRequest req, Authentication auth) {
+        notificationService.markRead(auth.getName(), req.getIds());
+    }
+
+    private NotificationDto toDto(Notification n) {
+        NotificationDto dto = new NotificationDto();
+        dto.setId(n.getId());
+        dto.setType(n.getType());
+        dto.setPostId(n.getPost() != null ? n.getPost().getId() : null);
+        dto.setCommentId(n.getComment() != null ? n.getComment().getId() : null);
+        dto.setApproved(n.getApproved());
+        dto.setRead(n.isRead());
+        dto.setCreatedAt(n.getCreatedAt());
+        return dto;
+    }
+
+    @Data
+    private static class MarkReadRequest {
+        private List<Long> ids;
+    }
+
+    @Data
+    private static class NotificationDto {
+        private Long id;
+        private NotificationType type;
+        private Long postId;
+        private Long commentId;
+        private Boolean approved;
+        private boolean read;
+        private LocalDateTime createdAt;
+    }
+}