Add reaction module

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

@@ -0,0 +1,61 @@
+package com.openisle.controller;
+
+import com.openisle.model.Reaction;
+import com.openisle.model.ReactionType;
+import com.openisle.service.ReactionService;
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api")
+@RequiredArgsConstructor
+public class ReactionController {
+    private final ReactionService reactionService;
+
+    @PostMapping("/posts/{postId}/reactions")
+    public ResponseEntity<ReactionDto> reactToPost(@PathVariable Long postId,
+                                                  @RequestBody ReactionRequest req,
+                                                  Authentication auth) {
+        Reaction reaction = reactionService.reactToPost(auth.getName(), postId, req.getType());
+        return ResponseEntity.ok(toDto(reaction));
+    }
+
+    @PostMapping("/comments/{commentId}/reactions")
+    public ResponseEntity<ReactionDto> reactToComment(@PathVariable Long commentId,
+                                                     @RequestBody ReactionRequest req,
+                                                     Authentication auth) {
+        Reaction reaction = reactionService.reactToComment(auth.getName(), commentId, req.getType());
+        return ResponseEntity.ok(toDto(reaction));
+    }
+
+    private ReactionDto toDto(Reaction reaction) {
+        ReactionDto dto = new ReactionDto();
+        dto.setId(reaction.getId());
+        dto.setType(reaction.getType());
+        dto.setUser(reaction.getUser().getUsername());
+        if (reaction.getPost() != null) {
+            dto.setPostId(reaction.getPost().getId());
+        }
+        if (reaction.getComment() != null) {
+            dto.setCommentId(reaction.getComment().getId());
+        }
+        return dto;
+    }
+
+    @Data
+    private static class ReactionRequest {
+        private ReactionType type;
+    }
+
+    @Data
+    private static class ReactionDto {
+        private Long id;
+        private ReactionType type;
+        private String user;
+        private Long postId;
+        private Long commentId;
+    }
+}