feat: add new generic response

src/main/java/aplp/backend/core/common/response/ApiError.java

@@ -1,17 +0,0 @@
-package aplp.backend.core.common.response;
-
-import java.time.Instant;
-
-public record ApiError(
-        Instant timestamp,
-        int status,
-        String error,
-        String code,
-        String message,
-        String traceId
-) {
-
-    public static ApiError of(int status, String error, String code, String message, String traceId) {
-        return new ApiError(Instant.now(), status, error, code, message, traceId);
-    }
-}

src/main/java/aplp/backend/core/common/response/ApiResponse.java

@@ -0,0 +1,28 @@
+package aplp.backend.core.common.response;
+
+import java.time.Instant;
+
+public record ApiResponse<T>(
+        boolean success,
+        String code,
+        String message,
+        T data,
+        Instant timestamp,
+        String traceId
+) {
+    public static <T> ApiResponse<T> ok(T data) {
+        return new ApiResponse<>(true, "OK", "Success", data, Instant.now(), null);
+    }
+
+    public static <T> ApiResponse<T> ok(String message, T data) {
+        return new ApiResponse<>(true, "OK", message, data, Instant.now(), null);
+    }
+
+    public static <T> ApiResponse<T> error(String code, String message) {
+        return new ApiResponse<>(false, code, message, null, Instant.now(), null);
+    }
+
+    public static <T> ApiResponse<T> error(String code, String message, String traceId) {
+        return new ApiResponse<>(false, code, message, null, Instant.now(), traceId);
+    }
+}

src/main/java/aplp/backend/core/common/response/ErrorResponse.java

@@ -1,10 +0,0 @@
-package aplp.backend.core.common.response;
-
-import java.time.LocalDateTime;
-
-public record ErrorResponse(
-        int status,
-        String message,
-        LocalDateTime timestamp
-) {
-}

src/main/java/aplp/backend/core/common/response/PagedResponse.java

@@ -0,0 +1,16 @@
+package aplp.backend.core.common.response;
+
+import java.util.List;
+
+public record PagedResponse<T>(
+        List<T> content,
+        int page,
+        int size,
+        long totalElements,
+        int totalPages
+) {
+    public static <T> PagedResponse<T> of(List<T> content, int page, int size, long totalElements) {
+        int totalPages = size <= 0 ? 0 : (int) Math.ceil((double) totalElements / size);
+        return new PagedResponse<>(content == null ? List.of() : List.copyOf(content), page, size, totalElements, totalPages);
+    }
+}

src/test/java/aplp/backend/core/common/response/ApiResponseTest.java

@@ -0,0 +1,45 @@
+package aplp.backend.core.common.response;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ApiResponseTest {
+
+    @Test
+    void ok_wrapsDataWithSuccessTrue() {
+        ApiResponse<String> res = ApiResponse.ok("hello");
+
+        assertTrue(res.success());
+        assertEquals("OK", res.code());
+        assertNotNull(res.message());
+        assertEquals("hello", res.data());
+        assertNotNull(res.timestamp());
+        assertNull(res.traceId());
+    }
+
+    @Test
+    void error_wrapsCodeWithoutData() {
+        ApiResponse<String> res = ApiResponse.error("USER_NOT_FOUND", "User not found");
+
+        assertFalse(res.success());
+        assertEquals("USER_NOT_FOUND", res.code());
+        assertEquals("User not found", res.message());
+        assertNull(res.data());
+        assertNotNull(res.timestamp());
+    }
+
+    @Test
+    void pagedResponse_computesTotalPages() {
+        PagedResponse<String> page = PagedResponse.of(List.of("a", "b"), 0, 10, 25);
+
+        assertEquals(3, page.totalPages());
+        assertEquals(2, page.content().size());
+
+        ApiResponse<PagedResponse<String>> res = ApiResponse.ok(page);
+        assertTrue(res.success());
+        assertEquals(3, res.data().totalPages());
+    }
+}