feat: add published_at field support to announcements with scheduled publishing and student visibility filtering

Add published_at field to announcement creation and updates, allowing instructors to schedule announcement publishing. Update student announcement filtering to only show PUBLISHED announcements where published_at <= now. Modify announcement creation to set published_at to provided value or current time for PUBLISHED status. Update announcement updates to handle published_at changes while

Backend/src/controllers/announcementsController.ts

@@ -75,6 +75,7 @@ export class AnnouncementsController {
             content: parsed.content,
             status: parsed.status,
             is_pinned: parsed.is_pinned,
+            published_at: parsed.published_at ? new Date(parsed.published_at) : undefined,
             files,
         });
     }
@@ -107,6 +108,7 @@ export class AnnouncementsController {
             content: body.content,
             status: body.status,
             is_pinned: body.is_pinned,
+            published_at: body.published_at ? new Date(body.published_at) : undefined,
         });
     }
 

Backend/src/services/announcements.service.ts

@@ -58,12 +58,19 @@ export class AnnouncementsService {
 
             const skip = (page - 1) * limit;
 
-            // Students only see PUBLISHED announcements
+            // Students only see PUBLISHED announcements with published_at <= now
-            const statusFilter = (isAdmin || isInstructor) ? {} : { status: 'PUBLISHED' as const };
+            const now = new Date();
+            const whereClause: any = { course_id };
+            
+            if (!(isAdmin || isInstructor)) {
+                // Students: only show PUBLISHED and published_at <= now
+                whereClause.status = 'PUBLISHED';
+                whereClause.published_at = { lte: now };
+            }
 
             const [announcements, total] = await Promise.all([
                 prisma.announcement.findMany({
-                    where: { course_id, ...statusFilter },
+                    where: whereClause,
                     include: {
                         attachments: true,
                     },
@@ -74,7 +81,7 @@ export class AnnouncementsService {
                     skip,
                     take: limit,
                 }),
-                prisma.announcement.count({ where: { course_id } }),
+                prisma.announcement.count({ where: whereClause }),
             ]);
 
             // Generate presigned URLs for attachments
@@ -105,6 +112,7 @@ export class AnnouncementsService {
                         content: a.content as { th: string; en: string },
                         status: a.status,
                         is_pinned: a.is_pinned,
+                        published_at: a.published_at,
                         created_at: a.created_at,
                         updated_at: a.updated_at,
                         attachments: attachmentsWithUrls,
@@ -132,12 +140,18 @@ export class AnnouncementsService {
      */
     async createAnnouncement(input: CreateAnnouncementInput): Promise<CreateAnnouncementResponse> {
         try {
-            const { token, course_id, title, content, status, is_pinned, files } = input;
+            const { token, course_id, title, content, status, is_pinned, published_at, files } = input;
             const decoded = jwt.verify(token, config.jwt.secret) as { id: number };
 
             // Validate instructor access
             await CoursesInstructorService.validateCourseInstructor(token, course_id);
 
+            // Determine published_at: use provided value or default to now if status is PUBLISHED
+            let finalPublishedAt: Date | null = null;
+            if (status === 'PUBLISHED') {
+                finalPublishedAt = published_at ? new Date(published_at) : new Date();
+            }
+
             // Create announcement
             const announcement = await prisma.announcement.create({
                 data: {
@@ -146,7 +160,7 @@ export class AnnouncementsService {
                     content,
                     status: status as any,
                     is_pinned,
-                    published_at: status === 'PUBLISHED' ? new Date() : null,
+                    published_at: finalPublishedAt,
                     created_by: decoded.id,
                 },
             });
@@ -204,6 +218,7 @@ export class AnnouncementsService {
                     content: announcement.content as { th: string; en: string },
                     status: announcement.status,
                     is_pinned: announcement.is_pinned,
+                    published_at: announcement.published_at,
                     created_at: announcement.created_at,
                     updated_at: announcement.updated_at,
                     attachments,
@@ -221,7 +236,7 @@ export class AnnouncementsService {
      */
     async updateAnnouncement(input: UpdateAnnouncementInput): Promise<UpdateAnnouncementResponse> {
         try {
-            const { token, course_id, announcement_id, title, content, status, is_pinned } = input;
+            const { token, course_id, announcement_id, title, content, status, is_pinned, published_at } = input;
             const decoded = jwt.verify(token, config.jwt.secret) as { id: number };
 
             // Validate instructor access
@@ -236,6 +251,16 @@ export class AnnouncementsService {
                 throw new NotFoundError('Announcement not found');
             }
 
+            // Determine published_at
+            let finalPublishedAt: Date | null = existing.published_at;
+            if (status === 'PUBLISHED') {
+                if (published_at) {
+                    finalPublishedAt = new Date(published_at);
+                } else if (existing.status !== 'PUBLISHED') {
+                    finalPublishedAt = new Date();
+                }
+            }
+
             const announcement = await prisma.announcement.update({
                 where: { id: announcement_id },
                 data: {
@@ -243,7 +268,7 @@ export class AnnouncementsService {
                     content,
                     status: status as any,
                     is_pinned,
-                    published_at: status === 'PUBLISHED' && existing.status !== 'PUBLISHED' ? new Date() : existing.published_at,
+                    published_at: finalPublishedAt,
                     updated_by: decoded.id,
                 },
                 include: {
@@ -260,6 +285,7 @@ export class AnnouncementsService {
                     content: announcement.content as { th: string; en: string },
                     status: announcement.status,
                     is_pinned: announcement.is_pinned,
+                    published_at: announcement.published_at,
                     created_at: announcement.created_at,
                     updated_at: announcement.updated_at,
                     attachments: announcement.attachments.map(att => ({

Backend/src/types/announcements.types.ts

@@ -6,6 +6,7 @@ export interface Announcement {
     content: MultiLanguageText;
     status: string;
     is_pinned: boolean;
+    published_at: Date | null;
     created_at: Date;
     updated_at: Date | null;
     attachments: AnnouncementAttachment[];
@@ -44,6 +45,7 @@ export interface CreateAnnouncementInput{
     content: MultiLanguageText;
     status: string;
     is_pinned: boolean;
+    published_at?: Date;
     files?: Express.Multer.File[];
 }
 
@@ -86,6 +88,7 @@ export interface UpdateAnnouncementInput{
     content: MultiLanguageText;
     status: string;
     is_pinned: boolean;
+    published_at?: Date;
     attachments?: AnnouncementAttachment[];
 }
 
@@ -112,6 +115,7 @@ export interface CreateAnnouncementBody {
     content: MultiLanguageText;
     status: string;
     is_pinned: boolean;
+    published_at?: string;
 }
 
 export interface UpdateAnnouncementBody {
@@ -119,4 +123,5 @@ export interface UpdateAnnouncementBody {
     content: MultiLanguageText;
     status: string;
     is_pinned: boolean;
+    published_at?: string;
 }