fix: complete display and channel group management

src/server/store/drizzle-playback.ts

@@ -7,6 +7,7 @@ import {
   playbackStates,
   selections,
   selectionVariants,
+  viewers,
 } from "../../schema/tables.js";
 import {
   type NewStoredSelection,
@@ -176,8 +177,21 @@ export function createPlaybackStore(database: ModuleDatabase): SignagePlaybackSt
       });
     },
 
-    async deleteChannelGroup(groupId: string): Promise<void> {
-      await database.delete(channelGroups).where(eq(channelGroups.id, groupId));
+    async deleteChannelGroup(groupId: string, fallbackChannelId: string): Promise<void> {
+      await database.transaction(async (transaction) => {
+        const removedChannels = await transaction
+          .select({ id: channels.id })
+          .from(channels)
+          .where(eq(channels.groupId, groupId));
+        const removedChannelIds = removedChannels.map((channel) => channel.id);
+        if (removedChannelIds.length > 0) {
+          await transaction
+            .update(viewers)
+            .set({ channelId: fallbackChannelId, updatedAt: new Date() })
+            .where(inArray(viewers.channelId, removedChannelIds));
+        }
+        await transaction.delete(channelGroups).where(eq(channelGroups.id, groupId));
+      });
     },
 
     async findChannelGroup(groupId: string): Promise<StoredChannelGroupDetail | undefined> {