feat: Update how messages load and sync, allow plugins to import messages

toju-app/src/app/infrastructure/persistence/browser-database.service.ts

@@ -70,12 +70,28 @@ export class BrowserDatabaseService {
    * @param roomId - Target room.
    * @param limit  - Maximum number of messages to return.
     * @param offset - Number of newer messages to skip (for pagination).
+   * @param channelId - Optional channel scope; 'general' includes null/empty.
+   * @param beforeTimestamp - Optional cursor; only messages strictly older
+   *                          than this timestamp are returned. Used for
+   *                          scroll-up history pagination.
    */
-  async getMessages(roomId: string, limit = 100, offset = 0): Promise<Message[]> {
+  async getMessages(
+    roomId: string,
+    limit = 100,
+    offset = 0,
+    channelId?: string,
+    beforeTimestamp?: number
+  ): Promise<Message[]> {
     const allRoomMessages = await this.getAllFromIndex<Message>(
       STORE_MESSAGES, 'roomId', roomId
     );
-    const sortedMessages = allRoomMessages.sort((first, second) => first.timestamp - second.timestamp);
+    const scopedMessages = channelId
+      ? allRoomMessages.filter((message) => (message.channelId || 'general') === channelId)
+      : allRoomMessages;
+    const cursorFiltered = beforeTimestamp === undefined
+      ? scopedMessages
+      : scopedMessages.filter((message) => message.timestamp < beforeTimestamp);
+    const sortedMessages = cursorFiltered.sort((first, second) => first.timestamp - second.timestamp);
     const endIndex = Math.max(sortedMessages.length - offset, 0);
     const startIndex = Math.max(endIndex - limit, 0);
     const messages = sortedMessages.slice(startIndex, endIndex);