Merge pull request #5960 from matrix-org/travis/msc2876

Support UI for MSC2762: Widgets reading events from rooms

src/stores/widgets/StopGapWidgetDriver.ts

@@ -44,6 +44,7 @@ import { CHAT_EFFECTS } from "../../effects";
 import { containsEmoji } from "../../effects/utils";
 import dis from "../../dispatcher/dispatcher";
 import {tryTransformPermalinkToLocalHref} from "../../utils/permalinks/Permalinks";
+import {MatrixEvent} from "matrix-js-sdk/src/models/event";
 
 // TODO: Purge this from the universe
 
@@ -144,6 +145,52 @@ export class StopGapWidgetDriver extends WidgetDriver {
         return {roomId, eventId: r.event_id};
     }
 
+    public async readRoomEvents(eventType: string, msgtype: string | undefined, limit: number): Promise<MatrixEvent[]> {
+        limit = limit > 0 ? Math.min(limit, 25) : 25; // arbitrary choice
+
+        const client = MatrixClientPeg.get();
+        const roomId = ActiveRoomObserver.activeRoomId;
+        const room = client.getRoom(roomId);
+        if (!client || !roomId || !room) throw new Error("Not in a room or not attached to a client");
+
+        const results: MatrixEvent[] = [];
+        const events = room.getLiveTimeline().getEvents(); // timelines are most recent last
+        for (let i = events.length - 1; i > 0; i--) {
+            if (results.length >= limit) break;
+
+            const ev = events[i];
+            if (ev.getType() !== eventType) continue;
+            if (eventType === EventType.RoomMessage && msgtype && msgtype !== ev.getContent()['msgtype']) continue;
+            results.push(ev);
+        }
+
+        return results.map(e => e.event);
+    }
+
+    public async readStateEvents(
+        eventType: string, stateKey: string | undefined, limit: number,
+    ): Promise<MatrixEvent[]> {
+        limit = limit > 0 ? Math.min(limit, 100) : 100; // arbitrary choice
+
+        const client = MatrixClientPeg.get();
+        const roomId = ActiveRoomObserver.activeRoomId;
+        const room = client.getRoom(roomId);
+        if (!client || !roomId || !room) throw new Error("Not in a room or not attached to a client");
+
+        const results: MatrixEvent[] = [];
+        const state = room.currentState.events.get(eventType);
+        if (state) {
+            if (stateKey === "" || !!stateKey) {
+                const forKey = state.get(stateKey);
+                if (forKey) results.push(forKey);
+            } else {
+                results.push(...Array.from(state.values()));
+            }
+        }
+
+        return results.slice(0, limit).map(e => e.event);
+    }
+
     public async askOpenID(observer: SimpleObservable<IOpenIDUpdate>) {
         const oidcState = WidgetPermissionStore.instance.getOIDCState(
             this.forWidget, this.forWidgetKind, this.inRoomId,