Implement client capability negotiation from mps.

Author: Gnuxie

src/Client/BotSDKBaseClient.ts

@@ -33,6 +33,8 @@ import {
   StateEvent,
   Logger,
   MultipleErrors,
+  ClientCapabilitiesNegotiation,
+  ClientCapabilitiesResponse,
 } from 'matrix-protection-suite';
 import { MatrixSendClient } from '../MatrixEmitter';
 import { getRelationsForEvent } from './PaginationAPIs';
@@ -148,6 +150,7 @@ export function resultifyBotSDKRequestError(
 
 export class BotSDKBaseClient
   implements
+    ClientCapabilitiesNegotiation,
     RoomBanner,
     RoomCreator,
     RoomEventGetter,
@@ -173,6 +176,17 @@ export class BotSDKBaseClient
     // nothing to do.
   }
 
+  public async getClientCapabilities(): Promise<
+    ActionResult<ClientCapabilitiesResponse>
+  > {
+    return await this.client
+      .doRequest('GET', '/_matrix/client/v3/capabilities')
+      .then(
+        (value) => Value.Decode(ClientCapabilitiesResponse, value),
+        resultifyBotSDKRequestError
+      );
+  }
+
   public async sendMessage<TContent extends MessageContent>(
     roomID: StringRoomID,
     content: TContent

src/Client/BotSDKClientPlatform.ts

@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: AFL-3.0
 
 import {
+  ClientCapabilitiesNegotiation,
   ClientPlatform,
   RoomBanner,
   RoomCreator,
@@ -25,6 +26,11 @@ export class BotSDKClientPlatform implements ClientPlatform {
   constructor(private readonly allClient: BotSDKBaseClient) {
     // nothing to do,
   }
+
+  toClientCapabilitiesNegotiation(): ClientCapabilitiesNegotiation {
+    return this.allClient;
+  }
+
   toRoomBanner(): RoomBanner {
     return this.allClient;
   }