Add consent-gated media exchange library

src/services/chat/matrix/client.ts

@@ -528,6 +528,87 @@ export class MatrixClient {
     return res.event_id;
   }
 
+  /** Upload an image to the Matrix content repository and return its mxc URI. */
+  async uploadImage(bytes: Buffer, mimeType: string, fileName: string): Promise<string> {
+    const candidates = [
+      '/_matrix/media/v3/upload',
+      '/_matrix/client/v1/media/upload',
+    ];
+    for (const endpoint of candidates) {
+      const url = new URL(this.creds.homeserver + endpoint);
+      url.searchParams.set('filename', fileName);
+      await this.acquireRequestSlot();
+      const response = await this.timedFetch(url.toString(), {
+        method: 'POST',
+        headers: {
+          Authorization: `Bearer ${this.creds.accessToken}`,
+          'Content-Type': mimeType,
+        },
+        body: Uint8Array.from(bytes).buffer,
+      });
+      if (response === null) throw new Error('Matrix media upload timed out');
+      if (response.status === 401 || response.status === 403) {
+        const failure = await readMatrixFailure(response);
+        if (isMatrixAuthenticationFailure(response.status, failure.errcode)) {
+          throw new MatrixAuthError(`Matrix media upload → ${response.status} (token rejected)`);
+        }
+        throw new Error(`Matrix media upload → ${response.status}: ${failure.text.slice(0, 200)}`);
+      }
+      if (response.status === 404 || response.status === 405) continue;
+      if (response.status === 429) {
+        const failure = await response.json().catch(() => ({})) as {
+          retry_after_ms?: unknown;
+          errcode?: unknown;
+          ['com.reddit.error.code']?: unknown;
+        };
+        throw new MatrixRateLimitError(
+          'Matrix media upload rate limited',
+          typeof failure.retry_after_ms === 'number' ? failure.retry_after_ms : 500,
+          typeof failure.errcode === 'string' ? failure.errcode : null,
+          typeof failure['com.reddit.error.code'] === 'string' ? failure['com.reddit.error.code'] : null,
+        );
+      }
+      if (!response.ok) {
+        const failure = await response.text().catch(() => '');
+        throw new Error(`Matrix media upload → ${response.status}: ${failure.slice(0, 200)}`);
+      }
+      const payload = await response.json() as { content_uri?: unknown };
+      if (typeof payload.content_uri !== 'string' || !payload.content_uri.startsWith('mxc://')) {
+        throw new Error('Matrix media upload returned no content URI');
+      }
+      return payload.content_uri;
+    }
+    throw new Error('Matrix homeserver does not expose a supported media upload endpoint');
+  }
+
+  async sendImageMessage(
+    roomId: string,
+    body: string,
+    mxcUri: string,
+    info: { mimeType: string; size: number; width: number; height: number },
+    txnId?: string,
+  ): Promise<string> {
+    const id = txnId ?? `rbot-image-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
+    const response = await this.request<{ event_id: string }>(
+      'PUT',
+      `/_matrix/client/v3/rooms/${encodeURIComponent(roomId)}/send/m.room.message/${encodeURIComponent(id)}`,
+      {
+        body: {
+          msgtype: 'm.image',
+          body,
+          url: mxcUri,
+          info: {
+            mimetype: info.mimeType,
+            size: info.size,
+            w: info.width,
+            h: info.height,
+          },
+        },
+      },
+    );
+    return response.event_id;
+  }
+
   /**
    * Convert an mxc:// URI to an HTTPS download URL on this homeserver.
    * Reddit's media is served from the same Matrix server.

src/services/chat/service.ts

@@ -582,7 +582,7 @@ export class ChatService {
    * `https://chat.reddit.com/room/<roomId>` URL (web UI compatibility) or
    * a raw Matrix room ID like `!abc:reddit.com`.
    */
-  async sendChatMessage(chatUrlOrRoomId: string, message: string): Promise<boolean> {
+  async sendChatMessage(chatUrlOrRoomId: string, message: string, txnId?: string): Promise<boolean> {
     if (!this.accountAuth?.isFullyAuthenticated()) return false;
     const active = this.getInvitationCooldown();
     if (active && this.blocksExistingRoomSends(active)) {
@@ -599,7 +599,7 @@ export class ChatService {
           this.logger.error(`[chat] cannot extract room ID from "${chatUrlOrRoomId}"`);
           return false;
         }
-        const eventId = await this.withAuth(() => this.matrix.sendTextMessage(roomId, message));
+        const eventId = await this.withAuth(() => this.matrix.sendTextMessage(roomId, message, txnId));
         this.logger.info(`[chat] sent message to ${roomId} (event_id=${eventId})`);
         const chat = this.cache.get().find((c) => c.roomId === roomId);
         if (chat) {
@@ -619,6 +619,47 @@ export class ChatService {
     });
   }
 
+  async sendChatImage(
+    chatUrlOrRoomId: string,
+    image: { bytes: Buffer; mimeType: string; fileName: string; width: number; height: number },
+    txnId: string,
+    existingMxcUri?: string | null,
+  ): Promise<{ eventId: string; mxcUri: string } | null> {
+    if (!this.accountAuth?.isFullyAuthenticated()) return null;
+    const active = this.getInvitationCooldown();
+    if (active && this.blocksExistingRoomSends(active)) return null;
+    return this.enqueue(async () => {
+      try {
+        const roomId = ChatService.extractRoomId(chatUrlOrRoomId);
+        if (!roomId) return null;
+        const mxcUri = existingMxcUri
+          ?? await this.withAuth(() => this.matrix.uploadImage(image.bytes, image.mimeType, image.fileName));
+        const eventId = await this.withAuth(() => this.matrix.sendImageMessage(
+          roomId,
+          image.fileName,
+          mxcUri,
+          { mimeType: image.mimeType, size: image.bytes.length, width: image.width, height: image.height },
+          txnId,
+        ));
+        this.logger.info(`[chat] sent image to ${roomId} (event_id=${eventId})`);
+        const chat = this.cache.get().find((item) => item.roomId === roomId);
+        if (chat) {
+          chat.lastMessageSnippet = '[Image]';
+          chat.lastMessageTime = Date.now();
+          chat.isFromUs = true;
+        }
+        return { eventId, mxcUri };
+      } catch (error) {
+        if (error instanceof MatrixRateLimitError) {
+          this.setInvitationCooldown(error, 'all-sends');
+          return null;
+        }
+        this.logger.error('[chat] sendChatImage failed:', error);
+        return null;
+      }
+    });
+  }
+
   /**
    * Start a brand-new DM with the given Reddit user and send the opening
    * line. Returns the new chat (or null on failure).