1 files changed, 256 insertions, 0 deletions
diff --git a/excalidraw-app/collab/Portal.tsx b/excalidraw-app/collab/Portal.tsx
new file mode 100644
index 0000000..1788d39
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+++ b/excalidraw-app/collab/Portal.tsx
@@ -0,0 +1,256 @@
+import type {
+  SocketUpdateData,
+  SocketUpdateDataSource,
+  SyncableExcalidrawElement,
+} from "../data";
+import { isSyncableElement } from "../data";
+
+import type { TCollabClass } from "./Collab";
+
+import type { OrderedExcalidrawElement } from "@excalidraw/excalidraw/element/types";
+import { WS_EVENTS, FILE_UPLOAD_TIMEOUT, WS_SUBTYPES } from "../app_constants";
+import type {
+  OnUserFollowedPayload,
+  SocketId,
+} from "@excalidraw/excalidraw/types";
+import type { UserIdleState } from "@excalidraw/excalidraw/constants";
+import { trackEvent } from "@excalidraw/excalidraw/analytics";
+import throttle from "lodash.throttle";
+import { newElementWith } from "@excalidraw/excalidraw/element/mutateElement";
+import { encryptData } from "@excalidraw/excalidraw/data/encryption";
+import type { Socket } from "socket.io-client";
+import { CaptureUpdateAction } from "@excalidraw/excalidraw";
+
+class Portal {
+  collab: TCollabClass;
+  socket: Socket | null = null;
+  socketInitialized: boolean = false; // we don't want the socket to emit any updates until it is fully initialized
+  roomId: string | null = null;
+  roomKey: string | null = null;
+  broadcastedElementVersions: Map<string, number> = new Map();
+
+  constructor(collab: TCollabClass) {
+    this.collab = collab;
+  }
+
+  open(socket: Socket, id: string, key: string) {
+    this.socket = socket;
+    this.roomId = id;
+    this.roomKey = key;
+
+    // Initialize socket listeners
+    this.socket.on("init-room", () => {
+      if (this.socket) {
+        this.socket.emit("join-room", this.roomId);
+        trackEvent("share", "room joined");
+      }
+    });
+    this.socket.on("new-user", async (_socketId: string) => {
+      this.broadcastScene(
+        WS_SUBTYPES.INIT,
+        this.collab.getSceneElementsIncludingDeleted(),
+        /* syncAll */ true,
+      );
+    });
+    this.socket.on("room-user-change", (clients: SocketId[]) => {
+      this.collab.setCollaborators(clients);
+    });
+
+    return socket;
+  }
+
+  close() {
+    if (!this.socket) {
+      return;
+    }
+    this.queueFileUpload.flush();
+    this.socket.close();
+    this.socket = null;
+    this.roomId = null;
+    this.roomKey = null;
+    this.socketInitialized = false;
+    this.broadcastedElementVersions = new Map();
+  }
+
+  isOpen() {
+    return !!(
+      this.socketInitialized &&
+      this.socket &&
+      this.roomId &&
+      this.roomKey
+    );
+  }
+
+  async _broadcastSocketData(
+    data: SocketUpdateData,
+    volatile: boolean = false,
+    roomId?: string,
+  ) {
+    if (this.isOpen()) {
+      const json = JSON.stringify(data);
+      const encoded = new TextEncoder().encode(json);
+      const { encryptedBuffer, iv } = await encryptData(this.roomKey!, encoded);
+
+      this.socket?.emit(
+        volatile ? WS_EVENTS.SERVER_VOLATILE : WS_EVENTS.SERVER,
+        roomId ?? this.roomId,
+        encryptedBuffer,
+        iv,
+      );
+    }
+  }
+
+  queueFileUpload = throttle(async () => {
+    try {
+      await this.collab.fileManager.saveFiles({
+        elements: this.collab.excalidrawAPI.getSceneElementsIncludingDeleted(),
+        files: this.collab.excalidrawAPI.getFiles(),
+      });
+    } catch (error: any) {
+      if (error.name !== "AbortError") {
+        this.collab.excalidrawAPI.updateScene({
+          appState: {
+            errorMessage: error.message,
+          },
+        });
+      }
+    }
+
+    let isChanged = false;
+    const newElements = this.collab.excalidrawAPI
+      .getSceneElementsIncludingDeleted()
+      .map((element) => {
+        if (this.collab.fileManager.shouldUpdateImageElementStatus(element)) {
+          isChanged = true;
+          // this will signal collaborators to pull image data from server
+          // (using mutation instead of newElementWith otherwise it'd break
+          // in-progress dragging)
+          return newElementWith(element, { status: "saved" });
+        }
+        return element;
+      });
+
+    if (isChanged) {
+      this.collab.excalidrawAPI.updateScene({
+        elements: newElements,
+        captureUpdate: CaptureUpdateAction.NEVER,
+      });
+    }
+  }, FILE_UPLOAD_TIMEOUT);
+
+  broadcastScene = async (
+    updateType: WS_SUBTYPES.INIT | WS_SUBTYPES.UPDATE,
+    elements: readonly OrderedExcalidrawElement[],
+    syncAll: boolean,
+  ) => {
+    if (updateType === WS_SUBTYPES.INIT && !syncAll) {
+      throw new Error("syncAll must be true when sending SCENE.INIT");
+    }
+
+    // sync out only the elements we think we need to to save bandwidth.
+    // periodically we'll resync the whole thing to make sure no one diverges
+    // due to a dropped message (server goes down etc).
+    const syncableElements = elements.reduce((acc, element) => {
+      if (
+        (syncAll ||
+          !this.broadcastedElementVersions.has(element.id) ||
+          element.version > this.broadcastedElementVersions.get(element.id)!) &&
+        isSyncableElement(element)
+      ) {
+        acc.push(element);
+      }
+      return acc;
+    }, [] as SyncableExcalidrawElement[]);
+
+    const data: SocketUpdateDataSource[typeof updateType] = {
+      type: updateType,
+      payload: {
+        elements: syncableElements,
+      },
+    };
+
+    for (const syncableElement of syncableElements) {
+      this.broadcastedElementVersions.set(
+        syncableElement.id,
+        syncableElement.version,
+      );
+    }
+
+    this.queueFileUpload();
+
+    await this._broadcastSocketData(data as SocketUpdateData);
+  };
+
+  broadcastIdleChange = (userState: UserIdleState) => {
+    if (this.socket?.id) {
+      const data: SocketUpdateDataSource["IDLE_STATUS"] = {
+        type: WS_SUBTYPES.IDLE_STATUS,
+        payload: {
+          socketId: this.socket.id as SocketId,
+          userState,
+          username: this.collab.state.username,
+        },
+      };
+      return this._broadcastSocketData(
+        data as SocketUpdateData,
+        true, // volatile
+      );
+    }
+  };
+
+  broadcastMouseLocation = (payload: {
+    pointer: SocketUpdateDataSource["MOUSE_LOCATION"]["payload"]["pointer"];
+    button: SocketUpdateDataSource["MOUSE_LOCATION"]["payload"]["button"];
+  }) => {
+    if (this.socket?.id) {
+      const data: SocketUpdateDataSource["MOUSE_LOCATION"] = {
+        type: WS_SUBTYPES.MOUSE_LOCATION,
+        payload: {
+          socketId: this.socket.id as SocketId,
+          pointer: payload.pointer,
+          button: payload.button || "up",
+          selectedElementIds:
+            this.collab.excalidrawAPI.getAppState().selectedElementIds,
+          username: this.collab.state.username,
+        },
+      };
+
+      return this._broadcastSocketData(
+        data as SocketUpdateData,
+        true, // volatile
+      );
+    }
+  };
+
+  broadcastVisibleSceneBounds = (
+    payload: {
+      sceneBounds: SocketUpdateDataSource["USER_VISIBLE_SCENE_BOUNDS"]["payload"]["sceneBounds"];
+    },
+    roomId: string,
+  ) => {
+    if (this.socket?.id) {
+      const data: SocketUpdateDataSource["USER_VISIBLE_SCENE_BOUNDS"] = {
+        type: WS_SUBTYPES.USER_VISIBLE_SCENE_BOUNDS,
+        payload: {
+          socketId: this.socket.id as SocketId,
+          username: this.collab.state.username,
+          sceneBounds: payload.sceneBounds,
+        },
+      };
+
+      return this._broadcastSocketData(
+        data as SocketUpdateData,
+        true, // volatile
+        roomId,
+      );
+    }
+  };
+
+  broadcastUserFollowed = (payload: OnUserFollowedPayload) => {
+    if (this.socket?.id) {
+      this.socket.emit(WS_EVENTS.USER_FOLLOW_CHANGE, payload);
+    }
+  };
+}
+
+export default Portal;