Process events list client side

matrixgw_frontend/src/utils/RoomEventsManager.ts

@@ -0,0 +1,101 @@
+import type {
+  MatrixEvent,
+  MatrixEventsList,
+} from "../api/matrix/MatrixApiEvent";
+import type { Room } from "../api/matrix/MatrixApiRoom";
+
+export interface MessageReaction {
+  event_id: string;
+  account: string;
+  key: string;
+}
+
+export interface Message {
+  event_id: string;
+  sent: number;
+  modified: boolean;
+  reactions: MessageReaction[];
+  content: string;
+  image?: string;
+}
+
+export class RoomEventsManager {
+  readonly room: Room;
+  private events: MatrixEvent[];
+  messages: Message[];
+  endToken?: string;
+
+  constructor(room: Room, initialMessages: MatrixEventsList) {
+    this.room = room;
+    this.events = [];
+    this.messages = [];
+
+    this.processNewEvents(initialMessages);
+  }
+
+  /**
+   * Process events given by the API
+   */
+  processNewEvents(evts: MatrixEventsList) {
+    this.endToken = evts.end;
+    this.events = [...this.events, ...evts.events];
+    this.rebuildMessagesList();
+  }
+
+  private rebuildMessagesList() {
+    // Sorts events list to process oldest events first
+    this.events.sort((a, b) => a.time - b.time);
+
+    // First, process redactions to skip redacted events
+    let redacted = new Set(
+      this.events
+        .map((e) =>
+          e.data.type === "m.room.redaction" ? e.data.redacts : undefined
+        )
+        .filter((e) => e !== undefined)
+    );
+
+    for (const evt of this.events) {
+      if (redacted.has(evt.id)) continue;
+
+      const data = evt.data;
+
+      // Message
+      if (data.type === "m.room.message") {
+        // Check if this message replaces another one
+        if (data.content["m.relates_to"]) {
+          const message = this.messages.find(
+            (m) => m.event_id === data.content["m.relates_to"]?.event_id
+          );
+          if (!message) continue;
+          message.modified = true;
+          message.content = data.content.body;
+          continue;
+        }
+
+        this.messages.push({
+          event_id: evt.id,
+          modified: false,
+          reactions: [],
+          sent: evt.time,
+          image: data.content.file?.url,
+          content: data.content.body,
+        });
+      }
+
+      // Reaction
+      if (data.type === "m.reaction") {
+        const message = this.messages.find(
+          (m) => m.event_id === data.content["m.relates_to"].event_id
+        );
+
+        if (!message) continue;
+        message.reactions.push({
+          account: evt.sender,
+          event_id: evt.id,
+          key: data.content["m.relates_to"].key,
+        });
+      }
+    }
+  }
+}