Add room not found view

src/room/GroupCallLoader.jsx

@@ -2,6 +2,8 @@ import React from "react";
 import { useLoadGroupCall } from "./useLoadGroupCall";
 import { ErrorView, FullScreenView } from "../FullScreenView";
 import { usePageTitle } from "../usePageTitle";
+import { isLocalRoomId } from "../matrix-utils";
+import { RoomNotFoundView } from "./RoomNotFoundView";
 
 export function GroupCallLoader({ client, roomId, viaServers, children }) {
   const { loading, error, groupCall } = useLoadGroupCall(
@@ -20,6 +22,10 @@ export function GroupCallLoader({ client, roomId, viaServers, children }) {
     );
   }
 
+  if (error && error.errcode === "M_UNKNOWN" && isLocalRoomId(roomId)) {
+    return <RoomNotFoundView client={client} roomId={roomId} />;
+  }
+
   if (error) {
     return <ErrorView error={error} />;
   }

src/room/RoomNotFoundView.jsx

@@ -0,0 +1,76 @@
+import React, { useState, useCallback } from "react";
+import { FullScreenView } from "../FullScreenView";
+import { Headline, Subtitle } from "../typography/Typography";
+import { createRoom, roomNameFromRoomId } from "../matrix-utils";
+import { FieldRow, ErrorMessage, InputField } from "../input/Input";
+import { Button } from "../button";
+import { Form } from "../form/Form";
+import { useHistory } from "react-router-dom";
+import styles from "./RoomNotFoundView.module.css";
+
+export function RoomNotFoundView({ client, roomId }) {
+  const history = useHistory();
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState();
+  const roomName = roomNameFromRoomId(roomId);
+  const onSubmit = useCallback(
+    (e) => {
+      e.preventDefault();
+
+      async function submit() {
+        setError(undefined);
+        setLoading(true);
+
+        const roomIdOrAlias = await createRoom(client, roomName);
+
+        if (roomIdOrAlias) {
+          history.push(`/room/${roomIdOrAlias}`);
+        }
+      }
+
+      submit().catch((error) => {
+        console.error(error);
+        setLoading(false);
+        setError(error);
+      });
+    },
+    [client, roomName]
+  );
+
+  return (
+    <FullScreenView>
+      <Headline>Call Not Found</Headline>
+      <Subtitle>Would you like to create this call?</Subtitle>
+      <Form onSubmit={onSubmit} className={styles.form}>
+        <FieldRow>
+          <InputField
+            id="callName"
+            name="callName"
+            label="Call name"
+            placeholder="Call name"
+            type="text"
+            required
+            autoComplete="off"
+            value={roomName}
+            disabled
+          />
+        </FieldRow>
+        <FieldRow>
+          <Button
+            type="submit"
+            size="lg"
+            disabled={loading}
+            className={styles.button}
+          >
+            {loading ? "Loading..." : "Create Room"}
+          </Button>
+        </FieldRow>
+        {error && (
+          <FieldRow>
+            <ErrorMessage>{error.message}</ErrorMessage>
+          </FieldRow>
+        )}
+      </Form>
+    </FullScreenView>
+  );
+}

src/room/RoomNotFoundView.module.css

@@ -0,0 +1,11 @@
+.form {
+  padding: 0 24px;
+  justify-content: center;
+  max-width: 409px;
+  width: calc(100% - 48px);
+  margin-bottom: 72px;
+}
+
+.button {
+  width: 100%;
+}