Disable create room button if no permission

src/app/components/RoomCreate.svelte

@@ -14,9 +14,10 @@
   import Icon from "@lib/components/Icon.svelte"
   import ModalHeader from "@lib/components/ModalHeader.svelte"
   import ModalFooter from "@lib/components/ModalFooter.svelte"
-  import {hasNip29, loadChannel} from "@app/core/state"
+  import {deriveUserCanCreateRoom, hasNip29, loadChannel} from "@app/core/state"
   import {makeSpacePath} from "@app/util/routes"
   import {pushToast} from "@app/util/toast"
+  import {get} from "svelte/store"
 
   const {url} = $props()
 
@@ -51,6 +52,8 @@
     goto(makeSpacePath(url, room.id))
   }
 
+  const canCreateRoom = get<boolean>(deriveUserCanCreateRoom(url))
+
   const create = async () => {
     loading = true
 
@@ -99,7 +102,10 @@
       <Icon icon={AltArrowLeft} />
       Go back
     </Button>
-    <Button type="submit" class="btn btn-primary" disabled={!name || loading || !hasNip29($relay)}>
+    <Button
+      type="submit"
+      class="btn btn-primary"
+      disabled={!name || loading || !hasNip29($relay) || !canCreateRoom}>
       <Spinner {loading}>Create Room</Spinner>
       <Icon icon={AltArrowRight} />
     </Button>

src/app/core/state.ts

@@ -22,6 +22,7 @@ import {
   groupBy,
   always,
   tryCatch,
+  last,
 } from "@welshman/lib"
 import type {Socket} from "@welshman/net"
 import {Pool, load, AuthStateEvent, AuthStatus, SocketEvent, netContext} from "@welshman/net"
@@ -760,6 +761,17 @@ export const deriveUserMembershipStatus = (url: string, room: string) =>
     },
   )
 
+export const deriveUserCanCreateRoom = (url: string) =>
+  derived([pubkey, deriveEventsForUrl(url, [{kinds: [39004]}])], ([$pubkey, $events]) => {
+    const latest = last($events)
+
+    if (!latest) {
+      return true
+    }
+
+    return getTagValues("p", latest.tags).includes($pubkey!)
+  })
+
 // Other utils
 
 export const encodeRelay = (url: string) =>