room-history: Implement Permalink creation for rooms

Enhances #891

Part-of: <https://gitlab.gnome.org/GNOME/fractal/-/merge_requests/1146>

data/resources/ui/content-room-history.ui

@@ -12,6 +12,10 @@
         <attribute name="action">room-history.invite-members</attribute>
         <attribute name="hidden-when">action-disabled</attribute>
       </item>
+      <item>
+        <attribute name="label" translatable="yes">Room _Permalink</attribute>
+        <attribute name="action">room-history.permalink</attribute>
+      </item>
     </section>
     <section>
       <item>

src/session/content/room_history/mod.rs

@@ -20,7 +20,7 @@ use gtk::{
     prelude::*,
     CompositeTemplate,
 };
-use log::warn;
+use log::{error, warn};
 use matrix_sdk::ruma::events::room::message::{
     EmoteMessageEventContent, FormattedBody, MessageType, RoomMessageEventContent,
     TextMessageEventContent,
@@ -40,7 +40,7 @@ use crate::{
         room::{Room, RoomType, SupportedEvent, Timeline, TimelineItem, TimelineState},
         user::UserExt,
     },
-    spawn, toast,
+    spawn, spawn_tokio, toast,
     utils::filename_for_mime,
 };
 
@@ -126,6 +126,12 @@ mod imp {
                 widget.try_again();
             });
 
+            klass.install_action("room-history.permalink", None, move |widget, _, _| {
+                spawn!(clone!(@weak widget => async move {
+                    widget.permalink().await;
+                }));
+            });
+
             klass.install_action("room-history.details", None, move |widget, _, _| {
                 widget.open_room_details("general");
             });
@@ -558,6 +564,23 @@ impl RoomHistory {
         }
     }
 
+    pub async fn permalink(&self) {
+        if let Some(room) = self.room() {
+            let room = room.matrix_room();
+            let handle = spawn_tokio!(async move { room.matrix_to_permalink().await });
+            match handle.await.unwrap() {
+                Ok(permalink) => {
+                    self.clipboard().set_text(&permalink.to_string());
+                    toast!(self, gettext("Permalink copied to clipboard"));
+                }
+                Err(error) => {
+                    error!("Could not get permalink: {}", error);
+                    toast!(self, gettext("Failed to copy the permalink"));
+                }
+            }
+        }
+    }
+
     /// Opens the room details on the page with the given name.
     pub fn open_room_details(&self, page_name: &str) {
         if let Some(room) = self.room() {

src/session/room/mod.rs

@@ -399,7 +399,7 @@ impl Room {
             .is_direct()
     }
 
-    fn matrix_room(&self) -> MatrixRoom {
+    pub fn matrix_room(&self) -> MatrixRoom {
         self.imp().matrix_room.borrow().as_ref().unwrap().clone()
     }