Handle sticky rooms when regenerating lists

`setKnownRooms` is called to regenerate the room list, and if we don't take the sticky room out of the equation we end up with the room being duplicated. So, to make this easy, we simply remove the sticky room and handle it after the fact.

src/stores/room-list/algorithms/Algorithm.ts

@@ -441,6 +441,13 @@ export class Algorithm extends EventEmitter {
         if (isNullOrUndefined(rooms)) throw new Error(`Array of rooms cannot be null`);
         if (!this.sortAlgorithms) throw new Error(`Cannot set known rooms without a tag sorting map`);
 
+        console.warn("Resetting known rooms, initiating regeneration");
+
+        // Before we go any further we need to clear (but remember) the sticky room to
+        // avoid accidentally duplicating it in the list.
+        const oldStickyRoom = this._stickyRoom;
+        await this.updateStickyRoom(null);
+
         this.rooms = rooms;
 
         const newTags: ITagMap = {};
@@ -500,6 +507,21 @@ export class Algorithm extends EventEmitter {
 
         this.cachedRooms = newTags;
         this.updateTagsFromCache();
+        this.recalculateFilteredRooms();
+
+        // Now that we've finished generation, we need to update the sticky room to what
+        // it was. It's entirely possible that it changed lists though, so if it did then
+        // we also have to update the position of it.
+        if (oldStickyRoom && oldStickyRoom.room) {
+            await this.updateStickyRoom(oldStickyRoom.room);
+            if (this._stickyRoom && this._stickyRoom.room) { // just in case the update doesn't go according to plan
+                if (this._stickyRoom.tag !== oldStickyRoom.tag) {
+                    // We put the sticky room at the top of the list to treat it as an obvious tag change.
+                    this._stickyRoom.position = 0;
+                    this.recalculateStickyRoom(this._stickyRoom.tag);
+                }
+            }
+        }
     }
 
     private getTagsForRoom(room: Room): TagID[] {