feat: Add chat seperator and restore last viewed chat on restart

toju-app/src/app/store/rooms/rooms.effects.ts

@@ -2,7 +2,10 @@
 /* eslint-disable id-length */
 /* eslint-disable @typescript-eslint/no-unused-vars,, complexity */
 import { Injectable, inject } from '@angular/core';
-import { Router } from '@angular/router';
+import {
+  NavigationEnd,
+  Router
+} from '@angular/router';
 import {
   Actions,
   createEffect,
@@ -15,7 +18,8 @@ import {
 import {
   of,
   from,
-  EMPTY
+  EMPTY,
+  merge
 } from 'rxjs';
 import {
   map,
@@ -38,7 +42,12 @@ import {
   selectSavedRooms
 } from './rooms.selectors';
 import { RealtimeSessionFacade } from '../../core/realtime';
-import { DatabaseService } from '../../infrastructure/persistence';
+import {
+  clearLastViewedChatFromStorage,
+  DatabaseService,
+  loadLastViewedChatFromStorage,
+  saveLastViewedChatToStorage
+} from '../../infrastructure/persistence';
 import {
   CLIENT_UPDATE_REQUIRED_MESSAGE,
   type ServerSourceSelector,
@@ -137,6 +146,19 @@ function resolveRoomChannels(
   return undefined;
 }
 
+function resolveTextChannelId(
+  channels: Room['channels'] | undefined,
+  preferredChannelId?: string | null
+): string | null {
+  const textChannels = (channels ?? []).filter((channel) => channel.type === 'text');
+
+  if (preferredChannelId && textChannels.some((channel) => channel.id === preferredChannelId)) {
+    return preferredChannelId;
+  }
+
+  return textChannels[0]?.id ?? null;
+}
+
 interface RoomPresenceSignalingMessage {
   type: string;
   reason?: string;
@@ -183,6 +205,51 @@ export class RoomsEffects {
     )
   );
 
+  /** Opens the routed room after login/refresh once saved rooms are available. */
+  syncViewedRoomToRoute$ = createEffect(() =>
+    merge(
+      this.actions$.pipe(
+        ofType(
+          RoomsActions.loadRoomsSuccess,
+          UsersActions.loadCurrentUserSuccess,
+          UsersActions.setCurrentUser
+        )
+      ),
+      this.router.events.pipe(
+        filter((event): event is NavigationEnd => event instanceof NavigationEnd)
+      )
+    ).pipe(
+      withLatestFrom(
+        this.store.select(selectCurrentUser),
+        this.store.select(selectCurrentRoom),
+        this.store.select(selectSavedRooms)
+      ),
+      mergeMap(([
+        , currentUser,
+        currentRoom,
+        savedRooms
+      ]) => {
+        if (!currentUser) {
+          return EMPTY;
+        }
+
+        const roomId = this.extractRoomIdFromUrl(this.router.url);
+
+        if (!roomId || currentRoom?.id === roomId) {
+          return EMPTY;
+        }
+
+        const room = savedRooms.find((savedRoom) => savedRoom.id === roomId) ?? null;
+
+        if (!room) {
+          return EMPTY;
+        }
+
+        return of(RoomsActions.viewServer({ room }));
+      })
+    )
+  );
+
   /** Searches the server directory with debounced input. */
   searchServers$ = createEffect(() =>
     this.actions$.pipe(
@@ -431,6 +498,106 @@ export class RoomsEffects {
     { dispatch: false }
   );
 
+    /** Remembers the viewed room whenever a room becomes active. */
+    persistLastViewedChatOnRoomActivation$ = createEffect(
+      () =>
+        this.actions$.pipe(
+          ofType(RoomsActions.createRoomSuccess, RoomsActions.joinRoomSuccess, RoomsActions.viewServerSuccess),
+          withLatestFrom(this.store.select(selectCurrentUser)),
+          tap(([
+            { room },
+            currentUser
+          ]) => {
+            if (!currentUser) {
+              return;
+            }
+
+            const persisted = loadLastViewedChatFromStorage(currentUser.id);
+            const channelId = persisted?.roomId === room.id
+              ? resolveTextChannelId(room.channels, persisted.channelId)
+              : resolveTextChannelId(room.channels);
+
+            saveLastViewedChatToStorage({
+              userId: currentUser.id,
+              roomId: room.id,
+              channelId
+            });
+          })
+        ),
+      { dispatch: false }
+    );
+
+    /** Remembers the currently selected text channel for the active room. */
+    persistLastViewedChatOnChannelSelection$ = createEffect(
+      () =>
+        this.actions$.pipe(
+          ofType(RoomsActions.selectChannel),
+          withLatestFrom(this.store.select(selectCurrentRoom), this.store.select(selectCurrentUser)),
+          tap(([
+            { channelId },
+            currentRoom,
+            currentUser
+          ]) => {
+            if (!currentRoom || !currentUser) {
+              return;
+            }
+
+            const resolvedChannelId = resolveTextChannelId(currentRoom.channels, channelId);
+
+            if (!resolvedChannelId || resolvedChannelId !== channelId) {
+              return;
+            }
+
+            saveLastViewedChatToStorage({
+              userId: currentUser.id,
+              roomId: currentRoom.id,
+              channelId
+            });
+          })
+        ),
+      { dispatch: false }
+    );
+
+    /** Restores the last viewed text channel once the active room's channels are known. */
+    restoreLastViewedTextChannel$ = createEffect(() =>
+      this.actions$.pipe(
+        ofType(
+          RoomsActions.createRoomSuccess,
+          RoomsActions.joinRoomSuccess,
+          RoomsActions.viewServerSuccess,
+          RoomsActions.updateRoom
+        ),
+        withLatestFrom(
+          this.store.select(selectCurrentUser),
+          this.store.select(selectCurrentRoom),
+          this.store.select(selectActiveChannelId)
+        ),
+        mergeMap(([
+          , currentUser,
+          currentRoom,
+          activeChannelId
+        ]) => {
+          if (!currentUser || !currentRoom) {
+            return EMPTY;
+          }
+
+          const persisted = loadLastViewedChatFromStorage(currentUser.id);
+
+          if (!persisted || persisted.roomId !== currentRoom.id) {
+            return EMPTY;
+          }
+
+          const channelId = resolveTextChannelId(currentRoom.channels, persisted.channelId);
+
+          if (!channelId || channelId === activeChannelId) {
+            return EMPTY;
+          }
+
+          return of(RoomsActions.selectChannel({ channelId }));
+        })
+      )
+    );
+
   refreshServerOwnedRoomMetadata$ = createEffect(() =>
     this.actions$.pipe(
       ofType(RoomsActions.joinRoomSuccess, RoomsActions.viewServerSuccess),
@@ -648,6 +815,22 @@ export class RoomsEffects {
     )
   );
 
+  /** Clears stale resume state when the remembered room is removed locally. */
+  clearLastViewedChatOnRoomRemoval$ = createEffect(
+    () =>
+      this.actions$.pipe(
+        ofType(RoomsActions.deleteRoomSuccess, RoomsActions.forgetRoomSuccess),
+        tap(({ roomId }) => {
+          const persisted = loadLastViewedChatFromStorage();
+
+          if (persisted?.roomId === roomId) {
+            clearLastViewedChatFromStorage();
+          }
+        })
+      ),
+    { dispatch: false }
+  );
+
   /** Updates room settings (host/admin-only) and broadcasts changes to all peers. */
   updateRoomSettings$ = createEffect(() =>
     this.actions$.pipe(