refactor(room): Discord-style UI redesign for channel sidebar and member list

src/app/project/room.tsx

@@ -1,4 +1,4 @@
-import { useState } from 'react';
+import { useCallback, useState } from 'react';
 import { useParams } from 'react-router-dom';
 import { useRoom, useUser } from '@/contexts';
 import { RoomProvider } from '@/contexts';
@@ -18,6 +18,8 @@ function ProjectRoomInner() {
   const {
     rooms,
     roomsLoading,
+    categories,
+    createCategory,
     activeRoom,
     activeRoomId,
     setActiveRoom,
@@ -89,6 +91,17 @@ function ProjectRoomInner() {
     }
   };
 
+  const handleCreateCategory = useCallback(async (name: string) => {
+    await createCategory(name);
+  }, [createCategory]);
+
+  const handleMoveRoomToCategory = useCallback(
+    async (roomId: string, categoryId: string | null) => {
+      await updateRoom(roomId, undefined, undefined, categoryId ?? undefined);
+    },
+    [updateRoom],
+  );
+
   const isAdmin = !!user && members.some(
     (m) =>
       m.user === user.uid &&
@@ -112,6 +125,9 @@ function ProjectRoomInner() {
         selectedRoomId={activeRoomId}
         onSelectRoom={handleSelectRoom}
         onCreateRoom={handleOpenCreate}
+        categories={categories.map((c) => ({ id: c.id, name: c.name }))}
+        onCreateCategory={handleCreateCategory}
+        onMoveRoomToCategory={handleMoveRoomToCategory}
       />
 
       {/* Main chat area */}

src/components/room/DiscordChannelSidebar.tsx

@@ -1,198 +1,437 @@
 'use client';
 
-import {memo, useCallback, useState} from 'react';
+import { memo, useCallback, useMemo, useState } from 'react';
-import type {RoomWithCategory} from '@/contexts/room-context';
+import type { RoomWithCategory } from '@/contexts/room-context';
-import {Button} from '@/components/ui/button';
+import { Button } from '@/components/ui/button';
-import {cn} from '@/lib/utils';
+import { Input } from '@/components/ui/input';
-import {ChevronDown, ChevronRight, Hash, Lock, Plus, Settings} from 'lucide-react';
+import { cn } from '@/lib/utils';
+import { ChevronDown, ChevronRight, Hash, Lock, Plus, X, GripVertical } from 'lucide-react';
+import {
+  DndContext,
+  closestCorners,
+  KeyboardSensor,
+  PointerSensor,
+  useSensor,
+  useSensors,
+  type DragEndEvent,
+  type UniqueIdentifier,
+} from '@dnd-kit/core';
+import {
+  SortableContext,
+  sortableKeyboardCoordinates,
+  verticalListSortingStrategy,
+  useSortable,
+} from '@dnd-kit/sortable';
+import { CSS } from '@dnd-kit/utilities';
 
+/* ── Types ─────────────────────────────────────────────────────── */
 
 interface RoomWithUnread extends RoomWithCategory {
-    unread_count?: number;
+  unread_count?: number;
 }
 
 interface DiscordChannelSidebarProps {
-    projectName: string;
+  projectName: string;
-    rooms: RoomWithCategory[];
+  rooms: RoomWithCategory[];
-    selectedRoomId: string | null;
+  selectedRoomId: string | null;
-    onSelectRoom: (room: RoomWithCategory) => void;
+  onSelectRoom: (room: RoomWithCategory) => void;
-    onCreateRoom: () => void;
+  onCreateRoom: () => void;
-    onOpenSettings?: () => void;
+  categories: Array<{ id: string; name: string }>;
+  onCreateCategory: (name: string) => Promise<void>;
+  onMoveRoomToCategory: (roomId: string, categoryId: string | null) => void;
+  onOpenSettings?: () => void;
 }
 
-interface ChannelGroupProps {
+type CatName = string;
-    categoryName: string;
+
-    rooms: RoomWithCategory[];
+const DRAG_PREFIX = 'room:';
-    selectedRoomId: string | null;
+
-    onSelectRoom: (room: RoomWithCategory) => void;
+/* ── Draggable row ─────────────────────────────────────────────── */
-    isCollapsed?: boolean;
+
-    onToggle?: () => void;
+const DraggableRow = memo(function DraggableRow({
-}
+  roomId,
+  children,
+}: {
+  roomId: string;
+  children: React.ReactNode;
+}) {
+  const {
+    attributes,
+    listeners,
+    setNodeRef,
+    transform,
+    transition,
+    isDragging,
+  } = useSortable({ id: `${DRAG_PREFIX}${roomId}` });
+
+  const style: React.CSSProperties = {
+    transform: CSS.Transform.toString(transform),
+    transition,
+  };
+
+  return (
+    <li
+      ref={setNodeRef}
+      style={style}
+      {...attributes}
+      {...listeners}
+      className={cn(
+        'cursor-grab active:cursor-grabbing',
+        isDragging && 'opacity-40',
+      )}
+    >
+      <div className="absolute left-0 top-0 h-full w-full opacity-0 group-hover:opacity-100 transition-opacity">
+        {children}
+      </div>
+    </li>
+  );
+});
+
+/* ── Single room button ────────────────────────────────────────── */
+
+const RoomButton = memo(function RoomButton({
+  room,
+  selectedRoomId,
+  onSelectRoom,
+}: {
+  room: RoomWithCategory;
+  selectedRoomId: string | null;
+  onSelectRoom: (room: RoomWithCategory) => void;
+}) {
+  const isSelected = selectedRoomId === room.id;
+  const unreadCount = (room as RoomWithUnread).unread_count ?? 0;
+
+  return (
+    <button
+      type="button"
+      onClick={() => onSelectRoom(room)}
+      className={cn('discord-channel-item w-full group', isSelected && 'active')}
+    >
+      <GripVertical className="h-3.5 w-3.5 text-muted-foreground opacity-0 group-hover:opacity-70 shrink-0 mr-1" />
+      <Hash className="discord-channel-hash" />
+      <span className="discord-channel-name">{room.room_name}</span>
+      {!room.public && (
+        <Lock className="h-3.5 w-3.5 opacity-50 shrink-0 ml-auto" />
+      )}
+      {unreadCount > 0 && (
+        <span className="discord-mention-badge">
+          {unreadCount > 99 ? '99+' : unreadCount}
+        </span>
+      )}
+    </button>
+  );
+});
+
+/* ── Category group ────────────────────────────────────────────── */
 
 const ChannelGroup = memo(function ChannelGroup({
-                                                    categoryName,
+  categoryName,
-                                                    rooms,
+  rooms,
-                                                    selectedRoomId,
+  selectedRoomId,
-                                                    onSelectRoom,
+  onSelectRoom,
-                                                    isCollapsed,
+  isCollapsed,
-                                                    onToggle,
+  onToggle,
-                                                }: ChannelGroupProps) {
+  canReceiveDrops,
-    if (rooms.length === 0) return null;
+}: {
+  categoryName: string;
+  rooms: RoomWithCategory[];
+  selectedRoomId: string | null;
+  onSelectRoom: (room: RoomWithCategory) => void;
+  isCollapsed?: boolean;
+  onToggle?: () => void;
+  canReceiveDrops?: true;
+}) {
+  const ids: UniqueIdentifier[] = rooms.map((r) => `${DRAG_PREFIX}${r.id}`);
 
-    return (
+  return (
-        <div className="discord-channel-category">
+    <div
-            <button
+      className="discord-channel-category"
-                className={cn('discord-channel-category-header w-full', isCollapsed && 'collapsed')}
+      onDragOver={(e) => e.preventDefault()}
-                onClick={onToggle}
+      onDrop={canReceiveDrops ? () => undefined /* handled by DnD */ : undefined}
-                title={isCollapsed ? 'Expand' : 'Collapse'}
+    >
-            >
+      <button
-                {isCollapsed ? (
+        className={cn('discord-channel-category-header w-full', isCollapsed && 'collapsed')}
-                    <ChevronRight className="h-3 w-3"/>
+        onClick={onToggle}
-                ) : (
+        title={isCollapsed ? 'Expand' : 'Collapse'}
-                    <ChevronDown className="h-3 w-3"/>
+      >
-                )}
+        {isCollapsed ? (
-                <span className="flex-1 text-left">{categoryName}</span>
+          <ChevronRight className="h-3 w-3" />
-            </button>
+        ) : (
+          <ChevronDown className="h-3 w-3" />
+        )}
+        <span className="flex-1 text-left">{categoryName}</span>
+      </button>
 
-            {!isCollapsed && (
+      {!isCollapsed && (
-                <ul className="space-y-0.5 pl-2">
+        <ul className="space-y-0.5 pl-2">
-                    {rooms.map((room) => {
+          <SortableContext items={ids} strategy={verticalListSortingStrategy}>
-                        const isSelected = selectedRoomId === room.id;
+            {rooms.map((room) => (
-                        const unreadCount = (room as RoomWithUnread).unread_count ?? 0;
+              <DraggableRow key={room.id} roomId={room.id}>
-                        return (
+                <RoomButton
-                            <li key={room.id}>
+                  room={room}
-                                <button
+                  selectedRoomId={selectedRoomId}
-                                    type="button"
+                  onSelectRoom={onSelectRoom}
-                                    onClick={() => onSelectRoom(room)}
+                />
-                                    className={cn('discord-channel-item w-full', isSelected && 'active')}
+              </DraggableRow>
-                                >
+            ))}
-                                    <Hash className="discord-channel-hash"/>
+          </SortableContext>
-                                    <span className="discord-channel-name">{room.room_name}</span>
+        </ul>
-                                    {!room.public && (
+      )}
-                                        <Lock className="h-3.5 w-3.5 opacity-50 shrink-0"/>
+    </div>
-                                    )}
+  );
-                                    {unreadCount > 0 && (
-                                        <span className="discord-mention-badge">
-                      {unreadCount > 99 ? '99+' : unreadCount}
-                    </span>
-                                    )}
-                                </button>
-                            </li>
-                        );
-                    })}
-                </ul>
-            )}
-        </div>
-    );
 });
 
+/* ── List content ──────────────────────────────────────────────── */
+
+function ChannelListContent({
+  rooms,
+  selectedRoomId,
+  onSelectRoom,
+  categories,
+  uncategorizedRooms,
+  categorizedRooms,
+  collapsedState,
+  toggleCategory,
+  onMoveRoom,
+}: {
+  rooms: RoomWithCategory[];
+  selectedRoomId: string | null;
+  onSelectRoom: (room: RoomWithCategory) => void;
+  categories: Array<{ id: string; name: string }>;
+  uncategorizedRooms: RoomWithCategory[];
+  categorizedRooms: Map<CatName, RoomWithCategory[]>;
+  collapsedState: Record<string, boolean>;
+  toggleCategory: (name: string) => void;
+  onMoveRoom: (roomId: string, catId: string | null) => void;
+}) {
+  const sensors = useSensors(
+    useSensor(PointerSensor, { activationConstraint: { distance: 4 } }),
+    useSensor(KeyboardSensor, { coordinateGetter: sortableKeyboardCoordinates }),
+  );
+
+  // Build flat list of all category names in display order for collision targets
+  const sortedCatNames = useMemo(
+    () => Array.from(categorizedRooms.keys()).sort(),
+    [categorizedRooms],
+  );
+
+  const handleDragEnd = useCallback(
+    (event: DragEndEvent) => {
+      const { over } = event;
+      if (!over) return;
+
+      const dragId = String(event.active.id);
+      if (!dragId.startsWith(DRAG_PREFIX)) return;
+
+      const draggedRoomId = dragId.slice(DRAG_PREFIX.length);
+
+      // Dropping onto a category (target id matches a category name)
+      const targetName = String(over.id);
+      const targetCat = categories.find((c) => c.name === targetName);
+      if (targetCat) {
+        const currentRoom = rooms.find((r) => r.id === draggedRoomId);
+        if (currentRoom && currentRoom.category_info?.id !== targetCat.id) {
+          onMoveRoom(draggedRoomId, targetCat.id);
+        }
+        return;
+      }
+
+      // Dropping onto another room's sort position → nothing to change visually
+      // dnd-kit handles the reorder via SortableContext automatically
+    },
+    [categories, rooms, onMoveRoom],
+  );
+
+  return (
+    <DndContext
+      sensors={sensors}
+      collisionDetection={closestCorners}
+      onDragEnd={handleDragEnd}
+    >
+      {/* Uncategorized channels at top */}
+      {uncategorizedRooms.length > 0 && (
+        <ChannelGroup
+          categoryName="Channels"
+          rooms={uncategorizedRooms}
+          selectedRoomId={selectedRoomId}
+          onSelectRoom={onSelectRoom}
+        />
+      )}
+
+      {/* Categorized groups */}
+      {sortedCatNames.map((catName) => (
+        <ChannelGroup
+          key={catName}
+          categoryName={catName}
+          rooms={categorizedRooms.get(catName)!}
+          selectedRoomId={selectedRoomId}
+          onSelectRoom={onSelectRoom}
+          isCollapsed={!!collapsedState[catName]}
+          onToggle={() => toggleCategory(catName)}
+          canReceiveDrops
+        />
+      ))}
+    </DndContext>
+  );
+}
+
+/* ── Public component ──────────────────────────────────────────── */
+
 export const DiscordChannelSidebar = memo(function DiscordChannelSidebar({
-                                                                             projectName,
+  projectName,
-                                                                             rooms,
+  rooms,
-                                                                             selectedRoomId,
+  selectedRoomId,
-                                                                             onSelectRoom,
+  onSelectRoom,
-                                                                             onCreateRoom,
+  onCreateRoom,
-                                                                             onOpenSettings,
+  categories,
-                                                                         }: DiscordChannelSidebarProps) {
+  onCreateCategory,
-    // Group rooms by category
+  onMoveRoomToCategory,
-    const uncategorized = rooms.filter((r) => !r.category_info?.name);
+  onOpenSettings,
-    const categorized = rooms.filter((r) => r.category_info?.name);
+}: DiscordChannelSidebarProps) {
+  const [collapsed, setCollapsed] = useState<Record<string, boolean>>({});
+  const toggleCategory = useCallback((name: string) => {
+    setCollapsed((prev) => ({ ...prev, [name]: !prev[name] }));
+  }, []);
 
-    // Build category map: categoryName → rooms[]
+  const [creatingCat, setCreatingCat] = useState(false);
-    const categoryMap = new Map<string, RoomWithCategory[]>();
+  const [newCatName, setNewCatName] = useState('');
+
+  const handleCreateCategory = useCallback(async () => {
+    const trimmed = newCatName.trim();
+    if (!trimmed) return;
+    await onCreateCategory(trimmed);
+    setNewCatName('');
+    setCreatingCat(false);
+  }, [newCatName, onCreateCategory]);
+
+  const handleMoveRoom = useCallback(
+    (roomId: string, categoryId: string | null) => {
+      onMoveRoomToCategory(roomId, categoryId);
+    },
+    [onMoveRoomToCategory],
+  );
+
+  // Group rooms by category
+  const uncategorized = useMemo(
+    () => rooms.filter((r) => !r.category_info?.name),
+    [rooms],
+  );
+  const categorized = useMemo(
+    () => rooms.filter((r) => r.category_info?.name),
+    [rooms],
+  );
+
+  const categoryMap = useMemo(() => {
+    const map = new Map<CatName, RoomWithCategory[]>();
     for (const room of categorized) {
-        const name = room.category_info!.name;
+      const name = room.category_info!.name;
-        if (!categoryMap.has(name)) categoryMap.set(name, []);
+      if (!map.has(name)) map.set(name, []);
-        categoryMap.get(name)!.push(room);
+      map.get(name)!.push(room);
     }
+    return map;
+  }, [categorized]);
 
-    // Collapse state per category
+  return (
-    const [collapsed, setCollapsed] = useState<Record<string, boolean>>({});
+    <div className="discord-channel-sidebar flex flex-col h-full">
-
+      {/* Header */}
-    const toggleCategory = useCallback((name: string) => {
+      <div className="discord-channel-header flex items-center justify-between px-3 py-2 border-b">
-        setCollapsed((prev) => ({...prev, [name]: !prev[name]}));
+        <div
-    }, []);
+          className="flex items-center gap-2 font-bold truncate"
-
+          style={{ color: 'var(--room-text)' }}
-    // Uncategorized channels at top, then alphabetical categories
+        >
-    const sortedCategoryNames = Array.from(categoryMap.keys()).sort();
+          <span className="truncate">{projectName}</span>
-
-    return (
-        <div className="discord-channel-sidebar">
-            {/* Header */}
-            <div className="discord-channel-header">
-                <div
-                    className="discord-channel-header-title flex items-center gap-2 font-bold"
-                    style={{color: 'var(--room-text)'}}
-                >
-                    <span>{projectName}</span>
-                </div>
-                <div className="flex items-center gap-1">
-                    {onOpenSettings && (
-                        <button
-                            onClick={onOpenSettings}
-                            className="flex h-8 w-8 items-center justify-center rounded-md transition-colors"
-                            style={{color: 'var(--room-text-muted)'}}
-                            title="Channel settings"
-                        >
-                            <Settings className="h-4 w-4"/>
-                        </button>
-                    )}
-                </div>
-            </div>
-
-            {/* Channel list */}
-            <div className="discord-channel-list">
-                {/* Uncategorized */}
-                {uncategorized.length > 0 && (
-                    <ChannelGroup
-                        categoryName="Channels"
-                        rooms={uncategorized}
-                        selectedRoomId={selectedRoomId}
-                        onSelectRoom={onSelectRoom}
-                    />
-                )}
-
-                {/* Categorized */}
-                {sortedCategoryNames.map((catName) => (
-                    <ChannelGroup
-                        key={catName}
-                        categoryName={catName}
-                        rooms={categoryMap.get(catName)!}
-                        selectedRoomId={selectedRoomId}
-                        onSelectRoom={onSelectRoom}
-                        isCollapsed={collapsed[catName]}
-                        onToggle={() => toggleCategory(catName)}
-                    />
-                ))}
-
-                {rooms.length === 0 && (
-                    <div className="px-4 py-8 text-center">
-                        <p className="text-sm mb-3" style={{color: 'var(--room-text-muted)'}}>No channels yet</p>
-                        <Button
-                            size="sm"
-                            onClick={onCreateRoom}
-                            className="bg-primary hover:bg-primary/90 text-primary-foreground border-none"
-                        >
-                            <Plus className="mr-1 h-3.5 w-3.5"/>
-                            Create Channel
-                        </Button>
-                    </div>
-                )}
-            </div>
-
-            {/* Footer: user / add channel */}
-            <div
-                className="border-t px-2 py-2"
-                style={{borderColor: 'var(--room-border)', background: 'var(--room-sidebar)'}}
-            >
-                <button
-                    onClick={onCreateRoom}
-                    className="discord-add-channel-btn w-full"
-                >
-                    <Plus className="h-4 w-4"/>
-                    <span>Add Channel</span>
-                </button>
-            </div>
         </div>
-    );
+        <div className="flex items-center gap-1">
+          {onOpenSettings && (
+            <Button
+              variant="ghost"
+              size="icon"
+              className="h-7 w-7"
+              style={{ color: 'var(--room-text-muted)' }}
+              title="Channel settings"
+              onClick={onOpenSettings}
+            >
+              <svg className="h-4 w-4" viewBox="0 0 24 24" fill="currentColor">
+                <path d="M12 15a3 3 0 1 0 0-6 3 3 0 0 0 0 6Z" />
+                <path fillRule="evenodd" clipRule="evenodd" d="M1.786 9.476 1.12 7.236l2.14-.665a6.013 6.013 0 0 1 1.634-2.824l-1.29-1.872 2.142-1.237 1.676 1.478a6.013 6.013 0 0 1 3.07 0l1.677-1.478 2.14 1.237-1.288 1.872a6.013 6.013 0 0 1 1.634 2.824l2.14.665-1.12 2.827-2.142.664a6.013 6.013 0 0 1 0 3.088l2.142.664 1.12 2.827-2.14.665a6.013 6.013 0 0 1-1.634 2.824l1.29 1.872-2.142 1.237-1.677-1.478a6.013 6.013 0 0 1-3.07 0l-1.676 1.478-2.142-1.237 1.288-1.872a6.013 6.013 0 0 1-1.634-2.824l-2.14-.665 1.12-2.827 2.142-.664a6.013 6.013 0 0 1 0-3.088l-2.142-.664ZM12 16a4 4 0 1 0 0-8 4 4 0 0 0 0 8Z" />
+              </svg>
+            </Button>
+          )}
+        </div>
+      </div>
+
+      {/* Scrollable list */}
+      <div className="discord-channel-list flex-1 overflow-y-auto px-2 py-2">
+        <ChannelListContent
+          rooms={rooms}
+          selectedRoomId={selectedRoomId}
+          onSelectRoom={onSelectRoom}
+          categories={categories}
+          uncategorizedRooms={uncategorized}
+          categorizedRooms={categoryMap}
+          collapsedState={collapsed}
+          toggleCategory={toggleCategory}
+          onMoveRoom={handleMoveRoom}
+        />
+
+        {/* Create category */}
+        {creatingCat ? (
+          <div className="flex items-center gap-1 px-2 py-1">
+            <Input
+              autoFocus
+              value={newCatName}
+              onChange={(e) => setNewCatName(e.target.value)}
+              onKeyDown={(e) => {
+                if (e.key === 'Enter') handleCreateCategory();
+                if (e.key === 'Escape') { setCreatingCat(false); setNewCatName(''); }
+              }}
+              placeholder="Category name"
+              className="h-7 text-xs"
+            />
+            <Button size="icon" variant="ghost" className="h-7 w-7" onClick={handleCreateCategory}>
+              <Plus className="h-4 w-4" />
+            </Button>
+            <Button size="icon" variant="ghost" className="h-7 w-7" onClick={() => { setCreatingCat(false); setNewCatName(''); }}>
+              <X className="h-3 w-3" />
+            </Button>
+          </div>
+        ) : (
+          <button
+            onClick={() => setCreatingCat(true)}
+            className="discord-channel-item w-full px-2 py-1 text-xs text-muted-foreground hover:text-foreground"
+          >
+            + Add Category
+          </button>
+        )}
+
+        {rooms.length === 0 && (
+          <div className="px-4 py-8 text-center">
+            <p className="text-sm mb-3 text-muted-foreground">No channels yet</p>
+            <Button
+              size="sm"
+              onClick={onCreateRoom}
+              className="bg-primary hover:bg-primary/90 text-primary-foreground border-none"
+            >
+              <Plus className="mr-1 h-3.5 w-3.5" />
+              Create Channel
+            </Button>
+          </div>
+        )}
+      </div>
+
+      {/* Footer */}
+      <div
+        className="border-t px-2 py-2"
+        style={{ borderColor: 'var(--room-border)', background: 'var(--room-sidebar)' }}
+      >
+        <button
+          onClick={onCreateRoom}
+          className="discord-add-channel-btn w-full flex items-center gap-2 text-sm"
+        >
+          <Plus className="h-4 w-4" />
+          <span>Add Channel</span>
+        </button>
+      </div>
+    </div>
+  );
 });

src/contexts/room-context.tsx

@@ -439,45 +439,59 @@ export function RoomProvider({
             });
           }
         },
-        onAiStreamChunk: (chunk) => {
+    const onAiStreamChunk = useCallback((chunk: AiStreamChunkPayload) => {
-          if (chunk.done) {
+      if (chunk.done) {
-            setStreamingContent((prev) => {
+        setStreamingContent((prev) => {
-              const next = new Map(prev);
+          prev.delete(chunk.message_id);
-              next.delete(chunk.message_id);
+          return new Map(prev);
-              return next;
+        });
-            });
+        setMessages((prev) =>
-            setMessages((prev) =>
+          prev.map((m) =>
-              prev.map((m) =>
+            m.id === chunk.message_id
-                m.id === chunk.message_id
+              ? { ...m, content: chunk.content, display_content: chunk.content, is_streaming: false }
-                  ? { ...m, content: chunk.content, is_streaming: false }
+              : m,
-                  : m,
+          ),
-              ),
+        );
-            );
+      } else {
-          } else {
+        // Accumulate streaming content in dedicated map
-            setStreamingContent((prev) => {
+        setStreamingContent((prev) => {
-              const next = new Map(prev);
+          const next = new Map(prev);
-              const existing = next.get(chunk.message_id) ?? '';
+          next.set(chunk.message_id, (next.get(chunk.message_id) ?? '') + chunk.content);
-              next.set(chunk.message_id, existing + chunk.content);
+          return next;
-              return next;
+        });
-            });
+        // Update or insert the AI message with current accumulated content
-            setMessages((prev) => {
+        // Use streamingContent map as source of truth for display during streaming
-              if (prev.some((m) => m.id === chunk.message_id)) {
+        setStreamingContent((current) => {
-                return prev;
+          const accumulated = current.get(chunk.message_id) ?? '';
-              }
+          setMessages((prev) => {
-              const newMsg: MessageWithMeta = {
+            const idx = prev.findIndex((m) => m.id === chunk.message_id);
-                id: chunk.message_id,
+            if (idx !== -1) {
-                room: chunk.room_id,
+              const m = prev[idx];
-                seq: 0,
+              // Skip render if content hasn't changed (dedup protection)
-                sender_type: 'ai',
+              if (m.content === accumulated && m.is_streaming === true) return prev;
-                content: '',
+              const updated = [...prev];
-                content_type: 'text',
+              updated[idx] = { ...m, content: accumulated, display_content: accumulated };
-                send_at: new Date().toISOString(),
+              return updated;
-                is_streaming: true,
+            }
-              };
+            // New message — avoid adding empty content blocks
-              return [...prev, newMsg];
+            if (!accumulated) return prev;
-            });
+            const newMsg: MessageWithMeta = {
-          }
+              id: chunk.message_id,
-        },
+              room: chunk.room_id,
+              seq: 0,
+              sender_type: 'ai',
+              content: accumulated,
+              display_content: accumulated,
+              content_type: 'text',
+              send_at: new Date().toISOString(),
+              is_streaming: true,
+            };
+            return [...prev, newMsg];
+          });
+          return current;
+        });
+      }
+    }, []);
         onRoomReactionUpdated: (payload: RoomReactionUpdatedPayload) => {
           if (!activeRoomIdRef.current) return;
           setMessages((prev) => {