feat: create a new canvas by copying an existing one

Add a 'Copy from existing' option to the New Canvas modal. It lists every
canvas with node/group/text counts; picking one deep-copies its nodes, edges,
parent/child links and canvas state (viewport, custom style, floor plan) into
a fresh design.

Backend: POST /designs/{source_id}/copy remaps node ids, re-points edges and
parent links, and clones canvas state; GET /designs now returns per-design
counts for the picker. Standalone mode clones the localStorage canvas.

Closes #216

ha-relevant: maybe

backend/app/api/routes/designs.py

@@ -1,14 +1,21 @@
+import uuid
+
 from fastapi import APIRouter, Depends, HTTPException
-from sqlalchemy import select
+from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.api.deps import get_current_user
 from app.db.database import get_db
 from app.db.models import CanvasState, Design, Edge, Node
-from app.schemas.designs import DesignCreate, DesignResponse, DesignUpdate
+from app.schemas.designs import DesignCopy, DesignCreate, DesignResponse, DesignUpdate
 
 router = APIRouter()
 
+# Node.type values that are canvas annotations rather than real devices. Kept in
+# sync with the frontend (Sidebar counts, canvasSerializer types).
+_GROUP_TYPE = "groupRect"
+_TEXT_TYPE = "text"
+
 
 @router.get("", response_model=list[DesignResponse])
 async def list_designs(
@@ -16,7 +23,31 @@ async def list_designs(
     _: str = Depends(get_current_user),
 ) -> list[DesignResponse]:
     designs = (await db.execute(select(Design).order_by(Design.created_at))).scalars().all()
-    return [DesignResponse.model_validate(d) for d in designs]
+    # One grouped query for all designs → node/group/text counts per design.
+    rows = (
+        await db.execute(select(Node.design_id, Node.type, func.count()).group_by(Node.design_id, Node.type))
+    ).all()
+    counts: dict[str, dict[str, int]] = {}
+    for design_id, node_type, count in rows:
+        if design_id is None:
+            continue
+        bucket = counts.setdefault(design_id, {"node": 0, "group": 0, "text": 0})
+        if node_type == _GROUP_TYPE:
+            bucket["group"] += count
+        elif node_type == _TEXT_TYPE:
+            bucket["text"] += count
+        else:
+            bucket["node"] += count
+
+    result = []
+    for d in designs:
+        resp = DesignResponse.model_validate(d)
+        c = counts.get(d.id, {"node": 0, "group": 0, "text": 0})
+        resp.node_count = c["node"]
+        resp.group_count = c["group"]
+        resp.text_count = c["text"]
+        result.append(resp)
+    return result
 
 
 @router.post("", response_model=DesignResponse, status_code=201)
@@ -35,6 +66,73 @@ async def create_design(
     return DesignResponse.model_validate(design)
 
 
+@router.post("/{source_id}/copy", response_model=DesignResponse, status_code=201)
+async def copy_design(
+    source_id: str,
+    body: DesignCopy,
+    db: AsyncSession = Depends(get_db),
+    _: str = Depends(get_current_user),
+) -> DesignResponse:
+    """Create a new design that deep-copies the source's nodes, edges and canvas state."""
+    source = await db.get(Design, source_id)
+    if not source:
+        raise HTTPException(404, "Source design not found")
+
+    new_design = Design(name=body.name, icon=body.icon, design_type=source.design_type)
+    db.add(new_design)
+    await db.flush()
+
+    src_nodes = (await db.execute(select(Node).where(Node.design_id == source_id))).scalars().all()
+    src_edges = (await db.execute(select(Edge).where(Edge.design_id == source_id))).scalars().all()
+
+    # New id per source node so edges and parent links can be re-pointed at the copy.
+    id_map = {n.id: str(uuid.uuid4()) for n in src_nodes}
+
+    # Columns we set explicitly or let the DB default — never copy verbatim.
+    node_skip = {"id", "design_id", "parent_id", "created_at", "updated_at"}
+    for n in src_nodes:
+        cols = {c.name: getattr(n, c.name) for c in Node.__table__.columns if c.name not in node_skip}
+        db.add(Node(id=id_map[n.id], design_id=new_design.id, parent_id=None, **cols))
+    await db.flush()  # nodes must exist before we wire self-referential parent_id
+
+    # Second pass: re-point parent links inside the copy.
+    for n in src_nodes:
+        if n.parent_id and n.parent_id in id_map:
+            child = await db.get(Node, id_map[n.id])
+            if child:
+                child.parent_id = id_map[n.parent_id]
+
+    edge_skip = {"id", "design_id", "source", "target", "created_at"}
+    for e in src_edges:
+        # Skip edges whose endpoints aren't part of this design (dangling FKs).
+        if e.source not in id_map or e.target not in id_map:
+            continue
+        cols = {c.name: getattr(e, c.name) for c in Edge.__table__.columns if c.name not in edge_skip}
+        db.add(
+            Edge(
+                id=str(uuid.uuid4()),
+                design_id=new_design.id,
+                source=id_map[e.source],
+                target=id_map[e.target],
+                **cols,
+            )
+        )
+
+    # Copy canvas state (viewport, custom style, and the floor plan carried in viewport).
+    src_state = await db.get(CanvasState, source_id)
+    db.add(
+        CanvasState(
+            design_id=new_design.id,
+            viewport=src_state.viewport if src_state else {},
+            custom_style=src_state.custom_style if src_state else None,
+        )
+    )
+
+    await db.commit()
+    await db.refresh(new_design)
+    return DesignResponse.model_validate(new_design)
+
+
 @router.put("/{design_id}", response_model=DesignResponse)
 async def update_design(
     design_id: str,

backend/app/schemas/designs.py

@@ -16,6 +16,13 @@ class DesignUpdate(BaseModel):
     icon: str | None = None
 
 
+class DesignCopy(BaseModel):
+    """Create a new design by deep-copying an existing one's canvas."""
+
+    name: str
+    icon: str = "dashboard"
+
+
 class DesignResponse(BaseModel):
     id: str
     name: str
@@ -23,5 +30,10 @@ class DesignResponse(BaseModel):
     icon: str | None = None
     created_at: datetime
     updated_at: datetime
+    # Populated by list_designs so the "copy from existing" picker can show what
+    # each canvas holds. None on create/update/copy responses (not computed there).
+    node_count: int | None = None
+    group_count: int | None = None
+    text_count: int | None = None
 
     model_config = {"from_attributes": True}

backend/tests/test_designs.py

@@ -100,6 +100,118 @@ async def test_list_returns_created_designs_ordered(client: AsyncClient, headers
     assert ids == [a["id"], b["id"]]
 
 
+# ── counts in list ──────────────────────────────────────────────────────────
+
+async def test_list_includes_node_group_text_counts(client: AsyncClient, headers: dict):
+    design = await _create(client, headers, name="Counted")
+    server = node_payload(label="S", type="server")
+    group = node_payload(label="G", type="groupRect")
+    text = node_payload(label="T", type="text")
+    save = await client.post(
+        "/api/v1/canvas/save",
+        json={"nodes": [server, group, text], "edges": [], "viewport": {}, "design_id": design["id"]},
+        headers=headers,
+    )
+    assert save.status_code == 200
+    listed = (await client.get("/api/v1/designs", headers=headers)).json()
+    d = next(x for x in listed if x["id"] == design["id"])
+    assert d["node_count"] == 1
+    assert d["group_count"] == 1
+    assert d["text_count"] == 1
+
+
+async def test_list_counts_zero_for_empty_design(client: AsyncClient, headers: dict):
+    design = await _create(client, headers, name="Empty")
+    listed = (await client.get("/api/v1/designs", headers=headers)).json()
+    d = next(x for x in listed if x["id"] == design["id"])
+    assert d["node_count"] == 0
+    assert d["group_count"] == 0
+    assert d["text_count"] == 0
+
+
+# ── copy ──────────────────────────────────────────────────────────────────────
+
+async def test_copy_requires_auth(client: AsyncClient):
+    res = await client.post(f"/api/v1/designs/{uuid.uuid4()}/copy", json={"name": "X"})
+    assert res.status_code == 401
+
+
+async def test_copy_missing_source_returns_404(client: AsyncClient, headers: dict):
+    res = await client.post(f"/api/v1/designs/{uuid.uuid4()}/copy", json={"name": "X"}, headers=headers)
+    assert res.status_code == 404
+
+
+async def test_copy_duplicates_nodes_edges_and_remaps_ids(client: AsyncClient, headers: dict):
+    source = await _create(client, headers, name="Source", icon="server")
+    n1 = node_payload(label="A")
+    n2 = node_payload(label="B")
+    e1 = edge_payload(n1["id"], n2["id"], label="link")
+    save = await client.post(
+        "/api/v1/canvas/save",
+        json={"nodes": [n1, n2], "edges": [e1], "viewport": {"x": 5, "y": 6, "zoom": 2}, "design_id": source["id"]},
+        headers=headers,
+    )
+    assert save.status_code == 200
+
+    res = await client.post(
+        f"/api/v1/designs/{source['id']}/copy", json={"name": "Copy", "icon": "network"}, headers=headers,
+    )
+    assert res.status_code == 201, res.text
+    copy = res.json()
+    assert copy["name"] == "Copy"
+    assert copy["icon"] == "network"
+    assert copy["design_type"] == "network"
+    assert copy["id"] != source["id"]
+
+    # Copied canvas has the same shape but fresh node ids, and edge re-pointed.
+    canvas = (await client.get("/api/v1/canvas", params={"design_id": copy["id"]}, headers=headers)).json()
+    assert {n["label"] for n in canvas["nodes"]} == {"A", "B"}
+    copied_ids = {n["id"] for n in canvas["nodes"]}
+    assert copied_ids.isdisjoint({n1["id"], n2["id"]})
+    assert len(canvas["edges"]) == 1
+    edge = canvas["edges"][0]
+    assert edge["source"] in copied_ids
+    assert edge["target"] in copied_ids
+    assert edge["label"] == "link"
+    assert canvas["viewport"] == {"x": 5, "y": 6, "zoom": 2}
+
+
+async def test_copy_remaps_parent_child_relationship(client: AsyncClient, headers: dict):
+    source = await _create(client, headers, name="Nested")
+    parent = node_payload(label="P", type="proxmox", container_mode=True)
+    child = node_payload(label="C", type="vm", parent_id=parent["id"])
+    save = await client.post(
+        "/api/v1/canvas/save",
+        json={"nodes": [parent, child], "edges": [], "viewport": {}, "design_id": source["id"]},
+        headers=headers,
+    )
+    assert save.status_code == 200
+
+    res = await client.post(f"/api/v1/designs/{source['id']}/copy", json={"name": "Copy"}, headers=headers)
+    assert res.status_code == 201
+    copy = res.json()
+
+    canvas = (await client.get("/api/v1/canvas", params={"design_id": copy["id"]}, headers=headers)).json()
+    by_label = {n["label"]: n for n in canvas["nodes"]}
+    # Child's parent_id points at the COPIED parent, not the original.
+    assert by_label["C"]["parent_id"] == by_label["P"]["id"]
+    assert by_label["C"]["parent_id"] != parent["id"]
+
+
+async def test_copy_leaves_source_untouched(client: AsyncClient, headers: dict):
+    source = await _create(client, headers, name="Source")
+    n1 = node_payload(label="A")
+    await client.post(
+        "/api/v1/canvas/save",
+        json={"nodes": [n1], "edges": [], "viewport": {}, "design_id": source["id"]},
+        headers=headers,
+    )
+    await client.post(f"/api/v1/designs/{source['id']}/copy", json={"name": "Copy"}, headers=headers)
+    src_canvas = (await client.get("/api/v1/canvas", params={"design_id": source["id"]}, headers=headers)).json()
+    assert len(src_canvas["nodes"]) == 1
+    assert src_canvas["nodes"][0]["id"] == n1["id"]
+
+
 # ── update ────────────────────────────────────────────────────────────────────
 
 async def test_update_design_renames(client: AsyncClient, headers: dict):

frontend/src/api/client.ts

@@ -169,6 +169,8 @@ export const designsApi = {
   list: () => api.get<import('@/types').Design[]>('/designs'),
   create: (data: { name: string; icon?: string; design_type?: string }) =>
     api.post<import('@/types').Design>('/designs', data),
+  copy: (sourceId: string, data: { name: string; icon?: string }) =>
+    api.post<import('@/types').Design>(`/designs/${sourceId}/copy`, data),
   update: (id: string, data: { name?: string; icon?: string }) =>
     api.put<import('@/types').Design>(`/designs/${id}`, data),
   delete: (id: string) => api.delete(`/designs/${id}`),

frontend/src/components/modals/DesignModal.tsx

@@ -3,8 +3,8 @@ import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from '
 import { Button } from '@/components/ui/button'
 import { Label } from '@/components/ui/label'
 import { Input } from '@/components/ui/input'
-import { DESIGN_ICONS, DEFAULT_DESIGN_ICON } from '@/utils/designIcons'
+import { DESIGN_ICONS, DEFAULT_DESIGN_ICON, resolveDesignIcon } from '@/utils/designIcons'
-import type { FloorMapConfig } from '@/types'
+import type { Design, FloorMapConfig } from '@/types'
 
 export interface DesignFormData {
   name: string
@@ -15,6 +15,11 @@ export interface DesignFormData {
    * plan"; `undefined` means "leave it untouched".
    */
   floorMap?: FloorMapConfig | null
+  /**
+   * When set, create the new canvas by deep-copying this existing design instead
+   * of starting blank. Only offered in create mode with `sourceDesigns` present.
+   */
+  sourceId?: string
 }
 
 interface DesignModalProps {
@@ -34,6 +39,11 @@ interface DesignModalProps {
    * base64. Rejects on failure (caller surfaces the error).
    */
   onUploadImage?: (file: File) => Promise<string>
+  /**
+   * Existing designs offered as a copy source (create mode only). When non-empty,
+   * a "Copy from existing" option appears; choosing it clones the picked canvas.
+   */
+  sourceDesigns?: Design[]
 }
 
 export function DesignModal({
@@ -46,10 +56,16 @@ export function DesignModal({
   showFloorMap = false,
   initialFloorMap = null,
   onUploadImage,
+  sourceDesigns = [],
 }: DesignModalProps) {
   const [name, setName] = useState(initial?.name ?? '')
   const [icon, setIcon] = useState(initial?.icon ?? DEFAULT_DESIGN_ICON)
 
+  // "Copy from existing" is create-mode only (no floor-plan section shown).
+  const canCopy = !showFloorMap && sourceDesigns.length > 0
+  const [fromExisting, setFromExisting] = useState(false)
+  const [sourceId, setSourceId] = useState<string>(sourceDesigns[0]?.id ?? '')
+
   // Floor plan state (only used when showFloorMap)
   const [imageData, setImageData] = useState(initialFloorMap?.imageData ?? '')
   const [width, setWidth] = useState(initialFloorMap?.width ?? 800)
@@ -85,7 +101,11 @@ export function DesignModal({
   const handleSubmit = () => {
     const trimmed = name.trim()
     if (!trimmed) return
+    if (canCopy && fromExisting && !sourceId) return
     const data: DesignFormData = { name: trimmed, icon }
+    if (canCopy && fromExisting && sourceId) {
+      data.sourceId = sourceId
+    }
     if (showFloorMap) {
       data.floorMap = imageData
         ? {
@@ -153,6 +173,68 @@ export function DesignModal({
             </div>
           </div>
 
+          {canCopy && (
+            <div className="space-y-2 pt-2 border-t border-border">
+              <div className="grid grid-cols-2 gap-1.5">
+                <button
+                  type="button"
+                  aria-pressed={!fromExisting}
+                  onClick={() => setFromExisting(false)}
+                  className={`text-xs rounded-md border py-2 transition-colors cursor-pointer ${
+                    !fromExisting
+                      ? 'border-[#00d4ff] bg-[#00d4ff]/10 text-[#00d4ff]'
+                      : 'border-border text-muted-foreground hover:text-foreground'
+                  }`}
+                >
+                  Blank canvas
+                </button>
+                <button
+                  type="button"
+                  aria-pressed={fromExisting}
+                  onClick={() => setFromExisting(true)}
+                  className={`text-xs rounded-md border py-2 transition-colors cursor-pointer ${
+                    fromExisting
+                      ? 'border-[#00d4ff] bg-[#00d4ff]/10 text-[#00d4ff]'
+                      : 'border-border text-muted-foreground hover:text-foreground'
+                  }`}
+                >
+                  Copy from existing
+                </button>
+              </div>
+
+              {fromExisting && (
+                <div className="space-y-1 max-h-48 overflow-y-auto pr-1" role="radiogroup" aria-label="Source canvas">
+                  {sourceDesigns.map((d) => {
+                    const Icon = resolveDesignIcon(d.icon)
+                    const selected = d.id === sourceId
+                    return (
+                      <button
+                        key={d.id}
+                        type="button"
+                        role="radio"
+                        aria-checked={selected}
+                        onClick={() => setSourceId(d.id)}
+                        className={`w-full flex items-center gap-2.5 rounded-md border px-2.5 py-2 text-left transition-colors cursor-pointer ${
+                          selected
+                            ? 'border-[#00d4ff] bg-[#00d4ff]/10'
+                            : 'border-border hover:border-[#30363d]'
+                        }`}
+                      >
+                        <Icon size={16} className={selected ? 'text-[#00d4ff]' : 'text-muted-foreground'} />
+                        <div className="min-w-0 flex-1">
+                          <div className="truncate text-sm">{d.name}</div>
+                          <div className="text-xs text-muted-foreground">
+                            {d.node_count ?? 0} nodes · {d.group_count ?? 0} groups · {d.text_count ?? 0} text
+                          </div>
+                        </div>
+                      </button>
+                    )
+                  })}
+                </div>
+              )}
+            </div>
+          )}
+
           {showFloorMap && (
             <div className="space-y-2 pt-2 border-t border-border">
               <Label>Floor Plan</Label>

frontend/src/components/modals/__tests__/DesignModal.test.tsx

@@ -65,6 +65,60 @@ describe('DesignModal', () => {
     expect(onSubmit).not.toHaveBeenCalled()
   })
 
+  describe('copy from existing', () => {
+    const sourceDesigns = [
+      { id: 's1', name: 'Home Net', icon: 'network', design_type: 'network' as const,
+        created_at: '', updated_at: '', node_count: 4, group_count: 1, text_count: 2 },
+      { id: 's2', name: 'Lab', icon: 'server', design_type: 'network' as const,
+        created_at: '', updated_at: '', node_count: 7, group_count: 0, text_count: 0 },
+    ]
+
+    it('offers no copy option when there are no source designs', () => {
+      renderModal({ sourceDesigns: [] })
+      expect(screen.queryByRole('button', { name: 'Copy from existing' })).toBeNull()
+    })
+
+    it('shows the source list with counts once "Copy from existing" is chosen', () => {
+      renderModal({ sourceDesigns })
+      // Hidden until the user opts into copying.
+      expect(screen.queryByText('Home Net')).toBeNull()
+      fireEvent.click(screen.getByRole('button', { name: 'Copy from existing' }))
+      expect(screen.getByText('Home Net')).toBeDefined()
+      expect(screen.getByText('4 nodes · 1 groups · 2 text')).toBeDefined()
+      expect(screen.getByText('7 nodes · 0 groups · 0 text')).toBeDefined()
+    })
+
+    it('includes sourceId (first design by default) on submit', () => {
+      const { onSubmit } = renderModal({ sourceDesigns })
+      fireEvent.change(screen.getByLabelText('Name'), { target: { value: 'Copy of Home' } })
+      fireEvent.click(screen.getByRole('button', { name: 'Copy from existing' }))
+      fireEvent.click(screen.getByRole('button', { name: 'Create' }))
+      expect(onSubmit).toHaveBeenCalledWith({ name: 'Copy of Home', icon: DEFAULT_DESIGN_ICON, sourceId: 's1' })
+    })
+
+    it('includes the picked sourceId on submit', () => {
+      const { onSubmit } = renderModal({ sourceDesigns })
+      fireEvent.change(screen.getByLabelText('Name'), { target: { value: 'Copy of Lab' } })
+      fireEvent.click(screen.getByRole('button', { name: 'Copy from existing' }))
+      fireEvent.click(screen.getByRole('radio', { name: /Lab/ }))
+      fireEvent.click(screen.getByRole('button', { name: 'Create' }))
+      expect(onSubmit).toHaveBeenCalledWith({ name: 'Copy of Lab', icon: DEFAULT_DESIGN_ICON, sourceId: 's2' })
+    })
+
+    it('omits sourceId when the blank option is kept', () => {
+      const { onSubmit } = renderModal({ sourceDesigns })
+      fireEvent.change(screen.getByLabelText('Name'), { target: { value: 'Fresh' } })
+      fireEvent.click(screen.getByRole('button', { name: 'Create' }))
+      expect(onSubmit).toHaveBeenCalledWith({ name: 'Fresh', icon: DEFAULT_DESIGN_ICON })
+      expect('sourceId' in onSubmit.mock.calls[0][0]).toBe(false)
+    })
+
+    it('is hidden in edit mode (floor-plan shown)', () => {
+      renderModal({ sourceDesigns, showFloorMap: true, initial: { name: 'Home', icon: DEFAULT_DESIGN_ICON } })
+      expect(screen.queryByRole('button', { name: 'Copy from existing' })).toBeNull()
+    })
+  })
+
   describe('floor plan section', () => {
     const fm = {
       imageData: 'data:image/png;base64,abc',

frontend/src/components/panels/Sidebar.tsx

@@ -56,9 +56,17 @@ export function Sidebar({ onAddNode, onAddGroupRect, onAddText, onScan, onZigbee
     if (!designModal) return
     try {
       if (designModal.mode === 'create') {
-        const created = STANDALONE
+        let created: Design
-          ? standaloneStorage.createDesign(data.name, data.icon)
+        if (data.sourceId) {
-          : (await designsApi.create({ name: data.name, icon: data.icon })).data
+          // Copy from an existing canvas (nodes, edges, viewport, floor plan).
+          created = STANDALONE
+            ? standaloneStorage.copyDesign(data.sourceId, data.name, data.icon)
+            : (await designsApi.copy(data.sourceId, { name: data.name, icon: data.icon })).data
+        } else {
+          created = STANDALONE
+            ? standaloneStorage.createDesign(data.name, data.icon)
+            : (await designsApi.create({ name: data.name, icon: data.icon })).data
+        }
         addDesign(created)
       } else if (designModal.design) {
         const updated = STANDALONE
@@ -306,6 +314,11 @@ export function Sidebar({ onAddNode, onAddGroupRect, onAddText, onScan, onZigbee
         showFloorMap={!STANDALONE && isActiveEdit}
         initialFloorMap={!STANDALONE && isActiveEdit ? floorMap : null}
         onUploadImage={handleUploadImage}
+        sourceDesigns={
+          designModal?.mode === 'create'
+            ? (STANDALONE ? standaloneStorage.listDesignsWithCounts() : designs)
+            : []
+        }
       />
     </aside>
   )

frontend/src/types/index.ts

@@ -8,6 +8,10 @@ export interface Design {
   icon?: string | null
   created_at: string
   updated_at: string
+  /** Populated by the design list endpoint for the "copy from existing" picker. */
+  node_count?: number | null
+  group_count?: number | null
+  text_count?: number | null
 }
 
 export type NodeType =

frontend/src/utils/__tests__/standaloneStorage.test.ts

@@ -16,6 +16,7 @@ import type { Node, Edge } from '@xyflow/react'
 import type { NodeData, EdgeData } from '@/types'
 import { useCanvasStore } from '@/stores/canvasStore'
 import { demoNodes, demoEdges } from '@/utils/demoData'
+import * as standaloneStorage from '@/utils/standaloneStorage'
 
 const STORAGE_KEY = 'homelable_canvas'
 
@@ -261,3 +262,75 @@ describe('Demo data (standalone fallback)', () => {
     expect(router.position).toEqual({ x: 300, y: 140 })
   })
 })
+
+describe('Standalone copy-from-existing', () => {
+  beforeEach(() => localStorage.clear())
+
+  function typedNode(id: string, type: string): Node<NodeData> {
+    return {
+      id,
+      type,
+      position: { x: 0, y: 0 },
+      data: { label: id, type: type as NodeData['type'], status: 'unknown', services: [] },
+    }
+  }
+
+  it('designCounts buckets node / group / text types', () => {
+    const d = standaloneStorage.createDesign('Src')
+    standaloneStorage.saveCanvas(d.id, {
+      nodes: [typedNode('a', 'server'), typedNode('g', 'groupRect'), typedNode('t', 'text'), typedNode('b', 'router')],
+      edges: [],
+    })
+    expect(standaloneStorage.designCounts(d.id)).toEqual({ node_count: 2, group_count: 1, text_count: 1 })
+  })
+
+  it('designCounts returns zeros for a never-saved design', () => {
+    const d = standaloneStorage.createDesign('Empty')
+    expect(standaloneStorage.designCounts(d.id)).toEqual({ node_count: 0, group_count: 0, text_count: 0 })
+  })
+
+  it('listDesignsWithCounts attaches counts to every design', () => {
+    const a = standaloneStorage.createDesign('A')
+    standaloneStorage.saveCanvas(a.id, { nodes: [typedNode('a', 'server')], edges: [] })
+    standaloneStorage.createDesign('B')
+    const listed = standaloneStorage.listDesignsWithCounts()
+    expect(listed.find((x) => x.id === a.id)?.node_count).toBe(1)
+    expect(listed.find((x) => x.name === 'B')?.node_count).toBe(0)
+  })
+
+  it('copyDesign clones the source canvas into a new design', () => {
+    const src = standaloneStorage.createDesign('Source', 'server')
+    const edge: Edge<EdgeData> = { id: 'e1', source: 'a', target: 'b', data: { type: 'ethernet' } as EdgeData }
+    standaloneStorage.saveCanvas(src.id, { nodes: [typedNode('a', 'server'), typedNode('b', 'router')], edges: [edge] })
+
+    const copy = standaloneStorage.copyDesign(src.id, 'Copy', 'network')
+    expect(copy.id).not.toBe(src.id)
+    expect(copy.name).toBe('Copy')
+
+    const copied = standaloneStorage.loadCanvas(copy.id)!
+    expect(copied.nodes.map((n) => n.id).sort()).toEqual(['a', 'b'])
+    expect(copied.edges).toHaveLength(1)
+    // Source untouched.
+    expect(standaloneStorage.loadCanvas(src.id)!.nodes).toHaveLength(2)
+  })
+
+  it('copyDesign detaches the copy (mutating it leaves the source intact)', () => {
+    const src = standaloneStorage.createDesign('Source')
+    standaloneStorage.saveCanvas(src.id, { nodes: [typedNode('a', 'server')], edges: [] })
+    const copy = standaloneStorage.copyDesign(src.id, 'Copy')
+
+    const copied = standaloneStorage.loadCanvas(copy.id)!
+    copied.nodes.push(typedNode('z', 'server'))
+    standaloneStorage.saveCanvas(copy.id, copied)
+
+    expect(standaloneStorage.loadCanvas(src.id)!.nodes).toHaveLength(1)
+    expect(standaloneStorage.loadCanvas(copy.id)!.nodes).toHaveLength(2)
+  })
+
+  it('copyDesign on a never-saved source yields an empty new design', () => {
+    const src = standaloneStorage.createDesign('Bare')
+    const copy = standaloneStorage.copyDesign(src.id, 'Copy')
+    expect(standaloneStorage.loadCanvas(copy.id)).toBeNull()
+    expect(standaloneStorage.listDesigns().some((d) => d.id === copy.id)).toBe(true)
+  })
+})

frontend/src/utils/standaloneStorage.ts

@@ -90,6 +90,41 @@ export function createDesign(name: string, icon?: string | null, design_type: De
   return design
 }
 
+const GROUP_TYPE = 'groupRect'
+const TEXT_TYPE = 'text'
+
+/** Node/group/text counts for a design's saved canvas (0s when never saved). */
+export function designCounts(designId: string): Pick<Design, 'node_count' | 'group_count' | 'text_count'> {
+  const canvas = loadCanvas(designId)
+  const nodes = canvas?.nodes ?? []
+  let group = 0
+  let text = 0
+  let node = 0
+  for (const n of nodes) {
+    if (n.data?.type === GROUP_TYPE) group++
+    else if (n.data?.type === TEXT_TYPE) text++
+    else node++
+  }
+  return { node_count: node, group_count: group, text_count: text }
+}
+
+/** Return the design list with per-canvas counts filled in (for the copy picker). */
+export function listDesignsWithCounts(): Design[] {
+  return listDesigns().map((d) => ({ ...d, ...designCounts(d.id) }))
+}
+
+/** Deep-copy a design's canvas into a new design. Returns the new design. */
+export function copyDesign(sourceId: string, name: string, icon?: string | null): Design {
+  const design = createDesign(name, icon)
+  const source = loadCanvas(sourceId)
+  if (source) {
+    // localStorage canvas already stores React Flow nodes/edges by value; a fresh
+    // JSON round-trip is enough to detach the copy from the source.
+    saveCanvas(design.id, JSON.parse(JSON.stringify(source)) as StandaloneCanvas)
+  }
+  return design
+}
+
 export function updateDesign(id: string, patch: Partial<Pick<Design, 'name' | 'icon'>>): Design | null {
   const designs = listDesigns()
   const idx = designs.findIndex((d) => d.id === id)