feat: [US-017] - Editor page with React Flow canvas

Implement the flowchart editor page with React Flow integration:
- Install reactflow package for canvas rendering
- Create editor page that fetches project data from Supabase
- Add loading state with spinner while fetching
- Handle unauthorized access and not found with appropriate responses
- Render React Flow canvas with grid background
- Add header with project name and back link to dashboard
- Initialize React Flow with nodes and edges from flowchart_data
- Add type converters for FlowchartNode/Edge to React Flow types

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package-lock.json

@@ -1,18 +1,19 @@
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       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.8.tgz",
@@ -1625,6 +1981,12 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/geojson": {
+      "version": "7946.0.16",
+      "resolved": "https://registry.npmjs.org/@types/geojson/-/geojson-7946.0.16.tgz",
+      "integrity": "sha512-6C8nqWur3j98U6+lXDfTUWIfgvZU+EumvpHKcYjujKH7woYyLj2sUmff0tRhrqM7BohUw7Pz3ZB1jj2gW9Fvmg==",
+      "license": "MIT"
+    },
     "node_modules/@types/json-schema": {
       "version": "7.0.15",
       "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.15.tgz",
@@ -1658,7 +2020,7 @@
       "version": "19.2.9",
       "resolved": "https://registry.npmjs.org/@types/react/-/react-19.2.9.tgz",
       "integrity": "sha512-Lpo8kgb/igvMIPeNV2rsYKTgaORYdO1XGVZ4Qz3akwOj0ySGYMPlQWa8BaLn0G63D1aSaAQ5ldR06wCpChQCjA==",
-      "dev": true,
+      "devOptional": true,
       "license": "MIT",
       "dependencies": {
         "csstype": "^3.2.2"
@@ -2678,6 +3040,12 @@
         "url": "https://github.com/chalk/chalk?sponsor=1"
       }
     },
+    "node_modules/classcat": {
+      "version": "5.0.5",
+      "resolved": "https://registry.npmjs.org/classcat/-/classcat-5.0.5.tgz",
+      "integrity": "sha512-JhZUT7JFcQy/EzW605k/ktHtncoo9vnyW/2GspNYwFlN1C/WmjuV/xtS04e9SOkL2sTdw0VAZ2UGCcQ9lR6p6w==",
+      "license": "MIT"
+    },
     "node_modules/client-only": {
       "version": "0.0.1",
       "resolved": "https://registry.npmjs.org/client-only/-/client-only-0.0.1.tgz",
@@ -2750,9 +3118,114 @@
       "version": "3.2.3",
       "resolved": "https://registry.npmjs.org/csstype/-/csstype-3.2.3.tgz",
       "integrity": "sha512-z1HGKcYy2xA8AGQfwrn0PAy+PB7X/GSj3UVJW9qKyn43xWa+gl5nXmU4qqLMRzWVLFC8KusUX8T/0kCiOYpAIQ==",
-      "dev": true,
+      "devOptional": true,
       "license": "MIT"
     },
+    "node_modules/d3-color": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/d3-color/-/d3-color-3.1.0.tgz",
+      "integrity": "sha512-zg/chbXyeBtMQ1LbD/WSoW2DpC3I0mpmPdW+ynRTj/x2DAWYrIY7qeZIHidozwV24m4iavr15lNwIwLxRmOxhA==",
+      "license": "ISC",
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-dispatch": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/d3-dispatch/-/d3-dispatch-3.0.1.tgz",
+      "integrity": "sha512-rzUyPU/S7rwUflMyLc1ETDeBj0NRuHKKAcvukozwhshr6g6c5d8zh4c2gQjY2bZ0dXeGLWc1PF174P2tVvKhfg==",
+      "license": "ISC",
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-drag": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/d3-drag/-/d3-drag-3.0.0.tgz",
+      "integrity": "sha512-pWbUJLdETVA8lQNJecMxoXfH6x+mO2UQo8rSmZ+QqxcbyA3hfeprFgIT//HW2nlHChWeIIMwS2Fq+gEARkhTkg==",
+      "license": "ISC",
+      "dependencies": {
+        "d3-dispatch": "1 - 3",
+        "d3-selection": "3"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-ease": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/d3-ease/-/d3-ease-3.0.1.tgz",
+      "integrity": "sha512-wR/XK3D3XcLIZwpbvQwQ5fK+8Ykds1ip7A2Txe0yxncXSdq1L9skcG7blcedkOX+ZcgxGAmLX1FrRGbADwzi0w==",
+      "license": "BSD-3-Clause",
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-interpolate": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/d3-interpolate/-/d3-interpolate-3.0.1.tgz",
+      "integrity": "sha512-3bYs1rOD33uo8aqJfKP3JWPAibgw8Zm2+L9vBKEHJ2Rg+viTR7o5Mmv5mZcieN+FRYaAOWX5SJATX6k1PWz72g==",
+      "license": "ISC",
+      "dependencies": {
+        "d3-color": "1 - 3"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-selection": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/d3-selection/-/d3-selection-3.0.0.tgz",
+      "integrity": "sha512-fmTRWbNMmsmWq6xJV8D19U/gw/bwrHfNXxrIN+HfZgnzqTHp9jOmKMhsTUjXOJnZOdZY9Q28y4yebKzqDKlxlQ==",
+      "license": "ISC",
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-timer": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/d3-timer/-/d3-timer-3.0.1.tgz",
+      "integrity": "sha512-ndfJ/JxxMd3nw31uyKoY2naivF+r29V+Lc0svZxe1JvvIRmi8hUsrMvdOwgS1o6uBHmiz91geQ0ylPP0aj1VUA==",
+      "license": "ISC",
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/d3-transition": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/d3-transition/-/d3-transition-3.0.1.tgz",
+      "integrity": "sha512-ApKvfjsSR6tg06xrL434C0WydLr7JewBB3V+/39RMHsaXTOG0zmt/OAXeng5M5LBm0ojmxJrpomQVZ1aPvBL4w==",
+      "license": "ISC",
+      "dependencies": {
+        "d3-color": "1 - 3",
+        "d3-dispatch": "1 - 3",
+        "d3-ease": "1 - 3",
+        "d3-interpolate": "1 - 3",
+        "d3-timer": "1 - 3"
+      },
+      "engines": {
+        "node": ">=12"
+      },
+      "peerDependencies": {
+        "d3-selection": "2 - 3"
+      }
+    },
+    "node_modules/d3-zoom": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/d3-zoom/-/d3-zoom-3.0.0.tgz",
+      "integrity": "sha512-b8AmV3kfQaqWAuacbPuNbL6vahnOJflOhexLzMMNLga62+/nh0JzvJ0aO/5a5MVgUFGS7Hu1P9P03o3fJkDCyw==",
+      "license": "ISC",
+      "dependencies": {
+        "d3-dispatch": "1 - 3",
+        "d3-drag": "2 - 3",
+        "d3-interpolate": "1 - 3",
+        "d3-selection": "2 - 3",
+        "d3-transition": "2 - 3"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
     "node_modules/damerau-levenshtein": {
       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/damerau-levenshtein/-/damerau-levenshtein-1.0.8.tgz",
@@ -5536,6 +6009,24 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/reactflow": {
+      "version": "11.11.4",
+      "resolved": "https://registry.npmjs.org/reactflow/-/reactflow-11.11.4.tgz",
+      "integrity": "sha512-70FOtJkUWH3BAOsN+LU9lCrKoKbtOPnz2uq0CV2PLdNSwxTXOhCbsZr50GmZ+Rtw3jx8Uv7/vBFtCGixLfd4Og==",
+      "license": "MIT",
+      "dependencies": {
+        "@reactflow/background": "11.3.14",
+        "@reactflow/controls": "11.2.14",
+        "@reactflow/core": "11.11.4",
+        "@reactflow/minimap": "11.7.14",
+        "@reactflow/node-resizer": "2.2.14",
+        "@reactflow/node-toolbar": "1.3.14"
+      },
+      "peerDependencies": {
+        "react": ">=17",
+        "react-dom": ">=17"
+      }
+    },
     "node_modules/reflect.getprototypeof": {
       "version": "1.0.10",
       "resolved": "https://registry.npmjs.org/reflect.getprototypeof/-/reflect.getprototypeof-1.0.10.tgz",
@@ -6505,6 +6996,15 @@
         "punycode": "^2.1.0"
       }
     },
+    "node_modules/use-sync-external-store": {
+      "version": "1.6.0",
+      "resolved": "https://registry.npmjs.org/use-sync-external-store/-/use-sync-external-store-1.6.0.tgz",
+      "integrity": "sha512-Pp6GSwGP/NrPIrxVFAIkOQeyw8lFenOHijQWkUTrDvrF4ALqylP2C/KCkeS9dpUM3KvYRQhna5vt7IL95+ZQ9w==",
+      "license": "MIT",
+      "peerDependencies": {
+        "react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0"
+      }
+    },
     "node_modules/which": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
@@ -6683,6 +7183,34 @@
       "peerDependencies": {
         "zod": "^3.25.0 || ^4.0.0"
       }
+    },
+    "node_modules/zustand": {
+      "version": "4.5.7",
+      "resolved": "https://registry.npmjs.org/zustand/-/zustand-4.5.7.tgz",
+      "integrity": "sha512-CHOUy7mu3lbD6o6LJLfllpjkzhHXSBlX8B9+qPddUsIfeF5S/UZ5q0kmCsnRqT1UHFQZchNFDDzMbQsuesHWlw==",
+      "license": "MIT",
+      "dependencies": {
+        "use-sync-external-store": "^1.2.2"
+      },
+      "engines": {
+        "node": ">=12.7.0"
+      },
+      "peerDependencies": {
+        "@types/react": ">=16.8",
+        "immer": ">=9.0.6",
+        "react": ">=16.8"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "immer": {
+          "optional": true
+        },
+        "react": {
+          "optional": true
+        }
+      }
     }
   }
 }

package.json

@@ -14,7 +14,8 @@
     "@supabase/supabase-js": "^2.91.0",
     "next": "16.1.4",
     "react": "19.2.3",
-    "react-dom": "19.2.3"
+    "react-dom": "19.2.3",
+    "reactflow": "^11.11.4"
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4",

src/app/editor/[projectId]/FlowchartEditor.tsx

@@ -0,0 +1,73 @@
+'use client'
+
+import { useCallback } from 'react'
+import ReactFlow, {
+  Background,
+  BackgroundVariant,
+  useNodesState,
+  useEdgesState,
+  addEdge,
+  Connection,
+  Node,
+  Edge,
+} from 'reactflow'
+import 'reactflow/dist/style.css'
+import type { FlowchartData, FlowchartNode, FlowchartEdge } from '@/types/flowchart'
+
+type FlowchartEditorProps = {
+  projectId: string
+  initialData: FlowchartData
+}
+
+// Convert our FlowchartNode type to React Flow Node type
+function toReactFlowNodes(nodes: FlowchartNode[]): Node[] {
+  return nodes.map((node) => ({
+    id: node.id,
+    type: node.type,
+    position: node.position,
+    data: node.data,
+  }))
+}
+
+// Convert our FlowchartEdge type to React Flow Edge type
+function toReactFlowEdges(edges: FlowchartEdge[]): Edge[] {
+  return edges.map((edge) => ({
+    id: edge.id,
+    source: edge.source,
+    sourceHandle: edge.sourceHandle,
+    target: edge.target,
+    targetHandle: edge.targetHandle,
+    data: edge.data,
+  }))
+}
+
+export default function FlowchartEditor({
+  initialData,
+}: FlowchartEditorProps) {
+  const [nodes, setNodes, onNodesChange] = useNodesState(
+    toReactFlowNodes(initialData.nodes)
+  )
+  const [edges, setEdges, onEdgesChange] = useEdgesState(
+    toReactFlowEdges(initialData.edges)
+  )
+
+  const onConnect = useCallback(
+    (params: Connection) => setEdges((eds) => addEdge(params, eds)),
+    [setEdges]
+  )
+
+  return (
+    <div className="h-full w-full">
+      <ReactFlow
+        nodes={nodes}
+        edges={edges}
+        onNodesChange={onNodesChange}
+        onEdgesChange={onEdgesChange}
+        onConnect={onConnect}
+        fitView
+      >
+        <Background variant={BackgroundVariant.Dots} gap={16} size={1} />
+      </ReactFlow>
+    </div>
+  )
+}

src/app/editor/[projectId]/loading.tsx

@@ -0,0 +1,40 @@
+export default function EditorLoading() {
+  return (
+    <div className="flex h-screen flex-col">
+      <header className="flex items-center justify-between border-b border-zinc-200 bg-white px-4 py-3 dark:border-zinc-700 dark:bg-zinc-900">
+        <div className="flex items-center gap-4">
+          <div className="h-5 w-5 animate-pulse rounded bg-zinc-200 dark:bg-zinc-700" />
+          <div className="h-6 w-32 animate-pulse rounded bg-zinc-200 dark:bg-zinc-700" />
+        </div>
+      </header>
+
+      <div className="flex flex-1 items-center justify-center bg-zinc-100 dark:bg-zinc-800">
+        <div className="flex flex-col items-center gap-3">
+          <svg
+            className="h-8 w-8 animate-spin text-blue-500"
+            xmlns="http://www.w3.org/2000/svg"
+            fill="none"
+            viewBox="0 0 24 24"
+          >
+            <circle
+              className="opacity-25"
+              cx="12"
+              cy="12"
+              r="10"
+              stroke="currentColor"
+              strokeWidth="4"
+            />
+            <path
+              className="opacity-75"
+              fill="currentColor"
+              d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"
+            />
+          </svg>
+          <p className="text-sm text-zinc-600 dark:text-zinc-400">
+            Loading editor...
+          </p>
+        </div>
+      </div>
+    </div>
+  )
+}

src/app/editor/[projectId]/page.tsx

@@ -0,0 +1,74 @@
+import { createClient } from '@/lib/supabase/server'
+import { notFound } from 'next/navigation'
+import Link from 'next/link'
+import FlowchartEditor from './FlowchartEditor'
+import type { FlowchartData } from '@/types/flowchart'
+
+type PageProps = {
+  params: Promise<{ projectId: string }>
+}
+
+export default async function EditorPage({ params }: PageProps) {
+  const { projectId } = await params
+  const supabase = await createClient()
+
+  const {
+    data: { user },
+  } = await supabase.auth.getUser()
+
+  if (!user) {
+    return null
+  }
+
+  const { data: project, error } = await supabase
+    .from('projects')
+    .select('id, name, flowchart_data')
+    .eq('id', projectId)
+    .eq('user_id', user.id)
+    .single()
+
+  if (error || !project) {
+    notFound()
+  }
+
+  const flowchartData = (project.flowchart_data || {
+    nodes: [],
+    edges: [],
+  }) as FlowchartData
+
+  return (
+    <div className="flex h-screen flex-col">
+      <header className="flex items-center justify-between border-b border-zinc-200 bg-white px-4 py-3 dark:border-zinc-700 dark:bg-zinc-900">
+        <div className="flex items-center gap-4">
+          <Link
+            href="/dashboard"
+            className="text-zinc-600 hover:text-zinc-900 dark:text-zinc-400 dark:hover:text-zinc-50"
+          >
+            <svg
+              xmlns="http://www.w3.org/2000/svg"
+              className="h-5 w-5"
+              viewBox="0 0 20 20"
+              fill="currentColor"
+            >
+              <path
+                fillRule="evenodd"
+                d="M9.707 16.707a1 1 0 01-1.414 0l-6-6a1 1 0 010-1.414l6-6a1 1 0 011.414 1.414L5.414 9H17a1 1 0 110 2H5.414l4.293 4.293a1 1 0 010 1.414z"
+                clipRule="evenodd"
+              />
+            </svg>
+          </Link>
+          <h1 className="text-lg font-semibold text-zinc-900 dark:text-zinc-50">
+            {project.name}
+          </h1>
+        </div>
+      </header>
+
+      <div className="flex-1">
+        <FlowchartEditor
+          projectId={project.id}
+          initialData={flowchartData}
+        />
+      </div>
+    </div>
+  )
+}