feat: collection picker in product creation flow

- API /api/creation/collections liste toutes les collections Shopify
- Détection automatique depuis la colonne ID FAMILLE du Sheets
- Sélecteur avec recherche si absente ou pour modifier
- Collection affichée dans l'écran de confirmation
- collectionOverride passé à l'exécution comme fallback

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/(dashboard)/creation/page.tsx

@@ -1,5 +1,5 @@
 'use client'
-import { useState, useCallback } from 'react'
+import { useState, useCallback, useEffect } from 'react'
 import { Header } from '@/components/layout/Header'
 import { PendingRowsTable } from '@/components/creation/PendingRowsTable'
 import { MetafieldResolver } from '@/components/creation/MetafieldResolver'
@@ -9,6 +9,8 @@ import type { PendingProduct, MetafieldResolution, CreationStreamEvent } from '@
 
 type Step = 'famille' | 'analyse' | 'metafields' | 'confirmation' | 'execution'
 
+interface ShopifyCollection { id: string; title: string }
+
 export default function CreationPage() {
   const [step, setStep] = useState<Step>('famille')
   const [selectedTab, setSelectedTab] = useState<string | null>(null)
@@ -23,9 +25,28 @@ export default function CreationPage() {
   const [events, setEvents] = useState<CreationStreamEvent[]>([])
   const [done, setDone] = useState(false)
 
+  // Collection
+  const [collections, setCollections] = useState<ShopifyCollection[]>([])
+  const [detectedCollectionId, setDetectedCollectionId] = useState<string>('')
+  const [collectionOverride, setCollectionOverride] = useState<string>('')
+  const [collectionSearch, setCollectionSearch] = useState('')
+  const [loadingCollections, setLoadingCollections] = useState(false)
+
+  useEffect(() => {
+    setLoadingCollections(true)
+    fetch('/api/creation/collections')
+      .then(r => r.json())
+      .then(d => setCollections(d.collections ?? []))
+      .finally(() => setLoadingCollections(false))
+  }, [])
+
   const handleSelectTab = (tab: string) => {
     setSelectedTab(tab)
     setStep('analyse')
+    setDetectedCollectionId('')
+    setCollectionOverride('')
+    setCollectionSearch('')
+    setClearResult(null)
   }
 
   const analyse = async () => {
@@ -41,6 +62,17 @@ export default function CreationPage() {
       setByTab(data.byTab)
       setTotal(data.total)
       setSpecificColumns(data.specificColumns)
+
+      // Détecter la collection depuis les produits analysés
+      const products: PendingProduct[] = Object.values(data.byTab as Record<string, PendingProduct[]>).flat()
+      const ids = Array.from(new Set(products.map(p => p.collectionId).filter(Boolean)))
+      if (ids.length === 1) {
+        setDetectedCollectionId(ids[0])
+        setCollectionOverride(ids[0])
+      } else {
+        setDetectedCollectionId('')
+        setCollectionOverride('')
+      }
       setStep('metafields')
     } catch (e) {
       setError(e instanceof Error ? e.message : 'Erreur')
@@ -58,7 +90,7 @@ export default function CreationPage() {
     const res = await fetch('/api/creation/execute', {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ resolutions, tab: selectedTab }),
+      body: JSON.stringify({ resolutions, tab: selectedTab, collectionOverride: collectionOverride || undefined }),
     })
     if (!res.body) return
     const reader = res.body.getReader()
@@ -114,8 +146,16 @@ export default function CreationPage() {
     setDone(false)
     setByTab({})
     setTotal(0)
+    setDetectedCollectionId('')
+    setCollectionOverride('')
   }
 
+  const filteredCollections = collectionSearch
+    ? collections.filter(c => c.title.toLowerCase().includes(collectionSearch.toLowerCase()))
+    : collections
+
+  const selectedCollection = collections.find(c => c.id === collectionOverride)
+
   return (
     <>
       <Header title="Création produits" />
@@ -171,6 +211,57 @@ export default function CreationPage() {
               <PendingRowsTable byTab={byTab} total={total} />
               {total > 0 && (
                 <>
+                  <hr className="border-slate-700" />
+
+                  {/* Collection Shopify */}
+                  <div>
+                    <h2 className="text-base font-semibold text-white mb-1">Collection Shopify</h2>
+                    {detectedCollectionId ? (
+                      <div className="flex items-center gap-2 mb-2">
+                        <span className="text-xs text-green-400">✓ Détectée depuis le Sheets :</span>
+                        <span className="text-xs text-white font-medium">
+                          {collections.find(c => c.id === detectedCollectionId)?.title ?? `ID ${detectedCollectionId}`}
+                        </span>
+                        <button type="button" onClick={() => { setDetectedCollectionId(''); setCollectionOverride('') }}
+                          className="text-xs text-gray-500 hover:text-gray-300">modifier</button>
+                      </div>
+                    ) : (
+                      <p className="text-xs text-amber-400 mb-2">⚠ Aucune collection détectée dans le Sheets — choisissez-en une :</p>
+                    )}
+                    {(!detectedCollectionId || collectionOverride !== detectedCollectionId) && (
+                      <div className="space-y-2">
+                        {selectedCollection && (
+                          <div className="flex items-center gap-2">
+                            <span className="text-xs text-blue-300 font-medium">→ {selectedCollection.title}</span>
+                            <button type="button" onClick={() => setCollectionOverride('')}
+                              className="text-xs text-gray-500 hover:text-gray-300">✕</button>
+                          </div>
+                        )}
+                        <input
+                          type="text"
+                          value={collectionSearch}
+                          onChange={e => setCollectionSearch(e.target.value)}
+                          placeholder={loadingCollections ? 'Chargement…' : 'Rechercher une collection Shopify…'}
+                          className="w-full max-w-sm bg-slate-700 border border-slate-600 rounded px-2 py-1.5 text-sm text-white focus:outline-none focus:ring-1 focus:ring-indigo-500"
+                        />
+                        {collectionSearch && filteredCollections.length > 0 && (
+                          <div className="max-w-sm bg-slate-700 border border-slate-600 rounded shadow-lg max-h-48 overflow-y-auto">
+                            {filteredCollections.map(c => (
+                              <button key={c.id} type="button"
+                                onClick={() => { setCollectionOverride(c.id); setCollectionSearch('') }}
+                                className="w-full text-left px-3 py-1.5 text-sm text-white hover:bg-slate-600">
+                                {c.title}
+                              </button>
+                            ))}
+                          </div>
+                        )}
+                        {collectionSearch && filteredCollections.length === 0 && (
+                          <p className="text-xs text-gray-400">Aucune collection trouvée</p>
+                        )}
+                      </div>
+                    )}
+                  </div>
+
                   <hr className="border-slate-700" />
                   <div>
                     <h2 className="text-base font-semibold text-white mb-3">Résolution des métachamps</h2>
@@ -189,6 +280,11 @@ export default function CreationPage() {
             <div className="space-y-4">
               <div className="space-y-2 text-sm">
                 <p className="text-gray-300"><span className="text-white font-medium">{total} produit{total > 1 ? 's' : ''}</span> à créer dans Shopify</p>
+                <p className="text-gray-300">
+                  Collection : <span className="text-white font-medium">
+                    {collections.find(c => c.id === collectionOverride)?.title ?? (collectionOverride ? `ID ${collectionOverride}` : <span className="text-amber-400">Aucune</span>)}
+                  </span>
+                </p>
                 <p className="text-gray-300"><span className="text-white font-medium">{resolutions.filter(r => r.action !== 'skip').length}</span> type{resolutions.filter(r => r.action !== 'skip').length > 1 ? 's' : ''} de métachamps à assigner</p>
                 <p className="text-gray-300"><span className="text-white font-medium">{resolutions.filter(r => r.action === 'create').length}</span> nouvelle{resolutions.filter(r => r.action === 'create').length > 1 ? 's' : ''} définition{resolutions.filter(r => r.action === 'create').length > 1 ? 's' : ''} à créer dans Shopify</p>
                 <p className="text-yellow-300 text-xs mt-2">⚠ Les descriptions seront générées par OpenAI GPT-4o (~0.01$ par produit)</p>

src/app/api/creation/collections/route.ts

@@ -0,0 +1,32 @@
+import { NextResponse } from 'next/server'
+import { getServerSession } from 'next-auth'
+import { authOptions } from '@/lib/auth'
+
+const API_VERSION = '2024-01'
+
+export async function GET() {
+  const session = await getServerSession(authOptions)
+  if (!session) return NextResponse.json({ error: 'Non authentifié' }, { status: 401 })
+
+  const domain = process.env.SHOPIFY_STORE_DOMAIN
+  const token = process.env.SHOPIFY_ADMIN_API_TOKEN
+  if (!domain || !token) return NextResponse.json({ error: 'Config Shopify manquante' }, { status: 500 })
+
+  const baseUrl = `https://${domain}/admin/api/${API_VERSION}`
+  const headers = { 'X-Shopify-Access-Token': token, 'Content-Type': 'application/json' }
+
+  // Récupère custom collections + smart collections
+  const [customRes, smartRes] = await Promise.all([
+    fetch(`${baseUrl}/custom_collections.json?limit=250&fields=id,title`, { headers }),
+    fetch(`${baseUrl}/smart_collections.json?limit=250&fields=id,title`, { headers }),
+  ])
+
+  const custom = customRes.ok ? (await customRes.json()).custom_collections as { id: number; title: string }[] : []
+  const smart = smartRes.ok ? (await smartRes.json()).smart_collections as { id: number; title: string }[] : []
+
+  const collections = [...custom, ...smart]
+    .map(c => ({ id: String(c.id), title: c.title }))
+    .sort((a, b) => a.title.localeCompare(b.title))
+
+  return NextResponse.json({ collections })
+}

src/app/api/creation/execute/route.ts

@@ -20,9 +20,10 @@ export async function POST(req: NextRequest) {
   }
 
   const userId = (session.user as { id: string }).id
-  const body = await req.json().catch(() => ({})) as { resolutions?: MetafieldResolution[]; tab?: string }
+  const body = await req.json().catch(() => ({})) as { resolutions?: MetafieldResolution[]; tab?: string; collectionOverride?: string }
   const resolutions: MetafieldResolution[] = body.resolutions ?? []
   const tabFilter: string | undefined = body.tab ?? undefined
+  const collectionOverride: string | undefined = body.collectionOverride ?? undefined
   const resolutionMap = new Map<string, MetafieldResolution>(resolutions.map(r => [r.columnHeader, r]))
 
   const stream = new ReadableStream({
@@ -83,7 +84,8 @@ export async function POST(req: NextRequest) {
               weightKg: product.weightKg,
               status: 'active',
             })
-            if (product.collectionId) await addProductToCollection(shopifyId, product.collectionId)
+            const effectiveCollectionId = product.collectionId || collectionOverride || ''
+            if (effectiveCollectionId) await addProductToCollection(shopifyId, effectiveCollectionId)
             if (product.subCollectionId) await addProductToCollection(shopifyId, product.subCollectionId)
             send({ type: 'progress', current: i + 1, total, tab: product.tab, title: product.title, step: 'Métachamps…' })
             for (const [colHeader, value] of Object.entries(product.specificFields)) {