feat(rental): Sprint D — panier + checkout + intégration carbet

Cart lib + cookie persistence (karbe-rental-cart, 30j) avec context React
useCart(). Provider wrappé dans layout pour hydratation server→client.

Page /panier :
- Récap regroupé par prestataire (sous-totaux, caution)
- Édition lignes (dates, qté), suppression, vider panier
- Bouton « Valider et payer » → POST /api/rentals/checkout
- Badge 🛒 dans SiteHeader avec total items

Composant <AddToCart /> sur /materiel/[itemId] avec date picker + qté.

API POST /api/rentals/checkout :
- Validation auth + items actifs + provider approved + qté/dates
- Transaction Prisma : recheck stock par fenêtre + crée 1 RentalBooking
  par prestataire + RentalLines (snapshot prix) + RentalItemAvailability
  (blocage des dispos)
- Calcul commissionAmount selon provider.commissionPct
- Si Stripe activé : Checkout Session unique avec 1 line_item par
  RentalBooking, metadata {type:"rental-bundle", rentalBookingIds:[]}
- Sinon : crée en PENDING, retourne rentalBookingIds
- Vide le cookie panier après création
- Audit log rental.checkout.created

Webhook Stripe étendu :
- checkout.session.completed type=rental-bundle → CONFIRMED+SUCCEEDED
  sur toutes les RentalBookings du bundle
- payment_intent.payment_failed metadata.rentalBookingIds → CANCELLED
  + supprime les RentalItemAvailability (libère le stock)

Intégration carbet :
- /carbets/[slug] : panneau « Compléter votre séjour » avec items des
  prestataires de la même rivière + System D (recommandation contextuelle)
- /reservations/[id] : section « Matériel associé » listant les
  RentalBookings liées
- /mes-locations : page récap toutes les locations (System D + tiers,
  liées carbet ou standalone)
- Lien « Mes locations » dans SiteHeader

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/api/rentals/checkout/route.ts

@@ -0,0 +1,313 @@
+import { cookies } from "next/headers";
+import { NextResponse } from "next/server";
+
+import { auth } from "@/auth";
+import { PaymentStatus, RentalBookingStatus } from "@/generated/prisma/enums";
+import { Prisma } from "@/generated/prisma/client";
+import { recordAudit } from "@/lib/admin/audit";
+import { prisma } from "@/lib/prisma";
+import { CART_COOKIE, EMPTY_CART, diffDays, parseCart } from "@/lib/rental-cart";
+import {
+  getStripeClient,
+  isStripeConfigured,
+  toStripeAmountCents,
+} from "@/lib/stripe";
+
+export const runtime = "nodejs";
+
+type LineInput = {
+  itemId: string;
+  qty: number;
+  startDate: Date;
+  endDate: Date;
+  nights: number;
+};
+
+function parseDateOnly(s: string): Date {
+  return new Date(s + "T00:00:00Z");
+}
+
+export async function POST() {
+  const session = await auth();
+  if (!session?.user?.id || !session.user.email) {
+    return NextResponse.json({ error: "Connectez-vous pour finaliser." }, { status: 401 });
+  }
+
+  const jar = await cookies();
+  const cart = parseCart(jar.get(CART_COOKIE)?.value);
+  if (cart.items.length === 0) {
+    return NextResponse.json({ error: "Panier vide." }, { status: 400 });
+  }
+
+  // Charge tous les items du panier
+  const itemIds = Array.from(new Set(cart.items.map((e) => e.itemId)));
+  const items = await prisma.rentalItem.findMany({
+    where: { id: { in: itemIds }, active: true },
+    include: {
+      provider: {
+        select: {
+          id: true,
+          name: true,
+          active: true,
+          approved: true,
+          commissionPct: true,
+          isSystemD: true,
+        },
+      },
+    },
+  });
+  const itemById = new Map(items.map((i) => [i.id, i]));
+
+  // Validations préliminaires : items valides + provider actif/approved
+  for (const entry of cart.items) {
+    const it = itemById.get(entry.itemId);
+    if (!it) {
+      return NextResponse.json(
+        { error: `Item ${entry.itemId} introuvable ou désactivé.` },
+        { status: 409 },
+      );
+    }
+    if (!it.provider.active || !it.provider.approved) {
+      return NextResponse.json(
+        { error: `Prestataire ${it.provider.name} indisponible.` },
+        { status: 409 },
+      );
+    }
+    if (entry.qty < 1 || entry.qty > it.totalQty) {
+      return NextResponse.json(
+        { error: `Quantité invalide pour « ${it.name} ».` },
+        { status: 400 },
+      );
+    }
+    const start = parseDateOnly(entry.startDate);
+    const end = parseDateOnly(entry.endDate);
+    if (Number.isNaN(start.getTime()) || Number.isNaN(end.getTime()) || end <= start) {
+      return NextResponse.json(
+        { error: `Dates invalides pour « ${it.name} ».` },
+        { status: 400 },
+      );
+    }
+  }
+
+  // Groupe par provider
+  type Group = {
+    providerId: string;
+    providerName: string;
+    commissionPct: number;
+    lines: LineInput[];
+    itemsTotal: Prisma.Decimal;
+    depositTotal: Prisma.Decimal;
+    startDate: Date;
+    endDate: Date;
+  };
+
+  const groups = new Map<string, Group>();
+  for (const entry of cart.items) {
+    const it = itemById.get(entry.itemId)!;
+    const start = parseDateOnly(entry.startDate);
+    const end = parseDateOnly(entry.endDate);
+    const nights = Math.max(1, diffDays(entry.startDate, entry.endDate));
+    const lineSub = new Prisma.Decimal(it.pricePerDay).mul(entry.qty).mul(nights);
+    const lineDeposit = new Prisma.Decimal(it.deposit).mul(entry.qty);
+
+    let g = groups.get(it.provider.id);
+    if (!g) {
+      g = {
+        providerId: it.provider.id,
+        providerName: it.provider.name,
+        commissionPct: Number(it.provider.commissionPct),
+        lines: [],
+        itemsTotal: new Prisma.Decimal(0),
+        depositTotal: new Prisma.Decimal(0),
+        startDate: start,
+        endDate: end,
+      };
+      groups.set(it.provider.id, g);
+    }
+    g.lines.push({ itemId: it.id, qty: entry.qty, startDate: start, endDate: end, nights });
+    g.itemsTotal = g.itemsTotal.add(lineSub);
+    g.depositTotal = g.depositTotal.add(lineDeposit);
+    if (start < g.startDate) g.startDate = start;
+    if (end > g.endDate) g.endDate = end;
+  }
+
+  // Transaction : recheck stock + crée RentalBookings + Lines + Availabilities
+  let grandTotal = new Prisma.Decimal(0);
+  let grandDeposit = new Prisma.Decimal(0);
+  let rentalBookingIds: string[] = [];
+
+  try {
+    rentalBookingIds = await prisma.$transaction(async (tx) => {
+      const created: string[] = [];
+
+      for (const g of groups.values()) {
+        // Recheck stock disponible pour chaque ligne
+        for (const line of g.lines) {
+          const blocked = await tx.rentalItemAvailability.aggregate({
+            where: {
+              itemId: line.itemId,
+              startDate: { lt: line.endDate },
+              endDate: { gt: line.startDate },
+            },
+            _sum: { qty: true },
+          });
+          const item = itemById.get(line.itemId)!;
+          const used = Number(blocked._sum.qty ?? 0);
+          const free = item.totalQty - used;
+          if (line.qty > free) {
+            throw new Error(`Stock insuffisant pour « ${item.name} » sur les dates demandées (libre: ${free}).`);
+          }
+        }
+
+        const commissionAmount = g.itemsTotal
+          .mul(g.commissionPct)
+          .div(100)
+          .toDecimalPlaces(2);
+        const amount = g.itemsTotal.add(g.depositTotal).toDecimalPlaces(2);
+
+        const rb = await tx.rentalBooking.create({
+          data: {
+            tenantId: session.user!.id!,
+            providerId: g.providerId,
+            startDate: g.startDate,
+            endDate: g.endDate,
+            status: RentalBookingStatus.PENDING,
+            paymentStatus: PaymentStatus.PENDING,
+            itemsTotal: g.itemsTotal.toDecimalPlaces(2),
+            depositTotal: g.depositTotal.toDecimalPlaces(2),
+            commissionAmount,
+            amount,
+            currency: "EUR",
+            lines: {
+              create: g.lines.map((line) => {
+                const item = itemById.get(line.itemId)!;
+                const lineTotal = new Prisma.Decimal(item.pricePerDay)
+                  .mul(line.qty)
+                  .mul(line.nights)
+                  .toDecimalPlaces(2);
+                return {
+                  itemId: line.itemId,
+                  qty: line.qty,
+                  pricePerDay: new Prisma.Decimal(item.pricePerDay),
+                  deposit: new Prisma.Decimal(item.deposit),
+                  lineTotal,
+                };
+              }),
+            },
+          },
+          select: { id: true },
+        });
+
+        // Bloque les dispos
+        for (const line of g.lines) {
+          await tx.rentalItemAvailability.create({
+            data: {
+              itemId: line.itemId,
+              startDate: line.startDate,
+              endDate: line.endDate,
+              qty: line.qty,
+              reason: "RENTAL_BOOKING",
+              rentalBookingId: rb.id,
+            },
+          });
+        }
+
+        created.push(rb.id);
+        grandTotal = grandTotal.add(g.itemsTotal);
+        grandDeposit = grandDeposit.add(g.depositTotal);
+      }
+
+      return created;
+    });
+  } catch (e) {
+    return NextResponse.json(
+      { error: e instanceof Error ? e.message : "Erreur lors de la création." },
+      { status: 409 },
+    );
+  }
+
+  const totalAmount = grandTotal.add(grandDeposit).toDecimalPlaces(2);
+
+  await recordAudit({
+    scope: "rental",
+    event: "rental.checkout.created",
+    target: rentalBookingIds.join(","),
+    actorEmail: session.user.email,
+    details: {
+      rentalBookingIds,
+      amount: totalAmount.toNumber(),
+      depositTotal: grandDeposit.toNumber(),
+      providers: Array.from(groups.keys()),
+    },
+  });
+
+  // Vide le panier
+  jar.set(CART_COOKIE, JSON.stringify(EMPTY_CART), {
+    httpOnly: false,
+    sameSite: "lax",
+    path: "/",
+    maxAge: 0,
+  });
+
+  // Stripe ou paiement différé
+  if (!isStripeConfigured()) {
+    return NextResponse.json(
+      { rentalBookingIds, totalAmount: totalAmount.toNumber() },
+      { status: 201 },
+    );
+  }
+
+  const appUrl = process.env.APP_URL;
+  if (!appUrl) {
+    return NextResponse.json({ error: "APP_URL manquante." }, { status: 500 });
+  }
+
+  // Une session Stripe avec une ligne par RentalBooking (agrégée)
+  const stripe = getStripeClient();
+  const bookingDetails = await prisma.rentalBooking.findMany({
+    where: { id: { in: rentalBookingIds } },
+    include: {
+      provider: { select: { name: true } },
+      lines: { select: { qty: true, item: { select: { name: true } } } },
+    },
+  });
+
+  const line_items = bookingDetails.map((rb) => ({
+    quantity: 1,
+    price_data: {
+      currency: "eur",
+      unit_amount: toStripeAmountCents(Number(rb.amount)),
+      product_data: {
+        name: `Matériel — ${rb.provider.name}`,
+        description: rb.lines.map((l) => `${l.qty}× ${l.item.name}`).join(", ").slice(0, 500),
+      },
+    },
+  }));
+
+  const checkoutSession = await stripe.checkout.sessions.create({
+    mode: "payment",
+    success_url: `${appUrl}/mes-locations?payment=success&ids=${rentalBookingIds.join(",")}`,
+    cancel_url: `${appUrl}/panier?payment=cancel`,
+    customer_email: session.user.email,
+    line_items,
+    metadata: {
+      type: "rental-bundle",
+      rentalBookingIds: rentalBookingIds.join(","),
+    },
+  });
+
+  await prisma.rentalBooking.updateMany({
+    where: { id: { in: rentalBookingIds } },
+    data: { stripeSessionId: checkoutSession.id },
+  });
+
+  return NextResponse.json(
+    {
+      rentalBookingIds,
+      totalAmount: totalAmount.toNumber(),
+      checkoutSessionId: checkoutSession.id,
+      checkoutUrl: checkoutSession.url,
+    },
+    { status: 201 },
+  );
+}

src/app/api/stripe/webhook/route.ts

@@ -4,6 +4,7 @@ import Stripe from "stripe";
 import {
   BookingStatus,
   PaymentStatus,
+  RentalBookingStatus,
   SubscriptionStatus,
 } from "@/generated/prisma/enums";
 import { refreshCarbetLastBookedAt } from "@/lib/carbet-last-booked";
@@ -51,6 +52,21 @@ async function handleCheckoutCompleted(session: Stripe.Checkout.Session) {
     return;
   }
 
+  if (type === "rental-bundle") {
+    const idsRaw = session.metadata?.rentalBookingIds;
+    if (!idsRaw) return;
+    const ids = idsRaw.split(",").map((s) => s.trim()).filter(Boolean);
+    if (ids.length === 0) return;
+    await prisma.rentalBooking.updateMany({
+      where: { id: { in: ids } },
+      data: {
+        paymentStatus: PaymentStatus.SUCCEEDED,
+        status: RentalBookingStatus.CONFIRMED,
+      },
+    });
+    return;
+  }
+
   if (type === "owner_subscription") {
     const ownerId = session.metadata?.ownerId;
     const carbetId = session.metadata?.carbetId;
@@ -79,6 +95,27 @@ async function handleCheckoutCompleted(session: Stripe.Checkout.Session) {
 
 async function handlePaymentIntentFailed(paymentIntent: Stripe.PaymentIntent) {
   const bookingId = paymentIntent.metadata?.bookingId;
+  const rentalIdsRaw = paymentIntent.metadata?.rentalBookingIds;
+
+  if (rentalIdsRaw) {
+    const ids = rentalIdsRaw.split(",").map((s) => s.trim()).filter(Boolean);
+    if (ids.length > 0) {
+      // Marque les paiements échoués + libère les blocages de dispo
+      await prisma.$transaction([
+        prisma.rentalBooking.updateMany({
+          where: { id: { in: ids } },
+          data: {
+            paymentStatus: PaymentStatus.FAILED,
+            status: RentalBookingStatus.CANCELLED,
+          },
+        }),
+        prisma.rentalItemAvailability.deleteMany({
+          where: { rentalBookingId: { in: ids } },
+        }),
+      ]);
+    }
+  }
+
   if (!bookingId) {
     return;
   }