import { prisma } from "@/lib/prisma";
import type { Review } from "@/generated/prisma/client";

export type ReviewWithCustomer = Review & {
  customer: { firstName: string; lastName: string };
};

export interface ReviewSummary {
  average: number | null;
  count: number;
}

export async function getApprovedReviews(productId: string): Promise<ReviewWithCustomer[]> {
  return prisma.review.findMany({
    where: { productId, isApproved: true },
    include: { customer: { select: { firstName: true, lastName: true } } },
    orderBy: { createdAt: "desc" },
  });
}

export async function getReviewSummary(productId: string): Promise<ReviewSummary> {
  const result = await prisma.review.aggregate({
    where: { productId, isApproved: true },
    _avg: { rating: true },
    _count: true,
  });
  return { average: result._avg.rating, count: result._count };
}

/**
 * Wie getReviewSummary, aber fuer mehrere Produkte in einer Abfrage — vermeidet
 * N+1-Abfragen beim Rendern von Produktrastern (Shop-Uebersicht u.ae.).
 */
export async function getReviewSummariesByProductIds(
  productIds: string[]
): Promise<Map<string, ReviewSummary>> {
  if (productIds.length === 0) return new Map();

  const results = await prisma.review.groupBy({
    by: ["productId"],
    where: { productId: { in: productIds }, isApproved: true },
    _avg: { rating: true },
    _count: true,
  });

  return new Map(results.map((r) => [r.productId, { average: r._avg.rating, count: r._count }]));
}

/** Eigene Bewertung des Kunden fuer dieses Produkt, unabhaengig vom Freischaltungsstatus. */
export async function getCustomerReview(productId: string, customerId: string): Promise<Review | null> {
  return prisma.review.findUnique({
    where: { productId_customerId: { productId, customerId } },
  });
}

/**
 * "Verifizierter Kauf": mindestens eine bezahlte, nicht stornierte Bestellung
 * des Kunden enthaelt dieses Produkt. Gastbestellungen (ohne customerId)
 * zaehlen bewusst nicht, da eine Bewertung an ein Kundenkonto gebunden ist.
 */
export async function hasCustomerPurchased(productId: string, customerId: string): Promise<boolean> {
  const orderItem = await prisma.orderItem.findFirst({
    where: {
      productId,
      order: {
        customerId,
        status: { notIn: ["NEU", "STORNIERT"] },
      },
    },
    select: { id: true },
  });
  return orderItem !== null;
}