import { NextResponse } from "next/server";
import { z } from "zod";
import { ItemSource } from "@prisma/client";
import { db } from "@/lib/db";
import { requireAuth } from "@/lib/auth";

const PANTRY_SELECT = {
  id: true, name: true, description: true, quantity: true, unit: true,
  storedAt: true, bestBefore: true, source: true, plantId: true, notes: true,
  pantryCategory: true, pantrySubcategory: true, pricePaid: true, priceUnit: true,
  location: { select: { id: true, name: true } },
  plant: { select: { id: true, commonName: true, variety: true } },
  labels: { select: { label: { select: { id: true, name: true } } } },
} as const;

async function syncTags(itemId: string, tags: string[]) {
  const names = Array.from(new Set(tags.map(t => t.trim()).filter(Boolean)));
  const labels = await Promise.all(
    names.map(name => db.label.upsert({ where: { name }, update: {}, create: { name }, select: { id: true } }))
  );
  await db.labelOnItem.deleteMany({ where: { itemId } });
  if (labels.length) {
    await db.labelOnItem.createMany({
      data: labels.map(l => ({ itemId, labelId: l.id })),
      skipDuplicates: true,
    });
  }
}

const updateSchema = z.object({
  name: z.string().min(1).optional(),
  description: z.string().nullable().optional(),
  quantity: z.number().min(0).optional(),
  unit: z.string().nullable().optional(),
  packageSize: z.string().nullable().optional(),
  locationId: z.string().nullable().optional(),
  storedAt: z.string().nullable().optional(),
  bestBefore: z.string().nullable().optional(),
  source: z.nativeEnum(ItemSource).nullable().optional(),
  plantId: z.string().nullable().optional(),
  pantryCategory: z.string().nullable().optional(),
  pantrySubcategory: z.string().nullable().optional(),
  pricePaid: z.number().nullable().optional(),
  priceUnit: z.string().nullable().optional(),
  notes: z.string().nullable().optional(),
  tags: z.array(z.string()).optional(),
});

export async function PATCH(req: Request, { params }: { params: { id: string } }) {
  try {
    const session = await requireAuth();
    const data = updateSchema.parse(await req.json());

    await db.item.update({
      where: { id: params.id },
      data: {
        ...(data.name !== undefined && { name: data.name }),
        ...(data.description !== undefined && { description: data.description ?? data.packageSize ?? null }),
        ...(data.quantity !== undefined && { quantity: data.quantity }),
        ...(data.unit !== undefined && { unit: data.unit ?? null }),
        ...(data.locationId !== undefined && { locationId: data.locationId ?? null }),
        ...(data.storedAt !== undefined && { storedAt: data.storedAt ? new Date(data.storedAt) : null }),
        ...(data.bestBefore !== undefined && { bestBefore: data.bestBefore ? new Date(data.bestBefore) : null }),
        ...(data.source !== undefined && { source: data.source ?? null }),
        ...(data.plantId !== undefined && { plantId: data.plantId ?? null }),
        ...(data.pantryCategory !== undefined && { pantryCategory: data.pantryCategory ?? null }),
        ...(data.pantrySubcategory !== undefined && { pantrySubcategory: data.pantrySubcategory ?? null }),
        ...(data.pricePaid !== undefined && { pricePaid: data.pricePaid ?? null }),
        ...(data.priceUnit !== undefined && { priceUnit: data.priceUnit ?? null }),
        ...(data.notes !== undefined && { notes: data.notes ?? null }),
      },
    });

    if (data.tags !== undefined) await syncTags(params.id, data.tags);

    const item = await db.item.findUniqueOrThrow({ where: { id: params.id }, select: PANTRY_SELECT });

    await db.auditEvent.create({
      data: { action: "pantry.update", entityId: item.id, actorId: session.user.id, payload: { name: item.name } },
    });

    return NextResponse.json({
      ...item,
      quantity: Number(item.quantity),
      pricePaid: item.pricePaid != null ? Number(item.pricePaid) : null,
      tags: item.labels.map(l => l.label.name),
    });
  } catch (err) {
    if (err instanceof z.ZodError) return NextResponse.json({ error: "Invalid input" }, { status: 400 });
    if (err instanceof Error && err.message === "Unauthorized") return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    console.error(err);
    return NextResponse.json({ error: "Server error" }, { status: 500 });
  }
}

export async function DELETE(_req: Request, { params }: { params: { id: string } }) {
  try {
    const session = await requireAuth();
    await db.item.update({ where: { id: params.id }, data: { active: false } });
    await db.auditEvent.create({
      data: { action: "pantry.delete", entityId: params.id, actorId: session.user.id },
    });
    return NextResponse.json({ ok: true });
  } catch (err) {
    if (err instanceof Error && err.message === "Unauthorized") return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    console.error(err);
    return NextResponse.json({ error: "Server error" }, { status: 500 });
  }
}