import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { db, pantryItems, eq } from "@epicure/db";
import { requireSession } from "@/lib/api-auth";

const Schema = z.object({
  items: z.array(z.object({
    rawName: z.string().min(1).max(200),
    quantity: z.string().optional(),
    unit: z.string().max(50).optional(),
  })).min(1).max(100),
});

export async function POST(req: NextRequest) {
  const { session, response } = await requireSession();
  if (response) return response;

  const body = await req.json() as unknown;
  const parsed = Schema.safeParse(body);
  if (!parsed.success) return NextResponse.json({ error: "Validation error" }, { status: 400 });

  const userId = session!.user.id;
  const existing = await db.query.pantryItems.findMany({
    where: eq(pantryItems.userId, userId),
  });

  for (const incoming of parsed.data.items) {
    const key = incoming.rawName.toLowerCase();
    const match = existing.find(
      (e) => e.rawName.toLowerCase() === key && (e.unit ?? "") === (incoming.unit ?? "")
    );

    if (match) {
      const existingQty = match.quantity ? parseFloat(match.quantity) : null;
      const incomingQty = incoming.quantity ? parseFloat(incoming.quantity) : null;
      if (existingQty !== null && incomingQty !== null && !isNaN(existingQty) && !isNaN(incomingQty)) {
        const merged = existingQty + incomingQty;
        await db.update(pantryItems)
          .set({ quantity: String(merged) })
          .where(eq(pantryItems.id, match.id));
      }
      // if quantities aren't numeric, leave as-is (item already exists)
    } else {
      await db.insert(pantryItems).values({
        id: crypto.randomUUID(),
        userId,
        rawName: incoming.rawName,
        quantity: incoming.quantity,
        unit: incoming.unit,
      });
    }
  }

  return NextResponse.json({ ok: true });
}