import { auth } from "@/auth";
import { db } from "@/lib/db";
import { redirect } from "next/navigation";
import { ImportForm } from "./import-form";
import type { CostCentreOption, AccountGroup } from "@/app/(portal)/po/new/new-po-form";
import type { Metadata } from "next";

export const metadata: Metadata = { title: "Import Purchase Order" };

export default async function ImportPoPage() {
  const session = await auth();
  if (!session?.user) redirect("/login");

  const { role } = session.user;
  if (!["MANAGER", "SUPERUSER", "ADMIN"].includes(role)) redirect("/dashboard");

  const [vessels, sites, accounts, vendors] = await Promise.all([
    db.vessel.findMany({ where: { isActive: true }, orderBy: { name: "asc" }, select: { id: true, name: true, code: true } }),
    db.site.findMany({ where: { isActive: true }, orderBy: { name: "asc" }, select: { id: true, name: true, code: true } }),
    db.account.findMany({
      where: { isActive: true, children: { none: {} } },
      orderBy: { code: "asc" },
      select: { id: true, code: true, name: true, parent: { select: { name: true, code: true, parent: { select: { name: true, code: true } } } } },
    }),
    db.vendor.findMany({ orderBy: { name: "asc" } }),
  ]);

  const accountGroupMap = new Map<string, typeof accounts>();
  for (const a of accounts) {
    const subLabel = a.parent ? `${a.parent.code} — ${a.parent.name}` : "Uncategorised";
    const topLabel = a.parent?.parent ? `${a.parent.parent.name} › ` : "";
    const groupKey = `${topLabel}${subLabel}`;
    if (!accountGroupMap.has(groupKey)) accountGroupMap.set(groupKey, []);
    accountGroupMap.get(groupKey)!.push(a);
  }
  const accountGroups: AccountGroup[] = Array.from(accountGroupMap.entries()).map(([group, items]) => ({ group, items }));

  const costCentres: CostCentreOption[] = [
    ...vessels.map((v) => ({ ref: `v:${v.id}`, label: `${v.code} — ${v.name}`, group: "Vessels" as const })),
    ...sites.map((s) => ({ ref: `s:${s.id}`, label: `${s.code} — ${s.name}`, group: "Sites" as const })),
  ];

  return (
    <div className="max-w-6xl">
      <div className="mb-6">
        <h1 className="text-2xl font-semibold text-neutral-900">Import Purchase Order</h1>
        <p className="mt-1 text-sm text-neutral-500">
          Upload a Pelagia-format Excel PO file. Line items and vendor details are extracted automatically.
          You then select the cost centre, accounting code, and confirm before saving as a draft.
        </p>
      </div>
      <ImportForm costCentres={costCentres} accounts={accountGroups} vendors={vendors} />
    </div>
  );
}