import { serverAuth } from "@/lib/pb";
import { revalidateInvoicePages } from "@/lib/invoice-revalidate";
import { parseInvoicePdf, ParseError, registerCodeFrom } from "@/lib/invoice-parser";
import { syncSitesFromInvoices, findSiteContainer, resolveSiteName } from "@/lib/sites";

export const dynamic = "force-dynamic";

const MAX_BYTES = 20 * 1024 * 1024;

// GET /api/invoices/intake
// The problem-invoice inbox: every PDF offered to the app and what became of it.
// `?status=failed` narrows it to the ones that need attention.
export async function GET(req: Request) {
  const url = new URL(req.url);
  const status = url.searchParams.get("status");
  try {
    const pb = await serverAuth();
    // PocketBase rejects an empty filter string, so only send one when filtering.
    const opts: Record<string, unknown> = { sort: "-created" };
    if (status) opts.filter = `status = "${status}"`;
    const records = await pb.collection("invoice_intake").getFullList(opts);
    return Response.json({
      ok: true,
      items: records.map((r: any) => ({
        id: r.id,
        file_name: r.file_name,
        file_size: r.file_size,
        invoice_no: r.invoice_no,
        status: r.status,
        error: r.error,
        parsed: r.parsed,
        invoice: r.invoice,
        created: r.created,
      })),
    });
  } catch (e: any) {
    return Response.json({ ok: false, error: e?.message || "Could not read the inbox" }, { status: 500 });
  }
}

// POST /api/invoices/intake
// Multipart: `file` (a PDF). The PDF is parsed deterministically, checked arithmetically,
// and only then written. A PDF that does not reconcile is stored in the inbox as a
// problem invoice with the reason attached — it is never partially imported.
export async function POST(req: Request) {
  let form: FormData;
  try {
    form = await req.formData();
  } catch {
    return Response.json({ ok: false, error: "Expected multipart/form-data" }, { status: 400 });
  }

  const file = form.get("file");
  if (!(file instanceof File) || file.size === 0) {
    return Response.json({ ok: false, error: "No file received" }, { status: 400 });
  }
  if (file.type !== "application/pdf" && !file.name.toLowerCase().endsWith(".pdf")) {
    return Response.json({ ok: false, error: "Only PDF invoices are accepted" }, { status: 400 });
  }
  if (file.size > MAX_BYTES) {
    return Response.json(
      { ok: false, error: `File is ${(file.size / 1048576).toFixed(1)} MB — limit is 20 MB` },
      { status: 400 },
    );
  }

  const bytes = new Uint8Array(await file.arrayBuffer());
  const pb = await serverAuth();

  // Always record the attempt, so a bad PDF is never lost.
  const recordFailure = async (reason: string, parsed?: unknown) => {
    const form2 = new FormData();
    form2.append("file_name", file.name);
    form2.append("file_size", String(file.size));
    form2.append("status", "failed");
    form2.append("error", reason);
    if (parsed) form2.append("parsed", JSON.stringify(parsed));
    form2.append(
      "source_pdf",
      new File([bytes], file.name.replace(/[^\w.\- ]+/g, "_"), { type: "application/pdf" }),
    );
    const rec = await pb.collection("invoice_intake").create(form2);
    revalidateInvoicePages();
    return Response.json({ ok: false, status: "failed", intakeId: rec.id, error: reason }, { status: 422 });
  };

  let parsed;
  try {
    parsed = await parseInvoicePdf(bytes);
  } catch (e: any) {
    if (e instanceof ParseError) return recordFailure(e.reason);
    return recordFailure(`Could not read the PDF: ${e?.message ?? "unknown error"}`);
  }

  // Match each line to a plant item by the code the invoice prints. No match means the
  // line is left unassigned for manual booking — never guessed.
  const assets = await pb.collection("assets").getFullList();
  const byCode = new Map<string, string>();
  for (const a of assets) if (a.code) byCode.set(a.code, a.id);

  // A duplicate is NOT a problem invoice. Nothing failed, and re-offering the same file
  // can never succeed without first deleting the original — so it must not land in the
  // retry inbox, where it would sit looking like something to fix. It is reported with
  // its own status so the UI can say "you already have this" instead of "this failed".
  const allInvoices = (await pb.collection("invoices").getFullList()) as any[];
  const existing = allInvoices.find((i: any) => i.invoice_no === parsed.invoice_no);
  if (existing) {
    return Response.json(
      {
        ok: false,
        status: "duplicate",
        invoice_no: parsed.invoice_no,
        error: `Invoice ${parsed.invoice_no} is already in the register — nothing was added.`,
        existing: {
          invoice_no: existing.invoice_no,
          site: existing.site,
          invoice_date: existing.invoice_date,
          total_incl: existing.total_incl,
          lines: (await pb.collection("invoice_lines").getFullList({ filter: `invoice = "${existing.id}"` })).length,
          invoiceId: existing.id,
        },
      },
      { status: 409 },
    );
  }

  // The supplier abbreviates the site on the invoice ("…Sep 2026 Cosmo" for the site the
  // register calls "Cosmo City"). Resolve it BEFORE writing, because sites are derived
  // from the invoice wording — saving the abbreviation would create a second "Cosmo" and
  // split this customer across two sites on /sites.
  parsed.site = resolveSiteName(
    parsed.site,
    [...new Set(allInvoices.map((i: any) => i.site).filter((s: unknown): s is string => typeof s === "string" && !!s.trim()))],
  );

  const periodEnd = new Date(parsed.period_to);
  const bookedMonth = periodEnd.getUTCMonth() + 1;
  const bookedYear = periodEnd.getUTCFullYear();

  let invoiceRec;
  try {
    invoiceRec = await pb.collection("invoices").create({
      invoice_no: parsed.invoice_no,
      invoice_date: parsed.invoice_date,
      order_no: parsed.order_no,
      debtor: parsed.debtor,
      debtor_no: parsed.debtor_no,
      period_from: parsed.period_from,
      period_to: parsed.period_to,
      description: parsed.description,
      site: parsed.site,
      section: parsed.section,
      category: parsed.category,
      currency: parsed.currency,
      vat_reg_no: parsed.vat_reg_no,
      source_file: file.name,
      subtotal: parsed.subtotal,
      escalation: parsed.escalation,
      vat: parsed.vat,
      vat_pct: parsed.vat_pct,
      total_excl: parsed.total_excl,
      total_incl: parsed.total_incl,
      booked_month: bookedMonth,
      booked_year: bookedYear,
      is_booked: false,
    });
  } catch (e: any) {
    return recordFailure(
      `Parsed correctly but could not save the invoice: ${e?.response?.data?.message || e?.message}`,
      parsed,
    );
  }

  // The invoice is written, so this site is now real. Sites are derived, never typed.
  const sites = await syncSitesFromInvoices(pb, [...allInvoices, invoiceRec as any]);

  // A container line carries a generic code the plant register does not have. If the
  // site this invoice belongs to has a container hired under that code, the line is
  // booked to it automatically rather than waiting for a human to notice.
  const siteContainerFor = (machineCode: string) => {
    const site = findSiteContainer(sites, parsed.site, machineCode);
    return site?.container_asset || "";
  };

  const unassigned: string[] = [];
  for (let i = 0; i < parsed.lines.length; i++) {
    const l = parsed.lines[i];
    const registerCode = registerCodeFrom(l.machine_code);
    // Plant register first, then this site's own container, then nothing.
    const assetId = byCode.get(registerCode) || siteContainerFor(l.machine_code) || "";
    if (!assetId) unassigned.push(l.machine_code);
    try {
      await pb.collection("invoice_lines").create({
        invoice: invoiceRec.id,
        line_no: i + 1,
        machine_code: l.machine_code,
        asset_code: registerCode,
        description: l.description,
        qty: l.qty,
        unit: l.unit,
        rate: l.rate,
        rate_type: l.rate_type,
        amount_excl: l.amount_excl,
        vat: l.vat,
        total_incl: l.total_incl,
        booked_asset: assetId,
        booked_month: bookedMonth,
        booked_year: bookedYear,
      });
    } catch (e: any) {
      // A half-written invoice is worse than none — roll it back and report.
      const written = await pb
        .collection("invoice_lines")
        .getFullList({ filter: `invoice = "${invoiceRec.id}"` });
      for (const w of written) await pb.collection("invoice_lines").delete(w.id);
      await pb.collection("invoices").delete(invoiceRec.id);
      return recordFailure(
        `Parsed correctly but a line could not be saved, so the import was rolled back: ${e?.response?.data?.message || e?.message}`,
        parsed,
      );
    }
  }

  // Book whatever could be matched. Anything unassigned stays visibly unbooked.
  const lines = await pb.collection("invoice_lines").getFullList({ filter: `invoice = "${invoiceRec.id}"` });
  for (const line of lines) {
    if (!line.booked_asset) continue;
    await pb.collection("monthly_income").create({
      asset: line.booked_asset,
      year: bookedYear,
      month: bookedMonth,
      income: line.total_incl,
      fixed_expenses: 0,
      is_forecast: false,
      invoice_line: line.id,
    });
  }
  const allBooked = lines.every((l: any) => l.booked_asset);
  await pb.collection("invoices").update(invoiceRec.id, { is_booked: allBooked });

  const form2 = new FormData();
  form2.append("file_name", file.name);
  form2.append("file_size", String(file.size));
  form2.append("invoice_no", parsed.invoice_no);
  form2.append("status", "imported");
  form2.append("invoice", invoiceRec.id);
  form2.append("parsed", JSON.stringify(parsed));
  form2.append(
    "source_pdf",
    new File([bytes], file.name.replace(/[^\w.\- ]+/g, "_"), { type: "application/pdf" }),
  );
  await pb.collection("invoice_intake").create(form2);

  revalidateInvoicePages("/income");

  return Response.json({
    ok: true,
    status: "imported",
    invoice_no: parsed.invoice_no,
    invoiceId: invoiceRec.id,
    site: parsed.site,
    total_incl: parsed.total_incl,
    lines: lines.length,
    booked: lines.filter((l: any) => l.booked_asset).length,
    unassigned,
    fullyBooked: allBooked,
  });
}