import "server-only";

import * as z from "zod";
import { getCommissionSlipProvider, slipProviderConfigured } from "./slip-provider";
import { HttpError } from "@/lib/security/http";
import { normalizePromptPayIdentifier } from "@/lib/commission/promptpay";

const slipResponse = z.object({ code: z.string() }).passthrough();
const verifiedSlip = z.object({
  referenceId: z.string().min(1),
  transRef: z.string().min(1),
  amount: z.number(),
  dateTime: z.string().refine((value) => !Number.isNaN(Date.parse(value))),
}).passthrough();

function required(name: string) {
  const value = process.env[name];
  if (!value) throw new HttpError(503, `${name}-not-configured`);
  return value;
}

export function promptPayConfig() {
  const type = required("COMMISSION_PROMPTPAY_TYPE");
  if (type !== "mobile" && type !== "nationalId" && type !== "ewallet")
    throw new HttpError(503, "invalid-promptpay-type");
  let identifier;
  try {
    identifier = normalizePromptPayIdentifier({ type, value: required("COMMISSION_PROMPTPAY_VALUE") });
  } catch {
    throw new HttpError(503, "invalid-promptpay-value");
  }
  return { identifier, receiverNumber: required("COMMISSION_RECEIVER_ACCOUNT_NUMBER") };
}

async function verifySlip2Go(file: File, amountBaht: number) {
  const url = new URL(required("SLIP2GO_VERIFY_URL"));
  if (url.protocol !== "https:") throw new HttpError(503, "invalid-slip2go-url");
  const { identifier, receiverNumber } = promptPayConfig();
  const form = new FormData();
  form.set("file", file);
  form.set("payload", JSON.stringify({
    checkReceiver: [{
      accountType: { mobile: "02001", nationalId: "02003", ewallet: "02004" }[identifier.type],
      accountNumber: receiverNumber,
    }],
    checkAmount: { type: "eq", amount: amountBaht.toFixed(2) },
  }));
  let response: Response;
  try {
    response = await fetch(url, { method: "POST", headers: { Authorization: `Bearer ${required("SLIP2GO_API_SECRET")}` },
      body: form, signal: AbortSignal.timeout(15000), cache: "no-store" });
  } catch {
    throw new HttpError(503, "slip-verification-unavailable");
  }
  const body = slipResponse.safeParse(await response.json().catch(() => null));
  if (!body.success) throw new HttpError(503, "invalid-slip-verification-response");
  const code = body.data.code;
  if (response.status >= 500 || response.status === 401 || code.startsWith("401") ||
    code === "400400" || code === "200502")
    throw new HttpError(503, `slip2go-service:${code}`);
  if (!response.ok || code !== "200200")
    throw new HttpError(422, `slip-rejected:${code}`);
  const parsedSlip = verifiedSlip.safeParse(body.data.data);
  if (!parsedSlip.success) {
    const field = parsedSlip.error.issues[0]?.path[0] ?? "data";
    throw new HttpError(503, `invalid-slip-verification-response:${String(field)}`);
  }
  const slip = parsedSlip.data;
  return { referenceId: slip.referenceId, transRef: slip.transRef, amountBaht: slip.amount,
    transferredAt: new Date(slip.dateTime), providerData: body.data as Record<string, unknown> };
}

const slipOKResponse = z.object({
  success: z.literal(true),
  data: z.object({
    success: z.literal(true),
    transRef: z.string().min(1),
    amount: z.number().finite(),
    transTimestamp: z.string().optional(),
    transDate: z.string().optional(),
    transTime: z.string().optional(),
  }).passthrough(),
}).passthrough();

function slipOKTransferTime(data: z.infer<typeof slipOKResponse>["data"]): Date {
  let timestamp = data.transTimestamp;
  if (timestamp === undefined) {
    if (!/^\d{8}$/.test(data.transDate ?? "") || !/^\d{2}:\d{2}:\d{2}$/.test(data.transTime ?? ""))
      throw new HttpError(503, "invalid-slip-verification-response:transTimestamp");
    const date = data.transDate!;
    timestamp = `${date.slice(0, 4)}-${date.slice(4, 6)}-${date.slice(6, 8)}T${data.transTime}+07:00`;
  }
  // Require an explicit timezone and reject dates that JavaScript silently normalizes.
  const match = /^(\d{4}-\d{2}-\d{2})T(\d{2}:\d{2}:\d{2})(?:\.\d+)?(Z|[+-]\d{2}:\d{2})$/.exec(timestamp);
  const millis = Date.parse(timestamp);
  if (!match || !Number.isFinite(millis))
    throw new HttpError(503, "invalid-slip-verification-response:transTimestamp");
  const dateCheck = new Date(`${match[1]}T${match[2]}Z`);
  if (!Number.isFinite(dateCheck.getTime()) || dateCheck.toISOString().slice(0, 19) !== `${match[1]}T${match[2]}`)
    throw new HttpError(503, "invalid-slip-verification-response:transTimestamp");
  return new Date(millis);
}

async function verifySlipOK(file: File, amountBaht: number) {
  const form = new FormData();
  form.set("files", file);
  form.set("log", "true");
  form.set("amount", String(amountBaht));
  let response: Response;
  try {
    response = await fetch(`https://api.slipok.com/api/line/apikey/${required("SLIPOK_BRANCH_ID")}`, {
      method: "POST", headers: { "x-authorization": required("SLIPOK_API_KEY") },
      body: form, signal: AbortSignal.timeout(15000), cache: "no-store",
    });
  } catch { throw new HttpError(503, "slip-verification-unavailable"); }
  const body: unknown = await response.json().catch(() => null);
  const error = z.object({ code: z.number().int() }).safeParse(body);
  if (error.success) {
    const code = error.data.code;
    const unavailable = response.status >= 500 || response.status === 401 || response.status === 429 ||
      [1000, 1001, 1002, 1003, 1004, 1009, 1010, 1015].includes(code);
    throw new HttpError(unavailable ? 503 : 422, `slipok-${unavailable ? "service" : "rejected"}:${code}`);
  }
  if (!response.ok) throw new HttpError(503, "slip-verification-unavailable");
  const parsed = slipOKResponse.safeParse(body);
  if (!parsed.success) throw new HttpError(503, "invalid-slip-verification-response");
  const slip = parsed.data.data;
  return { referenceId: `slipok:${slip.transRef}`, transRef: slip.transRef, amountBaht: slip.amount,
    transferredAt: slipOKTransferTime(slip), providerData: parsed.data as Record<string, unknown> };
}

export async function verifyCommissionSlip(file: File, amountBaht: number, checkoutCreatedAt: Date) {
  const provider = await getCommissionSlipProvider();
  if (!slipProviderConfigured(provider)) throw new HttpError(503, "slip-provider-not-configured");
  const slip = provider === "slipok" ? await verifySlipOK(file, amountBaht) : await verifySlip2Go(file, amountBaht);
  if (slip.amountBaht !== amountBaht ||
    slip.transferredAt.getTime() < checkoutCreatedAt.getTime() - 120000 ||
    slip.transferredAt.getTime() > Date.now() + 120000)
    throw new HttpError(422, "slip-amount-or-date-mismatch");
  return { ...slip, provider };
}