import { createHash, randomUUID, timingSafeEqual } from "crypto";
import { eq } from "drizzle-orm";
import { db } from "../db";
import { billingPayments } from "@shared/schema";
import type {
  PaymentProvider,
  CreatePaymentParams,
  PaymentCreated,
  WebhookVerification,
  PaymentStatusInfo,
  PaymentStatus,
} from "./payment-provider";

// Тестовый провайдер: платежи создаются локально в статусе pending,
// подтверждение — через кнопку «Подтвердить (тест)» или настоящий webhook
// с подписью sha256(externalId + ':' + secret) в заголовке x-mock-signature.

const DEFAULT_SECRET = "mock-payment-dev-secret";
const WEBHOOK_STATUSES: PaymentStatus[] = ['pending', 'succeeded', 'canceled'];

export function getMockSecret(): string {
  return process.env.MOCK_PAYMENT_SECRET || DEFAULT_SECRET;
}

export function signMockWebhook(externalId: string): string {
  return createHash("sha256").update(`${externalId}:${getMockSecret()}`).digest("hex");
}

export class MockPaymentProvider implements PaymentProvider {
  readonly name = "mock";

  async createPayment(_params: CreatePaymentParams): Promise<PaymentCreated> {
    return {
      externalId: `mock_${randomUUID()}`,
      status: 'pending',
    };
  }

  verifyWebhook(headers: Record<string, unknown>, body: unknown): WebhookVerification {
    const payload = (body ?? {}) as { externalId?: unknown; status?: unknown; idempotencyKey?: unknown };
    const externalId = typeof payload.externalId === "string" ? payload.externalId : undefined;
    if (!externalId) {
      return { valid: false, error: "Поле externalId отсутствует" };
    }

    const signature = typeof headers["x-mock-signature"] === "string" ? headers["x-mock-signature"] : "";
    const expected = signMockWebhook(externalId);
    const sigBuf = Buffer.from(signature);
    const expBuf = Buffer.from(expected);
    if (sigBuf.length !== expBuf.length || !timingSafeEqual(sigBuf, expBuf)) {
      return { valid: false, externalId, error: "Неверная подпись webhook" };
    }

    if (!WEBHOOK_STATUSES.includes(payload.status as PaymentStatus)) {
      return { valid: false, externalId, error: "Неизвестный статус платежа" };
    }

    return {
      valid: true,
      externalId,
      status: payload.status as PaymentStatus,
      idempotencyKey: typeof payload.idempotencyKey === "string" ? payload.idempotencyKey : undefined,
    };
  }

  // Статус берём из локальной таблицы платежей — внешней системы у mock нет.
  async getPaymentStatus(externalId: string): Promise<PaymentStatusInfo> {
    const [row] = await db
      .select({ status: billingPayments.status })
      .from(billingPayments)
      .where(eq(billingPayments.externalId, externalId))
      .limit(1);
    if (!row) {
      throw new Error(`Платёж не найден: ${externalId}`);
    }
    return { externalId, status: row.status as PaymentStatus };
  }
}