import { createHash, createHmac } from 'node:crypto';
import { BadRequestException, HttpException } from '@nestjs/common';
import type { LookupFunction } from 'node:net';

/** Keep the validated address pinned while honoring Node's all-address lookup contract. */
export function pinnedWebhookLookup(address: string, family: number): LookupFunction {
  return (_hostname, options, callback) => {
    if (options.all) callback(null, [{ address, family }]);
    else callback(null, address, family);
  };
}

/** Validate calendar components before Date can normalize an impossible day. */
export function parseOpenApiDate(value: string): Date {
  const parts = /^(\d{4})-(\d{2})-(\d{2})(?:T(\d{2}):(\d{2})(?::(\d{2})(?:\.(\d{1,3}))?)?(Z|[+-]\d{2}:\d{2}))?$/.exec(
    value,
  );
  if (parts) {
    const year = Number(parts[1]);
    const month = Number(parts[2]);
    const day = Number(parts[3]);
    const leap = year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0);
    const days = [31, leap ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
    const zone = parts[8];
    const validZone = !zone || zone === 'Z' || (Number(zone.slice(1, 3)) < 24 && Number(zone.slice(4)) < 60);
    const date = new Date(value);
    if (
      month >= 1 &&
      month <= 12 &&
      day >= 1 &&
      day <= days[month - 1] &&
      Number(parts[4] ?? 0) < 24 &&
      Number(parts[5] ?? 0) < 60 &&
      Number(parts[6] ?? 0) < 60 &&
      validZone &&
      Number.isFinite(date.getTime())
    )
      return date;
  }
  throw new BadRequestException({ code: 'TIME_RANGE_INVALID', message: '时间必须为有效的ISO8601日期或带时区时间' });
}

export type OpenApiProblemResponse = {
  setHeader(name: string, value: string): void;
  status(code: number): { type(value: string): { send(body: unknown): void } };
};

export function sendOpenApiProblem(
  response: OpenApiProblemResponse,
  requestId: string,
  failure: { status: number; code: string; message: string },
) {
  response.setHeader('X-Request-Id', requestId);
  response
    .status(failure.status)
    .type('application/problem+json')
    .send({
      type: `https://cmpp-platform.local/problems/${failure.code.toLowerCase()}`,
      title: failure.status >= 500 ? 'Internal Server Error' : 'Request failed',
      status: failure.status,
      code: failure.code,
      detail: failure.message,
      requestId,
    });
}

/** v1 compatibility: an absent parsed body hashes as {}, never try alternate hashes. */
export function openApiBodyHash(rawBody: Buffer | undefined, body: unknown) {
  return createHash('sha256')
    .update(rawBody ?? Buffer.from(JSON.stringify(body ?? {})))
    .digest('hex');
}

export function openApiSignature(
  secret: string,
  method: string,
  path: string,
  timestamp: string,
  nonce: string,
  bodyHash: string,
) {
  return createHmac('sha256', secret)
    .update([method.toUpperCase(), path.split('?')[0], timestamp, nonce, bodyHash].join('\n'))
    .digest('hex');
}

export function publicOpenApiFailure(error: unknown) {
  if (!(error instanceof HttpException) || error.getStatus() >= 500) {
    return { status: 500, code: 'INTERNAL_ERROR', message: 'Internal server error' };
  }
  const value = error.getResponse();
  const object = typeof value === 'object' && value ? (value as Record<string, unknown>) : {};
  const message = object.message ?? value;
  return {
    status: error.getStatus(),
    code: String(object.code ?? 'REQUEST_FAILED'),
    message: Array.isArray(message) ? message.join('；') : String(message),
  };
}

export function webhookJobId(deliveryId: string, attemptNo: number) {
  return `webhook-${createHash('sha256').update(deliveryId).digest('hex')}-${attemptNo}`;
}