import crypto from 'crypto';

const config = {
  merchantId: process.env.PAYUNI_MERCHANT_ID!,
  hashKey: process.env.PAYUNI_HASH_KEY!,
  hashIV: process.env.PAYUNI_HASH_IV!,
  isTest: process.env.PAYUNI_TEST_MODE === 'true',
};

function getQueryEndpoint(): string {
  return config.isTest
    ? 'https://sandbox-api.payuni.com.tw/api/query'
    : 'https://api.payuni.com.tw/api/query';
}

function encrypt(data: string): string {
  const key = Buffer.from(config.hashKey.padEnd(32, '\0').slice(0, 32), 'utf8');
  const iv = Buffer.from(config.hashIV.padEnd(16, '\0').slice(0, 16), 'utf8');
  
  const cipher = crypto.createCipheriv('aes-256-cbc', key, iv);
  let encrypted = cipher.update(data, 'utf8', 'hex');
  encrypted += cipher.final('hex');
  return encrypted;
}

function generateHashInfo(encryptInfo: string): string {
  return crypto
    .createHash('sha256')
    .update(encryptInfo)
    .digest('hex')
    .toUpperCase();
}

async function queryTrade(orderNo: string): Promise<{
  success: boolean;
  data?: any;
  error?: string;
}> {
  try {
    const queryData = {
      MerID: config.merchantId,
      MerTradeNo: orderNo,
    };
    
    const queryString = new URLSearchParams(queryData).toString();
    const encryptInfo = encrypt(queryString);
    const hashInfo = generateHashInfo(encryptInfo);
    
    const response = await fetch(getQueryEndpoint(), {
      method: 'POST',
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
      body: new URLSearchParams({
        MerID: config.merchantId,
        EncryptInfo: encryptInfo,
        HashInfo: hashInfo,
      }),
    });
    
    const result = await response.json();
    
    return {
      success: result.Status === 'SUCCESS',
      data: result,
    };
  } catch (error) {
    return {
      success: false,
      error: error instanceof Error ? error.message : 'Query failed',
    };
  }
}

// 使用範例
const result = await queryTrade('ORDER-123');
if (result.success) {
  console.log('交易狀態:', result.data.TradeStatus);
}