import axios from 'axios';
import { fileURLToPath } from 'url';

const FRANKFURTER_API = 'https://api.frankfurter.app';

async function fetch(startDate = null, endDate = null) {
  try {
    const currentDate = new Date();

    if (!startDate) {
      startDate = new Date(currentDate);
      startDate.setDate(startDate.getDate() - 30);
      startDate = startDate.toISOString().split('T')[0];
    }

    if (!endDate) {
      endDate = currentDate.toISOString().split('T')[0];
    }

  console.log('正在获取人民币美元汇率数据...');
    console.log(`时间范围: ${startDate} 至 ${endDate}`);
    console.log(`数据源: Frankfurter API (欧洲央行汇率数据)`);

    const response = await axios.get(`${FRANKFURTER_API}/${startDate}..${endDate}`, {
      params: {
        from: 'USD',
        to: 'CNY'
      },
      headers: {
        'Accept': 'application/json'
      }
    });

    const data = response.data;
    console.log(`\nAPI状态: ${response.status}`);
    console.log(`数据条数: ${Object.keys(data.rates || {}).length}`);

    const allRates = [];

    if (data.rates) {
      for (const [date, rateObj] of Object.entries(data.rates)) {
        const rateValue = rateObj.CNY;
        allRates.push({
          date: date,
          currency: 'USD/CNY',
          centerPrice: parseFloat(rateValue.toFixed(4)),
          sellingRate: parseFloat(rateValue.toFixed(4)),
          buyingRate: parseFloat(rateValue.toFixed(4)),
          source: '欧洲央行 (Frankfurter API)',
          fetchTime: new Date().toISOString()
        });
      }
    }

    allRates.sort((a, b) => a.date.localeCompare(b.date));

    console.log(`\n共获取到 ${allRates.length} 条汇率数据`);

    return {
      currency: 'USD/CNY',
      startDate,
      endDate,
      count: allRates.length,
      data: allRates,
      fetchTime: new Date().toISOString(),
      note: '数据来源: 欧洲央行, 通过 Frankfurter API 提供'
    };

  } catch (error) {
    console.error('获取汇率数据失败:', error.message);
    if (error.response) {
      console.error(`HTTP状态码: ${error.response.status}`);
      console.error(`响应数据:`, error.response.data);
    }
    throw error;
  }
}

export {
  fetch
};

const isMainModule = () => {
  const currentFile = fileURLToPath(import.meta.url);
  const mainFile = process.argv[1];
  return currentFile === mainFile;
};

function parseCommandLineArgs() {
  const args = process.argv.slice(2);
  let startDate = null;
  let endDate = null;

  for (let i = 0; i < args.length; i++) {
    if (args[i] === '--start' && i + 1 < args.length) {
      startDate = args[i + 1];
      i++;
    } else if (args[i] === '--end' && i + 1 < args.length) {
      endDate = args[i + 1];
      i++;
    } else if (args[i] === '--help') {
      console.log('使用方法:');
      console.log('  bun usd-cny-rate.fetcher.js [选项]');
      console.log('');
      console.log('选项:');
      console.log('  --start YYYY-MM-DD  指定开始日期（默认：30天前）');
      console.log('  --end YYYY-MM-DD    指定结束日期（默认：今天）');
      console.log('  --help              显示帮助信息');
      console.log('');
      console.log('示例:');
      console.log('  bun usd-cny-rate.fetcher.js');
      console.log('  bun usd-cny-rate.fetcher.js --start 2024-01-01 --end 2024-01-31');
      process.exit(0);
    }
  }

  return { startDate, endDate };
}

if (isMainModule()) {
  const { startDate, endDate } = parseCommandLineArgs();

  console.log('='.repeat(50));
  console.log('人民币美元汇率获取脚本');
  console.log('='.repeat(50));

  fetch(startDate, endDate)
    .then(result => {
      console.log('\n' + '='.repeat(50));
      console.log('获取结果:');
      console.log(`  货币对: ${result.currency}`);
      console.log(`  开始日期: ${result.startDate}`);
      console.log(`  结束日期: ${result.endDate}`);
      console.log(`  数据条数: ${result.count}`);
      console.log(`  获取时间: ${result.fetchTime}`);
      console.log(`  提示: ${result.note}`);
      if (result.count > 0) {
        console.log('-'.repeat(50));
        console.log('汇率数据:');
        result.data.forEach(item => {
          console.log(`  ${item.date}  中间价: ${item.centerPrice}`);
        });
      }
      console.log('='.repeat(50));
    })
    .catch(error => {
      console.error('执行失败:', error);
      process.exit(1);
    });
}