const path = require('path');

const configs = {
  cjs: {
    output: {
      path: path.resolve(__dirname, 'dist'),
      filename: 'windychen-utils.cjs.js',
      libraryTarget: 'commonjs2',
    },
  },
  esm: {
    experiments: { outputModule: true },
    output: {
      path: path.resolve(__dirname, 'dist'),
      filename: 'windychen-utils.esm.js',
      libraryTarget: 'module',
    },
  },
  umd: {
    output: {
      path: path.resolve(__dirname, 'dist'),
      filename: 'windychen-utils.js',
      library: { name: 'WindychenUtils', type: 'umd', export: 'default' },
    },
  },
};

module.exports = (env = {}) => {
  const format = env.format;

  if (!format || format === 'all') {
    return Object.keys(configs).map((key) => ({
      name: key,
      entry: './index.js',
      ...configs[key],
    }));
  }

  if (!configs[format]) {
    throw new Error(`不支持的格式: ${format}，可选值: cjs, esm, umd`);
  }

  return { entry: './index.js', ...configs[format] };
};