const { nodeResolve } = require('@rollup/plugin-node-resolve');
const commonjs = require('@rollup/plugin-commonjs');
const babel = require('@rollup/plugin-babel');
const fs = require('fs');
const path = require('path');

// each file in utils
const utilsDir = path.join(__dirname, 'src', 'utils');
const utilsFiles = fs.readdirSync(utilsDir).filter((file) => file.endsWith('.js') && file !== 'index.js');

const srcDir = path.join(__dirname, 'src');
const hasIndexFiles = [];
const srcItems = fs.readdirSync(srcDir);
srcItems.forEach((item) => {
  const itemPath = path.join(srcDir, item);
  if (fs.statSync(itemPath).isDirectory()) {
    const _Files = fs.readdirSync(itemPath).filter((file) => file.endsWith('.js') && file === 'index.js');
    if (_Files.length > 0) {
      hasIndexFiles.push(item);
    }
  }
});
const indexEntries = [];
hasIndexFiles.forEach(subDir => {
  indexEntries.push(...generateEntries(['index.js'], subDir));
});
// src/index.js
indexEntries.push(...generateEntries(['index.js']));

function generateEntries(files, parentDir) {
  // Create entries with both ESM and CJS outputs
  const _Entries = files.flatMap((file) => {
    const moduleName = path.basename(file, '.js');

    return [
      // ESM output
      {
        input: parentDir ? `src/${parentDir}/${file}` : `src/${file}`,
        output: {
          file: parentDir ? `build/esm/${parentDir}/${moduleName}.js` : `build/esm/${moduleName}.js`,
          format: 'es',
          exports: 'named',
        },
        external: [],
        plugins: [
          nodeResolve({
            preferBuiltins: false,
          }),
          commonjs(),
          babel({
            babelHelpers: 'bundled',
            presets: [
              [
                '@babel/preset-env',
                {
                  modules: false,
                  targets: '> 0.25%, not dead',
                  exclude: ['transform-parameters'],
                },
              ],
            ],
            exclude: 'node_modules/**',
          }),
        ],
      },
      // CJS output
      {
        input: parentDir ? `src/${parentDir}/${file}` : `src/${file}`,
        output: {
          file: parentDir ? `build/cjs/${parentDir}/${moduleName}.js` : `build/cjs/${moduleName}.js`,
          format: 'cjs',
          exports: 'named',
        },
        external: [],
        plugins: [
          nodeResolve({
            preferBuiltins: false,
          }),
          commonjs(),
          babel({
            babelHelpers: 'bundled',
            presets: [
              [
                '@babel/preset-env',
                {
                  modules: false,
                  targets: 'node 14',
                },
              ],
            ],
            exclude: 'node_modules/**',
          }),
        ],
      },
    ];
  });
  return _Entries;
}

module.exports = [
  // ...utilsEntries
  ...generateEntries(utilsFiles, 'utils'),
  ...indexEntries,
];