const webpack = require('webpack');
const WorkBoxPlugin = require('workbox-webpack-plugin');

// Fail the build loudly when an API base is missing, instead of emitting a
// bundle in which every request URL is the string "undefined/orders/..." —
// a relative path that silently resolves against whatever host the console is
// served from. That produced a deploy where the API base appeared to be the
// front-end's own origin. Only enforced for production builds; `npm start`
// is left alone.
const REQUIRED_PROD_ENV = ['REACT_APP_URL', 'REACT_APP_URL2', 'REACT_APP_URL3'];

function assertRequiredEnv() {
  if (process.env.NODE_ENV !== 'production') return;
  const missing = REQUIRED_PROD_ENV.filter((k) => !process.env[k]);
  if (!missing.length) return;
  throw new Error(
    `\n\nBuild aborted — missing required environment variable(s): ${missing.join(', ')}.\n` +
      'Define them in .env (loaded by every build) or build via `npm run build:staging` / `build:dev`,\n' +
      'which load .env.staging / .env.development through env-cmd.\n'
  );
}

module.exports = function override(config) {
  assertRequiredEnv();

  config.resolve.fallback = {
    process: require.resolve('process/browser'),
    // zlib: require.resolve('browserify-zlib'),
    stream: require.resolve('stream-browserify'),
    crypto: require.resolve('crypto-browserify'),
    util: require.resolve('util'),
    buffer: require.resolve('buffer')
    // asset: require.resolve('assert')
  };

  // https://stackoverflow.com/questions/69135310/workaround-for-cache-size-limit-in-create-react-app-pwa-service-worker
  config.plugins.forEach((plugin) => {
    if (plugin instanceof WorkBoxPlugin.InjectManifest) {
      plugin.config.maximumFileSizeToCacheInBytes = 50 * 1024 * 1024;
    }
  });

  // Disable ESLint plugin in Webpack so lint warnings never block compilation
  config.plugins = config.plugins.filter(
    (plugin) => plugin.constructor && plugin.constructor.name !== 'ESLintWebpackPlugin'
  );

  config.plugins = [
    ...config.plugins,
    new webpack.ProvidePlugin({
      process: 'process/browser.js',
      Buffer: ['buffer', 'Buffer']
    })
  ];

  return config;
};