import {
  loadFile,
  // @ts-expect-error - magicast is ESM and TS complains about that. It works though
} from 'magicast';
import * as fs from 'fs';

import { findFile } from '../../utils/ast-utils';

// Try to find the Express server implementation that contains `createRequestHandler` from `@remix-run/express`
export async function findCustomExpressServerImplementation() {
  const possiblePaths = [
    'server',
    'server/index',
    'app/server',
    'app/server/index',
  ];

  for (const filePath of possiblePaths) {
    const filename = findFile(filePath);

    if (!filename) {
      continue;
    }

    const fileStat = fs.statSync(filename);

    if (!fileStat.isFile()) {
      continue;
    }

    const fileMod = await loadFile(filename);
    const createRequestHandlerImport = fileMod.imports.$items.find(
      (imp) =>
        imp.from === '@remix-run/express' &&
        imp.imported === 'createRequestHandler',
    );

    if (createRequestHandlerImport) {
      return filename;
    }
  }

  return null;
}