rewrite_imports.dart

import 'dart:io';

import 'package:file/local.dart';
import 'package:glob/glob.dart';
import 'package:path/path.dart' as path;

void main(List<String> args) async {
  assert(args.length == 1);
  await updateRelativeImportsInPackage(args[0]);
}

Future<void> updateRelativeImportsInPackage(String packagePath) async {
  final globPattern = Glob('**.dart');
  final libPath = path.join(packagePath, 'lib');

  final files = await globPattern
      .listFileSystem(
        const LocalFileSystem(),
        root: libPath,
      )
      .toList();

  for (final file in files) {
    final filePath = file.path;
    await updateImportsInFile(
      filePath,
      (ref) {
        if (!isImportRelative(ref)) return ref;
        return relativeImportToPackageImport(
          filePath: filePath,
          ref: ref,
          libPath: libPath,
        );
      },
    );
  }
}

bool isImportRelative(String ref) {
  if (ref.startsWith('package:')) return false;
  return ref.contains('..');
}

String relativeImportToPackageImport({
  required String ref,
  required String filePath,
  required String libPath,
}) {
  assert(isImportRelative(ref));
  final fullPath = path.join(path.dirname(filePath), ref);
  final libName = path.basename(path.dirname(libPath));
  final pathRelativeToLibDir = path.relative(fullPath, from: libPath);
  // don't wanna look into why I need to do this replacement of ../ at the start
  return 'package:$libName/' + pathRelativeToLibDir.replaceFirst('../', '');
}

final importRegex = RegExp("import '(.+)';");
Future<void> updateImportsInFile(
    String filePath, String Function(String) update) {
  return updateFileContents(filePath, (code) {
    return code.replaceAllMapped(importRegex, (match) {
      final importRef = match.group(1)!;
      final newImportRef = update(importRef);
      return "import '${newImportRef}';";
    });
  });
}

Future<void> updateFileContents(
    String filePath, String Function(String) update) async {
  final file = File(filePath);
  final fileContents = await file.readAsString();
  final newFileContents = update(fileContents);
  await file.writeAsString(newFileContents, mode: FileMode.write);
  print('UPDATED: $filePath');
  // print(newFileContents.split('\n').take(25).join('\n'));
}