#!/usr/bin/env python
# Copyright 2018 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import argparse
import os
import re
import sys


def main():
    parser = argparse.ArgumentParser(
        sys.argv[0], description="Generate main file for Fuchsia dart test")
    parser.add_argument(
        "--out", help="Path to .dart file to generate", required=True)
    parser.add_argument(
        "--main-package", help="The main package", required=True)
    parser.add_argument(
        "--main", help="The name of the main file", required=True)

    args = parser.parse_args()

    print(args.out)
    outfile = open(args.out, 'w')

    # Ignores relative lib imports due to a few modules that complain about
    # this. It is also possible that a future may be unawaited given that main
    # may not always be synchronous across all functions.
    outfile.write('''// Generated by ''')
    outfile.write(os.path.basename(__file__))
    outfile.write(
        '''


// ignore_for_file: avoid_relative_lib_imports
import 'dart:async';

import 'package:flutter_driver/driver_extension.dart';
import 'package:flutter/services.dart';
''')
    outfile.write(
        "import 'package:%s/%s' as flutter_app_main;\n" %
        (args.main_package, args.main))
    outfile.write(
        '''
void main(List<String> args) async {
  // TODO(awdavies): Use the logger instead.
  print('Overriding app main method because flutter_driver_extendable '
      'is enabled in the build file');

  try {
    // Enables Flutter Driver VM service extension
    //
    // This extension is required for tests that use package:flutter_driver
    // to drive applications from a separate process.
    final handler = OptionalMethodChannel('flutter_driver/handler');
    enableFlutterDriverExtension(handler: (String data) async {
      return handler.invokeMethod(data);
    });

    // TODO(awdavies): Use the logger instead.
    print('flutter driver extensions enabled.');
    //ignore: avoid_catches_without_on_clauses
  } catch (e) {
    // TODO(awdavies): Use the logger instead.
    // Noop.
    print('flutter driver extensions not enabled. $e');
  }

  // Execute the main method of the app under test
  try {
    var res = (flutter_app_main.main as dynamic)(args);
    if (res != null && res is Future) {
      await res;
    }
  } on NoSuchMethodError catch(_) {
    var res = (flutter_app_main.main as dynamic)();
    if (res != null && res is Future) {
      await res;
    }
  }
}
''')
    outfile.close()


if __name__ == '__main__':
    main()