dart_tdlib_gen/bin/tdlib_gen.dart

import 'dart:io';
import 'dart:typed_data';

import 'tl_scheme.dart';

import 'package:recase/recase.dart';
import 'package:path/path.dart' as path;

Future<void> main(List<String> arguments) async {
  if (arguments.length != 2) {
    print('The program must be run with 2 arguments:');
    print('  path to .tl schema');
    print('  path to Dart project source folder');
    exit(1);
  }

  final schemeFileStr = arguments[0];
  final srcFolderStr = arguments[1];

  if (! await File.fromUri(Uri.file(schemeFileStr)).exists()) {
    print("Schema file $schemeFileStr doesn't exist");
    exit(1);
  }
  if (! await Directory.fromUri(Uri.directory(srcFolderStr)).exists()) {
    print("Dart project source folder $srcFolderStr doesn't exist");
    exit(1);
  }

  print('.tl schema folder: $schemeFileStr');
  print('Dart project source folder: $srcFolderStr');
  print('');

  print('Reading .tl schema file...');
  final schemeFileContents = await File.fromUri(Uri.file(schemeFileStr)).readAsString();
  print('Parsing .tl schema file...');
  final scheme = TlSchema.parse(schemeFileContents);
  
  print('Generating...');
  
  final baseFile = File.fromUri(Uri.file(path.join(srcFolderStr, 'base.dart'))); 
  final abstractFile = File.fromUri(Uri.file(path.join(srcFolderStr, 'abstract.dart'))); 
  final objFile = File.fromUri(Uri.file(path.join(srcFolderStr, 'obj.dart'))); 
  final fnFile = File.fromUri(Uri.file(path.join(srcFolderStr, 'fn.dart'))); 
  await baseFile.writeAsString(makeBaseFile(scheme));
  await abstractFile.writeAsString(makeAbstractFile(scheme));
  await objFile.writeAsString(makeObjFile(scheme));
  await fnFile.writeAsString(makeFnFile(scheme));

  print('Done!');
}

String findDartType(
  String type, 
  TlSchema scheme, 
  {String abstractPrefix = 'a.',
  String objectPrefix = 'o.',
  String functionPrefix = 'f.',
  bool noNullCheck = false}
) {
  if (type.startsWith('vector<')) {
    final tmp1 = type.replaceFirst('vector<', '');
    final tmp2 = tmp1.substring(0, tmp1.length - 1);
    final innerType = findDartType(
      tmp2, 
      scheme,
      abstractPrefix: abstractPrefix,
      functionPrefix: functionPrefix,
      objectPrefix: objectPrefix,
    );
    return 'List<$innerType>';
  }

  final predefined = {
    'double': 'double',
    'string': 'String',
    'int32': 'int',
    'int53': 'int',
    'int64': 'int',
    'bytes': 'Uint8List',
    'Bool': 'bool',
  };

  if (predefined.containsKey(type)) {
    return predefined[type]!;
  }

  final result = scheme.findType(type);
  if (result == null) {
    throw Exception("Couldn't find type: $type");
  }

  if (result is TlSchemeAbstractClass) {
    final name = abstractPrefix + result.name.pascalCase;
    if (noNullCheck) {
      return name;
    }
    else {
      return '$name?';
    }
  }
  else if (result is TlSchemeObject) {
    final name = objectPrefix + result.name.pascalCase;
    if (noNullCheck) {
      return name;
    }
    else {
      return '$name?';
    }
  }
  else if (result is TlSchemeFunction) {
    final name = functionPrefix + result.name.pascalCase;
    if (noNullCheck) {
      return name;
    }
    else {
      return '$name?';
    }
  }
  else {
    throw Exception('Unknown tl object: $result');
  }
}

String findToJsonHandling(
  String type, 
  String varName, 
  TlSchema scheme,
  ) {
  if (type.startsWith('vector<')) {
    final tmp1 = type.replaceFirst('vector<', '');
    final tmp2 = tmp1.substring(0, tmp1.length - 1);
    late String newVarName;
    if (varName.startsWith('_e')) {
      final num = int.parse(varName.substring(2));
      newVarName = '_e${num + 1}';
    }
    else {
      newVarName = '_e1';
    }
    final innerHandling = findToJsonHandling(
      tmp2, 
      newVarName,
      scheme,
    );
    return '$varName.map(($newVarName) => $innerHandling).toList(growable: false)';
  }

  final predefined = {
    'double': 'double',
    'string': 'String',
    'int32': 'int',
    'int53': 'int',
    'Bool': 'bool',
  };
  if (predefined.containsKey(type)) {
    return varName;
  }
  else if (type == 'int64') {
    return '$varName.toString()';
  }
  else if (type == 'bytes') {
    return 'base64.encode($varName)';
  }
  else {
    return '$varName?.toJson()';
  }
}

String findFromJsonHandling(
  String type, 
  String keyName, 
  TlSchema scheme,
  {String abstractPrefix = 'a.',
  String objectPrefix = 'o.',
  String functionPrefix = 'f.',
  String? varNameInsteadOfKeyName}
  ) {
  final varAccess = varNameInsteadOfKeyName ?? "json['$keyName']";
  if (type.startsWith('vector<')) {
    final tmp1 = type.replaceFirst('vector<', '');
    final tmp2 = tmp1.substring(0, tmp1.length - 1);
    // final innerType = findDartType(tmp2, scheme, abstractPrefix: abstractPrefix, functionPrefix: functionPrefix, objectPrefix: objectPrefix);
    final innerHandler = findFromJsonHandling(
      tmp2,
      '', 
      scheme, 
      abstractPrefix: abstractPrefix,
      functionPrefix: functionPrefix,
      objectPrefix: objectPrefix,
      varNameInsteadOfKeyName: 'e',
    );
    final innerType = findDartType(
      tmp2,
      scheme,
      abstractPrefix: abstractPrefix,
      functionPrefix: functionPrefix,
      objectPrefix: objectPrefix,
    );
    return '$varAccess == null ? <$innerType>[] : ($varAccess as List<dynamic>).map((e) => ($innerHandler)).toList(growable: false)';
  }

  final predefined = {
    'double': 'double',
    'string': 'String',
    'int32': 'int',
    'int53': 'int',
    'Bool': 'bool',
  };
  final predefinedDefault = {
    'double': '0',
    'string': "''",
    'int32': '0',
    'int53': '0',
    'Bool': 'false',
  };

  if (predefined.containsKey(type)) {
    return '($varAccess as ${predefined[type]}?) ?? ${predefinedDefault[type]}';
  }
  else if (type == 'int64') {
    return "int.parse($varAccess ?? '0')";
  }
  else if (type == 'bytes') {
    return '$varAccess == null ? Uint8List(0) : base64.decode($varAccess)';
  }
  else {
    return 'b.TdBase.fromJson($varAccess) as ${findDartType(type, scheme, abstractPrefix: abstractPrefix, functionPrefix: functionPrefix, objectPrefix: objectPrefix)}';
  }
}

String makeBaseFile(TlSchema scheme) {
  var result = r"""
import 'obj.dart' as o;

abstract class TdBase {
  Map<String, dynamic> toJson();

  @override
  String toString() {
    return 'td::TdBase()';
  }

  static final constructors = {
""";

  for (final o in scheme.objects) {
    final normName = o.name.pascalCase;
    result += '''
    '${o.name}': (json) => o.$normName.fromJson(json),
''';
  }

  result += """
  };

  static TdBase? fromJson(Map<String, dynamic>? json) {
    if (json == null) {
      return null;
    }
    final type = json['@type'] as String;
    return constructors[type]!(json);
  }
}
""";
  return result;
}
String makeAbstractFile(TlSchema scheme) {
  var result = r"""
import 'dart:core' as dc show Error;

import 'base.dart' as b;
import 'obj.dart' as o;

typedef Func1<T, TResult> = TResult Function(T);

class MatchError extends dc.Error {}

""";

  for (final ac in scheme.abstractClasses) {
    final normName = ac.name.pascalCase;
    final implementors = scheme.objects.where((element) => element.baseType == ac.name).toList(growable: false);
    result += '''
/// ${ac.doc}
abstract class $normName extends b.TdBase {
  TResult match<TResult>({
''';
    for (final impl in implementors) {
      final iNormName = impl.name.pascalCase;
      result += '''
    Func1<o.$iNormName, TResult>? is$iNormName,
''';
    }
    result += '''
    Func1<$normName, TResult>? otherwise,
  }) {
    if (false) {} // ignore: dead_code
''';
    for (final impl in implementors) {
      final iNormName = impl.name.pascalCase;
      result += '''
    else if (this is o.$iNormName) {
      if (is$iNormName != null) {
        return is$iNormName(this as o.$iNormName);
      }
      else if (otherwise != null) {
        return otherwise(this);
      }
    }
''';
    }
    result += '''
    else if (otherwise != null) {
      otherwise(this);
    }
    else if (TResult == null.runtimeType) {
      return null as TResult;
    }
    throw MatchError();
  }
}

''';
  }

  return result;
}

String makeObjFile(TlSchema scheme) {
  var result = r"""
import 'dart:convert';
import 'dart:typed_data';

import 'base.dart' as b;
import 'abstract.dart' as a;

""";

  for (final o in scheme.objects) {
    final normName = o.name.pascalCase;
    final baseName = findDartType(o.baseType, scheme, objectPrefix: '', noNullCheck: true);
    result += '''
/// ${o.doc}
class $normName extends $baseName {
''';

    for (final param in o.parameters) {
      final normParamName = param.name.camelCase;
      final paramType = findDartType(param.type, scheme, objectPrefix: '');
      result += '''
  /// ${param.doc}
  final $paramType $normParamName;
''';
    }

    // Constructor
    if (o.parameters.isNotEmpty) {
      result += '''

  $normName({
''';
      for (final param in o.parameters) {
        final normParamName = param.name.camelCase;
        result += '''
    required this.$normParamName,
''';
      }
      result += '''
  });

''';
    }
    else {
      result += '''
  $normName();

''';
    }
    
    // toString
    result += '''
  @override
  String toString() {
    var s = 'td::$normName(';

    // Params
    final params = <String>[];
''';
    for (final param in o.parameters) {
      final normParamName = param.name.camelCase;
      result += '''
    params.add($normParamName.toString());
''';
    }

    result += '''
    s += params.join(', ');

    s += ')';

    return s;
  }
''';

    // toJson
    result += '''
  @override
  Map<String, dynamic> toJson() => {
    '@type': '${o.name}',
''';
    for (final param in o.parameters) {
      final normParamName = param.name.camelCase;
      final jsonHandling = findToJsonHandling(param.type, normParamName, scheme);
      result += '''
    '${param.name}': $jsonHandling,
''';
    }
    result += '''
  };

''';

    // fromJson
    result += '''
  factory $normName.fromJson(Map<String, dynamic> json) => $normName(
''';
    for (final param in o.parameters) {
      final normParamName = param.name.camelCase;
      final handle = findFromJsonHandling(param.type, param.name, scheme, objectPrefix: '');
      result += '''
    $normParamName: $handle,
''';
    }
    result += '''
  );
''';

    result += '''
}

''';
  }

  return result;
}

String makeFnFile(TlSchema scheme) {
  var result = r"""
import 'dart:convert';
import 'dart:typed_data';

import 'base.dart' as b;
import 'abstract.dart' as a;
import 'obj.dart' as o;

abstract class TdFunction extends b.TdBase {}

""";

  for (final f in scheme.functions) {
    final normName = f.name.pascalCase;
    result += '''
/// ${f.doc}
class $normName extends TdFunction {
''';

    // Parameters
    for (final param in f.parameters) {
      final pNormName = param.name.camelCase;
      final pType = findDartType(param.type, scheme, functionPrefix: '');
      result += '''
  /// ${param.doc}
  final $pType $pNormName;
''';
    }

    // Constructor
    if (f.parameters.isEmpty) {
      result += '''
  $normName();

''';
    }
    else {
      result += '''

  $normName({
''';
      for (final param in f.parameters) {
        final pNormName = param.name.camelCase;
        result += '''
    required this.$pNormName,
''';
      }
      result += '''
  });

''';
    }
    
    // toString
    result += '''
  @override
  String toString() {
    var s = 'td::$normName(';

    // Params
    final params = <String>[];
''';
    for (final param in f.parameters) {
      final normParamName = param.name.camelCase;
      result += '''
    params.add($normParamName.toString());
''';
    }

    result += '''
    s += params.join(', ');

    s += ')';

    return s;
  }
''';

    // toJson
    result += '''
  @override
  Map<String, dynamic> toJson() => {
    '@type': '${f.name}',
''';
    for (final param in f.parameters) {
      final pNormName = param.name.camelCase;
      final jsonHandling = findToJsonHandling(param.type, pNormName, scheme);
      result += '''
    '${param.name}': $jsonHandling,
''';
    }
    result += '''
  };

''';

    // fromJson
    result += '''
  factory $normName.fromJson(Map<String, dynamic> json) => $normName(
''';
    for (final param in f.parameters) {
      final normParamName = param.name.camelCase;
      final handle = findFromJsonHandling(param.type, param.name, scheme);
      result += '''
    $normParamName: $handle,
''';
    }
    result += '''
  );
''';

    result += '''
}

''';
  }

  return result;
}