// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:_fe_analyzer_shared/src/scanner/token.dart';
import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
import 'package:analysis_server/src/services/correction/fix.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/src/dart/ast/utilities.dart';
import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
import 'package:analyzer_plugin/utilities/range_factory.dart';

class MakeVariableNotFinal extends CorrectionProducer {
  String _variableName;

  @override
  List<Object> get fixArguments => [_variableName];

  @override
  FixKind get fixKind => DartFixKind.MAKE_VARIABLE_NOT_FINAL;

  @override
  Future<void> compute(ChangeBuilder builder) async {
    var node = this.node;
    if (node is SimpleIdentifier &&
        node.staticElement is LocalVariableElement) {
      LocalVariableElement variable = node.staticElement;
      var id = NodeLocator(variable.nameOffset).searchWithin(unit);
      var decl = id?.parent;
      if (decl is VariableDeclaration &&
          decl.parent is VariableDeclarationList) {
        VariableDeclarationList declarationList = decl.parent;
        var keywordToken = declarationList.keyword;
        if (declarationList.variables.length == 1 &&
            keywordToken.keyword == Keyword.FINAL) {
          await builder.addDartFileEdit(file, (builder) {
            if (declarationList.type != null) {
              builder.addDeletion(
                  range.startStart(keywordToken, declarationList.type));
            } else {
              builder.addSimpleReplacement(range.token(keywordToken), 'var');
            }
          });
          declarationList.variables[0].name.name;
          _variableName = declarationList.variables[0].name.name;
        }
      }
    }
  }

  /// Return an instance of this class. Used as a tear-off in `FixProcessor`.
  static MakeVariableNotFinal newInstance() => MakeVariableNotFinal();
}