// 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:analysis_server/src/services/correction/dart/abstract_producer.dart';
import 'package:analysis_server/src/services/correction/fix.dart';
import 'package:analyzer/dart/analysis/features.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/element/nullability_suffix.dart';
import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
import 'package:analyzer_plugin/utilities/fixes/fixes.dart';

class AddNeNull extends CorrectionProducerWithDiagnostic {
  @override
  bool get canBeAppliedInBulk => false;

  @override
  bool get canBeAppliedToFile => true;

  @override
  FixKind get fixKind => DartFixKind.ADD_NE_NULL;

  @override
  FixKind get multiFixKind => DartFixKind.ADD_NE_NULL_MULTI;

  @override
  Future<void> compute(ChangeBuilder builder) async {
    if (unit.featureSet.isEnabled(Feature.non_nullable)) {
      final node = this.node;
      if (node is Expression &&
          node.staticType?.nullabilitySuffix == NullabilitySuffix.none) {
        return;
      }
    }
    var problemMessage = diagnostic.problemMessage;
    await builder.addDartFileEdit(file, (builder) {
      builder.addSimpleInsertion(
          problemMessage.offset + problemMessage.length, ' != null');
    });
  }

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