// 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/fix.dart';
import 'package:analysis_server_plugin/edit/dart/correction_producer.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer/src/dart/ast/extensions.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 ChangeTypeAnnotation extends ResolvedCorrectionProducer {
  String _oldAnnotation = '';

  String _newAnnotation = '';

  new({required super.context});

  @override
  CorrectionApplicability get applicability =>
      // TODO(applicability): comment on why.
      CorrectionApplicability.singleLocation;

  @override
  List<String> get fixArguments => [_oldAnnotation, _newAnnotation];

  @override
  FixKind get fixKind => DartFixKind.changeTypeAnnotation;

  @override
  Future<void> compute(ChangeBuilder builder) async {
    var declaration = coveringNode?.parent;
    if (declaration is! VariableDeclaration) {
      return;
    }

    var initializer = declaration.initializer;
    if (initializer == null || initializer != coveringNode) {
      return;
    }

    var variableList = declaration.parent;
    if (variableList is VariableDeclarationList &&
        variableList.variables.length == 1) {
      var typeNode = variableList.type;
      if (typeNode != null) {
        var newType = initializer.typeOrThrow;
        if (newType is InterfaceType ||
            newType is FunctionType ||
            newType is RecordType) {
          _oldAnnotation = typeNode.typeOrThrow.getDisplayString();
          _newAnnotation = newType.getDisplayString();
          await builder.addDartFileEdit(file, (builder) {
            if (builder.canWriteType(newType, offset: typeNode.offset)) {
              builder.addReplacement(range.node(typeNode), (builder) {
                builder.writeType(newType);
              });
            }
          });
        }
      }
    }
  }
}
