// Copyright (c) 2018, 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:analyzer/analyzer.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/token.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:linter/src/analyzer.dart';

const _desc = r'Unnecessary new keyword.';

const _details = r'''

**AVOID** new keyword to create instances.

**BAD:**
```
class A() { A(); }
m(){
  final a = new A();
}
```

**GOOD:**
```
class A() { A(); }
m(){
  final a = A();
}
```

''';

class UnnecessaryNew extends LintRule implements NodeLintRule {
  UnnecessaryNew()
      : super(
            name: 'unnecessary_new',
            description: _desc,
            details: _details,
            group: Group.style);

  @override
  void registerNodeProcessors(NodeLintRegistry registry) {
    final visitor = new _Visitor(this);
    registry.addInstanceCreationExpression(this, visitor);
  }
}

class _Visitor extends SimpleAstVisitor {
  final LintRule rule;
  _Visitor(this.rule);

  @override
  visitInstanceCreationExpression(InstanceCreationExpression node) {
    if (node.keyword?.type == Keyword.NEW) {
      rule.reportLint(node);
    }
  }
}
