// Copyright (c) 2016, 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 '../boolean_selector.dart';
import 'intersection_selector.dart';

/// A selector that matches inputs that either of its sub-selectors match.
class UnionSelector implements BooleanSelector {
  final BooleanSelector _selector1;
  final BooleanSelector _selector2;

  UnionSelector(this._selector1, this._selector2);

  List<String> get variables =>
      _selector1.variables.toList()..addAll(_selector2.variables);

  bool evaluate(semantics) =>
      _selector1.evaluate(semantics) || _selector2.evaluate(semantics);

  BooleanSelector intersection(BooleanSelector other) =>
      new IntersectionSelector(this, other);

  BooleanSelector union(BooleanSelector other) =>
      new UnionSelector(this, other);

  void validate(bool isDefined(String variable)) {
    _selector1.validate(isDefined);
    _selector2.validate(isDefined);
  }

  String toString() => "($_selector1) && ($_selector2)";

  bool operator ==(other) =>
      other is UnionSelector &&
      _selector1 == other._selector1 &&
      _selector2 == other._selector2;

  int get hashCode => _selector1.hashCode ^ _selector2.hashCode;
}
