// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'enum_util.dart';
import 'find.dart';
import 'message.dart';

/// Offset types that can be requested by [GetOffset].
enum OffsetType {
  /// The top left point.
  topLeft,

  /// The top right point.
  topRight,

  /// The bottom left point.
  bottomLeft,

  /// The bottom right point.
  bottomRight,

  /// The center point.
  center,
}

EnumIndex<OffsetType> _offsetTypeIndex = EnumIndex<OffsetType>(OffsetType.values);

/// A Flutter Driver command that returns the [offsetType] from the RenderObject
/// identified by [finder].
///
/// The requested offset is returned in logical pixels, which can be translated
/// to device pixels via [Window.devicePixelRatio].
class GetOffset extends CommandWithTarget {
  /// The `finder` looks for an element to get its rect.
  GetOffset(SerializableFinder finder,  this.offsetType, { Duration timeout }) : super(finder, timeout: timeout);

  /// Deserializes this command from the value generated by [serialize].
  GetOffset.deserialize(Map<String, String> json, DeserializeFinderFactory finderFactory)
      : offsetType = _offsetTypeIndex.lookupBySimpleName(json['offsetType']),
        super.deserialize(json, finderFactory);

  @override
  Map<String, String> serialize() => super.serialize()..addAll(<String, String>{
    'offsetType': _offsetTypeIndex.toSimpleName(offsetType),
  });

  /// The type of the requested offset.
  final OffsetType offsetType;

  @override
  String get kind => 'get_offset';
}

/// The result of the [GetOffset] command.
///
/// The offset is provided in logical pixels, which can be translated
/// to device pixels via [Window.devicePixelRatio].
class GetOffsetResult extends Result {
  /// Creates a result with the offset defined by [dx] and [dy].
  const GetOffsetResult({ this.dx = 0.0, this.dy = 0.0});

  /// The x component of the offset in logical pixels.
  ///
  /// The value can be translated to device pixels via
  /// [Window.devicePixelRatio].
  final double dx;

  /// The y component of the offset in logical pixels.
  ///
  /// The value can be translated to device pixels via
  /// [Window.devicePixelRatio].
  final double dy;

  /// Deserializes the result from JSON.
  static GetOffsetResult fromJson(Map<String, dynamic> json) {
    return GetOffsetResult(
      dx: json['dx'] as double,
      dy: json['dy'] as double,
    );
  }

  @override
  Map<String, dynamic> toJson() => <String, double>{
    'dx': dx,
    'dy': dy,
  };
}
