// 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 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'binding.dart';

/// Processes text input events that were not handled by the framework.
abstract class TestTextInputKeyHandler {
  /// Process key down event that was not handled by the framework.
  Future<void> handleKeyDownEvent(LogicalKeyboardKey key);

  /// Process key up event that was not handled by the framework.
  Future<void> handleKeyUpEvent(LogicalKeyboardKey key);
}

/// MacOS specific key input handler. This class translates standard macOS text editing shortcuts
/// into appropriate selectors similarly to what NSTextInputContext does in Flutter Engine.
class MacOSTestTextInputKeyHandler extends TestTextInputKeyHandler {
  /// Create a new macOS specific text input handler.
  MacOSTestTextInputKeyHandler(this.client);

  /// ClientId of TextInput
  final int client;

  Future<void> _sendSelectors(List<String> selectors) async {
    await TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .handlePlatformMessage(
      SystemChannels.textInput.name,
      SystemChannels.textInput.codec.encodeMethodCall(
        MethodCall(
            'TextInputClient.performSelectors', <dynamic>[client, selectors]),
      ),
      (ByteData? data) {/* response from framework is discarded */},
    );
  }

  // These combinations must match NSStandardKeyBindingResponding.
  static final Map<SingleActivator, List<String>> _macOSActivatorToSelectors =
      <SingleActivator, List<String>>{
    for (final bool pressShift in const <bool>[
      true,
      false
    ]) ...<SingleActivator, List<String>>{
      SingleActivator(LogicalKeyboardKey.backspace, shift: pressShift):
          <String>['deleteBackward:'],
      SingleActivator(LogicalKeyboardKey.backspace,
          alt: true, shift: pressShift): <String>['deleteWordBackward:'],
      SingleActivator(LogicalKeyboardKey.backspace,
          meta: true, shift: pressShift): <String>['deleteToBeginningOfLine:'],
      SingleActivator(LogicalKeyboardKey.backspace, control: true, shift: pressShift):
          <String>['deleteBackwardByDecomposingPreviousCharacter:'],
      SingleActivator(LogicalKeyboardKey.delete, shift: pressShift): <String>[
        'deleteForward:'
      ],
      SingleActivator(LogicalKeyboardKey.delete, alt: true, shift: pressShift):
          <String>['deleteWordForward:'],
      SingleActivator(LogicalKeyboardKey.delete, meta: true, shift: pressShift):
          <String>['deleteToEndOfLine:'],
    },
    const SingleActivator(LogicalKeyboardKey.arrowLeft): <String>['moveLeft:'],
    const SingleActivator(LogicalKeyboardKey.arrowRight): <String>[
      'moveRight:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowUp): <String>['moveUp:'],
    const SingleActivator(LogicalKeyboardKey.arrowDown): <String>['moveDown:'],
    const SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true): <String>[
      'moveLeftAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowRight, shift: true): <String>[
      'moveRightAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowUp, shift: true): <String>[
      'moveUpAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowDown, shift: true): <String>[
      'moveDownAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowLeft, alt: true): <String>[
      'moveWordLeft:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowRight, alt: true): <String>[
      'moveWordRight:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowUp, alt: true): <String>[
      'moveBackward:',
      'moveToBeginningOfParagraph:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowDown, alt: true): <String>[
      'moveForward:',
      'moveToEndOfParagraph:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowLeft, alt: true, shift: true):
        <String>['moveWordLeftAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowRight,
        alt: true, shift: true): <String>['moveWordRightAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowUp, alt: true, shift: true):
        <String>['moveParagraphBackwardAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowDown, alt: true, shift: true):
        <String>['moveParagraphForwardAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowLeft, meta: true): <String>[
      'moveToLeftEndOfLine:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowRight, meta: true): <String>[
      'moveToRightEndOfLine:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowUp, meta: true): <String>[
      'moveToBeginningOfDocument:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowDown, meta: true): <String>[
      'moveToEndOfDocument:'
    ],
    const SingleActivator(LogicalKeyboardKey.arrowLeft,
        meta: true,
        shift: true): <String>['moveToLeftEndOfLineAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowRight,
        meta: true,
        shift: true): <String>['moveToRightEndOfLineAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowUp, meta: true, shift: true):
        <String>['moveToBeginningOfDocumentAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.arrowDown,
        meta: true,
        shift: true): <String>['moveToEndOfDocumentAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyA, control: true, shift: true):
        <String>['moveToBeginningOfParagraphAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyA, control: true): <String>[
      'moveToBeginningOfParagraph:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyB, control: true, shift: true):
        <String>['moveBackwardAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyB, control: true): <String>[
      'moveBackward:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyE, control: true, shift: true):
        <String>['moveToEndOfParagraphAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyE, control: true): <String>[
      'moveToEndOfParagraph:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyF, control: true, shift: true):
        <String>['moveForwardAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyF, control: true): <String>[
      'moveForward:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyK, control: true): <String>[
      'deleteToEndOfParagraph'
    ],
    const SingleActivator(LogicalKeyboardKey.keyL, control: true): <String>[
      'centerSelectionInVisibleArea'
    ],
    const SingleActivator(LogicalKeyboardKey.keyN, control: true): <String>[
      'moveDown:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyN, control: true, shift: true):
        <String>['moveDownAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyO, control: true): <String>[
      'insertNewlineIgnoringFieldEditor:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyP, control: true): <String>[
      'moveUp:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyP, control: true, shift: true):
        <String>['moveUpAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyT, control: true): <String>[
      'transpose:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyV, control: true): <String>[
      'pageDown:'
    ],
    const SingleActivator(LogicalKeyboardKey.keyV, control: true, shift: true):
        <String>['pageDownAndModifySelection:'],
    const SingleActivator(LogicalKeyboardKey.keyY, control: true): <String>[
      'yank:'
    ],
    const SingleActivator(LogicalKeyboardKey.quoteSingle, control: true):
        <String>['insertSingleQuoteIgnoringSubstitution:'],
    const SingleActivator(LogicalKeyboardKey.quote, control: true): <String>[
      'insertDoubleQuoteIgnoringSubstitution:'
    ],
    const SingleActivator(LogicalKeyboardKey.home): <String>[
      'scrollToBeginningOfDocument:'
    ],
    const SingleActivator(LogicalKeyboardKey.end): <String>[
      'scrollToEndOfDocument:'
    ],
    const SingleActivator(LogicalKeyboardKey.home, shift: true): <String>[
      'moveToBeginningOfDocumentAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.end, shift: true): <String>[
      'moveToEndOfDocumentAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.pageUp): <String>['scrollPageUp:'],
    const SingleActivator(LogicalKeyboardKey.pageDown): <String>[
      'scrollPageDown:'
    ],
    const SingleActivator(LogicalKeyboardKey.pageUp, shift: true): <String>[
      'pageUpAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.pageDown, shift: true): <String>[
      'pageDownAndModifySelection:'
    ],
    const SingleActivator(LogicalKeyboardKey.escape): <String>[
      'cancelOperation:'
    ],
    const SingleActivator(LogicalKeyboardKey.enter): <String>['insertNewline:'],
    const SingleActivator(LogicalKeyboardKey.enter, alt: true): <String>[
      'insertNewlineIgnoringFieldEditor:'
    ],
    const SingleActivator(LogicalKeyboardKey.enter, control: true): <String>[
      'insertLineBreak:'
    ],
    const SingleActivator(LogicalKeyboardKey.tab): <String>['insertTab:'],
    const SingleActivator(LogicalKeyboardKey.tab, alt: true): <String>[
      'insertTabIgnoringFieldEditor:'
    ],
    const SingleActivator(LogicalKeyboardKey.tab, shift: true): <String>[
      'insertBacktab:'
    ],
  };

  @override
  Future<void> handleKeyDownEvent(LogicalKeyboardKey key) async {
    if (key == LogicalKeyboardKey.shift ||
        key == LogicalKeyboardKey.shiftLeft ||
        key == LogicalKeyboardKey.shiftRight) {
      _shift = true;
    } else if (key == LogicalKeyboardKey.alt ||
        key == LogicalKeyboardKey.altLeft ||
        key == LogicalKeyboardKey.altRight) {
      _alt = true;
    } else if (key == LogicalKeyboardKey.meta ||
        key == LogicalKeyboardKey.metaLeft ||
        key == LogicalKeyboardKey.metaRight) {
      _meta = true;
    } else if (key == LogicalKeyboardKey.control ||
        key == LogicalKeyboardKey.controlLeft ||
        key == LogicalKeyboardKey.controlRight) {
      _control = true;
    } else {
      for (final MapEntry<SingleActivator, List<String>> entry
          in _macOSActivatorToSelectors.entries) {
        final SingleActivator activator = entry.key;
        if (activator.triggers.first == key &&
            activator.shift == _shift &&
            activator.alt == _alt &&
            activator.meta == _meta &&
            activator.control == _control) {
          await _sendSelectors(entry.value);
          return;
        }
      }
    }
  }

  @override
  Future<void> handleKeyUpEvent(LogicalKeyboardKey key) async {
    if (key == LogicalKeyboardKey.shift ||
        key == LogicalKeyboardKey.shiftLeft ||
        key == LogicalKeyboardKey.shiftRight) {
      _shift = false;
    } else if (key == LogicalKeyboardKey.alt ||
        key == LogicalKeyboardKey.altLeft ||
        key == LogicalKeyboardKey.altRight) {
      _alt = false;
    } else if (key == LogicalKeyboardKey.meta ||
        key == LogicalKeyboardKey.metaLeft ||
        key == LogicalKeyboardKey.metaRight) {
      _meta = false;
    } else if (key == LogicalKeyboardKey.control ||
        key == LogicalKeyboardKey.controlLeft ||
        key == LogicalKeyboardKey.controlRight) {
      _control = false;
    }
  }

  bool _shift = false;
  bool _alt = false;
  bool _meta = false;
  bool _control = false;
}
