flutter/dev/tools/gen_keycodes/lib/android_code_gen.dart

// 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:path/path.dart' as path;

import 'base_code_gen.dart';
import 'constants.dart';
import 'logical_key_data.dart';
import 'physical_key_data.dart';
import 'utils.dart';

/// Generates the key mapping for Android, based on the information in the key
/// data structure given to it.
class AndroidCodeGenerator extends PlatformCodeGenerator {
  AndroidCodeGenerator(super.keyData, super.logicalData);

  /// This generates the map of Android key codes to logical keys.
  String get _androidKeyCodeMap {
    final StringBuffer androidKeyCodeMap = StringBuffer();
    for (final LogicalKeyEntry entry in logicalData.entries) {
      for (final int code in entry.androidValues) {
        androidKeyCodeMap.writeln(
          '          put(${toHex(code, digits: 10)}L, ${toHex(entry.value, digits: 10)}L); // ${entry.constantName}',
        );
      }
    }
    return androidKeyCodeMap.toString().trimRight();
  }

  /// This generates the map of Android scan codes to physical keys.
  String get _androidScanCodeMap {
    final StringBuffer androidScanCodeMap = StringBuffer();
    for (final PhysicalKeyEntry entry in keyData.entries) {
      for (final int code in entry.androidScanCodes.cast<int>()) {
        androidScanCodeMap.writeln(
          '          put(${toHex(code, digits: 10)}L, ${toHex(entry.usbHidCode, digits: 10)}L); // ${entry.constantName}',
        );
      }
    }
    return androidScanCodeMap.toString().trimRight();
  }

  String get _pressingGoals {
    final OutputLines<int> lines = OutputLines<int>('Android pressing goals');
    const Map<String, List<String>> goalsSource = <String, List<String>>{
      'SHIFT': <String>['ShiftLeft', 'ShiftRight'],
      'CTRL': <String>['ControlLeft', 'ControlRight'],
      'ALT': <String>['AltLeft', 'AltRight'],
    };
    goalsSource.forEach((String flagName, List<String> keys) {
      int? lineId;
      final List<String> keysString =
          keys.map((String keyName) {
            final PhysicalKeyEntry physicalKey = keyData.entryByName(keyName);
            final LogicalKeyEntry logicalKey = logicalData.entryByName(keyName);
            lineId ??= physicalKey.usbHidCode;
            return '              new KeyPair(${toHex(physicalKey.usbHidCode)}L, '
                '${toHex(logicalKey.value, digits: 10)}L), // ${physicalKey.name}';
          }).toList();
      lines.add(
        lineId!,
        '        new PressingGoal(\n'
        '            KeyEvent.META_${flagName}_ON,\n'
        '            new KeyPair[] {\n'
        '${keysString.join('\n')}\n'
        '            }),',
      );
    });
    return lines.sortedJoin().trimRight();
  }

  String get _togglingGoals {
    final OutputLines<int> lines = OutputLines<int>('Android toggling goals');
    const Map<String, String> goalsSource = <String, String>{'CAPS_LOCK': 'CapsLock'};
    goalsSource.forEach((String flagName, String keyName) {
      final PhysicalKeyEntry physicalKey = keyData.entryByName(keyName);
      final LogicalKeyEntry logicalKey = logicalData.entryByName(keyName);
      lines.add(
        physicalKey.usbHidCode,
        '      new TogglingGoal(KeyEvent.META_${flagName}_ON, '
        '${toHex(physicalKey.usbHidCode)}L, '
        '${toHex(logicalKey.value, digits: 10)}L),',
      );
    });
    return lines.sortedJoin().trimRight();
  }

  /// This generates the mask values for the part of a key code that defines its plane.
  String get _maskConstants {
    final StringBuffer buffer = StringBuffer();
    const List<MaskConstant> maskConstants = <MaskConstant>[
      kValueMask,
      kUnicodePlane,
      kAndroidPlane,
    ];
    for (final MaskConstant constant in maskConstants) {
      buffer.writeln(
        '  public static final long k${constant.upperCamelName} = ${toHex(constant.value, digits: 11)}L;',
      );
    }
    return buffer.toString().trimRight();
  }

  @override
  String get templatePath => path.join(dataRoot, 'android_keyboard_map_java.tmpl');

  @override
  String outputPath(String platform) => path.join(
    PlatformCodeGenerator.engineRoot,
    'shell',
    'platform',
    path.join('android', 'io', 'flutter', 'embedding', 'android', 'KeyboardMap.java'),
  );

  @override
  Map<String, String> mappings() {
    return <String, String>{
      'ANDROID_SCAN_CODE_MAP': _androidScanCodeMap,
      'ANDROID_KEY_CODE_MAP': _androidKeyCodeMap,
      'PRESSING_GOALS': _pressingGoals,
      'TOGGLING_GOALS': _togglingGoals,
      'MASK_CONSTANTS': _maskConstants,
    };
  }
}