packages/flutter_tools/lib/src/base/command_help.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 'dart:math' as math;

import 'package:meta/meta.dart';
import 'package:platform/platform.dart';

import 'logger.dart';
import 'terminal.dart';

// ignore_for_file: non_constant_identifier_names

const String fire = '🔥';
const int maxLineWidth = 84;

/// Encapsulates the help text construction and printing.
class CommandHelp {
  CommandHelp({
    @required Logger logger,
    @required AnsiTerminal terminal,
    @required Platform platform,
    @required OutputPreferences outputPreferences,
  }) : _logger = logger,
       _terminal = terminal,
       _platform = platform,
       _outputPreferences = outputPreferences;

  final Logger _logger;

  final AnsiTerminal _terminal;

  final Platform _platform;

  final OutputPreferences _outputPreferences;

  CommandHelpOption _L;
  CommandHelpOption get L => _L ??= _makeOption('L', 'Dump layer tree to the console.', 'debugDumpLayerTree');

  CommandHelpOption _P;
  CommandHelpOption get P => _P ??= _makeOption('P', 'Toggle performance overlay.', 'WidgetsApp.showPerformanceOverlay');

  CommandHelpOption _R;
  CommandHelpOption get R => _R ??= _makeOption('R', 'Hot restart.');

  CommandHelpOption _S;
  CommandHelpOption get S => _S ??= _makeOption('S', 'Dump accessibility tree in traversal order.', 'debugDumpSemantics');

  CommandHelpOption _U;
  CommandHelpOption get U => _U ??= _makeOption('U', 'Dump accessibility tree in inverse hit test order.', 'debugDumpSemantics');

  CommandHelpOption _a;
  CommandHelpOption get a => _a ??= _makeOption('a', 'Toggle timeline events for all widget build methods.', 'debugProfileWidgetBuilds');

  CommandHelpOption _d;
  CommandHelpOption get d => _d ??= _makeOption('d', 'Detach (terminate "flutter run" but leave application running).');

  CommandHelpOption _h;
  CommandHelpOption get h => _h ??= _makeOption('h', 'Repeat this help message.');

  CommandHelpOption _i;
  CommandHelpOption get i => _i ??= _makeOption('i', 'Toggle widget inspector.', 'WidgetsApp.showWidgetInspectorOverride');

  CommandHelpOption _o;
  CommandHelpOption get o => _o ??= _makeOption('o', 'Simulate different operating systems.', 'defaultTargetPlatform');

  CommandHelpOption _p;
  CommandHelpOption get p => _p ??= _makeOption('p', 'Toggle the display of construction lines.', 'debugPaintSizeEnabled');

  CommandHelpOption _q;
  CommandHelpOption get q => _q ??= _makeOption('q', 'Quit (terminate the application on the device).');

  CommandHelpOption _r;
  CommandHelpOption get r => _r ??= _makeOption('r', 'Hot reload. $fire$fire$fire');

  CommandHelpOption _s;
  CommandHelpOption get s => _s ??= _makeOption('s', 'Save a screenshot to flutter.png.');

  CommandHelpOption _t;
  CommandHelpOption get t => _t ??= _makeOption('t', 'Dump rendering tree to the console.', 'debugDumpRenderTree');

  CommandHelpOption _w;
  CommandHelpOption get w => _w ??= _makeOption('w', 'Dump widget hierarchy to the console.', 'debugDumpApp');

  CommandHelpOption _z;
  CommandHelpOption get z => _z ??= _makeOption('z', 'Toggle elevation checker.');

  CommandHelpOption _makeOption(String key, String description, [
    String inParenthesis = '',
  ]) {
    return CommandHelpOption(
      key,
      description,
      inParenthesis: inParenthesis,
      logger: _logger,
      terminal: _terminal,
      platform: _platform,
      outputPreferences: _outputPreferences,
    );
  }
}

/// Encapsulates printing help text for a single option.
class CommandHelpOption {
  CommandHelpOption(
    this.key,
    this.description, {
    this.inParenthesis = '',
    @required Logger logger,
    @required AnsiTerminal terminal,
    @required Platform platform,
    @required OutputPreferences outputPreferences,
  }) : _logger = logger,
       _terminal = terminal,
       _platform = platform,
       _outputPreferences = outputPreferences;

  final Logger _logger;

  final AnsiTerminal _terminal;

  final Platform _platform;

  final OutputPreferences _outputPreferences;

  /// The key associated with this command
  final String key;
  /// A description of what this command does
  final String description;
  /// Text shown in parenthesis to give the context
  final String inParenthesis;

  bool get _hasTextInParenthesis => inParenthesis != null && inParenthesis.isNotEmpty;

  int get _rawMessageLength => key.length + description.length;

  @override
  String toString() {
    final StringBuffer message = StringBuffer();
    message.writeAll(<String>[_terminal.bolden(key), description], ' ');

    if (_hasTextInParenthesis) {
      bool wrap = false;
      final int maxWidth = math.max(_outputPreferences.wrapColumn ?? 0,  maxLineWidth);
      int width = maxWidth - (_platform.stdoutSupportsAnsi ? _rawMessageLength + 1 : message.length);
      final String parentheticalText = '($inParenthesis)';
      if (width < parentheticalText.length) {
        width = maxWidth;
        wrap = true;
      }

      if (wrap) {
        message.write('\n');
      }
      // pad according to the raw text
      message.write(''.padLeft(width - parentheticalText.length));

      message.write(_terminal.color(parentheticalText, TerminalColor.grey));
    }
    return message.toString();
  }

  void print() {
    _logger.printStatus(toString());
  }
}