packages/flutter/lib/src/foundation/_platform_web.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:html' as html;
import 'platform.dart' as platform;

/// The dart:html implementation of [platform.defaultTargetPlatform].
platform.TargetPlatform get defaultTargetPlatform {
  // To get a better guess at the targetPlatform we need to be able to reference
  // the window, but that won't be available until we fix the platforms
  // configuration for Flutter.
  platform.TargetPlatform result = _browserPlatform();
  if (platform.debugDefaultTargetPlatformOverride != null)
    result = platform.debugDefaultTargetPlatformOverride!;
  return result;
}

platform.TargetPlatform _browserPlatform() {
  final String navigatorPlatform = html.window.navigator.platform?.toLowerCase() ?? '';
  if (navigatorPlatform.startsWith('mac')) {
    return platform.TargetPlatform.macOS;
  }
  if (navigatorPlatform.startsWith('win')) {
    return platform.TargetPlatform.windows;
  }
  if (navigatorPlatform.contains('iphone') ||
      navigatorPlatform.contains('ipad') ||
      navigatorPlatform.contains('ipod')) {
    return platform.TargetPlatform.iOS;
  }
  if (navigatorPlatform.contains('android')) {
    return platform.TargetPlatform.android;
  }
  // Since some phones can report a window.navigator.platform as Linux, fall
  // back to use CSS to disambiguate Android vs Linux desktop. If the CSS
  // indicates that a device has a "fine pointer" (mouse) as the primary
  // pointing device, then we'll assume desktop linux, and otherwise we'll
  // assume Android.
  if (html.window.matchMedia('only screen and (pointer: fine)').matches) {
    return platform.TargetPlatform.linux;
  }
  return platform.TargetPlatform.android;
}