isekai_wiki_app/lib/components/bottom_nav_bar.dart

import 'dart:ui';

import 'package:flutter/cupertino.dart';
import 'package:flutter/services.dart';
import 'package:get/get.dart';

/// Standard iOS navigation bar height without the status bar.
///
/// This height is constant and independent of accessibility as it is in iOS.
const double _kNavBarPersistentHeight = kMinInteractiveDimensionCupertino;

const Color _kDefaultNavBarBorderColor = Color(0x4D000000);

const Border _kDefaultNavBarBorder = Border(
  top: BorderSide(
    color: _kDefaultNavBarBorderColor,
    width: 0.0, // 0.0 means one physical pixel
  ),
);

/// Returns `child` wrapped with background and a bottom border if background color
/// is opaque. Otherwise, also blur with [BackdropFilter].
///
/// When `updateSystemUiOverlay` is true, the nav bar will update the OS
/// status bar's color theme based on the background color of the nav bar.
Widget _wrapWithBackground({
  Border? border,
  required Color backgroundColor,
  Brightness? brightness,
  required Widget child,
  bool updateSystemUiOverlay = true,
}) {
  Widget result = child;
  if (updateSystemUiOverlay) {
    final bool isDark = backgroundColor.computeLuminance() < 0.179;
    final Brightness newBrightness =
        brightness ?? (isDark ? Brightness.dark : Brightness.light);
    final SystemUiOverlayStyle overlayStyle;
    switch (newBrightness) {
      case Brightness.dark:
        overlayStyle = SystemUiOverlayStyle.light;
        break;
      case Brightness.light:
        overlayStyle = SystemUiOverlayStyle.dark;
        break;
    }
    /*result = AnnotatedRegion<SystemUiOverlayStyle>(
      value: overlayStyle,
      child: result,
    );*/
  }
  final DecoratedBox childWithBackground = DecoratedBox(
    decoration: BoxDecoration(
      border: border,
      color: backgroundColor,
    ),
    child: result,
  );

  if (backgroundColor.alpha == 0xFF) {
    return childWithBackground;
  }

  return ClipRect(
    child: BackdropFilter(
      filter: ImageFilter.blur(sigmaX: 10.0, sigmaY: 10.0),
      child: childWithBackground,
    ),
  );
}

class BottomNavigationBar extends StatefulWidget
    implements ObstructingPreferredSizeWidget {
  final Widget child;
  final Color? backgroundColor;
  final Brightness? brightness;
  final Border? border;

  const BottomNavigationBar({
    super.key,
    required this.child,
    this.backgroundColor,
    this.brightness,
    this.border = _kDefaultNavBarBorder,
  });

  @override
  bool shouldFullyObstruct(BuildContext context) {
    final Color backgroundColor =
        CupertinoDynamicColor.maybeResolve(this.backgroundColor, context) ??
            CupertinoTheme.of(context).barBackgroundColor;
    return backgroundColor.alpha == 0xFF;
  }

  @override
  Size get preferredSize {
    double scaleFactor = MediaQuery.of(Get.context!).textScaleFactor;
    return Size.fromHeight(_kNavBarPersistentHeight * scaleFactor);
  }

  @override
  State<StatefulWidget> createState() => _BottomNavigationBarState();
}

class _BottomNavigationBarState extends State<BottomNavigationBar> {
  @override
  Widget build(BuildContext context) {
    final Color backgroundColor =
        CupertinoDynamicColor.maybeResolve(widget.backgroundColor, context) ??
            CupertinoTheme.of(context).barBackgroundColor;

    final scaleFactor = MediaQuery.of(context).textScaleFactor;

    return _wrapWithBackground(
      border: widget.border,
      backgroundColor: backgroundColor,
      brightness: widget.brightness,
      child: DefaultTextStyle(
        style: CupertinoTheme.of(context).textTheme.textStyle,
        child: SizedBox(
          height: (_kNavBarPersistentHeight * scaleFactor) +
              MediaQuery.of(context).padding.bottom,
          child: SafeArea(
            top: false,
            child: widget.child,
          ),
        ),
      ),
    );
  }
}