Garage-SDKs/garage_ui/lib/theme/support.dart

import "dart:ui" show Color, ImageFilter;

import "package:flutter/painting.dart" show HSLColor;
import "package:flutter/widgets.dart";

import "package:garage_ui/theme/garage_theme.dart";

// small pile of helpers the GarageUI widgets used to pull off the shadcn barrel.
// theyre generic, nothing shadcn specific, so we just keep our own copies.

// shadcns Color helpers that the widgets lean on.
extension ColorExtension on Color {
  // scale the alpha channel by [factor] (0..1). shadcns scaleAlpha.
  Color scaleAlpha(double factor) {
    return withValues(alpha: (a * factor).clamp(0.0, 1.0));
  }

  // a readable foreground for this colour - flips lightness. shadcns getContrastColor.
  Color getContrastColor([double luminanceContrast = 1]) {
    final hsl = HSLColor.fromColor(this);
    final l = hsl.lightness;
    final target = l >= 0.5
        ? l - (l * luminanceContrast)
        : l + ((1 - l) * luminanceContrast);
    return hsl.withLightness(target.clamp(0.0, 1.0)).toColor();
  }
}

// default anim duration shadcn used all over (hover/colour transitions etc).
const Duration kDefaultDuration = Duration(milliseconds: 150);

// widget value wins, then theme value, then the hard default. shadcns styleValue.
T styleValue<T>({T? widgetValue, T? themeValue, required T defaultValue}) {
  return widgetValue ?? themeValue ?? defaultValue;
}

// we dropped shadcns density-insets system, so this is now just a passthrough -
// the GarageUI widgets only ever hand it plain EdgeInsets anyway.
EdgeInsetsGeometry resolveEdgeInsets(
  EdgeInsetsGeometry padding,
  double basePadding,
) {
  return padding;
}

// shrinks a border radius by the border width so an inner surface tucks neatly
// inside its border. shadcns subtractByBorder.
BorderRadius subtractByBorder(BorderRadius radius, double borderWidth) {
  Radius sub(Radius r) => Radius.elliptical(
    (r.x - borderWidth).clamp(0.0, double.infinity),
    (r.y - borderWidth).clamp(0.0, double.infinity),
  );
  return BorderRadius.only(
    topLeft: sub(radius.topLeft),
    topRight: sub(radius.topRight),
    bottomLeft: sub(radius.bottomLeft),
    bottomRight: sub(radius.bottomRight),
  );
}

// used to be a density-aware Padding in shadcn. our padding is already resolved
// by the time it gets here, so this is just a Padding.
class DensityContainerPadding extends StatelessWidget {
  const DensityContainerPadding({
    super.key,
    required this.padding,
    required this.child,
  });

  final EdgeInsetsGeometry padding;
  final Widget child;

  @override
  Widget build(BuildContext context) => Padding(padding: padding, child: child);
}

// shadcn used this to tell whether a surface was being rendered inside a sheet
// so it could drop its own rounding/border. the app doesnt use sheets, so its
// always false.
class SheetOverlayHandler {
  const SheetOverlayHandler._();
  static bool isSheetOverlay(BuildContext context) => false;
}

// draws a focus ring around a child when [focused]. shadcns FocusOutline, cut
// down to what the text field needs.
class FocusOutline extends StatelessWidget {
  const FocusOutline({
    super.key,
    required this.child,
    required this.focused,
    this.borderRadius,
    this.color,
    this.width = 1.0,
  });

  final Widget child;
  final bool focused;
  final BorderRadiusGeometry? borderRadius;
  final Color? color;
  final double width;

  @override
  Widget build(BuildContext context) {
    if (!focused) return child;
    final ring = color ?? GarageTheme.of(context).colorScheme.ring;
    return Container(
      decoration: BoxDecoration(
        borderRadius: borderRadius,
        // draw the ring OUTSIDE the box so it doesnt inset the child and
        // change the field size when focus comes and goes.
        border: Border.all(
          color: ring,
          width: width,
          strokeAlign: BorderSide.strokeAlignOutside,
        ),
      ),
      child: child,
    );
  }
}

// blurs whatever is behind the child (glassmorphism on popovers/cards). ported
// straight from shadcns outlined_container.dart.
class SurfaceBlur extends StatefulWidget {
  const SurfaceBlur({
    super.key,
    required this.child,
    this.surfaceBlur,
    this.borderRadius,
  });

  final Widget child;
  final double? surfaceBlur;
  final BorderRadiusGeometry? borderRadius;

  @override
  State<SurfaceBlur> createState() => _SurfaceBlurState();
}

class _SurfaceBlurState extends State<SurfaceBlur> {
  final GlobalKey _mainContainerKey = GlobalKey();

  @override
  Widget build(BuildContext context) {
    if (widget.surfaceBlur == null || widget.surfaceBlur! <= 0) {
      return KeyedSubtree(key: _mainContainerKey, child: widget.child);
    }
    return Stack(
      fit: StackFit.passthrough,
      children: [
        Positioned.fill(
          child: ClipRRect(
            borderRadius: widget.borderRadius ?? BorderRadius.zero,
            child: BackdropFilter(
              filter: ImageFilter.blur(
                sigmaX: widget.surfaceBlur!,
                sigmaY: widget.surfaceBlur!,
              ),
              // needs a child or it wont actually blur anything
              child: const SizedBox(),
            ),
          ),
        ),
        KeyedSubtree(key: _mainContainerKey, child: widget.child),
      ],
    );
  }
}