gps-speedo/lib/ui/shared/speed_display.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:provider/provider.dart';
import '../../../core/constants/overlay_constants.dart';
import '../../../core/theme/color_themes.dart';
import '../../providers/settings_provider.dart';

/// Shared speed display widget — integral + decimal parts with
/// staleness dimming and tap-to-cycle-theme.
///
/// Dumb widget — accepts data as parameters so it works in both
/// the old Provider-based and new ViewModel-based architectures.
class SpeedDisplay extends StatelessWidget {
  final double fontSize;
  final double opacity;
  final String speedText;
  final DateTime timestamp;

  const SpeedDisplay({
    super.key,
    required this.fontSize,
    required this.opacity,
    required this.speedText,
    required this.timestamp,
  });

  @override
  Widget build(BuildContext context) {
    return Selector<SettingsProvider, ColorTheme>(
      selector: (_, s) => s.currentTheme,
      builder: (context, theme, _) {
        // Staleness — UI-layer concern
        final age = DateTime.now().difference(timestamp);
        final showDashes = age >= OverlayConfig.STALENESS_DASH_THRESHOLD;
        final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
        final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
        final effectiveOpacity = opacity * staleOpacity;

        final displayText = showDashes ? '--' : speedText;

        return GestureDetector(
          onTap: () {
            HapticFeedback.lightImpact();
            context.read<SettingsProvider>().cycleTheme();
          },
          child: _buildSpeedText(displayText, theme, fontSize, effectiveOpacity),
        );
      },
    );
  }

  Widget _buildSpeedText(String speedText, ColorTheme theme, double fontSize, double opacity) {
    if (speedText == '--') {
      return Text(
        speedText,
        style: TextStyle(
          fontSize: fontSize,
          fontWeight: FontWeight.w300,
          color: theme.speedText.withValues(alpha: opacity),
          fontFamily: 'DIN1451Alt',
        ),
      );
    }

    final parts = speedText.split('.');
    final integralPart = parts[0];
    final decimalPart = parts.length > 1 ? '.${parts[1]}' : '.0';

    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      crossAxisAlignment: CrossAxisAlignment.baseline,
      textBaseline: TextBaseline.alphabetic,
      children: [
        Text(
          integralPart,
          style: TextStyle(
            fontSize: fontSize,
            fontWeight: FontWeight.w300,
            color: theme.speedText.withValues(alpha: opacity),
            fontFamily: 'DIN1451Alt',
          ),
        ),
        Text(
          decimalPart,
          style: TextStyle(
            fontSize: fontSize * 0.5,
            fontWeight: FontWeight.w300,
            color: theme.speedTextSub.withValues(alpha: opacity),
            fontFamily: 'DIN1451Alt',
          ),
        ),
      ],
    );
  }
}