GroundedHelper/frontend/lib/Grounded/designs/ProgressRing.dart

import 'dart:math' as math;

import 'package:flutter/material.dart';

import '../about/internal/application/TextType.dart';
import '../utils/Colors.dart';
import 'text/Text.dart';

/// A thin circular meter with its value in the middle — the routine row's
/// "how far did I get" dial, and the runner's phase clock ring.
class ProgressRing extends StatelessWidget {
  final double fraction;

  final double size;

  final double stroke;

  final Color? fill;

  final Color? track;

  /// Drawn in the centre. Defaults to the percentage.
  final Widget? child;

  const ProgressRing({
    super.key,
    required this.fraction,
    this.size = 44,
    this.stroke = 3,
    this.fill,
    this.track,
    this.child,
  });

  @override
  Widget build(BuildContext context) {
    final double clamped = fraction.isNaN ? 0 : fraction.clamp(0, 1).toDouble();

    return SizedBox(
      width: size,
      height: size,
      child: TweenAnimationBuilder<double>(
        tween: Tween<double>(end: clamped),
        duration: const Duration(milliseconds: 450),
        curve: Curves.easeOutCubic,
        builder: (context, value, _) {
          return CustomPaint(
            painter: _RingPainter(
              value,
              stroke,
              fill ?? colorPrimaryDark,
              track ?? colorMuted,
            ),
            child: Center(
              child: child ??
                  text("${(clamped * 100).round()}%", size * 0.22,
                      TextType.Bold,
                      color: colorPrimaryDark),
            ),
          );
        },
      ),
    );
  }
}

class _RingPainter extends CustomPainter {
  final double fraction;

  final double stroke;

  final Color fill;

  final Color track;

  _RingPainter(this.fraction, this.stroke, this.fill, this.track);

  @override
  void paint(Canvas canvas, Size size) {
    final Offset centre = Offset(size.width / 2, size.height / 2);
    final double radius = (math.min(size.width, size.height) - stroke) / 2;

    final Paint base = Paint()
      ..style = PaintingStyle.stroke
      ..strokeWidth = stroke
      ..color = track;

    canvas.drawCircle(centre, radius, base);

    if (fraction <= 0) {
      return;
    }

    final Paint arc = Paint()
      ..style = PaintingStyle.stroke
      ..strokeWidth = stroke
      ..strokeCap = StrokeCap.round
      ..color = fill;

    canvas.drawArc(
      Rect.fromCircle(center: centre, radius: radius),
      -math.pi / 2,
      2 * math.pi * fraction,
      false,
      arc,
    );
  }

  @override
  bool shouldRepaint(_RingPainter old) {
    return old.fraction != fraction ||
        old.fill != fill ||
        old.track != track ||
        old.stroke != stroke;
  }
}