import 'package:flutter/material.dart';

/// Vertical or horizontal audio level meter.
///
/// [level] is a normalised value 0.0 – 1.0.
/// Colour transitions green → amber → red above 0.7.
class LevelMeter extends StatelessWidget {
  final double level;
  final double width;
  final double height;
  final bool   vertical;

  const LevelMeter({
    super.key,
    required this.level,
    this.width    = 24,
    this.height   = 120,
    this.vertical = true,
  });

  @override
  Widget build(BuildContext context) {
    final clamped = level.clamp(0.0, 1.0);
    return SizedBox(
      width:  width,
      height: height,
      child:  CustomPaint(
        painter: _LevelPainter(level: clamped, vertical: vertical),
      ),
    );
  }
}

class _LevelPainter extends CustomPainter {
  final double level;
  final bool   vertical;
  const _LevelPainter({required this.level, required this.vertical});

  @override
  void paint(Canvas canvas, Size size) {
    // Background.
    canvas.drawRect(
      Rect.fromLTWH(0, 0, size.width, size.height),
      Paint()..color = const Color(0xFF1A1A2E),
    );

    // Filled bar.
    final barColor = level < 0.6
        ? const Color(0xFF00C853)   // green
        : level < 0.8
            ? const Color(0xFFFFAB00)  // amber
            : const Color(0xFFD50000); // red

    final paint = Paint()..color = barColor;

    if (vertical) {
      final fillH = size.height * level;
      canvas.drawRect(
        Rect.fromLTWH(0, size.height - fillH, size.width, fillH),
        paint,
      );
    } else {
      final fillW = size.width * level;
      canvas.drawRect(
        Rect.fromLTWH(0, 0, fillW, size.height),
        paint,
      );
    }

    // Tick marks at 25 %, 50 %, 75 %.
    final tickPaint = Paint()
      ..color = Colors.white24
      ..strokeWidth = 1;
    for (final frac in [0.25, 0.50, 0.75]) {
      if (vertical) {
        final y = size.height * (1.0 - frac);
        canvas.drawLine(Offset(0, y), Offset(size.width, y), tickPaint);
      } else {
        final x = size.width * frac;
        canvas.drawLine(Offset(x, 0), Offset(x, size.height), tickPaint);
      }
    }
  }

  @override
  bool shouldRepaint(_LevelPainter old) => old.level != level;
}