import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../../theme/autopilot_theme.dart';
import '../../theme/theme_provider.dart';

/// Rudder angle indicator — horizontal bar from –35° (port) to +35° (starboard).
///
/// [rudderDeg] is the actual rudder angle in degrees.
///   Negative = port, positive = starboard.
/// [limitDeg] is the hard stop (default 35°).
class RudderIndicator extends StatelessWidget {
  const RudderIndicator({
    super.key,
    required this.rudderDeg,
    this.limitDeg = 35.0,
    this.height = 48,
  });

  final double rudderDeg;
  final double limitDeg;
  final double height;

  @override
  Widget build(BuildContext context) {
    final theme = context.watch<AutopilotThemeProvider>().current;
    return SizedBox(
      height: height,
      child: CustomPaint(
        painter: _RudderPainter(
          theme: theme,
          rudderDeg: rudderDeg,
          limitDeg: limitDeg,
        ),
      ),
    );
  }
}

class _RudderPainter extends CustomPainter {
  const _RudderPainter({
    required this.theme,
    required this.rudderDeg,
    required this.limitDeg,
  });

  final AutopilotTheme theme;
  final double rudderDeg;
  final double limitDeg;

  @override
  void paint(Canvas canvas, Size size) {
    final t = theme;
    final cx = size.width / 2;
    final cy = size.height / 2;
    final halfW = size.width / 2 - 12;

    // Track
    canvas.drawRRect(
      RRect.fromRectAndRadius(
        Rect.fromCenter(center: Offset(cx, cy), width: size.width - 24, height: 6),
        const Radius.circular(3),
      ),
      Paint()..color = t.panelBorder,
    );

    // Centre line
    canvas.drawLine(
      Offset(cx, cy - 10),
      Offset(cx, cy + 10),
      Paint()
        ..color = t.textMuted
        ..strokeWidth = 1,
    );

    // Rudder fill
    final fraction = (rudderDeg / limitDeg).clamp(-1.0, 1.0);
    final fillWidth = (halfW * fraction.abs()).clamp(0.0, halfW);
    if (fillWidth > 1) {
      final left = fraction < 0 ? cx - fillWidth : cx;
      canvas.drawRRect(
        RRect.fromRectAndRadius(
          Rect.fromLTWH(left, cy - 3, fillWidth, 6),
          const Radius.circular(2),
        ),
        Paint()..color = t.accentMid,
      );
    }

    // Indicator knob
    final kx = cx + halfW * fraction;
    canvas.drawCircle(
      Offset(kx, cy),
      9,
      Paint()..color = t.accentLight,
    );
    if (t.accentGlowRadius > 0) {
      canvas.drawCircle(
        Offset(kx, cy),
        9,
        Paint()
          ..color = t.accentGlowColor
          ..maskFilter = MaskFilter.blur(BlurStyle.normal, t.accentGlowRadius / 2),
      );
    }

    // Labels
    final labelStyle = TextStyle(color: t.textMuted, fontSize: 10);
    _drawLabel(canvas, 'P', Offset(12, cy), labelStyle);
    _drawLabel(canvas, 'S', Offset(size.width - 12, cy), labelStyle);
  }

  void _drawLabel(Canvas canvas, String text, Offset center, TextStyle style) {
    final span = TextSpan(text: text, style: style);
    final tp = TextPainter(
      text: span,
      textDirection: TextDirection.ltr,
    )..layout();
    tp.paint(canvas, center - Offset(tp.width / 2, tp.height / 2));
  }

  @override
  bool shouldRepaint(_RudderPainter old) =>
      old.rudderDeg != rudderDeg || old.theme != theme;
}