// FaiStatusDot — small pulsing dot used as a "live" indicator.
// Goes still when [pulsing] is false, breathes gently when true.

import 'package:flutter/material.dart';

import '../theme/tokens.dart';

class FaiStatusDot extends StatefulWidget {
  final Color color;

  /// When true, the dot fades between full and 30% opacity.
  /// When false, it stays at full opacity (steady-state).
  final bool pulsing;

  final double size;

  const FaiStatusDot({
    super.key,
    required this.color,
    this.pulsing = false,
    this.size = 8,
  });

  @override
  State<FaiStatusDot> createState() => _FaiStatusDotState();
}

class _FaiStatusDotState extends State<FaiStatusDot>
    with SingleTickerProviderStateMixin {
  late final AnimationController _ctrl;

  @override
  void initState() {
    super.initState();
    _ctrl = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 1400),
    );
    if (widget.pulsing) _ctrl.repeat(reverse: true);
  }

  @override
  void didUpdateWidget(covariant FaiStatusDot old) {
    super.didUpdateWidget(old);
    if (widget.pulsing && !_ctrl.isAnimating) {
      _ctrl.repeat(reverse: true);
    } else if (!widget.pulsing && _ctrl.isAnimating) {
      _ctrl.stop();
      _ctrl.value = 0;
    }
  }

  @override
  void dispose() {
    _ctrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _ctrl,
      builder: (_, _) {
        final t = widget.pulsing ? _ctrl.value : 0.0;
        final alpha = 1.0 - (t * 0.6);
        return Container(
          width: widget.size,
          height: widget.size,
          decoration: BoxDecoration(
            color: widget.color.withValues(alpha: alpha),
            shape: BoxShape.circle,
            boxShadow: widget.pulsing
                ? [
                    BoxShadow(
                      color: widget.color.withValues(alpha: 0.4 * alpha),
                      blurRadius: 6 * (1 + t),
                      spreadRadius: 1 * t,
                    ),
                  ]
                : const [],
          ),
        );
      },
    );
  }
}

/// Convenience presets.
class FaiStatusDots {
  FaiStatusDots._();
  static Widget live() => const FaiStatusDot(
        color: FaiColors.success,
        pulsing: true,
      );
  static Widget idle() => const FaiStatusDot(
        color: FaiColors.muted,
      );
  static Widget down() => const FaiStatusDot(
        color: FaiColors.danger,
      );
}