import 'dart:async';

import 'package:flutter/material.dart';

/// Live-updating countdown to a target [DateTime].
///
/// Rebuilds once per second and renders one of:
///   * "in 3d 4h" — when more than a day out
///   * "in 4h 12m" — when same-day
///   * "in 12m 30s" — within the hour
///   * "Starting now!" — within the final minute window
///   * "Ended" — once the target has passed by more than the [grace] window
///
/// Pass [compact] true to render only the duration text (used in cards);
/// false renders a labelled card-friendly block (used on the detail screen).
class CountdownTimer extends StatefulWidget {
  const CountdownTimer({
    super.key,
    required this.target,
    this.compact = true,
    this.grace = const Duration(minutes: 60),
  });

  final DateTime target;
  final bool compact;

  /// How long after [target] we still show "Starting now!" before flipping
  /// to "Ended". Defaults to an hour so an in-progress match stays visible.
  final Duration grace;

  @override
  State<CountdownTimer> createState() => _CountdownTimerState();
}

class _CountdownTimerState extends State<CountdownTimer> {
  Timer? _timer;

  @override
  void initState() {
    super.initState();
    _timer = Timer.periodic(const Duration(seconds: 1), (_) {
      if (mounted) setState(() {});
    });
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final scheme = theme.colorScheme;
    final now = DateTime.now();
    final diff = widget.target.difference(now);

    final label = _formatLabel(diff);
    final isLive = diff.isNegative && diff.abs() < widget.grace;
    final isEnded = diff.isNegative && diff.abs() >= widget.grace;

    final Color bg;
    final Color fg;
    if (isEnded) {
      bg = scheme.surfaceContainerHighest;
      fg = scheme.onSurfaceVariant;
    } else if (isLive) {
      bg = scheme.tertiaryContainer;
      fg = scheme.onTertiaryContainer;
    } else {
      bg = scheme.primaryContainer;
      fg = scheme.onPrimaryContainer;
    }

    if (widget.compact) {
      return Container(
        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
        decoration: BoxDecoration(
          color: bg,
          borderRadius: BorderRadius.circular(999),
        ),
        child: Text(
          label,
          style: theme.textTheme.labelSmall?.copyWith(
            color: fg,
            fontWeight: FontWeight.w600,
          ),
        ),
      );
    }

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
      decoration: BoxDecoration(
        color: bg,
        borderRadius: BorderRadius.circular(16),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(
            isEnded
                ? Icons.event_busy
                : isLive
                    ? Icons.sports_soccer
                    : Icons.timer_outlined,
            color: fg,
          ),
          const SizedBox(width: 12),
          Text(
            label,
            style: theme.textTheme.titleMedium?.copyWith(
              color: fg,
              fontWeight: FontWeight.w700,
            ),
          ),
        ],
      ),
    );
  }

  String _formatLabel(Duration diff) {
    if (diff.isNegative) {
      if (diff.abs() < widget.grace) return 'Starting now!';
      return 'Ended';
    }
    if (diff.inSeconds <= 60) return 'Starting now!';

    if (diff.inDays >= 1) {
      final days = diff.inDays;
      final hours = diff.inHours - days * 24;
      if (hours == 0) {
        return 'in ${days}d';
      }
      return 'in ${days}d ${hours}h';
    }
    if (diff.inHours >= 1) {
      final hours = diff.inHours;
      final minutes = diff.inMinutes - hours * 60;
      return 'in ${hours}h ${minutes}m';
    }
    final minutes = diff.inMinutes;
    final seconds = diff.inSeconds - minutes * 60;
    return 'in ${minutes}m ${seconds}s';
  }
}