import 'dart:async';
import 'package:flutter/material.dart';
import '../../app/theme/app_colors.dart';
import '../../app/theme/app_typography.dart';
import '../../app/theme/app_spacing.dart';

/// 短信验证码倒计时按钮
///
/// - 初始: 显示 [label] (如 "获取验证码")
/// - 点击后: 显示 "XXs" 倒计时，禁用
/// - 倒计时结束: 恢复可点击
class CountdownButton extends StatefulWidget {
  final String label;
  final int seconds;
  final Future<void> Function() onPressed;
  final bool enabled;

  const CountdownButton({
    super.key,
    required this.label,
    this.seconds = 60,
    required this.onPressed,
    this.enabled = true,
  });

  @override
  State<CountdownButton> createState() => _CountdownButtonState();
}

class _CountdownButtonState extends State<CountdownButton> {
  Timer? _timer;
  int _remaining = 0;
  bool _loading = false;

  bool get _isCounting => _remaining > 0;

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

  Future<void> _handlePress() async {
    if (_isCounting || _loading || !widget.enabled) return;

    setState(() => _loading = true);
    try {
      await widget.onPressed();
      _startCountdown();
    } catch (_) {
      // 发送失败不启动倒计时，让用户重试
    } finally {
      if (mounted) setState(() => _loading = false);
    }
  }

  void _startCountdown() {
    setState(() => _remaining = widget.seconds);
    _timer?.cancel();
    _timer = Timer.periodic(const Duration(seconds: 1), (timer) {
      if (!mounted) {
        timer.cancel();
        return;
      }
      setState(() {
        _remaining--;
        if (_remaining <= 0) {
          timer.cancel();
        }
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    final disabled = _isCounting || _loading || !widget.enabled;
    final text = _isCounting ? '${_remaining}s' : widget.label;

    return SizedBox(
      height: AppSpacing.buttonHeightSm,
      child: TextButton(
        onPressed: disabled ? null : _handlePress,
        style: TextButton.styleFrom(
          foregroundColor: AppColors.primary,
          disabledForegroundColor: AppColors.textTertiary,
          padding: const EdgeInsets.symmetric(horizontal: 16),
          shape: RoundedRectangleBorder(
            borderRadius: AppSpacing.borderRadiusSm,
          ),
          textStyle: AppTypography.labelMedium,
        ),
        child: _loading
            ? const SizedBox(
                width: 18,
                height: 18,
                child: CircularProgressIndicator(strokeWidth: 2),
              )
            : Text(text),
      ),
    );
  }
}