import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/theme/app_theme.dart';
import '../../providers/payment_provider.dart';
import '../../providers/auth_provider.dart';
import '../../services/payment_service.dart';
import '../../services/user_service.dart';
import '../feed/widgets/feed_overlays.dart';

/// USDT 支付页：金额（含尾差）/ 收款地址 / 网络 / 倒计时 / 轮询到账 / 取消订单
class UsdtPayScreen extends ConsumerStatefulWidget {
  const UsdtPayScreen({super.key, required this.order});

  final RechargeOrderInfo order;

  @override
  ConsumerState<UsdtPayScreen> createState() => _UsdtPayScreenState();
}

class _UsdtPayScreenState extends ConsumerState<UsdtPayScreen> {
  Timer? _ticker;
  Duration _remain = Duration.zero;
  bool _resultHandled = false;

  @override
  void initState() {
    super.initState();
    _remain = _calcRemain();
    _ticker = Timer.periodic(const Duration(seconds: 1), (_) {
      final r = _calcRemain();
      if (!mounted) return;
      setState(() => _remain = r);
    });
  }

  Duration _calcRemain() {
    final expire = DateTime.tryParse(widget.order.expireAt);
    if (expire == null) return Duration.zero;
    final diff = expire.difference(DateTime.now());
    return diff.isNegative ? Duration.zero : diff;
  }

  @override
  void dispose() {
    _ticker?.cancel();
    ref.read(orderPollProvider(widget.order).notifier).stop();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final poll = ref.watch(orderPollProvider(widget.order));
    final order = widget.order;

    // 轮询结果处理（仅一次）
    if (!_resultHandled && poll.status != OrderPollStatus.polling) {
      _resultHandled = true;
      WidgetsBinding.instance.addPostFrameCallback((_) => _onResult(poll));
    }

    final mm = _remain.inMinutes.remainder(60).toString().padLeft(2, '0');
    final ss = _remain.inSeconds.remainder(60).toString().padLeft(2, '0');

    return Scaffold(
      appBar: AppBar(title: const Text('USDT 支付')),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          // 金额卡
          Container(
            padding: const EdgeInsets.all(20),
            decoration: BoxDecoration(
              color: AppColors.surface,
              borderRadius: BorderRadius.circular(12),
            ),
            child: Column(
              children: [
                const Text('请精确转账以下金额（含尾差用于订单匹配）',
                    style: TextStyle(
                        color: AppColors.textSecondary, fontSize: 12)),
                const SizedBox(height: 10),
                Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  crossAxisAlignment: CrossAxisAlignment.end,
                  children: [
                    Text(
                      order.usdtAmount ?? '-',
                      style: const TextStyle(
                          fontSize: 34,
                          fontWeight: FontWeight.w800,
                          color: AppColors.gold),
                    ),
                    const SizedBox(width: 6),
                    const Padding(
                      padding: EdgeInsets.only(bottom: 6),
                      child: Text('USDT',
                          style: TextStyle(
                              color: AppColors.textSecondary, fontSize: 14)),
                    ),
                  ],
                ),
                const SizedBox(height: 6),
                Text(
                  '≈ ¥${order.amountYuan}（汇率 ${order.usdtRate ?? '-'}）· 到账 ${order.points} 积分',
                  style: const TextStyle(
                      color: AppColors.textSecondary, fontSize: 12),
                ),
              ],
            ),
          ),
          const SizedBox(height: 12),

          // 收款信息
          _InfoRow(
            label: '收款地址',
            value: order.receiveAddress ?? '-',
            onCopy: () => _copy(order.receiveAddress, '地址已复制'),
          ),
          _InfoRow(label: '网络', value: order.network ?? 'TRC20'),
          _InfoRow(label: '订单号', value: order.orderNo),
          const SizedBox(height: 12),

          // 倒计时 + 轮询状态
          Container(
            padding: const EdgeInsets.all(14),
            decoration: BoxDecoration(
              color: AppColors.surface,
              borderRadius: BorderRadius.circular(12),
            ),
            child: Row(
              children: [
                const SizedBox(
                  width: 18,
                  height: 18,
                  child: CircularProgressIndicator(
                      strokeWidth: 2, color: AppColors.primary),
                ),
                const SizedBox(width: 10),
                Expanded(
                  child: Text(
                    _remain == Duration.zero
                        ? '订单已过期，请重新下单'
                        : '等待链上确认（19 个区块）… 剩余 $mm:$ss',
                    style: const TextStyle(fontSize: 13),
                  ),
                ),
              ],
            ),
          ),
          const SizedBox(height: 16),

          const Text(
            '注意事项：\n'
            '· 请务必按显示金额精确转账，金额不符将无法自动到账\n'
            '· 仅支持 TRC20 网络，其他网络转账无法找回\n'
            '· 满 19 个区块确认后积分自动到账',
            style: TextStyle(color: AppColors.textWeak, fontSize: 12, height: 1.6),
          ),
          const SizedBox(height: 20),

          TextButton(
            onPressed: () => _cancel(context),
            child: const Text('取消订单',
                style: TextStyle(color: AppColors.textSecondary)),
          ),
        ],
      ),
    );
  }

  void _copy(String? text, String tip) {
    if (text == null || text.isEmpty) return;
    Clipboard.setData(ClipboardData(text: text));
    showTopToast(context, tip);
  }

  void _refreshUser() async {
    // 支付成功后刷新全局用户信息（积分余额）
    try {
      final user = await UserService.fetchMe();
      await ref.read(authProvider.notifier).onLoginSuccess(user);
    } catch (_) {}
  }

  Future<void> _cancel(BuildContext context) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: AppColors.surface,
        title: const Text('取消订单', style: TextStyle(fontSize: 16)),
        content: const Text('取消后该笔订单将关闭，是否继续？'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: const Text('继续支付'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(ctx, true),
            child:
                const Text('取消订单', style: TextStyle(color: AppColors.primary)),
          ),
        ],
      ),
    );
    if (ok != true || !context.mounted) return;
    try {
      await ref.read(orderPollProvider(widget.order).notifier).cancel();
    } catch (_) {
      if (context.mounted) showTopToast(context, '取消失败，请稍后重试');
    }
  }

  void _onResult(OrderPollState poll) {
    if (!mounted) return;
    if (poll.status == OrderPollStatus.paid) {
      _refreshUser();
      showDialog<void>(
        context: context,
        barrierDismissible: false,
        builder: (ctx) => AlertDialog(
          backgroundColor: AppColors.surface,
          title: const Text('充值成功', style: TextStyle(fontSize: 16)),
          content: Text(
              '已到账 ${widget.order.points} 积分，当前余额 ${poll.walletPoints ?? '-'}'),
          actions: [
            TextButton(
              onPressed: () {
                Navigator.pop(ctx);
                context.pop(true); // 返回充值页并标记已支付
              },
              child: const Text('确定'),
            ),
          ],
        ),
      );
    } else {
      showTopToast(
          context, poll.status == OrderPollStatus.timeout ? '查询超时，请稍后在钱包查看' : '订单已关闭');
      context.pop();
    }
  }
}

class _InfoRow extends StatelessWidget {
  const _InfoRow({required this.label, required this.value, this.onCopy});

  final String label;
  final String value;
  final VoidCallback? onCopy;

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(bottom: 1),
      padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
      color: AppColors.surface,
      child: Row(
        children: [
          SizedBox(
            width: 64,
            child: Text(label,
                style: const TextStyle(
                    color: AppColors.textSecondary, fontSize: 13)),
          ),
          Expanded(
            child: Text(
              value,
              style: const TextStyle(fontSize: 13),
              overflow: TextOverflow.ellipsis,
            ),
          ),
          if (onCopy != null)
            GestureDetector(
              onTap: onCopy,
              child: const Padding(
                padding: EdgeInsets.only(left: 8),
                child:
                    Icon(Icons.copy, size: 16, color: AppColors.textSecondary),
              ),
            ),
        ],
      ),
    );
  }
}