// payment_page.dart — 支付页:按 session.render_type 多态渲染,轮询到
// activated 切成功态。crypto_address=地址+精确金额+复制;redirect=外链拉起;
// qr=预留(复制内容兜底)。
import 'dart:async';

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

import '../l10n/app_text.dart';
import '../models/payment.dart';
import '../pangolin_theme.dart';
import '../state/payment_provider.dart';
import '../widgets/pangolin_button.dart';
import '../widgets/pangolin_icons.dart';
import '../widgets/pangolin_toast.dart';

class PaymentScreen extends ConsumerStatefulWidget {
  const PaymentScreen({super.key, required this.t, this.onBack, this.onDone, this.embedded = false});

  final AppText t;
  final VoidCallback? onBack;
  /// 成功态「完成」/取消订单后的退出导航(壳层决定去向)。
  final VoidCallback? onDone;
  final bool embedded;

  @override
  ConsumerState<PaymentScreen> createState() => _PaymentScreenState();
}

class _PaymentScreenState extends ConsumerState<PaymentScreen> {
  AppText get t => widget.t;
  VoidCallback? get onBack => widget.onBack;
  VoidCallback? get onDone => widget.onDone;
  bool get embedded => widget.embedded;

  // dispose() 时 Riverpod 的 ref 已提前失效(ConsumerStatefulElement 在
  // unmount 阶段收口 ref,dispose() 里再 ref.read 会抛
  // "Cannot use ref after the widget was disposed")——必须用 build() 里
  // 缓存下来的 controller/phase,不能在 dispose() 现取。
  PaymentFlowController? _ctl;
  PaymentPhase _phase = PaymentPhase.idle;

  @override
  void dispose() {
    // paymentFlowProvider 非 autoDispose、轮询 Timer 无 expiry 自停:离开支付页时,
    // 若订单仍在等待付款(唯一存在活跃 Timer 的相位),只停轮询 Timer
    // (stopPolling(),不发远程 cancel、不改 state)——用户点其他导航 tab 离开支付页
    // 不等于放弃订单,订单在后台仍然存活,回来时(或轮询式重进)状态还在。真正的
    // 「放弃本单」只有显式点「取消订单」按钮时才走 cancel()(远程 cancel + 状态归 idle)。
    //
    // 本 widget 自己正是 paymentFlowProvider 的 watcher:在自身 dispose() 里同步触发
    // state= 会让 Riverpod 尝试 markNeedsBuild 一个此刻已 defunct 的 Element,
    // 炸框架断言;Riverpod 把该断言直接报给 zone(不走 Future 错误通道),光
    // catchError 接不住。stopPolling() 本身不写 state,理论上不触发该问题,但仍用
    // scheduleMicrotask 挪到本次 unmount 收尾之后再执行,统一收口、避免任何时序脆弱性。
    // 执行时点若容器已把 controller 一并 dispose(如整页 ProviderScope 随之销毁),用
    // 公开的 `mounted` 短路,不调用已销毁实例。
    if (_phase == PaymentPhase.awaitingPayment) {
      final ctl = _ctl;
      if (ctl != null) {
        scheduleMicrotask(() {
          if (ctl.mounted) ctl.stopPolling();
        });
      }
    }
    super.dispose();
  }

  bool get _zh => t.lang == AppLang.zh;

  Future<void> _copy(BuildContext context, String text) async {
    await Clipboard.setData(ClipboardData(text: text));
    if (context.mounted) showPangolinToast(context, t.copied);
  }

  // redirect 分支拉起外部 app(支付宝):桌面无支付宝、或平台层 PlatformException 时
  // launchUrl 会失败/抛异常——canLaunchUrl 判定 + try-catch 双保险,失败给可见 toast
  // 而非静默无反应。
  Future<void> _openRedirectUrl(BuildContext context, String url) async {
    final uri = Uri.tryParse(url);
    if (uri == null) {
      if (context.mounted) showPangolinToast(context, t.openAlipayFailed);
      return;
    }
    try {
      final can = await canLaunchUrl(uri);
      if (!can) {
        if (context.mounted) showPangolinToast(context, t.openAlipayFailed);
        return;
      }
      final ok = await launchUrl(uri, mode: LaunchMode.externalApplication);
      if (!ok && context.mounted) showPangolinToast(context, t.openAlipayFailed);
    } catch (_) {
      if (context.mounted) showPangolinToast(context, t.openAlipayFailed);
    }
  }

  // 卡片配方 = account_page.dart::_Card(真相源既有样式,非新造)。
  Widget _card(PangolinScheme c, {required Widget child}) => Container(
        width: double.infinity,
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: c.surface,
          borderRadius: BorderRadius.circular(PangolinRadius.lg),
          border: Border.all(color: c.border),
          boxShadow: PangolinShadow.sm,
        ),
        child: child,
      );

  Widget _kvRow(BuildContext context, String label, String value, {bool mono = true}) {
    final c = context.pangolin;
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 6),
      child: Row(crossAxisAlignment: CrossAxisAlignment.start, children: [
        SizedBox(
          width: 76,
          child: Text(label, style: PangolinText.sm.copyWith(color: c.fg3)),
        ),
        Expanded(
          child: SelectableText(value,
              style: (mono ? PangolinText.mono : PangolinText.body)
                  .copyWith(color: c.fg1, fontSize: 14)),
        ),
        IconButton(
          visualDensity: VisualDensity.compact,
          icon: Icon(PangolinIcons.copy, size: 16, color: c.fg3),
          onPressed: () => _copy(context, value),
        ),
      ]),
    );
  }

  String _planName(String sku) => switch (sku) {
        'pro_month' => t.proMonthly,
        'pro_quarter' => t.proQuarterly,
        'pro_year' => t.proYearly,
        _ => sku,
      };

  // 订单信息卡:套餐名 + 支付渠道 + 金额(金额按所选渠道币种显价)。
  Widget _orderCard(BuildContext context, PaymentFlowState s) {
    final c = context.pangolin;
    final ch = s.method == 'crypto' ? PayChannel.usdt : PayChannel.cny;
    final chanLabel = ch == PayChannel.usdt ? t.payChannelUsdt : t.payChannelCny;
    final item = s.item;
    return _card(c, child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
      Text(t.orderDetailTitle.toUpperCase(),
          style: PangolinText.caption
              .copyWith(color: c.fg3, fontWeight: FontWeight.w700, letterSpacing: 0.6)),
      const SizedBox(height: 10),
      if (item != null) _orderRow(c, t.orderPlanLabel, _planName(item.sku)),
      _orderRow(c, t.payChannel, chanLabel),
      if (item != null) _orderRow(c, t.orderAmountLabel, item.priceLabel(ch), amount: true),
    ]));
  }

  Widget _orderRow(PangolinScheme c, String k, String v, {bool amount = false}) => Padding(
        padding: const EdgeInsets.symmetric(vertical: 4),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          crossAxisAlignment: CrossAxisAlignment.baseline,
          textBaseline: TextBaseline.alphabetic,
          children: [
            Text(k, style: PangolinText.sm.copyWith(color: c.fg3)),
            Flexible(
              child: Text(v,
                  textAlign: TextAlign.right,
                  style: (amount ? PangolinText.mono : PangolinText.sm).copyWith(
                      color: amount ? c.accent : c.fg1, fontWeight: FontWeight.w700)),
            ),
          ],
        ),
      );

  Widget _awaiting(BuildContext context, WidgetRef ref, PaymentFlowState s) {
    final c = context.pangolin;
    final session = s.order!.session;
    final payload = session.payload;

    Widget renderBody;
    switch (session.renderType) {
      case 'crypto_address':
        renderBody = _card(c, child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
          _kvRow(context, t.payNetworkLabel, '${payload['currency'] ?? 'USDT'} · ${payload['network'] ?? 'TRC20'}'),
          _kvRow(context, t.payAddressLabel, '${payload['address'] ?? ''}'),
          _kvRow(context, t.payAmountLabel, '${payload['amount'] ?? ''}'),
          const SizedBox(height: 6),
          Text(t.payExactAmountHint, style: PangolinText.caption.copyWith(color: c.warning)),
        ]));
      case 'redirect':
        renderBody = _card(c, child: Column(children: [
          PangolinButton(
            label: t.openAlipay,
            icon: PangolinIcons.externalLink,
            expand: true,
            onPressed: () => _openRedirectUrl(context, '${payload['url'] ?? ''}'),
          ),
          const SizedBox(height: 10),
          Text(t.openAlipayHint, style: PangolinText.caption.copyWith(color: c.fg3)),
        ]));
      case 'qr': // 预留:复制内容兜底,不引入二维码渲染依赖
        renderBody = _card(c, child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
          _kvRow(context, t.payAmountLabel, '¥${payload['display_amount'] ?? ''}', mono: true),
          _kvRow(context, t.payAddressLabel, '${payload['qr_content'] ?? ''}'),
          const SizedBox(height: 6),
          Text(t.qrNotSupported, style: PangolinText.caption.copyWith(color: c.fg3)),
        ]));
      default:
        renderBody = _card(c, child: Text('${session.renderType}: ${_zh ? "暂不支持,请换支付方式" : "Unsupported, switch method"}',
            style: PangolinText.body.copyWith(color: c.fg2)));
    }

    return ListView(padding: const EdgeInsets.fromLTRB(20, 14, 20, 24), children: [
      _orderCard(context, s),
      const SizedBox(height: 14),
      renderBody,
      const SizedBox(height: 16),
      Row(children: [
        SizedBox(width: 14, height: 14, child: CircularProgressIndicator(strokeWidth: 2, color: c.accent)),
        const SizedBox(width: 10),
        Text(t.awaitingPayment, style: PangolinText.sm.copyWith(color: c.fg2)),
      ]),
      const SizedBox(height: 22),
      PangolinButton(
        label: t.switchPayMethod,
        variant: PangolinButtonVariant.secondary,
        expand: true,
        onPressed: () => _pickAndSwitch(context, ref, s),
      ),
      const SizedBox(height: 10),
      PangolinButton(
        label: t.cancelOrder,
        variant: PangolinButtonVariant.ghost,
        expand: true,
        onPressed: () async {
          await ref.read(paymentFlowProvider.notifier).cancel();
          onDone?.call();
        },
      ),
    ]);
  }

  Future<void> _pickAndSwitch(BuildContext context, WidgetRef ref, PaymentFlowState s) async {
    final other = s.method == 'crypto' ? 'nezha' : 'crypto';
    await ref.read(paymentFlowProvider.notifier).switchMethod(other);
  }

  Widget _succeeded(BuildContext context, PaymentFlowState s) {
    final c = context.pangolin;
    final exp = s.status?.expiresAt;
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(mainAxisSize: MainAxisSize.min, children: [
          Icon(PangolinIcons.checkCircle, size: 56, color: c.success),
          const SizedBox(height: 16),
          Text(t.paySucceeded, style: PangolinText.h2.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
          if (exp != null) ...[
            const SizedBox(height: 8),
            Text('${t.payExpiresAt} ${exp.toLocal().toString().split(' ').first}',
                style: PangolinText.sm.copyWith(color: c.fg2)),
          ],
          const SizedBox(height: 24),
          PangolinButton(label: t.payDone, expand: true, onPressed: () => onDone?.call()),
        ]),
      ),
    );
  }

  Widget _failed(BuildContext context, WidgetRef ref, PaymentFlowState s) {
    final c = context.pangolin;
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(mainAxisSize: MainAxisSize.min, children: [
          Text(t.payFailed, style: PangolinText.h3.copyWith(color: c.danger)),
          const SizedBox(height: 8),
          Text((_zh ? s.errorZh : s.errorEn) ?? '', style: PangolinText.sm.copyWith(color: c.fg3)),
          const SizedBox(height: 20),
          PangolinButton(
            label: t.payRetry,
            expand: true,
            onPressed: () {
              final item = s.item;
              if (item != null) ref.read(paymentFlowProvider.notifier).start(item, s.method);
            },
          ),
        ]),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    final s = ref.watch(paymentFlowProvider);
    _ctl = ref.read(paymentFlowProvider.notifier);
    _phase = s.phase;

    final body = switch (s.phase) {
      PaymentPhase.creating => const Center(child: CircularProgressIndicator()),
      PaymentPhase.awaitingPayment => _awaiting(context, ref, s),
      PaymentPhase.succeeded => _succeeded(context, s),
      PaymentPhase.failed => _failed(context, ref, s),
      PaymentPhase.idle => Center(
          child: Text(_zh ? '暂无进行中的订单' : 'No active order',
              style: PangolinText.body.copyWith(color: c.fg3))),
    };

    if (embedded) return body;
    return Scaffold(
      backgroundColor: c.bg,
      body: SafeArea(
        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(8, 6, 16, 10),
            child: Row(children: [
              IconButton(
                onPressed: onBack ?? () => Navigator.of(context).maybePop(),
                icon: Icon(PangolinIcons.arrowLeft, size: 22, color: c.fg1),
              ),
              Text(t.paymentTitle,
                  style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
            ]),
          ),
          Expanded(child: body),
        ]),
      ),
    );
  }
}