// nodes_page.dart — 节点页(置顶智能选择推荐卡 + 搜索 + 列表/双列网格)
import 'dart:async';

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

import '../l10n/app_text.dart';
import '../models/node.dart';
import '../pangolin_theme.dart';
import '../state/app_providers.dart';
import '../state/connection_provider.dart';
import '../state/nodes_provider.dart';
import '../widgets/app_top_bar.dart';
import '../widgets/country_code.dart';
import '../widgets/pangolin_field.dart';
import '../widgets/pangolin_icons.dart';
import '../widgets/server_tile.dart';
import '../widgets/smart_select_card.dart';

class NodesPage extends ConsumerStatefulWidget {
  const NodesPage({super.key, required this.isWide, required this.onPicked});
  final bool isWide;
  final VoidCallback onPicked;

  @override
  ConsumerState<NodesPage> createState() => _NodesPageState();
}

class _NodesPageState extends ConsumerState<NodesPage> {
  String _q = '';
  bool _refreshing = false;
  Timer? _poll;

  @override
  void initState() {
    super.initState();
    // 切到节点页自动刷新一次(受 nodesProvider 的 10s 限流)。
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) _refresh();
    });
    // 在页期间周期刷新,让服务端节点 status(如 down)及时浮现到列表(置灰/不可用)。
    _poll = Timer.periodic(const Duration(seconds: 15), (_) {
      if (mounted) ref.read(nodesProvider.notifier).refresh();
    });
  }

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

  Future<void> _refresh() async {
    if (_refreshing) return;
    setState(() => _refreshing = true);
    await ref.read(nodesProvider.notifier).refresh();
    if (mounted) setState(() => _refreshing = false);
  }

  void _pick(String code) {
    ref.read(selectedNodeCodeProvider.notifier).select(code);
    ref.read(connectionProvider.notifier).onNodeChanged();
    widget.onPicked();
  }

  // 点节点:未连接(off)直接选→跳连接页,无破坏性;已连接/连接中切换会断开重连,
  // 弹确认防误触(误碰把当前连接切走)。节点卡与智能选择卡共用此逻辑。
  void _onTapNode(Node n) => _onSelect(n.code, n.localizedName(ref.read(appTextProvider).lang));

  void _onTapSmart() => _onSelect(kSmartNodeCode, ref.read(appTextProvider).smartSelect);

  void _onSelect(String code, String name) {
    if (ref.read(connectionProvider).phase == VpnPhase.off) {
      _pick(code);
      return;
    }
    _confirmSwitch(code, name);
  }

  Future<void> _confirmSwitch(String code, String name) async {
    final c = context.pangolin;
    final t = ref.read(appTextProvider);
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: c.surface,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(PangolinRadius.xl)),
        title: Text(t.nodeSwitchTitle(name),
            style: PangolinText.body.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
        content: Text(t.nodeSwitchBody, style: PangolinText.sm.copyWith(color: c.fg2, height: 1.5)),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(t.devCancel, style: PangolinText.sm.copyWith(color: c.fg2, fontWeight: FontWeight.w600)),
          ),
          TextButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: Text(t.nodeSwitchConfirm, style: PangolinText.sm.copyWith(color: c.accent, fontWeight: FontWeight.w700)),
          ),
        ],
      ),
    );
    if (ok == true) _pick(code);
  }

  List<Node> _filtered(List<Node> nodes) {
    if (_q.trim().isEmpty) return nodes;
    final q = _q.toLowerCase();
    return nodes
        .where((n) => (n.nameZh + n.nameEn + n.code).toLowerCase().contains(q))
        .toList();
  }

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    final t = ref.watch(appTextProvider);
    final selected = ref.watch(selectedNodeCodeProvider);
    final nodes = _filtered(ref.watch(nodesProvider).valueOrNull ?? const <Node>[]);
    final smart = selected == kSmartNodeCode;

    final smartCard = SmartSelectCard(t: t, selected: smart, onTap: _onTapSmart);
    // 搜索框 + 刷新按钮(点击刷新);列表本身支持下拉刷新。
    final searchRow = Row(children: [
      Expanded(child: _SearchBox(hint: t.searchPh, onChanged: (v) => setState(() => _q = v))),
      const SizedBox(width: 10),
      _RefreshButton(refreshing: _refreshing, onTap: _refresh),
    ]);

    if (widget.isWide) {
      // 对照 dapp.jsx DServers：padding 4/28、网格 gap 10。智能卡置顶（CLAUDE.md §5 规范，三端一致）。
      return RefreshIndicator(
        color: c.accent,
        backgroundColor: c.surface,
        onRefresh: _refresh,
        child: ListView(
          padding: const EdgeInsets.fromLTRB(28, 4, 28, 24),
          children: [
            smartCard,
            const SizedBox(height: 14),
            ConstrainedBox(constraints: const BoxConstraints(maxWidth: 440), child: searchRow),
            const SizedBox(height: 14),
            GridView.count(
            crossAxisCount: 2,
            shrinkWrap: true,
            physics: const NeverScrollableScrollPhysics(),
            mainAxisSpacing: 10,
            crossAxisSpacing: 10,
            childAspectRatio: 4.4,
            children: [
              for (final n in nodes)
                _NodeGridTile(node: n, lang: t.lang, active: !smart && n.code == selected, onTap: () => _onTapNode(n)),
            ],
          ),
        ],
        ),
      );
    }

    // 窄屏:顶栏 + 标题 + 推荐卡 + 搜索 + 分组列表
    return Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
      AppTopBar(brand: t.brand),
      PageTitle(title: t.chooseNode),
      Expanded(
        child: RefreshIndicator(
          color: c.accent,
          backgroundColor: c.surface,
          onRefresh: _refresh,
          child: ListView(
            padding: const EdgeInsets.fromLTRB(20, 0, 20, 20),
            children: [
              smartCard,
              const SizedBox(height: 12),
              searchRow,
              const SizedBox(height: 12),
            Container(
              decoration: BoxDecoration(
                color: c.surface,
                borderRadius: BorderRadius.circular(PangolinRadius.lg),
                border: Border.all(color: c.border),
                boxShadow: PangolinShadow.sm,
              ),
              clipBehavior: Clip.antiAlias,
              child: Column(children: [
                for (var i = 0; i < nodes.length; i++) ...[
                  ServerTile(
                    node: nodes[i],
                    lang: t.lang,
                    active: !smart && nodes[i].code == selected,
                    onTap: () => _onTapNode(nodes[i]),
                  ),
                  if (i < nodes.length - 1) Divider(height: 1, thickness: 1, color: c.border),
                ],
              ]),
            ),
          ],
          ),
        ),
      ),
    ]);
  }
}

class _SearchBox extends StatelessWidget {
  const _SearchBox({required this.hint, required this.onChanged});
  final String hint;
  final ValueChanged<String> onChanged;

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    // 搜索框:只有底色无描边的统一输入框(PangolinFieldBox bordered:false)。
    return PangolinFieldBox(
      fill: c.bgSubtle,
      bordered: false,
      leading: PangolinIcons.search,
      child: TextField(
        onChanged: onChanged,
        style: PangolinText.sm.copyWith(color: c.fg1, fontSize: 15),
        decoration: bareInputDecoration(
          hintText: hint,
          hintStyle: PangolinText.sm.copyWith(color: c.fg3, fontSize: 15),
        ),
      ),
    );
  }
}

/// 宽屏双列网格中的节点块。
/// 刷新按钮(搜索框右侧):点击刷新节点列表(受 10s 限流);刷新中显示 spinner。
class _RefreshButton extends StatelessWidget {
  const _RefreshButton({required this.refreshing, required this.onTap});
  final bool refreshing;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    return Material(
      color: c.bgSubtle,
      borderRadius: BorderRadius.circular(PangolinRadius.md),
      clipBehavior: Clip.antiAlias,
      child: InkWell(
        onTap: refreshing ? null : onTap,
        child: SizedBox(
          width: 44,
          height: 44,
          child: Center(
            child: refreshing
                ? SizedBox(width: 16, height: 16, child: CircularProgressIndicator(strokeWidth: 2, color: c.accent))
                : Icon(PangolinIcons.refreshCw, size: 18, color: c.fg2),
          ),
        ),
      ),
    );
  }
}

class _NodeGridTile extends StatelessWidget {
  const _NodeGridTile({required this.node, required this.lang, required this.active, required this.onTap});
  final Node node;
  final AppLang lang;
  final bool active;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    final down = node.isDown; // 节点不可用(agent 离线):置灰 + 「不可用」+ 禁选。
    final unavail = lang == AppLang.zh ? '不可用' : 'Unavailable';
    return Opacity(
      opacity: down ? 0.55 : 1.0,
      child: Material(
        color: (active && !down) ? c.accentSubtle : c.surface,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(PangolinRadius.lg),
          side: BorderSide(color: (active && !down) ? c.accentBorder : c.border, width: 1.5),
        ),
        clipBehavior: Clip.antiAlias,
        child: InkWell(
          onTap: down ? null : onTap,
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 15, vertical: 11),
            child: Row(children: [
              CountryCode(code: node.code, active: active && !down),
              const SizedBox(width: 12),
              Expanded(
                child: Column(crossAxisAlignment: CrossAxisAlignment.start, mainAxisSize: MainAxisSize.min, children: [
                  Text(node.localizedName(lang),
                      overflow: TextOverflow.ellipsis,
                      style: PangolinText.sm.copyWith(color: c.fg1, fontWeight: FontWeight.w600, fontSize: 14.5)),
                  Text(node.localizedSub(lang),
                      overflow: TextOverflow.ellipsis,
                      style: PangolinText.caption.copyWith(color: c.fg3, fontWeight: FontWeight.w400)),
                ]),
              ),
              const SizedBox(width: 8),
              if (down)
                Text(unavail,
                    style: PangolinText.caption.copyWith(color: c.danger, fontWeight: FontWeight.w600, fontSize: 12))
              else ...[
                Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.end, children: [
                  Text(node.pingLabel, style: PangolinText.mono.copyWith(color: c.fg2, fontSize: 12)),
                  const SizedBox(height: 5),
                  SignalBars(ping: node.ping),
                ]),
                if (active) ...[const SizedBox(width: 8), Icon(PangolinIcons.check, size: 18, color: c.accent)],
              ],
            ]),
          ),
        ),
      ),
    );
  }
}