// home_shell.dart — 主框架(4 Tab:连接 / 节点 / 统计 / 账户)
//
// 自适应断点:同一份页面代码,宽度 ≥900 时从底部 Tab 切换为左侧栏分栏
// (LayoutBuilder 开关,不 fork 页面)。窄屏支持左右滑动切换 Tab。
import 'dart:async';

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

import '../pangolin_theme.dart';
import '../screens/account_page.dart';
import '../screens/connect_page.dart';
import '../screens/nodes_page.dart';
import '../screens/stats_page.dart';
import '../state/app_providers.dart';
import '../state/connection_provider.dart';
import '../state/nodes_provider.dart';
import 'pangolin_icons.dart';
import 'pangolin_logo.dart';
import 'tab_swipe.dart';

/// 宽屏断点(逻辑像素)。≥该值切侧栏分栏。
const double kWideBreakpoint = 900;

class HomeShell extends ConsumerStatefulWidget {
  const HomeShell({super.key});
  @override
  ConsumerState<HomeShell> createState() => _HomeShellState();
}

class _HomeShellState extends ConsumerState<HomeShell> {
  int _tab = 0;
  int _dir = 0;
  Timer? _dirReset;

  void _goTab(int i) {
    if (i == _tab) return;
    setState(() {
      _dir = i > _tab ? 1 : -1;
      _tab = i;
    });
    _dirReset?.cancel();
    _dirReset = Timer(const Duration(milliseconds: 260), () {
      if (mounted) setState(() => _dir = 0);
    });
  }

  void _swipe(int delta) => _goTab((_tab + delta).clamp(0, 3));

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

  List<Widget> _pages(bool isWide) => [
        ConnectPage(isWide: isWide, onOpenNodes: () => _goTab(1)),
        NodesPage(isWide: isWide, onPicked: () => _goTab(0)),
        StatsPage(isWide: isWide),
        AccountPage(isWide: isWide),
      ];

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    return Scaffold(
      backgroundColor: c.bg,
      body: LayoutBuilder(builder: (context, constraints) {
        final isWide = constraints.maxWidth >= kWideBreakpoint;
        final page = DirectionalTabSwitcher(index: _tab, direction: _dir, child: _pages(isWide)[_tab]);
        if (isWide) {
          return SafeArea(child: _WideLayout(tab: _tab, onTab: _goTab, child: page));
        }
        return SafeArea(
          bottom: false,
          child: Column(children: [
            Expanded(
              child: HorizontalSwipeArea(
                onSwipeLeft: () => _swipe(1),
                onSwipeRight: () => _swipe(-1),
                child: page,
              ),
            ),
            _BottomTab(index: _tab, onTap: _goTab),
          ]),
        );
      }),
    );
  }
}

/// ── 宽屏分栏:左侧栏导航 + 内容区 ──
class _WideLayout extends ConsumerWidget {
  const _WideLayout({required this.tab, required this.onTab, required this.child});
  final int tab;
  final ValueChanged<int> onTab;
  final Widget child;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final c = context.pangolin;
    final t = ref.watch(appTextProvider);
    final conn = ref.watch(connectionProvider);
    final node = ref.watch(effectiveNodeProvider);
    final titles = [t.tabConnect, t.tabServers, t.tabStats, t.tabMe];
    return Row(children: [
      _SideRail(tab: tab, onTab: onTab),
      Expanded(
        child: Column(children: [
          // 内容区顶栏:标题 + 在线状态
          SizedBox(
            height: 56,
            child: Padding(
              padding: const EdgeInsets.symmetric(horizontal: 28),
              child: Row(children: [
                Text(titles[tab], style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
                const Spacer(),
                Text(
                  conn.phase == VpnPhase.on ? '● ${node.code}' : '○',
                  style: PangolinText.mono.copyWith(
                      fontSize: 12.5,
                      fontWeight: FontWeight.w600,
                      color: conn.phase == VpnPhase.on ? c.success : c.fg3),
                ),
              ]),
            ),
          ),
          Expanded(child: child),
        ]),
      ),
    ]);
  }
}

class _SideRail extends ConsumerWidget {
  const _SideRail({required this.tab, required this.onTab});
  final int tab;
  final ValueChanged<int> onTab;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final c = context.pangolin;
    final t = ref.watch(appTextProvider);
    final isFree = ref.watch(isFreePlanProvider);
    final items = [
      (PangolinIcons.power, t.tabConnect),
      (PangolinIcons.globe, t.tabServers),
      (PangolinIcons.barChart, t.tabStats),
      (PangolinIcons.user, t.tabMe),
    ];
    return Container(
      width: 232,
      decoration: BoxDecoration(color: c.bgSubtle, border: Border(right: BorderSide(color: c.border))),
      padding: const EdgeInsets.fromLTRB(14, 18, 14, 16),
      child: Column(crossAxisAlignment: CrossAxisAlignment.stretch, children: [
        // 品牌锁版
        Padding(
          padding: const EdgeInsets.fromLTRB(8, 0, 8, 20),
          child: Row(children: [
            const PangolinMark(size: 30),
            const SizedBox(width: 10),
            Column(crossAxisAlignment: CrossAxisAlignment.start, mainAxisSize: MainAxisSize.min, children: [
              Text(t.brand, style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700, fontSize: 17, height: 1)),
              const SizedBox(height: 3),
              Text('PANGOLIN', style: PangolinText.overline.copyWith(color: c.accent, fontSize: 9, letterSpacing: 1.8)),
            ]),
          ]),
        ),
        for (var i = 0; i < items.length; i++)
          Padding(
            padding: const EdgeInsets.only(bottom: 4),
            child: _RailItem(icon: items[i].$1, label: items[i].$2, active: i == tab, onTap: () => onTab(i)),
          ),
        const Spacer(),
        // 套餐迷你卡
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 13, vertical: 12),
          decoration: BoxDecoration(
            color: isFree ? c.surface : null,
            gradient: isFree
                ? null
                : const LinearGradient(
                    begin: Alignment.topLeft, end: Alignment.bottomRight,
                    colors: [PangolinColors.clay600, PangolinColors.clay800]),
            border: isFree ? Border.all(color: c.border) : null,
            borderRadius: BorderRadius.circular(PangolinRadius.lg),
          ),
          child: Row(children: [
            Container(
              width: 32, height: 32,
              decoration: BoxDecoration(color: isFree ? c.bgSubtle : PangolinColors.white.withOpacity(0.18), shape: BoxShape.circle),
              child: Icon(isFree ? PangolinIcons.user : PangolinIcons.crown, size: 16, color: isFree ? c.fg2 : PangolinColors.white),
            ),
            const SizedBox(width: 9),
            Expanded(child: Column(crossAxisAlignment: CrossAxisAlignment.start, mainAxisSize: MainAxisSize.min, children: [
              Text(isFree ? t.freePlanName : t.proMember,
                  overflow: TextOverflow.ellipsis,
                  style: PangolinText.caption.copyWith(color: isFree ? c.fg1 : PangolinColors.white, fontWeight: FontWeight.w700, fontSize: 12.5)),
              Text(kDemoEmail,
                  overflow: TextOverflow.ellipsis,
                  style: PangolinText.caption.copyWith(color: isFree ? c.fg3 : PangolinColors.white.withOpacity(0.7), fontSize: 10.5)),
            ])),
          ]),
        ),
      ]),
    );
  }
}

class _RailItem extends StatelessWidget {
  const _RailItem({required this.icon, required this.label, required this.active, required this.onTap});
  final IconData icon;
  final String label;
  final bool active;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final c = context.pangolin;
    return Material(
      color: active ? c.accentSubtle : Colors.transparent,
      borderRadius: BorderRadius.circular(PangolinRadius.md),
      clipBehavior: Clip.antiAlias,
      child: InkWell(
        onTap: onTap,
        child: ConstrainedBox(
          constraints: const BoxConstraints(minHeight: 48), // 触控尺寸 ≥48
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 13),
            child: Row(children: [
              Icon(icon, size: 20, color: active ? c.accent : c.fg3),
              const SizedBox(width: 12),
              Text(label, style: PangolinText.body.copyWith(color: active ? c.accent : c.fg2, fontWeight: active ? FontWeight.w700 : FontWeight.w500)),
            ]),
          ),
        ),
      ),
    );
  }
}

/// ── 底部 Tab 栏(窄屏)──
class _BottomTab extends ConsumerWidget {
  const _BottomTab({required this.index, required this.onTap});
  final int index;
  final ValueChanged<int> onTap;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final c = context.pangolin;
    final t = ref.watch(appTextProvider);
    final items = [
      (PangolinIcons.power, t.tabConnect),
      (PangolinIcons.globe, t.tabServers),
      (PangolinIcons.barChart, t.tabStats),
      (PangolinIcons.user, t.tabMe),
    ];
    return Container(
      decoration: BoxDecoration(color: c.surface, border: Border(top: BorderSide(color: c.border))),
      padding: const EdgeInsets.only(top: 8, bottom: 22),
      child: Row(children: [
        for (var i = 0; i < items.length; i++)
          Expanded(
            child: GestureDetector(
              behavior: HitTestBehavior.opaque,
              onTap: () => onTap(i),
              child: Column(mainAxisSize: MainAxisSize.min, children: [
                Icon(items[i].$1, size: 22, color: i == index ? c.accent : c.fg3),
                const SizedBox(height: 4),
                Text(items[i].$2,
                    style: PangolinText.caption.copyWith(
                        color: i == index ? c.accent : c.fg3, fontWeight: i == index ? FontWeight.w700 : FontWeight.w500)),
              ]),
            ),
          ),
      ]),
    );
  }
}