// screens/auth/login_screen.dart — 登录页，照原型 login.html 1:1 重建。
// 结构：--page 底居中 .auth 两栏卡片（左 .brand 品牌渐变面板：logo+名+tag+三卖点；
// 右 .form：h1/lead + 门店编号/登录账号/密码 三字段 + 记住我行 + 主按钮 + foot）
// + 右上角 A/B/C 主题切换器。窄屏折叠单列、隐藏卖点（原型 @media 同构）。
// 原型之外保留的功能位（known diffs 见 design/CONTRACT.md）：
//   · 门店编号/账号历史下拉（后缀箭头）与密码可见切换（后缀眼睛）
//   · 离线提示条 / 服务器错误条 / 授权锁定引导卡（表单内、按钮上方）
//   · 会话失效弹窗（被顶下线提示）
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 'package:lucide_icons_flutter/lucide_icons.dart';
import 'package:url_launcher/url_launcher.dart';

import '../../core/auth/auth_state.dart';
import '../../core/config/app_config.dart';
import '../../core/config/app_constants.dart';
import '../../core/config/store_compliance.dart';
import '../../core/responsive/responsive.dart';
import '../../core/storage/login_history.dart';
import '../../core/theme/app_chrome.g.dart';
import '../../core/theme/app_dims.g.dart';
import '../../core/theme/context_tokens.dart';
import '../../providers/connectivity_provider.dart';
import '../../repositories/auth_repository.dart';
import '../../widgets/brand_mark.dart';
import '../../widgets/ds/ds_atoms.dart';
import '../../widgets/ds/ds_toast.dart';
import '../../widgets/network_retry_button.dart';
import 'auth_shared.dart';

class LoginScreen extends ConsumerStatefulWidget {
  const LoginScreen({super.key});

  @override
  ConsumerState<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends ConsumerState<LoginScreen> {
  final _shopCodeCtrl = TextEditingController();
  final _usernameCtrl = TextEditingController();
  final _passwordCtrl = TextEditingController();
  final _shopFocus = FocusNode();
  final _usernameFocus = FocusNode();
  final _shopLayerLink = LayerLink();
  final _usernameLayerLink = LayerLink();

  bool _loading = false;
  bool _obscure = true;
  bool _remember = true;
  String? _errorMessage;

  // 客服邮箱（授权续费 / 锁定协助）。单一来源 store_compliance.supportEmail，
  // 与官网 web/_data/site.json 的 support.email 保持一致。
  static const _supportEmail = supportEmail;

  /// 当前错误是否为「授权锁定」——后端返回固定文案
  /// `license locked, please renew or contact support`（见 service.ErrLicenseLocked）。
  bool get _isLicenseLocked {
    final m = _errorMessage?.toLowerCase() ?? '';
    return m.contains('license') &&
        (m.contains('lock') || m.contains('expire'));
  }

  List<String> _shopHistory = [];
  List<String> _usernameHistory = [];

  OverlayEntry? _shopEntry;
  OverlayEntry? _usernameEntry;
  Timer? _closeShopTimer;
  Timer? _closeUsernameTimer;

  bool get _shopShowing => _shopEntry != null;
  bool get _usernameShowing => _usernameEntry != null;

  @override
  void initState() {
    super.initState();
    _restorePrefill();
    _shopFocus.addListener(() {
      if (_shopFocus.hasFocus) {
        // 取消失焦延迟关闭：快速失焦→回焦时旧 Timer 会误关刚打开的下拉
        _closeShopTimer?.cancel();
        _closeShop();
        _loadHistory().then((_) {
          if (!mounted || !_shopFocus.hasFocus) return;
          if (_shopHistory.isNotEmpty) {
            _openDropdown(_shopLayerLink, _shopHistory, _shopCodeCtrl,
                isShop: true);
          }
        });
      } else {
        // 延迟关闭：让候选词的 onTap（pointer-up）先执行，再关闭下拉框
        _closeShopTimer?.cancel();
        _closeShopTimer = Timer(AppConstants.dropdownCloseDelay, _closeShop);
      }
    });
    _usernameFocus.addListener(() {
      if (_usernameFocus.hasFocus) {
        _closeUsernameTimer?.cancel();
        _closeUsername();
        _loadHistory().then((_) {
          if (!mounted || !_usernameFocus.hasFocus) return;
          if (_usernameHistory.isNotEmpty) {
            _openDropdown(_usernameLayerLink, _usernameHistory, _usernameCtrl,
                isShop: false);
          }
        });
      } else {
        _closeUsernameTimer?.cancel();
        _closeUsernameTimer =
            Timer(AppConstants.dropdownCloseDelay, _closeUsername);
      }
    });
    // 处理「进入登录页之前」就已置入的会话失效提示：登出在 login_screen 挂载前就
    // 设好了 sessionEndedMessageProvider，而 build 里的 ref.listen 只捕获注册之后的
    // 变化，会漏掉这个既有值 → 之前「被顶下线无提示」的根因。这里在首帧主动读一次。
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (!mounted) return;
      final msg = ref.read(sessionEndedMessageProvider);
      if (msg != null && msg.isNotEmpty) _showSessionEndedDialog(msg);
    });
  }

  /// 「记住我」开启时，用最近一次登录的门店编号/账号预填表单。
  Future<void> _restorePrefill() async {
    final remember = await LoginHistoryStorage.getRemember();
    await _loadHistory();
    if (!mounted) return;
    setState(() {
      _remember = remember;
      if (remember) {
        if (_shopCodeCtrl.text.isEmpty && _shopHistory.isNotEmpty) {
          _shopCodeCtrl.text = _shopHistory.first;
        }
        if (_usernameCtrl.text.isEmpty && _usernameHistory.isNotEmpty) {
          _usernameCtrl.text = _usernameHistory.first;
        }
      }
    });
  }

  /// 弹出「登录已失效 / 被强制下线」提示弹窗，并清空 provider 避免重复弹。
  void _showSessionEndedDialog(String msg) {
    if (!mounted) return;
    ref.read(sessionEndedMessageProvider.notifier).state = null;
    showDialog<void>(
      context: context,
      builder: (ctx) => AlertDialog(
        icon: Icon(LucideIcons.lock, color: context.tokens.danger),
        title: const Text('登录已失效'),
        content: Text(msg),
        actions: [
          DsButton('我知道了',
              variant: DsBtnVariant.primary,
              onPressed: () => Navigator.of(ctx).pop()),
        ],
      ),
    );
  }

  Future<void> _loadHistory() async {
    final shops = await LoginHistoryStorage.getHotelCodes();
    final users = await LoginHistoryStorage.getUsernames();
    if (!mounted) return;
    setState(() {
      _shopHistory = shops;
      _usernameHistory = users;
    });
  }

  void _openDropdown(
    LayerLink link,
    List<String> items,
    TextEditingController ctrl, {
    required bool isShop,
  }) {
    if (isShop) {
      if (_shopEntry != null) return;
      _closeUsername();
    } else {
      if (_usernameEntry != null) return;
      _closeShop();
    }

    final entry = OverlayEntry(
      builder: (_) => Stack(
        children: [
          // Transparent backdrop — tap outside closes dropdown
          Positioned.fill(
            child: GestureDetector(
              behavior: HitTestBehavior.translucent,
              onTap: isShop ? _closeShop : _closeUsername,
            ),
          ),
          // Dropdown positioned below the field（宽随字段：登录表单列宽 340）
          CompositedTransformFollower(
            link: link,
            targetAnchor: Alignment.bottomLeft,
            followerAnchor: Alignment.topLeft,
            showWhenUnlinked: false,
            offset: const Offset(0, 4),
            child: _HistoryMenu(
              width: context.dialogWidth(340),
              items: items,
              onSelected: (v) => _selectHistoryItem(v, ctrl, isShop: isShop),
            ),
          ),
        ],
      ),
    );

    if (isShop) {
      _shopEntry = entry;
    } else {
      _usernameEntry = entry;
    }
    Overlay.of(context).insert(entry);
    setState(() {}); // refresh arrow icon
  }

  void _selectHistoryItem(
    String value,
    TextEditingController ctrl, {
    required bool isShop,
  }) {
    ctrl.value = TextEditingValue(
      text: value,
      selection: TextSelection.collapsed(offset: value.length),
    );

    if (isShop) {
      _closeShop();
      _shopFocus.unfocus();
    } else {
      _closeUsername();
      _usernameFocus.unfocus();
    }

    setState(() {});
  }

  void _closeShop() {
    _shopEntry?.remove();
    _shopEntry = null;
    if (mounted) setState(() {});
  }

  void _closeUsername() {
    _usernameEntry?.remove();
    _usernameEntry = null;
    if (mounted) setState(() {});
  }

  @override
  void dispose() {
    _closeShopTimer?.cancel();
    _closeUsernameTimer?.cancel();
    _shopEntry?.remove();
    _usernameEntry?.remove();
    _shopCodeCtrl.dispose();
    _usernameCtrl.dispose();
    _passwordCtrl.dispose();
    _shopFocus.dispose();
    _usernameFocus.dispose();
    super.dispose();
  }

  Future<void> _login() async {
    // 原型式校验：逐项 toast 提示（无内联错误文案，保持 38 高盒式字段不抖动）
    if (_shopCodeCtrl.text.trim().isEmpty) {
      showDsToast(context, '请输入门店编号');
      return;
    }
    if (_usernameCtrl.text.trim().isEmpty) {
      showDsToast(context, '请输入登录账号');
      return;
    }
    if (_passwordCtrl.text.isEmpty) {
      showDsToast(context, '请输入密码');
      return;
    }

    // 登录前先检查连通性
    final isOnline = ref.read(connectivityProvider);
    if (!isOnline) {
      setState(() => _errorMessage = '服务器不可达，请检查网络连接后重试');
      return;
    }

    setState(() {
      _loading = true;
      _errorMessage = null;
    });
    try {
      final user = await AuthRepository.login(
        shopCode: _shopCodeCtrl.text.trim(),
        username: _usernameCtrl.text.trim(),
        password: _passwordCtrl.text,
      );
      await LoginHistoryStorage.setRemember(_remember);
      if (_remember) {
        await LoginHistoryStorage.record(
          _shopCodeCtrl.text.trim(),
          _usernameCtrl.text.trim(),
        );
      }
      await ref.read(authStateProvider.notifier).login(user);
      if (mounted) context.go('/stock-in');
    } on AuthException catch (e) {
      if (mounted) setState(() => _errorMessage = e.message);
    } catch (e) {
      if (mounted) setState(() => _errorMessage = '登录失败：$e');
    } finally {
      if (mounted) setState(() => _loading = false);
    }
  }

  Future<void> _openRenewSite() async {
    await launchUrl(
      Uri.parse(AppConfig.publicBaseUrl),
      mode: LaunchMode.externalApplication,
    );
  }

  Future<void> _copySupportEmail() async {
    await Clipboard.setData(const ClipboardData(text: _supportEmail));
    if (!mounted) return;
    showDsToast(context, '已复制客服邮箱：$_supportEmail');
  }

  @override
  Widget build(BuildContext context) {
    // 已在登录页时会话再失效（例如停留在登录页期间后台请求被吊销）：弹窗提示。
    // 进入登录页之前就置入的既有值由 initState 的首帧读取处理。
    ref.listen<String?>(sessionEndedMessageProvider, (prev, next) {
      if (next != null && next.isNotEmpty) {
        WidgetsBinding.instance.addPostFrameCallback((_) {
          _showSessionEndedDialog(next);
        });
      }
    });
    return AuthPageScaffold(
      maxWidth: 880,
      narrowMaxWidth: 440,
      formWidth: 420, // 原型 grid：minmax(0,1fr) 420px
      brand: _brand(context),
      form: _form(context),
    );
  }

  // ── 左栏 .brand：logo + 名 + tag + 三卖点 ────────────────────────────────
  Widget _brand(BuildContext context) {
    final t = context.tokens;
    final narrow = context.isMobile;
    Widget pt(IconData icon, String text) => Row(children: [
          Container(
            width: 30,
            height: 30,
            alignment: Alignment.center,
            decoration: BoxDecoration(
              color: AppChrome.heroGlass,
              borderRadius: BorderRadius.circular(AppDims.rMd),
            ),
            child: Icon(icon, size: 16, color: t.sideActiveFg),
          ),
          const SizedBox(width: 11),
          Expanded(
            child: Text(text,
                style: TextStyle(fontSize: AppDims.fsSm, color: t.sideFg)),
          ),
        ]);
    return AuthBrandPanel(
      padding: narrow
          ? const EdgeInsets.symmetric(horizontal: 32, vertical: 36)
          : const EdgeInsets.symmetric(horizontal: 40, vertical: 48),
      minHeight: narrow ? null : 480,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const BrandMark(size: 64),
          const SizedBox(height: 24),
          Text('岩美酒库',
              style: TextStyle(
                  fontSize: AppDims.fsDisplay,
                  fontWeight: FontWeight.w800,
                  letterSpacing: 1,
                  color: t.sideActiveFg)),
          const SizedBox(height: 8),
          Text('酒水进销存 · 审核驱动业务流',
              style: TextStyle(
                  fontSize: AppDims.fsBody, color: t.sideFg, height: 1.7)),
          if (!narrow) ...[
            const Spacer(),
            pt(LucideIcons.box, '入库出库 · 审核后实时改库存'),
            const SizedBox(height: 14),
            pt(LucideIcons.creditCard, '往来对账 · 财务一目了然'),
            const SizedBox(height: 14),
            pt(LucideIcons.circleCheck, '多端协同 · 多租户安全隔离'),
          ],
        ],
      ),
    );
  }

  // ── 右栏 .form ───────────────────────────────────────────────────────────
  Widget _form(BuildContext context) {
    final t = context.tokens;
    final narrow = context.isMobile;
    return Padding(
      padding: narrow
          ? const EdgeInsets.symmetric(horizontal: 32, vertical: 34)
          : const EdgeInsets.symmetric(horizontal: 40, vertical: 48),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('登录',
              style: TextStyle(
                  fontSize: AppDims.fsH1,
                  fontWeight: FontWeight.w700,
                  color: t.heading)),
          const SizedBox(height: 6),
          Text('欢迎回来，请输入账号信息',
              style: TextStyle(fontSize: AppDims.fsSm, color: t.muted)),
          const SizedBox(height: 26),
          DsField('门店编号',
              input: CompositedTransformTarget(
                link: _shopLayerLink,
                child: DsInput(
                  controller: _shopCodeCtrl,
                  focusNode: _shopFocus,
                  hintText: '例如 DSJH-001',
                  suffix: _shopHistory.isNotEmpty
                      ? Icon(
                          _shopShowing
                              ? LucideIcons.chevronUp
                              : LucideIcons.chevronDown,
                          size: 16,
                          color: t.muted)
                      : null,
                ),
              )),
          const SizedBox(height: 16),
          DsField('登录账号',
              input: CompositedTransformTarget(
                link: _usernameLayerLink,
                child: DsInput(
                  controller: _usernameCtrl,
                  focusNode: _usernameFocus,
                  hintText: '请输入登录账号',
                  suffix: _usernameHistory.isNotEmpty
                      ? Icon(
                          _usernameShowing
                              ? LucideIcons.chevronUp
                              : LucideIcons.chevronDown,
                          size: 16,
                          color: t.muted)
                      : null,
                ),
              )),
          const SizedBox(height: 16),
          DsField('密码',
              input: DsInput(
                controller: _passwordCtrl,
                hintText: '请输入密码',
                obscureText: _obscure,
                onSubmitted: (_) => _login(),
                suffix: MouseRegion(
                  cursor: SystemMouseCursors.click,
                  child: GestureDetector(
                    onTap: () => setState(() => _obscure = !_obscure),
                    child: Icon(_obscure ? LucideIcons.eyeOff : LucideIcons.eye,
                        size: 16, color: t.muted),
                  ),
                ),
              )),
          // .remember：记住我 + 忘记密码（margin 4 0 22）
          const SizedBox(height: 4),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 8),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                DsCheck(
                  value: _remember,
                  onChanged: (v) {
                    setState(() => _remember = v);
                    LoginHistoryStorage.setRemember(v);
                  },
                  label: Text('记住我',
                      style:
                          TextStyle(fontSize: AppDims.fsBody, color: t.text)),
                ),
                _Link('忘记密码？',
                    onTap: () => showDsToast(context, '找回密码请联系门店管理员')),
              ],
            ),
          ),
          const SizedBox(height: 14),

          // 离线提示（connectivityProvider 在 _AppBootstrap 中已预热）
          if (!ref.watch(connectivityProvider)) ...[
            _noticeBox(
              color: t.warn,
              bg: t.warnBg,
              child: Row(children: [
                Icon(LucideIcons.wifiOff, color: t.warn, size: 16),
                const SizedBox(width: 8),
                Expanded(
                  child: Text('服务器不可达，请检查网络连接',
                      style:
                          TextStyle(color: t.warn, fontSize: AppDims.fsBody)),
                ),
                NetworkRetryButton(foreground: t.warn),
              ]),
            ),
            const SizedBox(height: 12),
          ],

          // 服务器返回错误（授权锁定时换成引导卡）
          if (_errorMessage != null) ...[
            if (_isLicenseLocked)
              _licenseLockedNotice(context)
            else
              _noticeBox(
                color: t.danger,
                bg: t.dangerBg,
                child: Row(children: [
                  Icon(LucideIcons.circleAlert, color: t.danger, size: 16),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Text(_errorMessage!,
                        style: TextStyle(
                            color: t.danger, fontSize: AppDims.fsBody)),
                  ),
                ]),
              ),
            const SizedBox(height: 12),
          ],

          SizedBox(
            width: double.infinity,
            child: DsButton(_loading ? '登录中…' : '登录',
                variant: DsBtnVariant.primary,
                large: true,
                onPressed: _loading ? null : _login),
          ),
          const SizedBox(height: 24),
          Center(
            child: Wrap(
              crossAxisAlignment: WrapCrossAlignment.center,
              children: [
                Text('还没有门店账号？',
                    style: TextStyle(fontSize: AppDims.fsXs, color: t.faint)),
                _Link('注册新门店 →',
                    bold: true, onTap: () => context.go('/register')),
              ],
            ),
          ),
          const SizedBox(height: 8),
          Center(
            child: Text('岩美酒库 © 2026 · 仅授权门店可登录',
                style: TextStyle(fontSize: AppDims.fsXs, color: t.faint)),
          ),
        ],
      ),
    );
  }

  /// 提示条通用外框（离线 / 错误）：淡底 + 同色系边 + r-md。
  Widget _noticeBox(
      {required Color color, required Color bg, required Widget child}) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
      decoration: BoxDecoration(
        color: bg,
        borderRadius: BorderRadius.circular(AppDims.rMd),
        border: Border.all(color: color.withAlpha(80)),
      ),
      child: child,
    );
  }

  /// 授权锁定时的可操作提示：告诉用户「去哪里解决」——前往官网续费 / 联系客服。
  Widget _licenseLockedNotice(BuildContext context) {
    final t = context.tokens;
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: t.dangerBg,
        borderRadius: BorderRadius.circular(AppDims.rMd),
        border: Border.all(color: t.danger.withAlpha(80)),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(children: [
            Icon(LucideIcons.lock, color: t.danger, size: 18),
            const SizedBox(width: 8),
            Expanded(
              child: Text('授权已过期，账号已锁定',
                  style: TextStyle(
                      color: t.danger,
                      fontSize: AppDims.fsBody,
                      fontWeight: FontWeight.w600)),
            ),
          ]),
          const SizedBox(height: 6),
          Text('当前门店授权已到期，暂时无法登录。请续费授权后重试，或联系客服协助开通。',
              style: TextStyle(
                  color: t.muted, fontSize: AppDims.fsBody, height: 1.4)),
          const SizedBox(height: 12),
          Wrap(spacing: 8, runSpacing: 8, children: [
            DsButton('前往官网续费',
                icon: LucideIcons.externalLink,
                variant: DsBtnVariant.danger,
                small: true,
                onPressed: _openRenewSite),
            DsButton('复制客服邮箱',
                icon: LucideIcons.headset,
                small: true,
                onPressed: _copySupportEmail),
          ]),
        ],
      ),
    );
  }
}

/// 原型 .link：primary 色文字链接（hover 下划线从简）。
class _Link extends StatelessWidget {
  final String text;
  final bool bold;
  final VoidCallback onTap;
  const _Link(this.text, {this.bold = false, required this.onTap});

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    return MouseRegion(
      cursor: SystemMouseCursors.click,
      child: GestureDetector(
        onTap: onTap,
        child: Text(text,
            style: TextStyle(
                fontSize: bold ? AppDims.fsXs : AppDims.fsSm,
                fontWeight: bold ? FontWeight.w600 : FontWeight.w400,
                color: t.primary)),
      ),
    );
  }
}

/// 历史账号下拉（surface 浮层 + border + sh，条目 hover=rowHover）。
class _HistoryMenu extends StatelessWidget {
  final double width;
  final List<String> items;
  final ValueChanged<String> onSelected;
  const _HistoryMenu(
      {required this.width, required this.items, required this.onSelected});

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    return Material(
      color: Colors.transparent,
      child: Container(
        width: width,
        clipBehavior: Clip.antiAlias,
        decoration: BoxDecoration(
          color: t.surface,
          border: Border.all(color: t.border),
          borderRadius: BorderRadius.circular(AppDims.rMd),
          boxShadow: [
            BoxShadow(
                color: t.shadow, offset: const Offset(0, 4), blurRadius: 14),
          ],
        ),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            for (final v in items)
              _HistoryMenuItem(value: v, onSelected: () => onSelected(v)),
          ],
        ),
      ),
    );
  }
}

class _HistoryMenuItem extends StatefulWidget {
  final String value;
  final VoidCallback onSelected;

  const _HistoryMenuItem({
    required this.value,
    required this.onSelected,
  });

  @override
  State<_HistoryMenuItem> createState() => _HistoryMenuItemState();
}

class _HistoryMenuItemState extends State<_HistoryMenuItem> {
  bool _hovered = false;

  @override
  Widget build(BuildContext context) {
    final t = context.tokens;
    return MouseRegion(
      onEnter: (_) => setState(() => _hovered = true),
      onExit: (_) => setState(() => _hovered = false),
      cursor: SystemMouseCursors.click,
      child: GestureDetector(
        onTap: widget.onSelected,
        child: Container(
          width: double.infinity,
          color: _hovered ? t.rowHover : Colors.transparent,
          padding: const EdgeInsets.symmetric(horizontal: 11, vertical: 9),
          child: Row(
            children: [
              Icon(LucideIcons.history, size: 14, color: t.muted),
              const SizedBox(width: 8),
              Text(widget.value,
                  style: TextStyle(fontSize: AppDims.fsBody, color: t.text)),
            ],
          ),
        ),
      ),
    );
  }
}