import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../core/app_colors.dart';
import '../../core/navigation_provider.dart';
import '../../providers/auth_provider.dart';
import '../../providers/data_providers.dart';
import '../../widgets/app_gradient_widgets.dart';

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

class _LoginPageState extends ConsumerState<LoginPage> {
  static const _loginBg = 'assets/branding/login_background_v1.png';
  static const _loginActionGradient = AppColors.primaryGradient;

  void _openStaticText(String type) {
    pushRoute(ref, 'staticText', params: {'type': type});
  }

  final _phoneCtrl = TextEditingController();
  final _codeCtrl = TextEditingController();
  final _nameCtrl = TextEditingController();
  String? _selectedDoctorId;
  String? _selectedDoctorName;
  bool _agreed = false;
  bool _sending = false;
  int _countdown = 0;
  bool _loading = false;
  String? _error;
  bool _isLogin = true;
  String? _successMsg;

  @override
  void dispose() {
    _phoneCtrl.dispose();
    _codeCtrl.dispose();
    _nameCtrl.dispose();
    super.dispose();
  }

  Future<void> _sendSms() async {
    final phone = _phoneCtrl.text.trim();
    if (phone.length != 11 || !phone.startsWith('1')) {
      setState(() => _error = '请输入正确的手机号');
      return;
    }
    setState(() {
      _sending = true;
      _error = null;
    });
    final result = await ref.read(authProvider.notifier).sendSms(phone);
    setState(() => _sending = false);
    if (result.error != null) {
      setState(() => _error = result.error);
      return;
    }
    if (result.devCode != null) _codeCtrl.text = result.devCode!;
    setState(() => _countdown = 60);
    _startCountdown();
  }

  void _startCountdown() async {
    for (var i = 60; i > 0; i--) {
      await Future.delayed(const Duration(seconds: 1));
      if (mounted) setState(() => _countdown = i - 1);
    }
  }

  Future<void> _submit() async {
    if (!_agreed) {
      final accepted = await _showAgreementDialog();
      if (!mounted || accepted != true) return;
      setState(() {
        _agreed = true;
        _error = null;
      });
    }
    if (_phoneCtrl.text.trim().isEmpty || _codeCtrl.text.trim().isEmpty) {
      setState(() => _error = '请输入手机号和验证码');
      return;
    }
    setState(() {
      _loading = true;
      _error = null;
      _successMsg = null;
    });

    String? err;
    if (_isLogin) {
      err = await ref
          .read(authProvider.notifier)
          .login(_phoneCtrl.text.trim(), _codeCtrl.text.trim());
    } else {
      if (_selectedDoctorId == null) {
        setState(() {
          _loading = false;
          _error = '请选择医生';
        });
        return;
      }
      if (_nameCtrl.text.trim().isEmpty) {
        setState(() {
          _loading = false;
          _error = '请输入姓名';
        });
        return;
      }
      err = await ref
          .read(authProvider.notifier)
          .register(
            _phoneCtrl.text.trim(),
            _codeCtrl.text.trim(),
            _nameCtrl.text.trim(),
            _selectedDoctorId!,
          );
    }

    setState(() => _loading = false);
    if (err != null) {
      if (err.contains('未注册')) setState(() => _isLogin = false);
      setState(() => _error = err);
      return;
    }
    if (!_isLogin) {
      setState(() {
        _isLogin = true;
        _successMsg = '注册成功，请登录';
        _error = null;
        _phoneCtrl.clear();
        _codeCtrl.clear();
        _nameCtrl.clear();
        _selectedDoctorId = null;
        _selectedDoctorName = null;
      });
      ref.read(authProvider.notifier).logout();
    } else {
      _goHome();
    }
  }

  Future<bool?> _showAgreementDialog() {
    return showDialog<bool>(
      context: context,
      barrierDismissible: false,
      barrierColor: Colors.black.withValues(alpha: 0.54),
      builder: (ctx) => Dialog(
        insetPadding: const EdgeInsets.symmetric(horizontal: 28),
        backgroundColor: Colors.transparent,
        child: Container(
          width: double.infinity,
          constraints: const BoxConstraints(maxWidth: 380),
          padding: const EdgeInsets.fromLTRB(22, 28, 22, 22),
          decoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(28),
            boxShadow: [
              BoxShadow(
                color: Colors.black.withValues(alpha: 0.14),
                blurRadius: 34,
                offset: const Offset(0, 18),
              ),
            ],
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Text(
                '服务协议及隐私保护',
                textAlign: TextAlign.center,
                style: TextStyle(
                  fontSize: 21,
                  fontWeight: FontWeight.w900,
                  color: AppColors.textPrimary,
                  letterSpacing: 0,
                ),
              ),
              const SizedBox(height: 18),
              RichText(
                textAlign: TextAlign.center,
                text: TextSpan(
                  style: const TextStyle(
                    fontSize: 15,
                    height: 1.55,
                    fontWeight: FontWeight.w700,
                    color: AppColors.textSecondary,
                  ),
                  children: [
                    const TextSpan(text: '请阅读并同意'),
                    WidgetSpan(
                      alignment: PlaceholderAlignment.baseline,
                      baseline: TextBaseline.alphabetic,
                      child: GestureDetector(
                        onTap: () {
                          Navigator.pop(ctx, false);
                          _openStaticText('terms');
                        },
                        child: AppGradientText(
                          '《服务协议》',
                          style: TextStyle(
                            fontSize: 15,
                            height: 1.55,
                            fontWeight: FontWeight.w700,
                          ),
                        ),
                      ),
                    ),
                    const TextSpan(text: '和'),
                    WidgetSpan(
                      alignment: PlaceholderAlignment.baseline,
                      baseline: TextBaseline.alphabetic,
                      child: GestureDetector(
                        onTap: () {
                          Navigator.pop(ctx, false);
                          _openStaticText('privacy');
                        },
                        child: AppGradientText(
                          '《隐私政策》',
                          style: TextStyle(
                            fontSize: 15,
                            height: 1.55,
                            fontWeight: FontWeight.w700,
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(height: 26),
              Row(
                children: [
                  Expanded(
                    child: AppGradientOutlineButton(
                      label: '不同意',
                      onTap: () => Navigator.pop(ctx, false),
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: GestureDetector(
                      onTap: () => Navigator.pop(ctx, true),
                      child: Container(
                        height: 50,
                        alignment: Alignment.center,
                        decoration: BoxDecoration(
                          gradient: _loginActionGradient,
                          borderRadius: BorderRadius.circular(18),
                          boxShadow: AppColors.buttonShadow,
                        ),
                        child: const Text(
                          '同意',
                          style: TextStyle(
                            color: Colors.white,
                            fontSize: 16,
                            fontWeight: FontWeight.w900,
                          ),
                        ),
                      ),
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  void _goHome() {
    ref.invalidate(latestHealthProvider);
    ref.invalidate(medicationListProvider);
    ref.invalidate(medicationReminderProvider);
    ref.invalidate(currentExercisePlanProvider);
    final role = ref.read(authProvider).user?.role ?? 'User';
    if (role == 'Admin') {
      goRoute(ref, 'adminHome');
    } else if (role == 'Doctor') {
      goRoute(ref, 'doctorHome');
    } else {
      goRoute(ref, 'home');
    }
  }

  void _showDoctorPicker() {
    showModalBottomSheet(
      context: context,
      backgroundColor: Colors.white,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (ctx) => Consumer(
        builder: (ctx, ref, _) {
          final doctorsAsync = ref.watch(doctorListProvider);
          return doctorsAsync.when(
            data: (doctors) {
              final active = doctors
                  .where((d) => d['isActive'] != false)
                  .toList();
              if (active.isEmpty) {
                return const SizedBox(
                  height: 200,
                  child: Center(child: Text('暂无可用医生')),
                );
              }
              return SizedBox(
                height: 420,
                child: Column(
                  children: [
                    const Padding(
                      padding: EdgeInsets.all(18),
                      child: Text(
                        '请选择医生',
                        style: TextStyle(
                          fontSize: 18,
                          fontWeight: FontWeight.w800,
                          color: AppColors.textPrimary,
                        ),
                      ),
                    ),
                    const Divider(height: 1, color: AppColors.divider),
                    Expanded(
                      child: ListView.builder(
                        itemCount: active.length,
                        itemBuilder: (_, i) {
                          final d = active[i];
                          final name = d['name'] ?? '';
                          final title = d['title'] ?? '';
                          final dept = d['department'] ?? '';
                          return ListTile(
                            title: Text(
                              name,
                              style: const TextStyle(
                                fontWeight: FontWeight.w700,
                              ),
                            ),
                            subtitle: Text(
                              '$title · $dept',
                              style: const TextStyle(
                                fontSize: 13,
                                color: AppColors.textSecondary,
                              ),
                            ),
                            trailing: _selectedDoctorId == d['id']?.toString()
                                ? const AppGradientIcon(
                                    icon: Icons.check_circle,
                                    size: 22,
                                  )
                                : null,
                            onTap: () {
                              setState(() {
                                _selectedDoctorId = d['id']?.toString();
                                _selectedDoctorName = name;
                              });
                              Navigator.pop(ctx);
                            },
                          );
                        },
                      ),
                    ),
                  ],
                ),
              );
            },
            loading: () => const SizedBox(
              height: 200,
              child: Center(child: CircularProgressIndicator()),
            ),
            error: (_, _) =>
                const SizedBox(height: 200, child: Center(child: Text('加载失败'))),
          );
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final authState = ref.watch(authProvider);
    if (authState.isLoggedIn && !authState.isLoading) {
      WidgetsBinding.instance.addPostFrameCallback((_) => _goHome());
    }

    return Scaffold(
      resizeToAvoidBottomInset: false,
      backgroundColor: Colors.white,
      body: Stack(
        children: [
          Positioned.fill(
            child: Image.asset(
              _loginBg,
              fit: BoxFit.cover,
              alignment: Alignment.topCenter,
            ),
          ),
          Positioned.fill(
            child: DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: Alignment.bottomCenter,
                  colors: [
                    Colors.white.withValues(alpha: 0.10),
                    Colors.white.withValues(alpha: 0.28),
                    Colors.white.withValues(alpha: 0.54),
                  ],
                  stops: const [0.0, 0.52, 1.0],
                ),
              ),
            ),
          ),
          SafeArea(
            child: LayoutBuilder(
              builder: (context, constraints) {
                return SingleChildScrollView(
                  padding: const EdgeInsets.fromLTRB(20, 28, 20, 24),
                  child: ConstrainedBox(
                    constraints: BoxConstraints(
                      minHeight: (constraints.maxHeight - 52).clamp(
                        0.0,
                        double.infinity,
                      ),
                    ),
                    child: Center(
                      child: ConstrainedBox(
                        constraints: const BoxConstraints(maxWidth: 430),
                        child: Column(
                          mainAxisSize: MainAxisSize.min,
                          crossAxisAlignment: CrossAxisAlignment.stretch,
                          children: [
                            const _LoginHero(),
                            const SizedBox(height: 28),
                            _LoginFormCard(
                              child: Column(
                                mainAxisSize: MainAxisSize.min,
                                children: [
                                  if (_successMsg != null)
                                    _NoticeBanner(
                                      text: _successMsg!,
                                      success: true,
                                    ),
                                  if (!_isLogin) ...[
                                    _DoctorSelector(
                                      name: _selectedDoctorName,
                                      onTap: _showDoctorPicker,
                                    ),
                                    const SizedBox(height: 12),
                                    _TextField(
                                      _nameCtrl,
                                      '姓名',
                                      TextInputType.name,
                                      20,
                                      icon: Icons.person_outline_rounded,
                                    ),
                                    const SizedBox(height: 12),
                                  ],
                                  _TextField(
                                    _phoneCtrl,
                                    '手机号',
                                    TextInputType.phone,
                                    11,
                                    icon: Icons.local_phone_rounded,
                                    gradientIcon: true,
                                  ),
                                  const SizedBox(height: 12),
                                  Row(
                                    children: [
                                      Expanded(
                                        child: _TextField(
                                          _codeCtrl,
                                          '验证码',
                                          TextInputType.number,
                                          6,
                                          icon: Icons.sms_rounded,
                                          gradientIcon: true,
                                        ),
                                      ),
                                      const SizedBox(width: 10),
                                      _SmsButton(
                                        sending: _sending,
                                        countdown: _countdown,
                                        onTap: (_countdown > 0 || _sending)
                                            ? null
                                            : _sendSms,
                                      ),
                                    ],
                                  ),
                                  const SizedBox(height: 14),
                                  _Agreement(
                                    agreed: _agreed,
                                    onTap: () =>
                                        setState(() => _agreed = !_agreed),
                                    onTermsTap: () => _openStaticText('terms'),
                                    onPrivacyTap: () =>
                                        _openStaticText('privacy'),
                                  ),
                                  if (_error != null) ...[
                                    const SizedBox(height: 12),
                                    _NoticeBanner(
                                      text: _error!,
                                      success: false,
                                    ),
                                  ],
                                  const SizedBox(height: 22),
                                  _PrimaryButton(
                                    loading: _loading,
                                    label: _isLogin ? '登录' : '注册',
                                    onTap: _loading ? null : _submit,
                                  ),
                                  const SizedBox(height: 16),
                                  GestureDetector(
                                    onTap: () => setState(() {
                                      _isLogin = !_isLogin;
                                      _error = null;
                                      _successMsg = null;
                                    }),
                                    child: Center(
                                      child: AppGradientText(
                                        _isLogin ? '没有账号？去注册' : '已有账号？去登录',
                                        style: const TextStyle(
                                          fontSize: 14,
                                          fontWeight: FontWeight.w800,
                                        ),
                                      ),
                                    ),
                                  ),
                                ],
                              ),
                            ),
                          ],
                        ),
                      ),
                    ),
                  ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

class _LoginHero extends StatelessWidget {
  const _LoginHero();

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        _BrandMark(),
        const SizedBox(height: 16),
        const Text(
          '小脉健康',
          style: TextStyle(
            fontSize: 30,
            fontWeight: FontWeight.w900,
            color: AppColors.textPrimary,
            letterSpacing: 0,
          ),
        ),
        const SizedBox(height: 6),
        const Text(
          '血管病患者的 AI 健康管理助手',
          textAlign: TextAlign.center,
          style: TextStyle(
            fontSize: 14,
            height: 1.45,
            fontWeight: FontWeight.w700,
            color: AppColors.textSecondary,
          ),
        ),
      ],
    );
  }
}

class _LoginFormCard extends StatelessWidget {
  final Widget child;

  const _LoginFormCard({required this.child});

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.fromLTRB(18, 18, 18, 20),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.94),
        borderRadius: BorderRadius.circular(22),
        border: Border.all(color: AppColors.border, width: 1.1),
        boxShadow: [
          BoxShadow(
            color: const Color(0xFF475467).withValues(alpha: 0.10),
            blurRadius: 30,
            offset: const Offset(0, 16),
          ),
        ],
      ),
      child: child,
    );
  }
}

class _BrandMark extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 132,
      height: 132,
      child: Transform.scale(
        scale: 1.08,
        child: Image.asset(
          'assets/branding/health_icon_master.png',
          fit: BoxFit.cover,
        ),
      ),
    );
  }
}

class _TextField extends StatelessWidget {
  final TextEditingController ctrl;
  final String hint;
  final TextInputType type;
  final int maxLen;
  final IconData? icon;
  final bool gradientIcon;

  const _TextField(
    this.ctrl,
    this.hint,
    this.type,
    this.maxLen, {
    this.icon,
    this.gradientIcon = false,
  });

  @override
  Widget build(BuildContext context) => TextField(
    controller: ctrl,
    keyboardType: type,
    maxLength: maxLen,
    style: const TextStyle(
      fontSize: 15,
      fontWeight: FontWeight.w700,
      color: AppColors.textPrimary,
    ),
    decoration: InputDecoration(
      hintText: hint,
      counterText: '',
      prefixIcon: icon == null
          ? null
          : gradientIcon
          ? _GradientPrefixIcon(icon: icon!)
          : Icon(icon, size: 20, color: AppColors.textSecondary),
      filled: true,
      fillColor: const Color(0xFFF8FAFC),
      contentPadding: const EdgeInsets.symmetric(horizontal: 14, vertical: 15),
      enabledBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(14),
        borderSide: const BorderSide(color: AppColors.border, width: 1.1),
      ),
      focusedBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(14),
        borderSide: const BorderSide(color: AppColors.auraIndigo, width: 1.2),
      ),
    ),
  );
}

class _GradientPrefixIcon extends StatelessWidget {
  final IconData icon;
  const _GradientPrefixIcon({required this.icon});

  @override
  Widget build(BuildContext context) {
    return AppGradientIcon(
      icon: icon,
      size: 23,
      gradient: _LoginPageState._loginActionGradient,
    );
  }
}

class _DoctorSelector extends StatelessWidget {
  final String? name;
  final VoidCallback onTap;
  const _DoctorSelector({required this.name, required this.onTap});

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Container(
        height: 50,
        padding: const EdgeInsets.symmetric(horizontal: 14),
        decoration: BoxDecoration(
          color: const Color(0xFFF8FAFC),
          borderRadius: BorderRadius.circular(14),
          border: Border.all(color: AppColors.border, width: 1.1),
        ),
        child: Row(
          children: [
            const Icon(
              Icons.medical_services_outlined,
              size: 20,
              color: AppColors.textSecondary,
            ),
            const SizedBox(width: 12),
            Expanded(
              child: Text(
                name ?? '请选择医生',
                style: TextStyle(
                  fontSize: 15,
                  fontWeight: FontWeight.w700,
                  color: name != null
                      ? AppColors.textPrimary
                      : AppColors.textHint,
                ),
              ),
            ),
            const Icon(Icons.keyboard_arrow_down, color: AppColors.textHint),
          ],
        ),
      ),
    );
  }
}

class _SmsButton extends StatelessWidget {
  final bool sending;
  final int countdown;
  final VoidCallback? onTap;
  const _SmsButton({
    required this.sending,
    required this.countdown,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final disabled = countdown > 0 || sending;
    return GestureDetector(
      onTap: onTap,
      child: Container(
        width: 108,
        height: 50,
        alignment: Alignment.center,
        decoration: BoxDecoration(
          gradient: disabled ? null : _LoginPageState._loginActionGradient,
          color: disabled ? AppColors.cardInner : null,
          borderRadius: BorderRadius.circular(14),
          border: Border.all(
            color: disabled ? AppColors.border : Colors.transparent,
          ),
        ),
        child: Text(
          sending
              ? '发送中'
              : countdown > 0
              ? '${countdown}s'
              : '获取验证码',
          style: TextStyle(
            fontSize: 13,
            fontWeight: FontWeight.w700,
            color: disabled ? AppColors.textSecondary : Colors.white,
          ),
        ),
      ),
    );
  }
}

class _Agreement extends StatelessWidget {
  final bool agreed;
  final VoidCallback onTap;
  final VoidCallback onTermsTap;
  final VoidCallback onPrivacyTap;
  const _Agreement({
    required this.agreed,
    required this.onTap,
    required this.onTermsTap,
    required this.onPrivacyTap,
  });

  @override
  Widget build(BuildContext context) {
    const textStyle = TextStyle(fontSize: 13, color: AppColors.textHint);
    const linkStyle = TextStyle(fontSize: 13, fontWeight: FontWeight.w700);

    return Row(
      crossAxisAlignment: CrossAxisAlignment.center,
      children: [
        GestureDetector(
          onTap: onTap,
          behavior: HitTestBehavior.opaque,
          child: Container(
            width: 18,
            height: 18,
            margin: const EdgeInsets.only(right: 7),
            decoration: BoxDecoration(
              gradient: agreed ? _LoginPageState._loginActionGradient : null,
              color: agreed ? null : Colors.white,
              borderRadius: BorderRadius.circular(5),
              border: Border.all(
                color: agreed ? Colors.transparent : AppColors.border,
              ),
            ),
            child: agreed
                ? const Icon(Icons.check, size: 13, color: Colors.white)
                : null,
          ),
        ),
        Expanded(
          child: Wrap(
            crossAxisAlignment: WrapCrossAlignment.center,
            children: [
              GestureDetector(
                onTap: onTap,
                behavior: HitTestBehavior.opaque,
                child: const Text('已阅读并同意', style: textStyle),
              ),
              GestureDetector(
                onTap: onTermsTap,
                behavior: HitTestBehavior.opaque,
                child: const AppGradientText('《服务协议》', style: linkStyle),
              ),
              const Text('和', style: textStyle),
              GestureDetector(
                onTap: onPrivacyTap,
                behavior: HitTestBehavior.opaque,
                child: const AppGradientText('《隐私政策》', style: linkStyle),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _NoticeBanner extends StatelessWidget {
  final String text;
  final bool success;
  const _NoticeBanner({required this.text, required this.success});

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      margin: const EdgeInsets.only(bottom: 12),
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
      decoration: BoxDecoration(
        color: success ? AppColors.successLight : AppColors.errorLight,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(
          color: success
              ? AppColors.success.withValues(alpha: 0.16)
              : AppColors.error.withValues(alpha: 0.16),
        ),
      ),
      child: Row(
        children: [
          Icon(
            success ? Icons.check_circle : Icons.error_outline,
            color: success ? AppColors.success : AppColors.error,
            size: 18,
          ),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              text,
              style: TextStyle(
                color: success ? AppColors.success : AppColors.error,
                fontSize: 13,
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class _PrimaryButton extends StatelessWidget {
  final bool loading;
  final String label;
  final VoidCallback? onTap;
  const _PrimaryButton({
    required this.loading,
    required this.label,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Container(
        width: double.infinity,
        height: 52,
        alignment: Alignment.center,
        decoration: BoxDecoration(
          gradient: _LoginPageState._loginActionGradient,
          borderRadius: BorderRadius.circular(14),
          boxShadow: AppColors.buttonShadow,
        ),
        child: loading
            ? const SizedBox(
                width: 23,
                height: 23,
                child: CircularProgressIndicator(
                  strokeWidth: 2.5,
                  color: Colors.white,
                ),
              )
            : Text(
                label,
                style: const TextStyle(
                  fontSize: 17,
                  color: Colors.white,
                  fontWeight: FontWeight.w800,
                ),
              ),
      ),
    );
  }
}