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

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

class _LoginPageState extends ConsumerState<LoginPage> {
  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) {
      setState(() => _error = '请阅读并同意服务协议和隐私政策');
      return;
    }
    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();
    }
  }

  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 Icon(
                                    Icons.check_circle,
                                    color: AppColors.primary,
                                  )
                                : 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(
      body: AppBackground(
        safeArea: true,
        child: Center(
          child: SingleChildScrollView(
            padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 24),
            child: Container(
              padding: const EdgeInsets.fromLTRB(22, 24, 22, 22),
              decoration: BoxDecoration(
                gradient: AppColors.softGlassGradient,
                borderRadius: BorderRadius.circular(24),
                border: Border.all(color: AppColors.borderLight),
                boxShadow: AppColors.cardShadow,
              ),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  _BrandMark(),
                  const SizedBox(height: 16),
                  const Text(
                    '小脉健康',
                    style: TextStyle(
                      fontSize: 26,
                      fontWeight: FontWeight.w900,
                      color: AppColors.textPrimary,
                    ),
                  ),
                  const SizedBox(height: 4),
                  const Text(
                    '血管病患者的 AI 健康管理助手',
                    style: TextStyle(fontSize: 13, color: AppColors.textSecondary),
                  ),
                  const SizedBox(height: 8),
                  Text(
                    _isLogin ? '登录你的健康账户' : '创建新的健康账户',
                    style: const TextStyle(
                      fontSize: 14,
                      color: AppColors.textSecondary,
                    ),
                  ),
                  const SizedBox(height: 26),
                  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),
                    const SizedBox(height: 12),
                  ],
                  _TextField(_phoneCtrl, '手机号', TextInputType.phone, 11),
                  const SizedBox(height: 12),
                  Row(
                    children: [
                      Expanded(
                        child: _TextField(
                          _codeCtrl,
                          '验证码',
                          TextInputType.number,
                          6,
                        ),
                      ),
                      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),
                  ),
                  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: Text(
                      _isLogin ? '没有账号？去注册' : '已有账号？去登录',
                      style: const TextStyle(
                        fontSize: 14,
                        fontWeight: FontWeight.w700,
                        color: AppColors.primary,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _BrandMark extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      width: 68,
      height: 68,
      decoration: BoxDecoration(
        gradient: AppColors.primaryGradient,
        borderRadius: BorderRadius.circular(22),
        boxShadow: AppColors.buttonShadow,
      ),
      child: const Icon(
        Icons.monitor_heart_outlined,
        color: Colors.white,
        size: 34,
      ),
    );
  }
}

class _TextField extends StatelessWidget {
  final TextEditingController ctrl;
  final String hint;
  final TextInputType type;
  final int maxLen;
  const _TextField(this.ctrl, this.hint, this.type, this.maxLen);

  @override
  Widget build(BuildContext context) => TextField(
    controller: ctrl,
    keyboardType: type,
    maxLength: maxLen,
    style: const TextStyle(fontSize: 15, color: AppColors.textPrimary),
    decoration: InputDecoration(hintText: hint, counterText: ''),
  );
}

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: Colors.white,
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: AppColors.border),
        ),
        child: Row(
          children: [
            Expanded(
              child: Text(
                name ?? '请选择医生',
                style: TextStyle(
                  fontSize: 15,
                  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(
          color: disabled ? AppColors.cardInner : AppColors.primary,
          borderRadius: BorderRadius.circular(12),
          border: Border.all(
            color: disabled ? AppColors.border : AppColors.primary,
          ),
        ),
        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;
  const _Agreement({required this.agreed, required this.onTap});

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Container(
            width: 18,
            height: 18,
            margin: const EdgeInsets.only(right: 6),
            decoration: BoxDecoration(
              color: agreed ? AppColors.primary : Colors.white,
              borderRadius: BorderRadius.circular(5),
              border: Border.all(
                color: agreed ? AppColors.primary : AppColors.border,
              ),
            ),
            child: agreed
                ? const Icon(Icons.check, size: 13, color: Colors.white)
                : null,
          ),
          Flexible(
            child: RichText(
              text: const TextSpan(
                children: [
                  TextSpan(
                    text: '已阅读并同意',
                    style: TextStyle(fontSize: 12, color: AppColors.textHint),
                  ),
                  TextSpan(
                    text: '《服务协议》',
                    style: TextStyle(
                      fontSize: 12,
                      color: AppColors.primary,
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                  TextSpan(
                    text: '和',
                    style: TextStyle(fontSize: 12, color: AppColors.textHint),
                  ),
                  TextSpan(
                    text: '《隐私政策》',
                    style: TextStyle(
                      fontSize: 12,
                      color: AppColors.primary,
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}

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),
      ),
      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: AppColors.primaryGradient,
          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,
                ),
              ),
      ),
    );
  }
}