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

import '../core/app_colors.dart';
import '../core/app_design_tokens.dart';
import '../core/navigation_provider.dart';
import '../providers/ai_consent_provider.dart';
import '../providers/auth_provider.dart';

class AiConsentGate extends ConsumerStatefulWidget {
  final Widget child;
  const AiConsentGate({super.key, required this.child});

  @override
  ConsumerState<AiConsentGate> createState() => _AiConsentGateState();
}

class _AiConsentGateState extends ConsumerState<AiConsentGate> {
  String? _loadedUserId;

  @override
  Widget build(BuildContext context) {
    final user = ref.watch(authProvider).user;
    if (user == null || user.id.isEmpty || user.role != 'User') {
      return widget.child;
    }

    if (_loadedUserId != user.id) {
      _loadedUserId = user.id;
      Future<void>.microtask(
        () => ref.read(aiConsentProvider.notifier).load(user.id),
      );
    }

    final consent = ref.watch(aiConsentProvider);
    final currentRoute = ref.watch(currentRouteProvider).name;
    final isConsentInformationRoute =
        currentRoute == 'aiConsentDetails' || currentRoute == 'staticText';

    if (consent.userId != user.id || consent.isLoading) {
      return const _ConsentLoadingPage();
    }
    if (consent.granted || isConsentInformationRoute) return widget.child;

    return _ConsentPage(userId: user.id);
  }
}

class _ConsentLoadingPage extends StatelessWidget {
  const _ConsentLoadingPage();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: DecoratedBox(
        decoration: const BoxDecoration(gradient: AppColors.bgGradient),
        child: const SafeArea(
          child: Center(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                SizedBox(
                  width: 30,
                  height: 30,
                  child: CircularProgressIndicator(
                    strokeWidth: 3,
                    color: AppColors.primary,
                  ),
                ),
                SizedBox(height: 14),
                Text(
                  '正在加载授权状态…',
                  style: TextStyle(
                    fontSize: 15,
                    color: AppColors.textSecondary,
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

class _ConsentPage extends ConsumerWidget {
  final String userId;
  const _ConsentPage({required this.userId});

  Future<void> _grant(BuildContext context, WidgetRef ref) async {
    final succeeded = await ref.read(aiConsentProvider.notifier).grant(userId);
    if (!succeeded && context.mounted) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('授权保存失败，请稍后重试')));
    }
  }

  Future<void> _decline(WidgetRef ref) async {
    await ref.read(authProvider.notifier).logout();
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final consent = ref.watch(aiConsentProvider);

    return Scaffold(
      body: DecoratedBox(
        decoration: const BoxDecoration(gradient: AppColors.bgGradient),
        child: SafeArea(
          child: Center(
            child: SingleChildScrollView(
              padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 20),
              child: ConstrainedBox(
                constraints: const BoxConstraints(maxWidth: 400),
                child: Container(
                  padding: const EdgeInsets.fromLTRB(20, 10, 20, 20),
                  decoration: BoxDecoration(
                    color: Colors.white.withValues(alpha: 0.96),
                    borderRadius: AppRadius.cardBorder,
                    border: Border.all(color: AppColors.primaryLight, width: 1),
                    boxShadow: AppShadows.panel,
                  ),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      Align(
                        child: Image.asset(
                          'assets/branding/health_login_character_transparent.png',
                          height: 112,
                          fit: BoxFit.contain,
                          semanticLabel: '小脉健康智能助手',
                        ),
                      ),
                      const SizedBox(height: 2),
                      Align(
                        child: Container(
                          padding: const EdgeInsets.symmetric(
                            horizontal: 12,
                            vertical: 6,
                          ),
                          decoration: BoxDecoration(
                            color: AppColors.primarySoft,
                            borderRadius: AppRadius.pillBorder,
                          ),
                          child: const Text(
                            '小脉健康 · AI 服务',
                            style: TextStyle(
                              fontSize: 13,
                              fontWeight: FontWeight.w600,
                              color: AppColors.primaryDark,
                            ),
                          ),
                        ),
                      ),
                      const SizedBox(height: 14),
                      const Text(
                        'AI 健康服务授权',
                        textAlign: TextAlign.center,
                        style: TextStyle(
                          fontSize: 22,
                          height: 1.25,
                          fontWeight: FontWeight.w700,
                          color: AppColors.textPrimary,
                        ),
                      ),
                      const SizedBox(height: 14),
                      const Text(
                        '小脉健康的核心功能使用第三方 AI 服务。经你同意后，你主动输入的健康信息、对话内容、图片和报告可能会发送给相关 AI 服务，用于健康记录、饮食识别、报告整理和 AI 回复。',
                        style: TextStyle(
                          fontSize: 15,
                          height: 1.6,
                          color: AppColors.textSecondary,
                        ),
                      ),
                      const SizedBox(height: 10),
                      const Text(
                        'AI 生成内容仅供健康管理参考，不能替代医生诊断或治疗。',
                        style: TextStyle(
                          fontSize: 14,
                          height: 1.5,
                          color: AppColors.textSecondary,
                        ),
                      ),
                      if (consent.error != null) ...[
                        const SizedBox(height: 14),
                        _ConsentErrorBanner(
                          message: consent.error!,
                          onRetry: consent.isSaving
                              ? null
                              : () => ref
                                    .read(aiConsentProvider.notifier)
                                    .load(userId),
                        ),
                      ],
                      const SizedBox(height: 8),
                      TextButton(
                        onPressed: consent.isSaving
                            ? null
                            : () => pushRoute(ref, 'aiConsentDetails'),
                        child: const Text('查看《AI 数据处理说明》'),
                      ),
                      const SizedBox(height: 8),
                      Row(
                        children: [
                          Expanded(
                            child: _GradientConsentButton(
                              loading: consent.isSaving,
                              onTap: consent.isSaving
                                  ? null
                                  : () => _grant(context, ref),
                            ),
                          ),
                          const SizedBox(width: 12),
                          Expanded(
                            child: OutlinedButton(
                              onPressed: consent.isSaving
                                  ? null
                                  : () => _decline(ref),
                              style: OutlinedButton.styleFrom(
                                minimumSize: const Size.fromHeight(50),
                                foregroundColor: AppColors.textSecondary,
                                side: const BorderSide(color: AppColors.border),
                                shape: RoundedRectangleBorder(
                                  borderRadius: AppRadius.lgBorder,
                                ),
                              ),
                              child: const Text('不同意并退出'),
                            ),
                          ),
                        ],
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _ConsentErrorBanner extends StatelessWidget {
  final String message;
  final VoidCallback? onRetry;

  const _ConsentErrorBanner({required this.message, this.onRetry});

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.fromLTRB(12, 10, 8, 10),
      decoration: BoxDecoration(
        color: AppColors.errorLight,
        borderRadius: AppRadius.mdBorder,
      ),
      child: Row(
        children: [
          const Icon(
            Icons.error_outline_rounded,
            size: 20,
            color: AppColors.errorText,
          ),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              message,
              style: const TextStyle(fontSize: 13, color: AppColors.errorText),
            ),
          ),
          if (onRetry != null)
            TextButton(onPressed: onRetry, child: const Text('重试')),
        ],
      ),
    );
  }
}

class _GradientConsentButton extends StatelessWidget {
  final bool loading;
  final VoidCallback? onTap;

  const _GradientConsentButton({required this.loading, required this.onTap});

  @override
  Widget build(BuildContext context) {
    return Semantics(
      button: true,
      enabled: onTap != null,
      label: loading ? '正在保存授权' : '同意并继续',
      child: IgnorePointer(
        ignoring: onTap == null,
        child: AnimatedOpacity(
          duration: const Duration(milliseconds: 160),
          opacity: onTap == null && !loading ? 0.55 : 1,
          child: Container(
            height: 50,
            decoration: BoxDecoration(
              gradient: AppColors.primaryGradient,
              borderRadius: AppRadius.lgBorder,
              boxShadow: AppColors.buttonShadow,
            ),
            child: Material(
              color: Colors.transparent,
              child: InkWell(
                onTap: onTap,
                borderRadius: AppRadius.lgBorder,
                child: Center(
                  child: loading
                      ? const SizedBox(
                          width: 22,
                          height: 22,
                          child: CircularProgressIndicator(
                            strokeWidth: 2.4,
                            color: Colors.white,
                          ),
                        )
                      : const Text(
                          '同意并继续',
                          style: TextStyle(
                            fontSize: 16,
                            fontWeight: FontWeight.w700,
                            color: Colors.white,
                          ),
                        ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}