import 'package:english_learning/features/auth/provider/user_provider.dart';
import 'package:english_learning/features/learning/provider/section_provider.dart';
import 'package:english_learning/features/learning/widgets/section_card.dart';
import 'package:english_learning/features/learning/modules/topics/screens/topics_list_screen.dart';
import 'package:english_learning/features/learning/widgets/section_card_loading.dart';
import 'package:flutter/material.dart';
import 'package:english_learning/core/utils/styles/theme.dart';
import 'package:provider/provider.dart';

class LearningScreen extends StatefulWidget {
  const LearningScreen({super.key});

  @override
  State<LearningScreen> createState() => _LearningScreenState();
}

class _LearningScreenState extends State<LearningScreen>
    with AutomaticKeepAliveClientMixin {
  bool _isInitialLoading = true;

  @override
  bool get wantKeepAlive => true;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _initializeSections();
    });
  }

  Future<void> _initializeSections() async {
    final userProvider = Provider.of<UserProvider>(context, listen: false);
    final sectionProvider =
        Provider.of<SectionProvider>(context, listen: false);

    try {
      sectionProvider.resetData();

      final token = await userProvider.getValidToken();
      if (token != null) {
        await sectionProvider.fetchSections(token);
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Failed to load data: ${e.toString()}'),
            action: SnackBarAction(
              label: 'Retry',
              onPressed: _initializeSections,
            ),
          ),
        );
      }
    } finally {
      setState(() {
        _isInitialLoading = false;
      });
    }
  }

  Widget _buildErrorWidget(String error) {
    return Container(
      padding: const EdgeInsets.all(16),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(
            Icons.error_outline,
            size: 48,
            color: Colors.red[300],
          ),
          const SizedBox(height: 16),
          Text(
            'Oops! Something went wrong',
            style: AppTextStyles.blackTextStyle.copyWith(
              fontSize: 16,
              fontWeight: FontWeight.bold,
            ),
          ),
          const SizedBox(height: 8),
          Text(
            error,
            textAlign: TextAlign.center,
            style: AppTextStyles.disableTextStyle.copyWith(fontSize: 14),
          ),
          const SizedBox(height: 16),
          ElevatedButton.icon(
            onPressed: _initializeSections,
            icon: const Icon(Icons.refresh),
            label: const Text('Retry'),
            style: ElevatedButton.styleFrom(
              backgroundColor: AppColors.primaryColor,
              foregroundColor: Colors.white,
            ),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    super.build(context);
    return Scaffold(
      backgroundColor: AppColors.bgSoftColor,
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.only(top: 28.0, left: 16.0, right: 16.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'Choose what you want to learn!',
                style: AppTextStyles.blueTextStyle.copyWith(
                  fontSize: 18,
                  fontWeight: FontWeight.w900,
                ),
              ),
              const SizedBox(height: 8),
              Text(
                'Develop your English skills by studying the topics in each section below.',
                style: AppTextStyles.greyTextStyle.copyWith(
                  fontSize: 12,
                  fontWeight: FontWeight.w600,
                ),
              ),
              const SizedBox(height: 15),
              Expanded(
                child: Consumer<SectionProvider>(
                  builder: (context, sectionProvider, _) {
                    if (_isInitialLoading || sectionProvider.isLoading) {
                      return ListView.builder(
                        padding: const EdgeInsets.only(top: 8),
                        itemCount: 4,
                        itemBuilder: (context, index) =>
                            const SectionCardLoading(),
                      );
                    }

                    if (sectionProvider.error != null) {
                      return _buildErrorWidget(sectionProvider.error!);
                    }

                    if (sectionProvider.sections.isEmpty) {
                      return RefreshIndicator(
                        onRefresh: _initializeSections,
                        child: ListView(
                          children: [
                            Center(
                              child: Column(
                                mainAxisAlignment: MainAxisAlignment.center,
                                children: [
                                  const Icon(
                                    Icons.library_books_outlined,
                                    size: 80,
                                    color: Colors.grey,
                                  ),
                                  const SizedBox(height: 16),
                                  Text(
                                    'No sections available',
                                    style: AppTextStyles.greyTextStyle.copyWith(
                                      fontSize: 16,
                                      fontWeight: FontWeight.w600,
                                    ),
                                  ),
                                  const SizedBox(height: 16),
                                  ElevatedButton(
                                    onPressed: _initializeSections,
                                    child: const Text('Refresh'),
                                  )
                                ],
                              ),
                            ),
                          ],
                        ),
                      );
                    }

                    return RefreshIndicator(
                      onRefresh: _initializeSections,
                      child: ListView.builder(
                        itemCount: sectionProvider.sections.length,
                        itemBuilder: (context, index) {
                          final section = sectionProvider.sections[index];
                          return SectionCard(
                            section: section,
                            onTap: () => Navigator.push(
                              context,
                              MaterialPageRoute(
                                builder: (context) => TopicsListScreen(
                                  sectionId: section.id,
                                ),
                              ),
                            ),
                          );
                        },
                      ),
                    );
                  },
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}