import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:lucide_icons/lucide_icons.dart';
import 'package:intl/intl.dart';
import '../providers/product_categories_provider.dart';
import '../domain/category_rate_history.dart';

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

  @override
  ConsumerState<DailyRatesScreen> createState() => _DailyRatesScreenState();
}

class _DailyRatesScreenState extends ConsumerState<DailyRatesScreen> {
  final Map<int, TextEditingController> _rateControllers = {};
  final Map<int, bool> _isExpanded = {};
  final Map<int, List<CategoryRateHistory>> _historyCache = {};
  final Map<int, bool> _isLoadingHistory = {};

  @override
  void dispose() {
    for (var controller in _rateControllers.values) {
      controller.dispose();
    }
    super.dispose();
  }

  Future<void> _fetchHistory(int categoryId) async {
    setState(() => _isLoadingHistory[categoryId] = true);
    final historyData = await ref.read(productCategoriesProvider.notifier).fetchRateHistory(categoryId);
    setState(() {
      _historyCache[categoryId] = historyData.map((e) => CategoryRateHistory.fromJson(e)).toList();
      _isLoadingHistory[categoryId] = false;
    });
  }

  void _toggleExpand(int categoryId) {
    setState(() {
      _isExpanded[categoryId] = !(_isExpanded[categoryId] ?? false);
    });
    if (_isExpanded[categoryId] == true && _historyCache[categoryId] == null) {
      _fetchHistory(categoryId);
    }
  }

  Future<void> _saveRate(int categoryId) async {
    final text = _rateControllers[categoryId]?.text;
    if (text == null || text.isEmpty) return;
    
    final rate = double.tryParse(text);
    if (rate == null) return;

    try {
      showDialog(
        context: context, 
        barrierDismissible: false,
        builder: (_) => const Center(child: CircularProgressIndicator()),
      );
      
      await ref.read(productCategoriesProvider.notifier).updateCategoryRate(categoryId, rate);
      
      if (mounted) {
        Navigator.pop(context); // close loading
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Rate updated successfully!'), backgroundColor: Colors.green),
        );
        _fetchHistory(categoryId); // refresh history
      }
    } catch (e) {
      if (mounted) {
        Navigator.pop(context);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Error updating rate: $e'), backgroundColor: Colors.red),
        );
      }
    }
  }

  Future<void> _syncRates(int categoryId) async {
    try {
      showDialog(
        context: context, 
        barrierDismissible: false,
        builder: (_) => const Center(child: CircularProgressIndicator()),
      );
      
      final count = await ref.read(productCategoriesProvider.notifier).syncRates(categoryId);
      
      if (mounted) {
        Navigator.pop(context); // close loading
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Successfully synced rates for $count products!'), backgroundColor: Colors.green),
        );
      }
    } catch (e) {
      if (mounted) {
        Navigator.pop(context);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Error syncing rates: $e'), backgroundColor: Colors.red),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final categoriesState = ref.watch(productCategoriesProvider);

    return Scaffold(
      backgroundColor: Colors.grey[50],
      appBar: AppBar(
        title: const Text('Daily Commodity Rates', style: TextStyle(fontWeight: FontWeight.bold, fontSize: 20)),
        backgroundColor: Colors.white,
        foregroundColor: Colors.black,
        elevation: 0,
        centerTitle: true,
      ),
      body: categoriesState.when(
        data: (categories) {
          final commodities = categories.where((c) => c.isCommodity).toList();
          
          if (commodities.isEmpty) {
            return Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(LucideIcons.boxes, size: 64, color: Colors.grey.shade300),
                  const SizedBox(height: 16),
                  Text('No Commodity Categories', style: TextStyle(fontSize: 18, color: Colors.grey.shade600)),
                  const SizedBox(height: 8),
                  Text('Mark a category as a commodity to manage its daily rates.', style: TextStyle(color: Colors.grey.shade500)),
                ],
              ),
            );
          }

          return RefreshIndicator(
            onRefresh: () async {
              ref.invalidate(productCategoriesProvider);
              await ref.read(productCategoriesProvider.future);
            },
            child: ListView.builder(
            padding: const EdgeInsets.all(16),
            itemCount: commodities.length,
            itemBuilder: (context, index) {
              final category = commodities[index];
              if (!_rateControllers.containsKey(category.id)) {
                _rateControllers[category.id!] = TextEditingController(text: category.dailyRate?.toString() ?? '');
              }
              final controller = _rateControllers[category.id]!;
              final isExpanded = _isExpanded[category.id] ?? false;
              final history = _historyCache[category.id];
              final isLoadingHistory = _isLoadingHistory[category.id] ?? false;
              
              DateTime? lastSyncDate;
              if (history != null && history.isNotEmpty) {
                lastSyncDate = history.first.updatedAt;
              }

              return Container(
                margin: const EdgeInsets.only(bottom: 16),
                decoration: BoxDecoration(
                  color: Colors.white,
                  borderRadius: BorderRadius.circular(16),
                  boxShadow: [
                    BoxShadow(color: Colors.grey.withOpacity(0.05), blurRadius: 10, offset: const Offset(0, 4)),
                  ],
                  border: Border.all(color: Colors.grey.shade200),
                ),
                child: Column(
                  children: [
                    // Main Card Header
                    Padding(
                      padding: const EdgeInsets.all(20),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Row(
                            mainAxisAlignment: MainAxisAlignment.spaceBetween,
                            children: [
                              Row(
                                children: [
                                  Container(
                                    padding: const EdgeInsets.all(10),
                                    decoration: BoxDecoration(
                                      color: Colors.blue.shade50,
                                      borderRadius: BorderRadius.circular(12),
                                    ),
                                    child: Icon(LucideIcons.trendingUp, color: Colors.blue.shade700, size: 24),
                                  ),
                                  const SizedBox(width: 16),
                                  Column(
                                    crossAxisAlignment: CrossAxisAlignment.start,
                                    children: [
                                      Text(
                                        category.name,
                                        style: const TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                                      ),
                                      const SizedBox(height: 4),
                                      if (lastSyncDate != null)
                                        Text(
                                          'Last updated: ${DateFormat('MMM dd, yyyy HH:mm').format(lastSyncDate)}',
                                          style: TextStyle(fontSize: 12, color: Colors.grey.shade500),
                                        )
                                      else
                                        Text(
                                          'Base Unit: ${category.baseUnit}',
                                          style: TextStyle(fontSize: 12, color: Colors.grey.shade500),
                                        ),
                                    ],
                                  ),
                                ],
                              ),
                              IconButton(
                                icon: Icon(isExpanded ? LucideIcons.chevronUp : LucideIcons.history, color: Colors.grey.shade600),
                                onPressed: () => _toggleExpand(category.id!),
                                tooltip: 'View History',
                              ),
                            ],
                          ),
                          const SizedBox(height: 24),
                          Row(
                            children: [
                              Expanded(
                                flex: 3,
                                child: TextFormField(
                                  controller: controller,
                                  keyboardType: const TextInputType.numberWithOptions(decimal: true),
                                  decoration: InputDecoration(
                                    labelText: 'Today\'s Rate (per ${category.baseUnit})',
                                    prefixText: '₹ ',
                                    border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)),
                                    contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
                                  ),
                                ),
                              ),
                              const SizedBox(width: 12),
                              Expanded(
                                flex: 2,
                                child: ElevatedButton.icon(
                                  onPressed: () => _saveRate(category.id!),
                                  icon: const Icon(LucideIcons.save, size: 18),
                                  label: const Text('Save'),
                                  style: ElevatedButton.styleFrom(
                                    backgroundColor: Colors.blue.shade700,
                                    foregroundColor: Colors.white,
                                    padding: const EdgeInsets.symmetric(vertical: 14),
                                    shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                                  ),
                                ),
                              ),
                            ],
                          ),
                          const SizedBox(height: 16),
                          SizedBox(
                            width: double.infinity,
                            child: OutlinedButton.icon(
                              onPressed: () => _syncRates(category.id!),
                              icon: Icon(LucideIcons.refreshCw, size: 18, color: Colors.blue.shade700),
                              label: const Text('Sync Rate to All Products', style: TextStyle(fontWeight: FontWeight.bold)),
                              style: OutlinedButton.styleFrom(
                                foregroundColor: Colors.blue.shade700,
                                side: BorderSide(color: Colors.blue.shade700),
                                padding: const EdgeInsets.symmetric(vertical: 14),
                                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                              ),
                            ),
                          ),
                        ],
                      ),
                    ),
                    
                    // Expandable History Section
                    if (isExpanded)
                      Container(
                        decoration: BoxDecoration(
                          color: Colors.grey.shade50,
                          borderRadius: const BorderRadius.vertical(bottom: Radius.circular(16)),
                          border: Border(top: BorderSide(color: Colors.grey.shade200)),
                        ),
                        padding: const EdgeInsets.all(20),
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            const Text('Rate History', style: TextStyle(fontWeight: FontWeight.bold, fontSize: 14)),
                            const SizedBox(height: 12),
                            if (isLoadingHistory)
                              const Center(child: Padding(padding: EdgeInsets.all(16), child: CircularProgressIndicator()))
                            else if (history == null || history.isEmpty)
                              const Padding(
                                padding: EdgeInsets.all(16.0),
                                child: Text('No history found.'),
                              )
                            else
                              ListView.separated(
                                shrinkWrap: true,
                                physics: const NeverScrollableScrollPhysics(),
                                itemCount: history.length > 5 ? 5 : history.length, // Show up to 5 recent
                                separatorBuilder: (_, __) => Divider(color: Colors.grey.shade300),
                                itemBuilder: (context, idx) {
                                  final item = history[idx];
                                  return Padding(
                                    padding: const EdgeInsets.symmetric(vertical: 8),
                                    child: Row(
                                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                                      children: [
                                        Text(DateFormat('MMM dd, yyyy').format(item.date), style: const TextStyle(fontWeight: FontWeight.w500)),
                                        Text('₹ ${item.rate.toStringAsFixed(2)}', style: const TextStyle(fontWeight: FontWeight.bold)),
                                      ],
                                    ),
                                  );
                                },
                              ),
                          ],
                        ),
                      ),
                  ],
                ),
              );
            },
          ));
        },
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (err, stack) => Center(child: Text('Error: $err')),
      ),
    );
  }
}