import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:lucide_icons/lucide_icons.dart';
import '../../transactions/providers/providers.dart';
import '../../transactions/data/models.dart';
import '../../../core/widgets/shimmer_loading.dart';

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

  @override
  ConsumerState<BudgetScreen> createState() => _BudgetScreenState();
}

class _BudgetScreenState extends ConsumerState<BudgetScreen> {
  String _searchQuery = '';
  String? _filterNature;
  bool _isSearching = false;
  final TextEditingController _searchController = TextEditingController();

  @override
  void dispose() {
    _searchController.dispose();
    super.dispose();
  }

  Future<void> _onRefresh() async {
    ref.invalidate(budgetProvider);
    ref.invalidate(walletProvider);
    ref.invalidate(transactionProvider);
    await Future.delayed(const Duration(milliseconds: 500));
  }

  void _showSetBudgetDialog(BuildContext context, Wallet wallet, Budget? existingBudget) {
    final controller = TextEditingController(text: existingBudget?.monthlyLimit.toString() ?? '');
    bool isShared = existingBudget?.isShared ?? false;

    showDialog(
      context: context,
      builder: (ctx) => StatefulBuilder(
        builder: (context, setState) {
          return Dialog(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(28)),
            elevation: 0,
            backgroundColor: Colors.transparent,
            child: GestureDetector(
              onTap: () => FocusScope.of(context).unfocus(),
              child: Container(
                padding: const EdgeInsets.all(24),
                decoration: BoxDecoration(
                  color: Colors.white,
                  borderRadius: BorderRadius.circular(28),
                  boxShadow: [BoxShadow(color: Colors.black.withValues(alpha: 0.1), blurRadius: 20, offset: const Offset(0, 10))],
                ),
                child: SingleChildScrollView(
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text('Set Budget for ${wallet.name}', style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
                      const SizedBox(height: 24),
                      TextField(
                        controller: controller,
                        keyboardType: const TextInputType.numberWithOptions(decimal: true, signed: false),
                        textInputAction: TextInputAction.done,
                        style: const TextStyle(fontWeight: FontWeight.w500),
                        decoration: InputDecoration(
                          hintText: 'Monthly Limit',
                          prefixText: 'Rs. ',
                          prefixStyle: const TextStyle(color: Colors.black87, fontWeight: FontWeight.w500, fontSize: 16),
                          filled: true,
                          fillColor: Colors.grey.shade100,
                          border: OutlineInputBorder(borderRadius: BorderRadius.circular(16), borderSide: BorderSide.none),
                          focusedBorder: OutlineInputBorder(borderRadius: BorderRadius.circular(16), borderSide: const BorderSide(color: Color(0xFF6C63FF), width: 2)),
                        ),
                      ),
                      const SizedBox(height: 16),
                      SwitchListTile(
                        title: const Text('Share budget with wallet members', style: TextStyle(fontSize: 14, fontWeight: FontWeight.w500)),
                        value: isShared,
                        activeColor: const Color(0xFF6C63FF),
                        contentPadding: EdgeInsets.zero,
                        onChanged: (val) {
                          setState(() {
                            isShared = val;
                          });
                        },
                      ),
                      const SizedBox(height: 24),
                      Row(
                        mainAxisAlignment: MainAxisAlignment.end,
                        children: [
                          TextButton(
                            onPressed: () => Navigator.pop(ctx),
                            style: TextButton.styleFrom(foregroundColor: Colors.grey.shade700, padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12), shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12))),
                            child: const Text('Cancel', style: TextStyle(fontWeight: FontWeight.bold)),
                          ),
                          const SizedBox(width: 12),
                          ElevatedButton(
                            onPressed: () async {
                              final limit = double.tryParse(controller.text);
                              if (limit != null && limit > 0) {
                                final newBudget = Budget(
                                  id: existingBudget?.id ?? 0,
                                  walletId: wallet.id,
                                  monthlyLimit: limit,
                                  isShared: isShared,
                                );
                                await ref.read(budgetProvider.notifier).addOrUpdateBudget(newBudget);
                                if (mounted) Navigator.pop(ctx);
                              }
                            },
                            style: ElevatedButton.styleFrom(
                              backgroundColor: const Color(0xFF6C63FF),
                              foregroundColor: Colors.white,
                              padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
                              elevation: 0,
                            ),
                            child: const Text('Save', style: TextStyle(fontWeight: FontWeight.bold)),
                          )
                        ],
                      ),
                    ],
                  ),
                ),
              ),
            ),
          );
        }
      ),
    );
  }

  void _showFilterSheet() {
    final natures = ['ALL', 'CASH', 'SAVINGS', 'INVESTMENTS', 'LOAN', 'LENDING', 'PAYABLES', 'INCOME', 'EXPENSE', 'RECEIVABLES'];
    String? tempFilterNature = _filterNature;
    
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      shape: const RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.circular(20))),
      builder: (ctx) => StatefulBuilder(
        builder: (context, setSheetState) {
          return Container(
            padding: EdgeInsets.only(
              bottom: MediaQuery.of(context).viewInsets.bottom,
            ),
            child: SafeArea(
              child: Padding(
                padding: const EdgeInsets.all(24),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    Row(
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: [
                        Text('Filter Budgets', style: Theme.of(context).textTheme.titleLarge),
                        IconButton(icon: const Icon(LucideIcons.x), onPressed: () => Navigator.pop(ctx)),
                      ],
                    ),
                    const SizedBox(height: 24),
                    
                    Text('Account Nature', style: Theme.of(context).textTheme.titleSmall),
                    const SizedBox(height: 8),
                    DropdownButtonFormField<String>(
                      value: tempFilterNature ?? 'ALL',
                      style: const TextStyle(fontWeight: FontWeight.w500, color: Colors.black87, fontSize: 16),
                      decoration: InputDecoration(
                        filled: true,
                        fillColor: Colors.grey.shade100,
                        contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
                        border: OutlineInputBorder(borderRadius: BorderRadius.circular(16), borderSide: BorderSide.none),
                        focusedBorder: OutlineInputBorder(borderRadius: BorderRadius.circular(16), borderSide: const BorderSide(color: Color(0xFF6C63FF), width: 2)),
                      ),
                      items: natures.map((n) => DropdownMenuItem(value: n, child: Text(n))).toList(),
                      onChanged: (val) {
                        if (val != null) {
                          setSheetState(() {
                            tempFilterNature = val == 'ALL' ? null : val;
                          });
                        }
                      },
                    ),
                    const SizedBox(height: 32),
                    Row(
                      children: [
                        Expanded(
                          child: OutlinedButton(
                            onPressed: () {
                              setState(() => _filterNature = null);
                              Navigator.pop(ctx);
                            },
                            style: OutlinedButton.styleFrom(
                              padding: const EdgeInsets.symmetric(vertical: 16),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
                              side: BorderSide(color: Colors.grey.shade300),
                            ),
                            child: Text('Reset', style: TextStyle(color: Colors.grey.shade700, fontWeight: FontWeight.bold)),
                          ),
                        ),
                        const SizedBox(width: 16),
                        Expanded(
                          child: ElevatedButton(
                            onPressed: () {
                              setState(() => _filterNature = tempFilterNature);
                              Navigator.pop(ctx);
                            },
                            style: ElevatedButton.styleFrom(
                              padding: const EdgeInsets.symmetric(vertical: 16),
                              backgroundColor: const Color(0xFF6C63FF),
                              foregroundColor: Colors.white,
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
                              elevation: 0,
                            ),
                            child: const Text('Apply Filter', style: TextStyle(fontWeight: FontWeight.bold)),
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 16),
                  ],
                ),
              ),
            ),
          );
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final budgetsState = ref.watch(budgetProvider);
    final walletsState = ref.watch(walletProvider);
    final transState = ref.watch(transactionProvider);

    return Scaffold(
      backgroundColor: Colors.transparent,
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 16, 16, 12),
            child: Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: _searchController,
                    onChanged: (val) => setState(() => _searchQuery = val),
                    decoration: InputDecoration(
                      hintText: 'Search budgets...',
                      prefixIcon: const Icon(LucideIcons.search),
                      suffixIcon: _searchController.text.isNotEmpty ? IconButton(
                        icon: const Icon(LucideIcons.x),
                        onPressed: () {
                          _searchController.clear();
                          setState(() => _searchQuery = '');
                        },
                      ) : null,
                      filled: true,
                      fillColor: Colors.grey.shade100,
                      border: OutlineInputBorder(
                        borderRadius: BorderRadius.circular(16),
                        borderSide: BorderSide.none,
                      ),
                      contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
                    ),
                  ),
                ),
                const SizedBox(width: 8),
                IconButton(
                  icon: Icon(
                    LucideIcons.filter,
                    color: _filterNature != null ? const Color(0xFF6C63FF) : null,
                  ),
                  onPressed: _showFilterSheet,
                ),
              ],
            ),
          ),
          Expanded(
            child: budgetsState.when(
        loading: () => ListView.builder(
          padding: const EdgeInsets.all(16),
          itemCount: 4,
          itemBuilder: (context, index) => const ShimmerCard(),
        ),
        error: (err, stack) => Center(child: Text('Error: $err')),
        data: (budgets) {
          if (!walletsState.hasValue || !transState.hasValue) {
            return ListView.builder(
              padding: const EdgeInsets.all(16),
              itemCount: 4,
              itemBuilder: (context, index) => const ShimmerCard(),
            );
          }

          final wallets = walletsState.value!.where((w) {
            final nature = (w.nature ?? 'CASH').trim().toUpperCase();
            final hasBudget = budgets.any((b) => b.walletId == w.id);
            
            final matchSearch = _searchQuery.isEmpty || w.name.toLowerCase().contains(_searchQuery.toLowerCase());
            final matchNature = _filterNature == null || nature == _filterNature;
            
            final matchBaseCondition = hasBudget || nature == 'EXPENSE' || nature == 'INVESTMENTS';
            
            return matchBaseCondition && matchSearch && matchNature;
          }).toList();

          final transactions = transState.value!;
          final now = DateTime.now();

          // Calculate spent per wallet for the current month
          final currentMonthTxs = transactions.where((t) => t.date.month == now.month && t.date.year == now.year);
          final Map<int, double> spentByWallet = {};
          
          for (var t in currentMonthTxs) {
            if (t.toWalletId != null) {
              spentByWallet[t.toWalletId!] = (spentByWallet[t.toWalletId!] ?? 0) + t.amount;
            }
          }

          if (wallets.isEmpty) {
            return const Center(child: Padding(padding: EdgeInsets.all(16), child: Text('No budgets or eligible accounts found.')));
          }

          return RefreshIndicator(
            onRefresh: _onRefresh,
            child: ListView.builder(
              physics: const AlwaysScrollableScrollPhysics(),
              padding: const EdgeInsets.all(16),
              itemCount: wallets.length,
              itemBuilder: (context, index) {
              final wallet = wallets[index];
              final existingBudgetIndex = budgets.indexWhere((b) => b.walletId == wallet.id);
              final budget = existingBudgetIndex >= 0 ? budgets[existingBudgetIndex] : null;
              final spent = spentByWallet[wallet.id] ?? 0.0;
              
              if (budget == null) {
                return Card(
                  margin: const EdgeInsets.only(bottom: 12),
                  child: ListTile(
                    leading: const CircleAvatar(child: Icon(LucideIcons.wallet)),
                    title: Text(wallet.name),
                    subtitle: Text('${wallet.nature} • No budget set'),
                    trailing: TextButton(
                      onPressed: () => _showSetBudgetDialog(context, wallet, null),
                      child: const Text('Set Budget'),
                    ),
                  ),
                );
              }

              final limit = budget.monthlyLimit;
              final double progress;
              if (limit <= 0) {
                 progress = 1.0;
              } else {
                 progress = (spent / limit).clamp(0.0, 1.0);
              }
              Color progressColor = Colors.green;
              if (progress > 0.9) progressColor = Colors.red;
              else if (progress > 0.7) progressColor = Colors.orange;

              return Card(
                margin: const EdgeInsets.only(bottom: 16),
                child: Padding(
                  padding: const EdgeInsets.all(16.0),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          Expanded(
                            child: Row(
                              children: [
                                const Icon(LucideIcons.wallet, size: 20, color: Colors.blue),
                                const SizedBox(width: 8),
                                Expanded(child: Text(wallet.name, style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 16), overflow: TextOverflow.ellipsis)),
                              ],
                            ),
                          ),
                          IconButton(
                            icon: const Icon(LucideIcons.edit3, size: 18),
                            onPressed: () => _showSetBudgetDialog(context, wallet, budget),
                          )
                        ],
                      ),
                      const SizedBox(height: 12),
                      LinearProgressIndicator(
                        value: progress,
                        backgroundColor: Colors.grey.shade200,
                        valueColor: AlwaysStoppedAnimation<Color>(progressColor),
                        minHeight: 8,
                        borderRadius: BorderRadius.circular(4),
                      ),
                      const SizedBox(height: 12),
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          Text('Spent: Rs. ${spent.toStringAsFixed(2)}', style: TextStyle(color: Colors.grey.shade700)),
                          Text('Limit: Rs. ${limit.toStringAsFixed(2)}', style: const TextStyle(fontWeight: FontWeight.bold)),
                        ],
                      ),
                      if (progress >= 1.0)
                        Padding(
                          padding: const EdgeInsets.only(top: 8.0),
                          child: Text('Budget Exceeded!', style: TextStyle(color: Colors.red.shade700, fontSize: 12, fontWeight: FontWeight.bold)),
                        ),
                    ],
                  ),
                ),
              );
            }),
          );
        },
      ),
          ),
        ],
      ),
    );
  }
}