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/providers.dart';
import '../../dashboard/presentation/maturity_dialog.dart';
import '../providers/paginated_transaction_provider.dart';
import '../../../core/widgets/shimmer_loading.dart';
import '../../../core/widgets/empty_state.dart';
import 'add_transaction_screen.dart';
import '../presentation/widgets/transaction_filter_sheet.dart';
import '../../../core/theme/nature_colors.dart';

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

  @override
  ConsumerState<AllTransactionsScreen> createState() => _AllTransactionsScreenState();
}

class _AllTransactionsScreenState extends ConsumerState<AllTransactionsScreen> {
  final ScrollController _scrollController = ScrollController();
  final TextEditingController _searchController = TextEditingController();

  @override
  void initState() {
    super.initState();
    _scrollController.addListener(() {
      if (_scrollController.position.pixels >= _scrollController.position.maxScrollExtent - 200) {
        ref.read(paginatedTransactionProvider.notifier).loadMore();
      }
    });
  }

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

  void _onSearchChanged(String value) {
    // Basic debounce for text search
    Future.delayed(const Duration(milliseconds: 500), () {
      if (_searchController.text == value) {
        ref.read(paginatedTransactionProvider.notifier).updateFilters(search: value);
      }
    });
  }

  void _openFilterSheet() {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (context) => const TransactionFilterSheet(),
    );
  }

  @override
  Widget build(BuildContext context) {
    final paginatedState = ref.watch(paginatedTransactionProvider);
    final transactions = paginatedState.transactions;
    final categoriesState = ref.watch(categoryProvider);
    final walletsState = ref.watch(walletProvider);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Transactions'),
        actions: [
          IconButton(
            icon: const Icon(LucideIcons.filter),
            onPressed: _openFilterSheet,
          ),
          IconButton(
            icon: const Icon(LucideIcons.plus),
            onPressed: () {
              Navigator.push(context, MaterialPageRoute(builder: (_) => const AddTransactionScreen()));
            },
          ),
        ],
        bottom: PreferredSize(
          preferredSize: const Size.fromHeight(60),
          child: Padding(
            padding: const EdgeInsets.fromLTRB(16, 0, 16, 12),
            child: TextField(
              controller: _searchController,
              onChanged: _onSearchChanged,
              decoration: InputDecoration(
                hintText: 'Search transactions...',
                prefixIcon: const Icon(LucideIcons.search),
                suffixIcon: _searchController.text.isNotEmpty ? IconButton(
                  icon: const Icon(LucideIcons.x),
                  onPressed: () {
                    _searchController.clear();
                    _onSearchChanged('');
                  },
                ) : null,
                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)
                ),
                contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
              ),
            ),
          ),
        ),
      ),
      body: Builder(
        builder: (context) {
          if (transactions.isEmpty && paginatedState.isLoading) {
            return ListView.builder(
              padding: const EdgeInsets.all(16),
              itemCount: 8,
              itemBuilder: (context, index) => const ShimmerCard(),
            );
          }

          if (transactions.isEmpty) {
            return const EmptyStateWidget(
              icon: LucideIcons.fileText,
              title: 'No Transactions',
              message: 'No transactions found matching your criteria.',
            );
          }

          return RefreshIndicator(
            onRefresh: () async {
              ref.read(paginatedTransactionProvider.notifier).clearFilters();
              _searchController.clear();
            },
            child: ListView.builder(
              controller: _scrollController,
              physics: const AlwaysScrollableScrollPhysics(),
              padding: const EdgeInsets.all(16.0),
              itemCount: transactions.length + (paginatedState.hasMore ? 1 : 0),
              itemBuilder: (context, index) {
                if (index == transactions.length) {
                  return const Padding(
                    padding: EdgeInsets.all(16.0),
                    child: Center(child: CircularProgressIndicator()),
                  );
                }

                final t = transactions[index];
                final isIncome = t.type == 'INCOME' || (t.type == 'TRANSFER' && t.fromWalletId == null);
                final isInvestment = t.type == 'INVESTMENT';
                final isExpense = t.type == 'EXPENSE' || (t.type == 'TRANSFER' && t.toWalletId == null);
                final isTransfer = t.type == 'TRANSFER' && t.fromWalletId != null && t.toWalletId != null;
                
                Color typeColor = Colors.grey;
                IconData typeIcon = LucideIcons.arrowRightLeft;

                if (isIncome) {
                  typeColor = NatureColors.getColor('INCOME');
                  typeIcon = LucideIcons.arrowDownCircle;
                } else if (isExpense) {
                  typeColor = NatureColors.getColor('EXPENSE');
                  typeIcon = LucideIcons.arrowUpCircle;
                } else if (isInvestment) {
                  typeColor = NatureColors.getColor('INVESTMENTS');
                  typeIcon = LucideIcons.trendingUp;
                } else if (isTransfer) {
                  typeColor = NatureColors.getColor('TRANSFER');
                  if (walletsState.hasValue) {
                    final toW = walletsState.value!.where((w) => w.id == t.toWalletId).firstOrNull;
                    final fromW = walletsState.value!.where((w) => w.id == t.fromWalletId).firstOrNull;
                    
                    if (toW != null && (toW.nature == 'PAYABLES' || toW.nature == 'LOAN')) {
                      typeColor = NatureColors.getColor('PAYABLES');
                      typeIcon = LucideIcons.alertCircle;
                    } else if (toW != null && (toW.nature == 'RECEIVABLES' || toW.nature == 'LENDING')) {
                      typeColor = NatureColors.getColor('RECEIVABLES');
                      typeIcon = LucideIcons.arrowDownLeft;
                    } else if (fromW != null && (fromW.nature == 'PAYABLES' || fromW.nature == 'LOAN')) {
                      typeColor = NatureColors.getColor('PAYABLES');
                      typeIcon = LucideIcons.alertCircle;
                    } else if (fromW != null && (fromW.nature == 'RECEIVABLES' || fromW.nature == 'LENDING')) {
                      typeColor = NatureColors.getColor('RECEIVABLES');
                      typeIcon = LucideIcons.arrowDownLeft;
                    }
                  }
                }

                String categoryName = 'Unknown';
                if (categoriesState.hasValue) {
                  final match = categoriesState.value!.where((c) => c.id == t.categoryId);
                  if (match.isNotEmpty) categoryName = match.first.name;
                }

                String accountName = 'Unknown';
                if (walletsState.hasValue) {
                  if (isExpense && t.toWalletId != null) {
                    final match = walletsState.value!.where((w) => w.id == t.toWalletId);
                    if (match.isNotEmpty) accountName = match.first.name;
                  } else if (isIncome && t.toWalletId != null) {
                    final match = walletsState.value!.where((w) => w.id == t.toWalletId);
                    if (match.isNotEmpty) accountName = match.first.name;
                  } else if (isTransfer && t.toWalletId != null) {
                    final match = walletsState.value!.where((w) => w.id == t.toWalletId);
                    if (match.isNotEmpty) accountName = 'To ${match.first.name}';
                  }
                }
                
                String fromName = '';
                if (t.fromWalletId != null && walletsState.hasValue) {
                  final match = walletsState.value!.where((w) => w.id == t.fromWalletId);
                  if (match.isNotEmpty) fromName = match.first.name;
                }

                String toName = '';
                if (t.toWalletId != null && walletsState.hasValue) {
                  final match = walletsState.value!.where((w) => w.id == t.toWalletId);
                  if (match.isNotEmpty) toName = match.first.name;
                }
                
                String subtitleText = '';
                if (categoryName == 'Unknown' && fromName.isNotEmpty && toName.isNotEmpty) {
                  subtitleText = '$fromName → $toName • ${DateFormat('MMM dd, yyyy').format(t.date)}';
                } else if (categoryName == 'Unknown' && toName.isNotEmpty) {
                  subtitleText = 'To $toName • ${DateFormat('MMM dd, yyyy').format(t.date)}';
                } else if (categoryName == 'Unknown' && fromName.isNotEmpty) {
                  subtitleText = 'From $fromName • ${DateFormat('MMM dd, yyyy').format(t.date)}';
                } else {
                  subtitleText = '$categoryName • ${DateFormat('MMM dd, yyyy').format(t.date)}${fromName.isNotEmpty ? ' • 💼 $fromName' : ''}';
                }

                return Dismissible(
                  key: Key(t.id.toString()),
                  direction: DismissDirection.endToStart,
                  background: Container(
                    color: Colors.red,
                    alignment: Alignment.centerRight,
                    padding: const EdgeInsets.only(right: 20),
                    child: const Icon(LucideIcons.trash2, color: Colors.white),
                  ),
                  confirmDismiss: (dir) async {
                    return await showDialog<bool>(
                      context: context,
                      builder: (ctx) => AlertDialog(
                        title: const Text('Delete Transaction?'),
                        content: const Text('Are you sure you want to delete this transaction?'),
                        actions: [
                          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('Cancel')),
                          TextButton(
                            onPressed: () => Navigator.pop(ctx, true), 
                            child: const Text('Delete', style: TextStyle(color: Colors.red))
                          ),
                        ],
                      ),
                    );
                  },
                  onDismissed: (dir) {
                    ref.read(transactionProvider.notifier).deleteTransaction(t.id);
                    ref.read(paginatedTransactionProvider.notifier).removeTransactionFromState(t.id);
                  },
                  child: Card(
                    margin: const EdgeInsets.only(bottom: 12),
                    child: Column(
                      children: [
                        ListTile(
                          onTap: () {
                            Navigator.push(context, MaterialPageRoute(builder: (_) => AddTransactionScreen(transaction: t)));
                          },
                          leading: CircleAvatar(
                            backgroundColor: typeColor.withValues(alpha: 0.1),
                            child: Icon(typeIcon, color: typeColor),
                          ),
                          title: Text((t.description != null && t.description!.isNotEmpty) ? t.description! : accountName, style: const TextStyle(fontWeight: FontWeight.bold)),
                          subtitle: Text(subtitleText),
                          trailing: Column(
                            mainAxisAlignment: MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.end,
                            children: [
                              Text(
                                '${isIncome ? '+' : (isTransfer ? '' : '-')}Rs. ${t.amount.toStringAsFixed(0)}',
                                style: TextStyle(fontWeight: FontWeight.bold, color: typeColor),
                              ),
                              if (t.investmentStatus == 'OPEN' && (typeColor == NatureColors.getColor('INVESTMENTS') || typeColor == NatureColors.getColor('RECEIVABLES')))
                                GestureDetector(
                                  onTap: () {
                                    showDialog(context: context, builder: (_) => MaturityDialog(transaction: t));
                                  },
                                  child: const Padding(
                                    padding: EdgeInsets.only(top: 4.0),
                                    child: Text('Close', style: TextStyle(color: Colors.blue, fontWeight: FontWeight.bold, fontSize: 12)),
                                  ),
                                ),
                            ],
                          ),
                        ),
                      ],
                    ),
                  ),
                );
              },
            ),
          );
        }
      ),
    );
  }
}