import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';
import '../domain/customer.dart';
import '../providers/invoices_provider.dart';
import '../../transactions/providers/providers.dart';

class CustomerLedgerScreen extends ConsumerStatefulWidget {
  final Customer customer;

  const CustomerLedgerScreen({super.key, required this.customer});

  @override
  ConsumerState<CustomerLedgerScreen> createState() =>
      _CustomerLedgerScreenState();
}

class _CustomerLedgerScreenState extends ConsumerState<CustomerLedgerScreen> {
  @override
  Widget build(BuildContext context) {
    final invoicesState = ref.watch(invoicesProvider);
    final formatCurrency = NumberFormat.currency(symbol: '₹');

    return Scaffold(
      appBar: AppBar(
        title: Text('${widget.customer.name} Ledger'),
        backgroundColor: Colors.white,
        foregroundColor: Colors.black,
        elevation: 0,
      ),
      body: invoicesState.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (err, stack) => Center(child: Text('Error: $err')),
        data: (invoices) {
          final customerInvoices = invoices
              .where((i) => i.customerId == widget.customer.id)
              .toList();

          if (customerInvoices.isEmpty) {
            return const Center(
              child: Text('No invoices found for this customer.'),
            );
          }

          // Sort chronological
          customerInvoices.sort((a, b) => a.issueDate.compareTo(b.issueDate));

          double runningBalance = 0.0;
          List<DataRow> rows = [];
          final wallets = ref.read(walletProvider).value ?? [];

          int index = 1;
          for (var inv in customerInvoices) {
            // Add row for Invoice (Debit)
            runningBalance += inv.totalAmount;
            rows.add(
              DataRow(
                cells: [
                  DataCell(Text('${index++}')),
                  DataCell(
                    Text(DateFormat('dd MMM yyyy').format(inv.issueDate)),
                  ),
                  DataCell(
                    Text(
                      inv.invoiceNumber,
                      style: const TextStyle(fontWeight: FontWeight.w600),
                    ),
                  ),
                  const DataCell(Text('Invoice')),
                  const DataCell(Text('-')),
                  const DataCell(Text('-')),
                  DataCell(
                    Text(
                      formatCurrency.format(inv.totalAmount),
                      style: TextStyle(
                        color: Colors.red.shade700,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ),
                  DataCell(
                    Text(
                      formatCurrency.format(runningBalance),
                      style: const TextStyle(fontWeight: FontWeight.bold),
                    ),
                  ),
                ],
              ),
            );

            // Add row for Payment (Credit)
            if (inv.payments != null && inv.payments!.isNotEmpty) {
              for (var p in inv.payments!) {
                runningBalance -= p.amount;
                final walletName = wallets
                    .firstWhere(
                      (w) => w.id == p.walletId,
                      orElse: () => wallets.first,
                    )
                    .name;
                rows.add(
                  DataRow(
                    cells: [
                      DataCell(Text('${index++}')),
                      DataCell(
                        Text(
                          p.paymentDate != null
                              ? DateFormat('dd MMM yyyy').format(p.paymentDate!)
                              : DateFormat('dd MMM yyyy').format(inv.issueDate),
                        ),
                      ),
                      DataCell(
                        Text(
                          inv.invoiceNumber,
                          style: const TextStyle(fontWeight: FontWeight.w600),
                        ),
                      ),
                      const DataCell(Text('Payment')),
                      DataCell(Text(p.paymentMethod)),
                      DataCell(Text(p.walletId != null ? walletName : '-')),
                      DataCell(
                        Text(
                          formatCurrency.format(p.amount),
                          style: TextStyle(
                            color: Colors.green.shade700,
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                      ),
                      DataCell(
                        Text(
                          formatCurrency.format(runningBalance),
                          style: const TextStyle(fontWeight: FontWeight.bold),
                        ),
                      ),
                    ],
                  ),
                );
              }
            } else if (inv.amountPaid > 0) {
              runningBalance -= inv.amountPaid;
              rows.add(
                DataRow(
                  cells: [
                    DataCell(Text('${index++}')),
                    DataCell(
                      Text(DateFormat('dd MMM yyyy').format(inv.issueDate)),
                    ),
                    DataCell(
                      Text(
                        inv.invoiceNumber,
                        style: const TextStyle(fontWeight: FontWeight.w600),
                      ),
                    ),
                    const DataCell(Text('Payment')),
                    const DataCell(Text('-')),
                    const DataCell(Text('-')),
                    DataCell(
                      Text(
                        formatCurrency.format(inv.amountPaid),
                        style: TextStyle(
                          color: Colors.green.shade700,
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ),
                    DataCell(
                      Text(
                        formatCurrency.format(runningBalance),
                        style: const TextStyle(fontWeight: FontWeight.bold),
                      ),
                    ),
                  ],
                ),
              );
            }
          }

          return Column(
            children: [
              Container(
                width: double.infinity,
                color: Colors.blue.withOpacity(0.05),
                padding: const EdgeInsets.all(24),
                child: Column(
                  children: [
                    const Text(
                      'Outstanding Balance',
                      style: TextStyle(color: Colors.grey, fontSize: 14),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      formatCurrency.format(runningBalance),
                      style: TextStyle(
                        fontSize: 28,
                        fontWeight: FontWeight.bold,
                        color: runningBalance > 0
                            ? Colors.red.shade700
                            : Colors.green.shade700,
                      ),
                    ),
                  ],
                ),
              ),
              Expanded(
                child: SingleChildScrollView(
                  scrollDirection: Axis.vertical,
                  child: SingleChildScrollView(
                    scrollDirection: Axis.horizontal,
                    child: DataTable(
                      headingRowColor: WidgetStateProperty.resolveWith(
                        (states) => Colors.grey.shade100,
                      ),
                      columnSpacing: 24,
                      columns: const [
                        DataColumn(
                          label: Text(
                            'S.No',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Date',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Invoice #',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Type',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Mode',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Wallet',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Amount',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                        DataColumn(
                          label: Text(
                            'Balance',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ),
                      ],
                      rows: rows,
                    ),
                  ),
                ),
              ),
            ],
          );
        },
      ),
    );
  }
}