import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart';
import '../providers/dashboard_providers.dart';
import '../../../core/services/contract_service.dart';
import '../../../widgets/error_view.dart';
import '../../../widgets/status_badge.dart';

class ContractScreen extends ConsumerWidget {
  final String reservationId;

  const ContractScreen({super.key, required this.reservationId});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final async = ref.watch(contractProvider(reservationId));

    return Scaffold(
      appBar: AppBar(
        title: const Text('Rental Contract'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: () => ref.invalidate(contractProvider(reservationId)),
          ),
        ],
      ),
      body: async.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (e, _) => ErrorView(
          message: 'Could not load contract',
          onRetry: () => ref.invalidate(contractProvider(reservationId)),
        ),
        data: (c) => _ContractView(contract: c),
      ),
    );
  }
}

class _ContractView extends StatelessWidget {
  final ContractPayload contract;

  const _ContractView({required this.contract});

  @override
  Widget build(BuildContext context) {
    final fmt = DateFormat('MMM d, yyyy');
    final fmtMoney =
        NumberFormat.currency(symbol: '\$', decimalDigits: 2);

    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        // ── Header ──────────────────────────────────────────────
        _Section(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        if (contract.contractNumber != null)
                          Text(
                            'Contract ${contract.contractNumber}',
                            style: const TextStyle(
                              fontSize: 16,
                              fontWeight: FontWeight.bold,
                              color: Color(0xFF111928),
                            ),
                          ),
                        if (contract.invoiceNumber != null)
                          Text(
                            'Invoice ${contract.invoiceNumber}',
                            style: const TextStyle(
                                fontSize: 13,
                                color: Color(0xFF6B7280)),
                          ),
                      ],
                    ),
                  ),
                  StatusBadge(status: contract.status),
                ],
              ),
              const SizedBox(height: 8),
              Text(
                'Generated ${fmt.format(contract.generatedAt)}',
                style: const TextStyle(
                    fontSize: 12, color: Color(0xFF9CA3AF)),
              ),
              if (contract.notes != null && contract.notes!.isNotEmpty) ...[
                const SizedBox(height: 8),
                Container(
                  padding: const EdgeInsets.all(10),
                  decoration: BoxDecoration(
                    color: const Color(0xFFFFF3CD),
                    borderRadius: BorderRadius.circular(8),
                  ),
                  child: Row(
                    children: [
                      const Icon(Icons.notes_outlined,
                          size: 14, color: Color(0xFF92400E)),
                      const SizedBox(width: 6),
                      Expanded(
                        child: Text(
                          contract.notes!,
                          style: const TextStyle(
                              fontSize: 12, color: Color(0xFF92400E)),
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ],
          ),
        ),
        const SizedBox(height: 12),

        // ── Rental Period ────────────────────────────────────────
        _Section(
          title: 'Rental Period',
          icon: Icons.calendar_today_outlined,
          child: Column(
            children: [
              _Row2(
                left: _LabelValue(
                    label: 'Check-out',
                    value: fmt.format(contract.startDate)),
                right: _LabelValue(
                    label: 'Check-in',
                    value: fmt.format(contract.endDate)),
              ),
              const SizedBox(height: 10),
              _Row2(
                left: _LabelValue(
                    label: 'Duration',
                    value:
                        '${contract.totalDays} day${contract.totalDays == 1 ? '' : 's'}'),
                right: _LabelValue(
                    label: 'Payment',
                    value: _paymentLabel(contract.paymentStatus)),
              ),
              if (contract.pickupLocation != null ||
                  contract.returnLocation != null) ...[
                const SizedBox(height: 10),
                if (contract.pickupLocation != null)
                  _LabelValue(
                      label: 'Pick-up location',
                      value: contract.pickupLocation!),
                if (contract.returnLocation != null) ...[
                  const SizedBox(height: 6),
                  _LabelValue(
                      label: 'Return location',
                      value: contract.returnLocation!),
                ],
              ],
            ],
          ),
        ),
        const SizedBox(height: 12),

        // ── Vehicle ──────────────────────────────────────────────
        _Section(
          title: 'Vehicle',
          icon: Icons.directions_car_outlined,
          child: Column(
            children: [
              _Row2(
                left: _LabelValue(
                    label: 'Vehicle',
                    value: contract.vehicle.displayName),
                right: _LabelValue(
                    label: 'Plate',
                    value: contract.vehicle.licensePlate),
              ),
              const SizedBox(height: 10),
              _Row2(
                left: _LabelValue(
                    label: 'Category',
                    value: contract.vehicle.category),
                right: _LabelValue(
                    label: 'Color',
                    value: contract.vehicle.color ?? '—'),
              ),
              if (contract.vehicle.vin != null) ...[
                const SizedBox(height: 10),
                _LabelValue(
                    label: 'VIN', value: contract.vehicle.vin!),
              ],
            ],
          ),
        ),
        const SizedBox(height: 12),

        // ── Customer ─────────────────────────────────────────────
        _Section(
          title: 'Customer',
          icon: Icons.person_outline,
          child: Column(
            children: [
              _Row2(
                left: _LabelValue(
                    label: 'Name',
                    value: contract.driver.fullName),
                right: _LabelValue(
                    label: 'Email', value: contract.driver.email),
              ),
              if (contract.driver.phone != null) ...[
                const SizedBox(height: 10),
                _LabelValue(
                    label: 'Phone', value: contract.driver.phone!),
              ],
              if (contract.driver.driverLicense != null) ...[
                const SizedBox(height: 10),
                _Row2(
                  left: _LabelValue(
                      label: 'License #',
                      value: contract.driver.driverLicense!),
                  right: _LabelValue(
                      label: 'Country',
                      value:
                          contract.driver.licenseCountry ?? '—'),
                ),
              ],
              if (contract.driver.licenseExpiry != null) ...[
                const SizedBox(height: 10),
                _LabelValue(
                    label: 'License expiry',
                    value: contract.driver.licenseExpiry!),
              ],
            ],
          ),
        ),
        const SizedBox(height: 12),

        // ── Company ──────────────────────────────────────────────
        _Section(
          title: 'Rental Company',
          icon: Icons.business_outlined,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                contract.company.name,
                style: const TextStyle(
                    fontWeight: FontWeight.w600,
                    color: Color(0xFF111928)),
              ),
              if (contract.company.address != null) ...[
                const SizedBox(height: 4),
                Text(
                  contract.company.address!,
                  style: const TextStyle(
                      fontSize: 13, color: Color(0xFF6B7280)),
                ),
              ],
              if (contract.company.email != null ||
                  contract.company.phone != null) ...[
                const SizedBox(height: 8),
                _Row2(
                  left: _LabelValue(
                      label: 'Email',
                      value: contract.company.email ?? '—'),
                  right: _LabelValue(
                      label: 'Phone',
                      value: contract.company.phone ?? '—'),
                ),
              ],
            ],
          ),
        ),
        const SizedBox(height: 12),

        // ── Invoice ──────────────────────────────────────────────
        _Section(
          title: 'Invoice',
          icon: Icons.receipt_outlined,
          child: Column(
            children: [
              ...contract.lineItems.map((item) => Padding(
                    padding: const EdgeInsets.only(bottom: 8),
                    child: Row(
                      children: [
                        Expanded(
                          child: Column(
                            crossAxisAlignment:
                                CrossAxisAlignment.start,
                            children: [
                              Text(item.description,
                                  style: const TextStyle(
                                      fontSize: 13,
                                      color: Color(0xFF374151))),
                              if (item.qty > 1)
                                Text(
                                  '${item.qty} × ${fmtMoney.format(item.unitPrice / 100)}',
                                  style: const TextStyle(
                                      fontSize: 11,
                                      color: Color(0xFF9CA3AF)),
                                ),
                            ],
                          ),
                        ),
                        Text(
                          fmtMoney.format(item.total / 100),
                          style: const TextStyle(
                              fontSize: 13,
                              fontWeight: FontWeight.w500,
                              color: Color(0xFF111928)),
                        ),
                      ],
                    ),
                  )),
              const Divider(height: 16),
              if (contract.taxTotal > 0) ...[
                _AmountRow(
                    label: 'Subtotal',
                    amount: contract.subtotal,
                    currency: contract.currency),
                const SizedBox(height: 4),
                _AmountRow(
                    label: 'Taxes',
                    amount: contract.taxTotal,
                    currency: contract.currency),
                const Divider(height: 12),
              ],
              _AmountRow(
                label: 'Total',
                amount: contract.total,
                currency: contract.currency,
                bold: true,
                color: const Color(0xFF1A56DB),
              ),
              const SizedBox(height: 4),
              _AmountRow(
                label: 'Amount paid',
                amount: contract.amountPaid,
                currency: contract.currency,
                color: const Color(0xFF057A55),
              ),
              if (contract.balanceDue > 0) ...[
                const SizedBox(height: 4),
                _AmountRow(
                  label: 'Balance due',
                  amount: contract.balanceDue,
                  currency: contract.currency,
                  bold: true,
                  color: const Color(0xFFE02424),
                ),
              ],
            ],
          ),
        ),

        // ── Payments ─────────────────────────────────────────────
        if (contract.payments.isNotEmpty) ...[
          const SizedBox(height: 12),
          _Section(
            title: 'Payments',
            icon: Icons.payments_outlined,
            child: Column(
              children: contract.payments
                  .map((p) => _PaymentRow(payment: p))
                  .toList(),
            ),
          ),
        ],

        // ── Inspections ──────────────────────────────────────────
        if (contract.checkIn != null || contract.checkOut != null) ...[
          const SizedBox(height: 12),
          _Section(
            title: 'Vehicle Inspections',
            icon: Icons.fact_check_outlined,
            child: Column(
              children: [
                if (contract.checkIn != null) ...[
                  _InspectionRow(
                      label: 'Check-out',
                      inspection: contract.checkIn!),
                  if (contract.checkOut != null)
                    const SizedBox(height: 10),
                ],
                if (contract.checkOut != null)
                  _InspectionRow(
                      label: 'Check-in',
                      inspection: contract.checkOut!),
              ],
            ),
          ),
        ],

        // ── Terms ────────────────────────────────────────────────
        if (contract.terms != null && contract.terms!.isNotEmpty) ...[
          const SizedBox(height: 12),
          _Section(
            title: 'Terms & Conditions',
            icon: Icons.gavel_outlined,
            child: Text(
              contract.terms!,
              style: const TextStyle(
                  fontSize: 12,
                  color: Color(0xFF6B7280),
                  height: 1.5),
            ),
          ),
        ],

        if (contract.fuelPolicy != null &&
            contract.fuelPolicy!.isNotEmpty) ...[
          const SizedBox(height: 12),
          _Section(
            title: 'Fuel Policy',
            icon: Icons.local_gas_station_outlined,
            child: Text(
              contract.fuelPolicy!,
              style: const TextStyle(
                  fontSize: 12,
                  color: Color(0xFF6B7280),
                  height: 1.5),
            ),
          ),
        ],

        const SizedBox(height: 24),
      ],
    );
  }
}

// ── Helpers ───────────────────────────────────────────────────────────────────

class _Section extends StatelessWidget {
  final String? title;
  final IconData? icon;
  final Widget child;

  const _Section({this.title, this.icon, required this.child});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            if (title != null) ...[
              Row(
                children: [
                  if (icon != null) ...[
                    Icon(icon, size: 16, color: const Color(0xFF6B7280)),
                    const SizedBox(width: 6),
                  ],
                  Text(
                    title!,
                    style: const TextStyle(
                      fontWeight: FontWeight.bold,
                      fontSize: 13,
                      color: Color(0xFF374151),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 12),
              const Divider(height: 1),
              const SizedBox(height: 12),
            ],
            child,
          ],
        ),
      ),
    );
  }
}

class _LabelValue extends StatelessWidget {
  final String label;
  final String value;

  const _LabelValue({required this.label, required this.value});

  @override
  Widget build(BuildContext context) => Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label,
              style: const TextStyle(
                  fontSize: 10, color: Color(0xFF9CA3AF))),
          Text(value,
              style: const TextStyle(
                  fontSize: 13,
                  fontWeight: FontWeight.w500,
                  color: Color(0xFF111928))),
        ],
      );
}

class _Row2 extends StatelessWidget {
  final Widget left;
  final Widget right;

  const _Row2({required this.left, required this.right});

  @override
  Widget build(BuildContext context) => Row(
        children: [
          Expanded(child: left),
          const SizedBox(width: 8),
          Expanded(child: right),
        ],
      );
}

class _AmountRow extends StatelessWidget {
  final String label;
  final int amount;
  final String currency;
  final bool bold;
  final Color? color;

  const _AmountRow({
    required this.label,
    required this.amount,
    required this.currency,
    this.bold = false,
    this.color,
  });

  @override
  Widget build(BuildContext context) {
    final fmt = NumberFormat.currency(symbol: '\$', decimalDigits: 2);
    final style = TextStyle(
      fontWeight: bold ? FontWeight.bold : FontWeight.normal,
      color: color ?? const Color(0xFF374151),
      fontSize: bold ? 15 : 13,
    );
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceBetween,
      children: [
        Text(label, style: style),
        Text(fmt.format(amount / 100), style: style),
      ],
    );
  }
}

class _PaymentRow extends StatelessWidget {
  final ContractPayment payment;

  const _PaymentRow({required this.payment});

  @override
  Widget build(BuildContext context) {
    final fmt = NumberFormat.currency(symbol: '\$', decimalDigits: 2);
    final fmtDate = DateFormat('MMM d, yyyy');
    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: Row(
        children: [
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  payment.paymentMethod ?? payment.type,
                  style: const TextStyle(
                      fontSize: 13,
                      fontWeight: FontWeight.w500,
                      color: Color(0xFF374151)),
                ),
                if (payment.paidAt != null)
                  Text(
                    fmtDate.format(payment.paidAt!),
                    style: const TextStyle(
                        fontSize: 11, color: Color(0xFF9CA3AF)),
                  ),
              ],
            ),
          ),
          Text(
            fmt.format(payment.amount / 100),
            style: TextStyle(
              fontWeight: FontWeight.w600,
              color: payment.status == 'PAID'
                  ? const Color(0xFF057A55)
                  : const Color(0xFF374151),
            ),
          ),
        ],
      ),
    );
  }
}

class _InspectionRow extends StatelessWidget {
  final String label;
  final ContractInspection inspection;

  const _InspectionRow(
      {required this.label, required this.inspection});

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          label,
          style: const TextStyle(
              fontWeight: FontWeight.w600,
              fontSize: 12,
              color: Color(0xFF374151)),
        ),
        const SizedBox(height: 6),
        Row(
          children: [
            if (inspection.mileage != null)
              Expanded(
                child: _LabelValue(
                    label: 'Mileage',
                    value: '${inspection.mileage} km'),
              ),
            if (inspection.fuelLevel != null)
              Expanded(
                child: _LabelValue(
                    label: 'Fuel', value: inspection.fuelLevel!),
              ),
          ],
        ),
        if (inspection.generalCondition != null) ...[
          const SizedBox(height: 6),
          _LabelValue(
              label: 'Condition',
              value: inspection.generalCondition!),
        ],
        if (inspection.employeeNotes != null &&
            inspection.employeeNotes!.isNotEmpty) ...[
          const SizedBox(height: 6),
          Text(
            inspection.employeeNotes!,
            style: const TextStyle(
                fontSize: 12, color: Color(0xFF6B7280)),
          ),
        ],
      ],
    );
  }
}

String _paymentLabel(String status) {
  switch (status.toUpperCase()) {
    case 'PAID':
      return 'Paid';
    case 'PARTIAL':
      return 'Partial';
    case 'PENDING':
      return 'Pending';
    default:
      return status[0] + status.substring(1).toLowerCase();
  }
}