import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../labels.dart';
import '../models/models.dart';
import '../services/auth_controller.dart';
import '../theme/app_theme.dart';
import '../ui/feedback.dart';

class StockDetailScreen extends StatefulWidget {
  const StockDetailScreen({super.key, required this.stock, required this.dealers});

  final StockItem stock;
  final List<Dealer> dealers;

  @override
  State<StockDetailScreen> createState() => _StockDetailScreenState();
}

class _StockDetailScreenState extends State<StockDetailScreen> {
  late StockItem _stock = widget.stock;
  String _paymentType = 'cash';
  bool _useGci = true;
  bool _useFinance = false;
  String? _transferDealerId;
  final _financeName = TextEditingController();
  final _plateNumber = TextEditingController();
  bool _saving = false;

  @override
  void dispose() {
    _financeName.dispose();
    _plateNumber.dispose();
    super.dispose();
  }

  Future<void> _advance() async {
    final stage = nextStage(_stock.currentStage);
    if (stage == null) return;
    final body = <String, dynamic>{'stage': stage};
    if (stage == 'paymentApproved') {
      body['paymentType'] = _paymentType;
      if (_paymentType == 'lease') {
        if (!_useGci && !_useFinance) {
          showError(context, 'Choose GCI, finance, or both');
          return;
        }
        body['leaseProviderType'] = _useGci && _useFinance
            ? 'both'
            : _useGci
                ? 'gci'
                : 'thirdPartyFinance';
        if (_useFinance) body['financeCompanyName'] = _financeName.text.trim();
      }
    }
    if (stage == 'plateReceived') {
      final plateNumber = _plateNumber.text.trim();
      if (plateNumber.isEmpty) {
        showError(context, 'Enter the plate number');
        return;
      }
      body['plateNumber'] = plateNumber;
    }
    setState(() => _saving = true);
    try {
      final updated = await context.read<AuthController>().api.updateStage(_stock.chassisNumber, body);
      if (!mounted) return;
      setState(() => _stock = updated);
    } catch (error) {
      if (mounted) showError(context, error);
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  Future<void> _transfer() async {
    final dealerId = _transferDealerId;
    if (dealerId == null) return;
    setState(() => _saving = true);
    try {
      final updated = await context.read<AuthController>().api.transferStock(_stock.chassisNumber, dealerId);
      if (!mounted) return;
      setState(() {
        _stock = updated;
        _transferDealerId = null;
      });
    } catch (error) {
      if (mounted) showError(context, error);
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final role = context.watch<AuthController>().user?.role;
    final upcoming = nextStage(_stock.currentStage);
    final targets = widget.dealers.where((dealer) => dealer.id != _stock.currentDealerId).toList();

    return Scaffold(
        appBar: AppBar(title: Text(_stock.chassisNumber)),
        body: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            Row(
              children: [
                CircleAvatar(
                  backgroundColor: badgeColor(_stock.badge),
                  child: Text('${_stock.ageInDays}', style: const TextStyle(color: Colors.white, fontSize: 12)),
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: Text(
                    '${_stock.ageInDays} days in stock · ${stageLabel(_stock.currentStage)}',
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ),
              ],
            ),
            const SizedBox(height: 16),
            _line('Model', modelLabel(_stock.model)),
            _line('Color', _stock.color),
            _line('Engine', _stock.engineNumber),
            if (_stock.plateNumber != null) _line('Plate', _stock.plateNumber!),
            _line('Dealer', _stock.dealerName ?? _stock.currentDealerId),
            _line('Received', _stock.dateReceived.toLocal().toString().split(' ').first),
            if (_stock.paymentType != null) _line('Payment', _stock.paymentType!),
            if (_stock.leaseProviderType != null)
              _line('Lease', leaseProviderLabel(_stock.leaseProviderType!)),
            if (_stock.financeCompanyName != null) _line('Finance company', _stock.financeCompanyName!),
            const SizedBox(height: 16),
            Text('Stage log', style: Theme.of(context).textTheme.titleMedium),
            const SizedBox(height: 8),
            for (final stage in stageOrder)
              if (_stock.stageLogDates.containsKey(stage))
                ListTile(
                  contentPadding: EdgeInsets.zero,
                  title: Text(stageLabel(stage)),
                  trailing: Text(_stock.stageLogDates[stage]!.toLocal().toString().split(' ').first),
                ),
            if (upcoming != null) ...[
              const Divider(),
              Text('Advance to ${stageLabel(upcoming)}', style: Theme.of(context).textTheme.titleMedium),
              if (upcoming == 'paymentApproved') ...[
                const SizedBox(height: 12),
                SegmentedButton<String>(
                  segments: const [
                    ButtonSegment(value: 'cash', label: Text('Cash')),
                    ButtonSegment(value: 'lease', label: Text('Lease')),
                  ],
                  selected: {_paymentType},
                  onSelectionChanged: (value) => setState(() => _paymentType = value.first),
                ),
                if (_paymentType == 'lease') ...[
                  CheckboxListTile(
                    contentPadding: EdgeInsets.zero,
                    title: const Text('GCI'),
                    value: _useGci,
                    onChanged: (value) => setState(() => _useGci = value ?? false),
                  ),
                  CheckboxListTile(
                    contentPadding: EdgeInsets.zero,
                    title: const Text('Finance'),
                    value: _useFinance,
                    onChanged: (value) => setState(() => _useFinance = value ?? false),
                  ),
                  if (_useFinance)
                    TextField(
                      controller: _financeName,
                      decoration: const InputDecoration(labelText: 'Finance company'),
                    ),
                ],
              ],
              if (upcoming == 'plateReceived') ...[
                const SizedBox(height: 12),
                TextField(
                  controller: _plateNumber,
                  textCapitalization: TextCapitalization.characters,
                  decoration: const InputDecoration(labelText: 'Plate number'),
                ),
              ],
              const SizedBox(height: 12),
              FilledButton(
                onPressed: _saving ? null : _advance,
                child: Text(_saving ? 'Saving' : 'Update stage'),
              ),
            ],
            if (role != 'dealer' && targets.isNotEmpty) ...[
              const Divider(),
              Text('Transfer', style: Theme.of(context).textTheme.titleMedium),
              const SizedBox(height: 12),
              DropdownButtonFormField<String>(
                initialValue: _transferDealerId,
                decoration: const InputDecoration(labelText: 'Destination dealer'),
                items: [
                  for (final dealer in targets)
                    DropdownMenuItem(value: dealer.id, child: Text('${dealer.name} (${dealer.code})')),
                ],
                onChanged: (value) => setState(() => _transferDealerId = value),
              ),
              const SizedBox(height: 12),
              OutlinedButton(
                onPressed: _saving || _transferDealerId == null ? null : _transfer,
                child: const Text('Transfer unit'),
              ),
            ],
          ],
        ),
    );
  }

  Widget _line(String label, String value) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(width: 140, child: Text(label)),
          Expanded(child: Text(value)),
        ],
      ),
    );
  }
}