import "package:flutter/material.dart";

import "../main.dart";
import "../models.dart";
import "../format.dart";
import "../theme.dart";

/// Bottom-sheet form to create or edit a car, mirroring the web CarFormModal.
/// Pops with the saved [Car] on success, or null if cancelled.
class CarFormSheet extends StatefulWidget {
  final Car? car; // null => create
  const CarFormSheet({super.key, this.car});

  @override
  State<CarFormSheet> createState() => _CarFormSheetState();
}

class _CarFormSheetState extends State<CarFormSheet> {
  late final Map<String, TextEditingController> _c;
  String _fuelType = "";
  DateTime? _buildDate;
  DateTime? _firstRegistrationDate;
  bool _saving = false;
  String? _error;

  bool get _isEdit => widget.car != null;

  @override
  void initState() {
    super.initState();
    final car = widget.car;
    _fuelType = car?.fuelType ?? "";
    _buildDate = (car?.buildDate.isNotEmpty ?? false) ? DateTime.tryParse(car!.buildDate) : null;
    _firstRegistrationDate =
        (car?.firstRegistrationDate.isNotEmpty ?? false) ? DateTime.tryParse(car!.firstRegistrationDate) : null;
    _c = {
      "name": TextEditingController(text: car?.name ?? ""),
      "make": TextEditingController(text: car?.make ?? ""),
      "model": TextEditingController(text: car?.model ?? ""),
      "year": TextEditingController(text: (car != null && car.year > 0) ? "${car.year}" : ""),
      "registration": TextEditingController(text: car?.registration ?? ""),
      "registrationCountry": TextEditingController(text: car?.registrationCountry ?? ""),
      "vin": TextEditingController(text: car?.vin ?? ""),
      "oilSpec": TextEditingController(text: car?.oilSpec ?? ""),
      "transmissionOilSpec": TextEditingController(text: car?.transmissionOilSpec ?? ""),
      "differentialOilSpec": TextEditingController(text: car?.differentialOilSpec ?? ""),
      "brakeFluidSpec": TextEditingController(text: car?.brakeFluidSpec ?? ""),
      "coolantSpec": TextEditingController(text: car?.coolantSpec ?? ""),
      "currentKm":
          TextEditingController(text: (car != null && car.currentKm > 0) ? "${car.currentKm}" : ""),
      "serviceIntervalDays": TextEditingController(text: "${car?.serviceIntervalDays ?? 365}"),
      "serviceIntervalKm": TextEditingController(text: "${car?.serviceIntervalKm ?? 15000}"),
    };
  }

  @override
  void dispose() {
    for (final c in _c.values) {
      c.dispose();
    }
    super.dispose();
  }

  int _int(String key, int fallback) => int.tryParse(_c[key]!.text.trim()) ?? fallback;

  Future<void> _save() async {
    final name = _c["name"]!.text.trim();
    if (name.isEmpty) {
      setState(() => _error = "Name is required.");
      return;
    }
    setState(() {
      _saving = true;
      _error = null;
    });
    final payload = {
      "name": name,
      "make": _c["make"]!.text.trim(),
      "model": _c["model"]!.text.trim(),
      "year": _int("year", 0),
      "registration": _c["registration"]!.text.trim(),
      "registrationCountry": _c["registrationCountry"]!.text.trim(),
      "vin": _c["vin"]!.text.trim(),
      "fuelType": _fuelType,
      "buildDate": _isoOrEmpty(_buildDate),
      "firstRegistrationDate": _isoOrEmpty(_firstRegistrationDate),
      "oilSpec": _c["oilSpec"]!.text.trim(),
      "transmissionOilSpec": _c["transmissionOilSpec"]!.text.trim(),
      "differentialOilSpec": _c["differentialOilSpec"]!.text.trim(),
      "brakeFluidSpec": _c["brakeFluidSpec"]!.text.trim(),
      "coolantSpec": _c["coolantSpec"]!.text.trim(),
      "currentKm": _int("currentKm", 0),
      "serviceIntervalDays": _int("serviceIntervalDays", 365),
      "serviceIntervalKm": _int("serviceIntervalKm", 15000),
    };
    try {
      final saved = _isEdit
          ? await apiClient.updateCar(widget.car!.id, payload)
          : await apiClient.createCar(payload);
      if (mounted) Navigator.pop(context, saved);
    } catch (e) {
      setState(() => _error = e.toString());
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  static String _isoOrEmpty(DateTime? d) => d == null
      ? ""
      : "${d.year.toString().padLeft(4, '0')}-${d.month.toString().padLeft(2, '0')}-${d.day.toString().padLeft(2, '0')}";

  Widget _field(String key, String label,
      {TextInputType? keyboard, TextCapitalization caps = TextCapitalization.none}) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 10),
      child: TextField(
        controller: _c[key],
        keyboardType: keyboard,
        textCapitalization: caps,
        decoration: InputDecoration(labelText: label, border: const OutlineInputBorder(), isDense: true),
      ),
    );
  }

  /// A tappable read-only field that opens a date picker. Shows a clear button
  /// when a date is set, otherwise a calendar icon.
  Widget _dateField(String label, DateTime? value, ValueChanged<DateTime?> onChanged) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 10),
      child: InkWell(
        onTap: () async {
          final picked = await showDatePicker(
            context: context,
            initialDate: value ?? DateTime.now(),
            firstDate: DateTime(1950),
            lastDate: DateTime.now().add(const Duration(days: 365)),
          );
          if (picked != null) setState(() => onChanged(picked));
        },
        child: InputDecorator(
          decoration: InputDecoration(
            labelText: label,
            border: const OutlineInputBorder(),
            isDense: true,
            suffixIcon: value == null
                ? const Icon(Icons.calendar_today, size: 18)
                : IconButton(
                    icon: const Icon(Icons.clear, size: 18),
                    onPressed: () => setState(() => onChanged(null)),
                  ),
          ),
          child: Text(value == null ? "—" : formatDate(value)),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.only(
        left: 16,
        right: 16,
        top: 16,
        bottom: MediaQuery.of(context).viewInsets.bottom + 16,
      ),
      child: SingleChildScrollView(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(_isEdit ? "Edit car" : "Add a car",
                style: const TextStyle(fontSize: 18, fontWeight: FontWeight.w600)),
            const SizedBox(height: 12),
            if (_error != null)
              Padding(
                padding: const EdgeInsets.only(bottom: 8),
                child: Text(_error!, style: const TextStyle(color: DriverVault.danger)),
              ),
            _field("name", "Name *", caps: TextCapitalization.words),
            Row(children: [
              Expanded(child: _field("make", "Make")),
              const SizedBox(width: 8),
              Expanded(child: _field("model", "Model")),
            ]),
            Row(children: [
              Expanded(child: _field("year", "Year", keyboard: TextInputType.number)),
              const SizedBox(width: 8),
              Expanded(child: _field("registration", "Registration")),
            ]),
            _field("registrationCountry", "Registration country", caps: TextCapitalization.words),
            _field("vin", "VIN"),
            Padding(
              padding: const EdgeInsets.only(bottom: 10),
              child: DropdownButtonFormField<String>(
                initialValue: _fuelType.isEmpty ? null : _fuelType,
                decoration: const InputDecoration(
                    labelText: "Fuel type", border: OutlineInputBorder(), isDense: true),
                items: const [
                  DropdownMenuItem(value: "petrol", child: Text("Petrol (gasoline)")),
                  DropdownMenuItem(value: "diesel", child: Text("Diesel")),
                  DropdownMenuItem(value: "hybrid", child: Text("Hybrid")),
                  DropdownMenuItem(value: "electric", child: Text("Electric")),
                ],
                onChanged: (v) => setState(() => _fuelType = v ?? ""),
              ),
            ),
            Row(children: [
              Expanded(child: _dateField("Build date", _buildDate, (v) => _buildDate = v)),
              const SizedBox(width: 8),
              Expanded(
                  child: _dateField("First registration", _firstRegistrationDate,
                      (v) => _firstRegistrationDate = v)),
            ]),
            _field("oilSpec", "Engine oil spec"),
            Row(children: [
              Expanded(child: _field("transmissionOilSpec", "Transmission oil spec")),
              const SizedBox(width: 8),
              Expanded(child: _field("differentialOilSpec", "Differential oil spec")),
            ]),
            Row(children: [
              Expanded(child: _field("brakeFluidSpec", "Brake fluid spec")),
              const SizedBox(width: 8),
              Expanded(child: _field("coolantSpec", "Coolant spec")),
            ]),
            _field("currentKm", "Current odometer (km)", keyboard: TextInputType.number),
            Row(children: [
              Expanded(
                  child: _field("serviceIntervalDays", "Service interval (days)",
                      keyboard: TextInputType.number)),
              const SizedBox(width: 8),
              Expanded(
                  child: _field("serviceIntervalKm", "Service interval (km)",
                      keyboard: TextInputType.number)),
            ]),
            const SizedBox(height: 8),
            SizedBox(
              width: double.infinity,
              child: FilledButton(
                onPressed: _saving ? null : _save,
                child: Text(_saving ? "Saving…" : (_isEdit ? "Save changes" : "Add car")),
              ),
            ),
          ],
        ),
      ),
    );
  }
}