import 'package:flutter/material.dart';

import 'package:pshared/provider/payment/amount.dart';
import 'package:pshared/utils/currency.dart';
import 'package:pshared/utils/money.dart';


class PaymentAmountFieldController extends ChangeNotifier {
  final TextEditingController textController;
  PaymentAmountProvider? _provider;
  bool _isSyncingText = false;

  PaymentAmountFieldController({required double initialAmount})
      : textController = TextEditingController(
          text: amountToString(initialAmount),
        );

  void update(PaymentAmountProvider provider) {
    if (identical(_provider, provider)) return;
    _provider?.removeListener(_handleProviderChanged);
    _provider = provider;
    _provider?.addListener(_handleProviderChanged);
    _syncTextWithAmount(provider.amount);
  }

  void handleChanged(String value) {
    if (_isSyncingText) return;
    final parsed = _parseAmount(value);
    if (parsed != null) {
      _provider?.setAmount(parsed);
    }
  }

  void _handleProviderChanged() {
    final provider = _provider;
    if (provider == null) return;
    _syncTextWithAmount(provider.amount);
  }

  double? _parseAmount(String value) {
    final parsed = parseMoneyAmount(
      value.replaceAll(',', '.'),
      fallback: double.nan,
    );
    return parsed.isNaN ? null : parsed;
  }

  void _syncTextWithAmount(double amount) {
    final parsedText = _parseAmount(textController.text);
    if (parsedText != null && parsedText == amount) return;

    final nextText = amountToString(amount);
    _isSyncingText = true;
    textController.value = TextEditingValue(
      text: nextText,
      selection: TextSelection.collapsed(offset: nextText.length),
    );
    _isSyncingText = false;
  }

  @override
  void dispose() {
    _provider?.removeListener(_handleProviderChanged);
    textController.dispose();
    super.dispose();
  }
}