// lib/widgets/transaction_calculator.dart
import 'package:flutter/material.dart';

class TransactionCalculator extends StatefulWidget {
  final Function(double) onAmountChanged;
  final VoidCallback onSave;

  const TransactionCalculator({
    super.key,
    required this.onAmountChanged,
    required this.onSave,
  });

  @override
  State<TransactionCalculator> createState() => _TransactionCalculatorState();
}

class _TransactionCalculatorState extends State<TransactionCalculator> {
  String _currentInput = '0';
  bool _decimalAdded = false;

  void _onNumberTap(String number) {
    setState(() {
      if (_currentInput == '0' && number != '.') {
        _currentInput = number;
      } else if (number == '.' && !_decimalAdded) {
        _currentInput += number;
        _decimalAdded = true;
      } else if (number != '.') {
        _currentInput += number;
      }
      widget.onAmountChanged(double.tryParse(_currentInput) ?? 0.0);
    });
  }

  void _onClear() {
    setState(() {
      _currentInput = '0';
      _decimalAdded = false;
      widget.onAmountChanged(0.0);
    });
  }

  void _onBackspace() {
    setState(() {
      if (_currentInput.length > 1) {
        if (_currentInput.endsWith('.')) {
          _decimalAdded = false;
        }
        _currentInput = _currentInput.substring(0, _currentInput.length - 1);
      } else {
        _currentInput = '0';
        _decimalAdded = false;
      }
      widget.onAmountChanged(double.tryParse(_currentInput) ?? 0.0);
    });
  }

  Widget _buildButton(String text, {Color? backgroundColor, Color? textColor, Function? onTap, int flex = 1}) {
    return Expanded(
      flex: flex,
      child: Padding(
        padding: const EdgeInsets.all(4.0),
        child: Material(
          color: backgroundColor ?? Colors.grey[200],
          borderRadius: BorderRadius.circular(8.0),
          child: InkWell(
            onTap: () => onTap?.call(),
            borderRadius: BorderRadius.circular(8.0),
            child: Container(
              height: 60,
              alignment: Alignment.center,
              child: Text(
                text,
                style: TextStyle(
                  fontSize: 24,
                  fontWeight: FontWeight.bold,
                  color: textColor ?? Colors.black,
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.white, // Fundo branco para a calculadora
      padding: const EdgeInsets.all(8.0),
      child: Column(
        children: [
          Row(
            children: [
              _buildButton('C', onTap: _onClear, textColor: Colors.red),
              _buildButton('⌫', onTap: _onBackspace),
              _buildButton('%', onTap: () { /* Implementar lógica de percentagem se necessário */ }),
              _buildButton('÷', backgroundColor: Colors.blue, textColor: Colors.white, onTap: () { /* Operador */ }),
            ],
          ),
          Row(
            children: [
              _buildButton('7', onTap: () => _onNumberTap('7')),
              _buildButton('8', onTap: () => _onNumberTap('8')),
              _buildButton('9', onTap: () => _onNumberTap('9')),
              _buildButton('×', backgroundColor: Colors.blue, textColor: Colors.white, onTap: () { /* Operador */ }),
            ],
          ),
          Row(
            children: [
              _buildButton('4', onTap: () => _onNumberTap('4')),
              _buildButton('5', onTap: () => _onNumberTap('5')),
              _buildButton('6', onTap: () => _onNumberTap('6')),
              _buildButton('-', backgroundColor: Colors.blue, textColor: Colors.white, onTap: () { /* Operador */ }),
            ],
          ),
          Row(
            children: [
              _buildButton('1', onTap: () => _onNumberTap('1')),
              _buildButton('2', onTap: () => _onNumberTap('2')),
              _buildButton('3', onTap: () => _onNumberTap('3')),
              _buildButton('+', backgroundColor: Colors.blue, textColor: Colors.white, onTap: () { /* Operador */ }),
            ],
          ),
          Row(
            children: [
              _buildButton('.', onTap: () => _onNumberTap('.')),
              _buildButton('0', onTap: () => _onNumberTap('0')),
              _buildButton('=', onTap: () { /* Implementar lógica de igual se for uma calculadora completa */ }),
              _buildButton(
                'OK',
                backgroundColor: Colors.blue,
                textColor: Colors.white,
                onTap: widget.onSave,
                flex: 2, // OK button takes more space
              ),
            ],
          ),
        ],
      ),
    );
  }
}