kalkulator/lib/main.dart

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

void main() {
  runApp(const KalkulatorApp());
}

class KalkulatorApp extends StatelessWidget {
  const KalkulatorApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Kalkulator',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: Colors.blueGrey,
          brightness: Brightness.dark,
        ),
        useMaterial3: true,
      ),
      home: const CalculatorScreen(),
    );
  }
}

class CalculatorScreen extends StatefulWidget {
  const CalculatorScreen({super.key});

  @override
  State<CalculatorScreen> createState() => _CalculatorScreenState();
}

class _CalculatorScreenState extends State<CalculatorScreen> {
  final _logic = CalculatorLogic();

  void _onPressed(String label) {
    setState(() {
      switch (label) {
        case 'C':
          _logic.clear();
        case '+/-':
          _logic.toggleSign();
        case '%':
          _logic.percent();
        case '=':
          _logic.calculate();
        case '.':
          _logic.inputDecimal();
        case '+' || '-' || '*' || '/':
          _logic.inputOperator(label);
        default:
          _logic.inputDigit(label);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      body: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: Container(
                alignment: Alignment.bottomRight,
                padding: const EdgeInsets.all(24),
                child: Text(
                  _logic.display,
                  style: const TextStyle(
                    fontSize: 64,
                    fontWeight: FontWeight.w300,
                    color: Colors.white,
                  ),
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                ),
              ),
            ),
            _buildButtonRow(['C', '+/-', '%', '/']),
            _buildButtonRow(['7', '8', '9', '*']),
            _buildButtonRow(['4', '5', '6', '-']),
            _buildButtonRow(['1', '2', '3', '+']),
            _buildButtonRow(['0', '.', '=']),
            const SizedBox(height: 8),
          ],
        ),
      ),
    );
  }

  Widget _buildButtonRow(List<String> labels) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      child: Row(
        children: labels.map((label) {
          final isWide = label == '0' && labels.length == 3;
          return Expanded(
            flex: isWide ? 2 : 1,
            child: Padding(
              padding: const EdgeInsets.all(4),
              child: _CalcButton(
                label: label,
                onPressed: () => _onPressed(label),
                color: _buttonColor(label),
                textColor: _textColor(label),
              ),
            ),
          );
        }).toList(),
      ),
    );
  }

  Color _buttonColor(String label) {
    if (['+', '-', '*', '/', '='].contains(label)) return Colors.orange;
    if (['C', '+/-', '%'].contains(label)) return Colors.grey.shade700;
    return Colors.grey.shade900;
  }

  Color _textColor(String label) {
    if (['C', '+/-', '%'].contains(label)) return Colors.black;
    return Colors.white;
  }
}

class _CalcButton extends StatelessWidget {
  final String label;
  final VoidCallback onPressed;
  final Color color;
  final Color textColor;

  const _CalcButton({
    required this.label,
    required this.onPressed,
    required this.color,
    required this.textColor,
  });

  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
      onPressed: onPressed,
      style: ElevatedButton.styleFrom(
        backgroundColor: color,
        foregroundColor: textColor,
        padding: const EdgeInsets.all(20),
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(16),
        ),
      ),
      child: Text(
        label,
        style: const TextStyle(fontSize: 28, fontWeight: FontWeight.w400),
      ),
    );
  }
}