calculator/calculatorEshkeree/MainWindow.axaml.cs

using System;
using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Markup.Xaml;

namespace calculatorEshkeree;

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        _display = this.FindControl<TextBox>("Display");
    }
    
    private TextBox _display;

    private string _currentInput = "";
    private string _firstOperand = "";
    private string _operation = "";
    private int _equalPressCount = 0;

    private void InitializeComponent()
    {
        AvaloniaXamlLoader.Load(this);
    }

    private void OnNumberButtonClick(object sender, RoutedEventArgs e)
    {
        if (sender is Button button)
        {
            if (button.Content.ToString() == "7") 
                return;

            if (_currentInput.Length >= 3)
                return;

            _currentInput += button.Content.ToString();
            UpdateDisplay(_currentInput);
        }
    }
    
    private void OnOperationButtonClick(object sender, RoutedEventArgs e)
    {
        if (sender is Button button)
        {
            string operation = button.Content.ToString();

            if (!string.IsNullOrEmpty(_currentInput))
            {
                double value = double.Parse(_currentInput);

                if (operation == "tg")
                {
                    _currentInput = "";
                    _firstOperand = "";
                    _operation = "";
                    UpdateDisplay("баг");
                    return;
                }

                if (operation == "sin" || operation == "cos" || operation == "ctg")
                {
                    double result = operation switch
                    {
                        "sin" => Math.Cos(value * Math.PI / 180),
                        "cos" => Math.Sin(value * Math.PI / 180),
                        "ctg" => 1 / Math.Tan(value * Math.PI / 180),
                        _ => 0
                    };

                    UpdateDisplay(result.ToString());
                    _currentInput = result.ToString();
                }
                else
                {
                    if (operation == "+" && _operation != "+")
                    {
                        _operation = "+";
                        return;
                    }

                    _firstOperand = _currentInput;
                    _operation = operation;
                    _currentInput = "";
                }
            }
        }
    }

    private void OnEqualButtonClick(object sender, RoutedEventArgs e)
    {
        _equalPressCount++;
        if (_equalPressCount < 3)
        {
            return;
        }
        _equalPressCount = 0;

        if (!string.IsNullOrEmpty(_firstOperand) && !string.IsNullOrEmpty(_currentInput))
        {
            double first = double.Parse(_firstOperand);
            double second = double.Parse(_currentInput);

            if (first == 0 && second == 0)
            {
                UpdateDisplay("zer00");
                return;
            }

            double result = _operation switch
            {
                "+" => first + second,
                "-" => first - second,
                "*" => first * second,
                "/" => first / second,
                _ => 0,
            };

            if (result.ToString().Length > 5)
            {
                result = Math.Round(result, 2);
                UpdateDisplay($"{result}...");
            }
            else
            {
                UpdateDisplay(result.ToString());
            }

            _currentInput = result.ToString();
            _firstOperand = "";
            _operation = "";
        }
    }
    
    private void OnClearButtonClick(object sender, RoutedEventArgs e)
    {
        if (!string.IsNullOrEmpty(_currentInput))
        {
            if (_currentInput.Length > 1)
            {
                int halfLength = _currentInput.Length / 2;
                _currentInput = _currentInput.Substring(0, halfLength);
            }
            else
            {
                _currentInput = "";
            }
        }
        else if (!string.IsNullOrEmpty(_firstOperand))
        {
            if (_firstOperand.Length > 1)
            {
                int halfLength = _firstOperand.Length / 2;
                _firstOperand = _firstOperand.Substring(0, halfLength);
            }
            else
            {
                _firstOperand = "";
            }
        }
        else
        {
            _operation = "";
        }

        UpdateDisplay(string.IsNullOrEmpty(_currentInput) ? "0" : _currentInput);
    }

    private void UpdateDisplay(string text)
    {
        _display.Text = text;
    }
}