SpdUp/ViewModels/DebugLogViewModel.cs

using System.Collections.ObjectModel;
using System.Windows.Input;
using System.Windows.Threading;
using SpdUp.Core;

namespace SpdUp.ViewModels;

/// <summary>
/// Debug Log page – live scrolling log of every action the application performs.
/// </summary>
public sealed class DebugLogViewModel : ObservableObject
{
    private const int MaxLines = 2000;
    private readonly Dispatcher _dispatcher;

    public ObservableCollection<string> LogLines { get; } = new();

    private string _filterText = string.Empty;
    public string FilterText
    {
        get => _filterText;
        set
        {
            if (SetProperty(ref _filterText, value))
                OnPropertyChanged(nameof(FilteredLogLines));
        }
    }

    public IEnumerable<string> FilteredLogLines =>
        string.IsNullOrWhiteSpace(_filterText)
            ? LogLines
            : LogLines.Where(l => l.Contains(_filterText, StringComparison.OrdinalIgnoreCase));

    private bool _autoScroll = true;
    public bool AutoScroll
    {
        get => _autoScroll;
        set => SetProperty(ref _autoScroll, value);
    }

    public ICommand ClearCommand { get; }
    public ICommand CopyAllCommand { get; }

    public DebugLogViewModel()
    {
        _dispatcher = Dispatcher.CurrentDispatcher;

        ClearCommand = new RelayCommand(() => { LogLines.Clear(); OnPropertyChanged(nameof(FilteredLogLines)); });
        CopyAllCommand = new RelayCommand(() =>
        {
            try
            {
                var text = string.Join(Environment.NewLine, LogLines);
                System.Windows.Clipboard.SetText(text);
            }
            catch { }
        });

        // Subscribe to all log events
        Logger.LogWritten += OnLogWritten;
    }

    private void OnLogWritten(string line)
    {
        _dispatcher.BeginInvoke(() =>
        {
            LogLines.Add(line);
            while (LogLines.Count > MaxLines)
                LogLines.RemoveAt(0);

            OnPropertyChanged(nameof(FilteredLogLines));
        });
    }
}