LlamaCasty/ViewModels/MainViewModel.Logs.cs

using System.Collections.ObjectModel;
using System.Linq;
using System.Windows.Threading;
using ytLive.Helpers;

namespace ytLive.ViewModels;

public partial class MainViewModel
{
    private const int VisibleLogEntryLimit = 500;
    private readonly ObservableCollection<AppLogEntry> _currentLaunchLogEntries = new();
    private DispatcherTimer? _currentLaunchLogTimer;
    private long _lastCurrentLaunchLogSequence;
    private bool _isLogsTabSelected;

    public ObservableCollection<AppLogEntry> CurrentLaunchLogEntries => _currentLaunchLogEntries;

    public bool IsLiveChatTabSelected
    {
        get => !_isLogsTabSelected;
        set
        {
            if (value)
                SelectLogsTab(false);
            else if (!_isLogsTabSelected)
                OnPropertyChanged(nameof(IsLiveChatTabSelected));
        }
    }

    public bool IsLogsTabSelected
    {
        get => _isLogsTabSelected;
        set
        {
            if (value)
                SelectLogsTab(true);
            else if (_isLogsTabSelected)
                OnPropertyChanged(nameof(IsLogsTabSelected));
        }
    }

    private void InitializeCurrentLaunchLogs()
    {
        foreach (var entry in AppLog.SnapshotCurrentLaunch()
                     .OrderByDescending(entry => entry.Sequence)
                     .Take(VisibleLogEntryLimit))
            _currentLaunchLogEntries.Add(entry);

        _lastCurrentLaunchLogSequence = _currentLaunchLogEntries.FirstOrDefault()?.Sequence ?? 0;
        _currentLaunchLogTimer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(250) };
        _currentLaunchLogTimer.Tick += (_, _) => RefreshCurrentLaunchLogs();
    }

    private void SelectLogsTab(bool selected)
    {
        if (_isLogsTabSelected == selected)
        {
            OnPropertyChanged(nameof(IsLiveChatTabSelected));
            OnPropertyChanged(nameof(IsLogsTabSelected));
            return;
        }

        _isLogsTabSelected = selected;
        OnPropertyChanged(nameof(IsLiveChatTabSelected));
        OnPropertyChanged(nameof(IsLogsTabSelected));
        if (selected)
        {
            RefreshCurrentLaunchLogs();
            _currentLaunchLogTimer?.Start();
        }
        else
        {
            _currentLaunchLogTimer?.Stop();
        }
    }

    internal void RefreshCurrentLaunchLogs()
    {
        var newEntries = AppLog.SnapshotCurrentLaunch()
            .Where(entry => entry.Sequence > _lastCurrentLaunchLogSequence)
            .OrderBy(entry => entry.Sequence)
            .ToArray();

        foreach (var entry in newEntries)
        {
            _currentLaunchLogEntries.Insert(0, entry);
            if (_currentLaunchLogEntries.Count > VisibleLogEntryLimit)
                _currentLaunchLogEntries.RemoveAt(_currentLaunchLogEntries.Count - 1);
            _lastCurrentLaunchLogSequence = entry.Sequence;
        }
    }

    private void StopCurrentLaunchLogFeed()
        => _currentLaunchLogTimer?.Stop();
}