using System;
using System.Collections.ObjectModel;
using System.IO;
using System.Text;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace Sln.Wcs.UI.ViewModels;

public partial class SystemMonitorViewModel : ObservableObject
{
    [ObservableProperty]
    private ObservableCollection<LogEntry> _logs = new();

    [ObservableProperty]
    private int _logCount;

    [ObservableProperty]
    private string _filterText = string.Empty;

    [ObservableProperty]
    private bool _autoScroll = true;

    private const int MaxLogs = 5000;

    public SystemMonitorViewModel()
    {
        // 安装控制台输出拦截器
        var original = Console.Out;
        var writer = new LogTextWriter(original, entry =>
        {
            Avalonia.Threading.Dispatcher.UIThread.Post(() =>
            {
                Logs.Add(entry);
                if (Logs.Count > MaxLogs) Logs.RemoveAt(0);
                LogCount = Logs.Count;
            });
        });
        Console.SetOut(writer);
    }

    [RelayCommand]
    private void Clear()
    {
        Logs.Clear();
        LogCount = 0;
    }

    [RelayCommand]
    private void ToggleAutoScroll()
    {
        AutoScroll = !AutoScroll;
    }
}

public class LogEntry
{
    public DateTime Time { get; set; }
    public string TimeText => Time.ToString("HH:mm:ss.fff");
    public string Message { get; set; } = string.Empty;
    public string Level { get; set; } = "INFO";
}

/// <summary>
/// 拦截 Console.WriteLine 输出，同时写入原始输出和 ObservableCollection
/// </summary>
internal class LogTextWriter : TextWriter
{
    private readonly TextWriter _original;
    private readonly Action<LogEntry> _onWrite;
    private readonly StringBuilder _buffer = new();

    public LogTextWriter(TextWriter original, Action<LogEntry> onWrite)
    {
        _original = original;
        _onWrite = onWrite;
    }

    public override Encoding Encoding => Encoding.UTF8;

    public override void Write(char value)
    {
        _original.Write(value);
        if (value == '\n')
        {
            FlushBuffer();
        }
        else if (value != '\r')
        {
            _buffer.Append(value);
        }
    }

    public override void WriteLine(string? message)
    {
        _original.WriteLine(message);
        if (message != null)
        {
            _onWrite(new LogEntry { Time = DateTime.Now, Message = message, Level = "INFO" });
        }
    }

    private void FlushBuffer()
    {
        var msg = _buffer.ToString();
        _buffer.Clear();
        if (msg.Length > 0)
        {
            _onWrite(new LogEntry { Time = DateTime.Now, Message = msg, Level = "INFO" });
        }
    }
}