using System;
using BetterGenshinImpact.Model;
using System.Threading;

namespace BetterGenshinImpact.Core.Script;

public class CancellationContext : Singleton<CancellationContext>
{
    private readonly object _sync = new();
    public CancellationTokenSource Cts { get; private set; } = new();
    public bool IsManualStop { get; private set; }

    public bool IsCancellationRequested
    {
        get
        {
            lock (_sync) 
            {
                return !disposed && Cts.IsCancellationRequested; 
            }
        }
    }

    private bool disposed;

    public void Set()
    {
        lock (_sync)
        {
            Cts = new CancellationTokenSource();
            IsManualStop = false;
            disposed = false;
        }
    }

    public void ManualCancel()
    {
        CancellationTokenSource cts;
        lock (_sync)
        {
            if (disposed)
            {
                return;
            }

            IsManualStop = true;
            cts = Cts;
        }

        try
        {
            cts.Cancel();
        }
        catch (ObjectDisposedException)
        {
            // 并发 Clear 可能已释放 CTS，这里视为已取消/已清理。
        }
    }

    public void Cancel()
    {
        CancellationTokenSource cts;
        lock (_sync)
        {
            if (disposed)
            {
                return;
            }

            cts = Cts;
        }

        try
        {
            cts.Cancel();
        }
        catch (ObjectDisposedException)
        {
            // 并发 Clear 可能已释放 CTS，这里视为已取消/已清理。
        }
    }

    public void Clear()
    {
        CancellationTokenSource cts;
        lock (_sync)
        {
            if (disposed)
            {
                return;
            }

            cts = Cts;
            disposed = true;
        }

        cts.Dispose();
    }
}