using Microsoft.UI.Dispatching;

namespace FluidExplorer.Helpers;

/// <summary>DispatcherQueue 的 await 化封装：把 UI 线程更新变成可等待的操作，便于批量提交与顺序保证。</summary>
public static class DispatcherQueueExtensions
{
    public static Task EnqueueAsync(this DispatcherQueue queue, Action action)
    {
        var tcs = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
        if (!queue.TryEnqueue(() =>
        {
            try
            {
                action();
                tcs.TrySetResult();
            }
            catch (Exception ex)
            {
                tcs.TrySetException(ex);
            }
        }))
        {
            tcs.TrySetException(new InvalidOperationException("DispatcherQueue 已关闭，无法调度到 UI 线程。"));
        }
        return tcs.Task;
    }

    public static Task<T> EnqueueAsync<T>(this DispatcherQueue queue, Func<T> func)
    {
        var tcs = new TaskCompletionSource<T>(TaskCreationOptions.RunContinuationsAsynchronously);
        if (!queue.TryEnqueue(() =>
        {
            try
            {
                tcs.TrySetResult(func());
            }
            catch (Exception ex)
            {
                tcs.TrySetException(ex);
            }
        }))
        {
            tcs.TrySetException(new InvalidOperationException("DispatcherQueue 已关闭，无法调度到 UI 线程。"));
        }
        return tcs.Task;
    }

    /// <summary>即发即忘的 UI 调度（不需要等待结果的场合）。</summary>
    public static void Post(this DispatcherQueue queue, Action action) => queue.TryEnqueue(() => action());
}