using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Threading;

namespace AnotherReplayReader.Utils
{
    internal class TaskQueue
    {
        private readonly object _lock = new();
        private readonly Dispatcher _dispatcher;
        private Task _current = Task.CompletedTask;

        public TaskQueue(Dispatcher dispatcher)
        {
            _dispatcher = dispatcher;
        }

        public Task Enqueue(Func<Task> getTask, CancellationToken cancelToken)
        {
            using var locker = new Lock(_lock);
            _current = _current.ContinueWith(async t =>
            {
                var task = await _dispatcher.InvokeAsync(getTask, DispatcherPriority.Background, cancelToken);
                await task.ConfigureAwait(false);
            }, cancelToken).Unwrap();
            return _current.IgnoreCancel();
        }

    }
}