using Sony.Filtr.Functional;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Sony.Filtr.Utility.Extensions
{
    public static class TaskExtensions
    {
        public static async Task<Result<T>> ToResult<T>(this Task<T> task)
        {
            try
            {
                return await task;
            }
            catch (Exception ex)
            {
                return Result<T>.FromException(ex);
            }
        }

        public static void FireAndForget(this Task task)
        {
            // We don't want anything to happen here.
        }

        public static async Task EnsureAllSuccessAsync(this IEnumerable<Task> tasks)
        {
            await EnsureAllSuccessAsync(tasks, TaskScheduler.Current);
        }

        public static async Task EnsureAllSuccessAsync(this IEnumerable<Task> tasks, TaskScheduler taskScheduler)
        {
            if (tasks.Any())
            {
                if (taskScheduler == null)
                    throw new ArgumentNullException(nameof(taskScheduler));

                await Task.WhenAll(tasks).ContinueWith(x =>
                {
                    if (x.Exception != null)
                    {
                        throw new InvalidOperationException(
                            "Chain of tasks was not completed successfully. " +
                            "Some of tasks are failed to complete. " +
                            "See inner exception for more details.", x.Exception);
                    }
                }, taskScheduler);
            }
        }

        public static void DoNotAwaitContinueWith(this Task task, Action<Task> continuation)
        {
            task.ContinueWith(continuation);
        }

        public static void DoNotAwait(this Task task)
        {
        }
    }
}