// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Diagnostics.CodeAnalysis;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.ErrorReporting;
 
namespace Roslyn.Utilities
{
    // TODO: revisit https://github.com/dotnet/roslyn/issues/39222
 
    [SuppressMessage("ApiDesign", "CA1068:CancellationToken parameters must come last", Justification = "Matching TPL Signatures")]
    internal static partial class TaskFactoryExtensions
    {
        [SuppressMessage("Style", "VSTHRD200:Use \"Async\" suffix for async methods", Justification = "This is a Task wrapper, not an asynchronous method.")]
        public static Task SafeStartNew(this TaskFactory factory, Action action, CancellationToken cancellationToken, TaskScheduler scheduler)
        {
            void wrapped()
            {
                try
                {
                    action();
                }
                catch (Exception e) when (FatalError.ReportAndPropagateUnlessCanceled(e))
                {
                    throw ExceptionUtilities.Unreachable();
                }
            }
 
            return factory.StartNew(wrapped, cancellationToken, TaskCreationOptions.None, scheduler);
        }
 
        [SuppressMessage("Style", "VSTHRD200:Use \"Async\" suffix for async methods", Justification = "This is a Task wrapper, not an asynchronous method.")]
        public static Task<TResult> SafeStartNew<TResult>(this TaskFactory factory, Func<TResult> func, CancellationToken cancellationToken, TaskScheduler scheduler)
        {
            TResult wrapped()
            {
                try
                {
                    return func();
                }
                catch (Exception e) when (FatalError.ReportAndPropagateUnlessCanceled(e))
                {
                    throw ExceptionUtilities.Unreachable();
                }
            }
 
            return factory.StartNew(wrapped, cancellationToken, TaskCreationOptions.None, scheduler);
        }
 
        public static Task SafeStartNewFromAsync(this TaskFactory factory, Func<Task> actionAsync, CancellationToken cancellationToken, TaskScheduler scheduler)
        {
            // The one and only place we can call StartNew<>().
            var task = factory.StartNew(actionAsync, cancellationToken, TaskCreationOptions.None, scheduler).Unwrap();
            TaskExtensions.ReportNonFatalError(task, actionAsync);
            return task;
        }
 
        public static Task<TResult> SafeStartNewFromAsync<TResult>(this TaskFactory factory, Func<Task<TResult>> funcAsync, CancellationToken cancellationToken, TaskScheduler scheduler)
        {
            // The one and only place we can call StartNew<>().
            var task = factory.StartNew(funcAsync, cancellationToken, TaskCreationOptions.None, scheduler).Unwrap();
            TaskExtensions.ReportNonFatalError(task, funcAsync);
            return task;
        }
    }
}