// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
 
#if AspNetCoreTesting
namespace Microsoft.AspNetCore.InternalTesting;
#else
namespace System.Threading.Tasks.Extensions;
#endif
 
#if AspNetCoreTesting
public
#else
internal
#endif
static class TaskExtensions
{
#if DEBUG
    // Shorter duration when running tests with debug.
    // Less time waiting for hang unit tests to fail in aspnetcore solution.
    public const int DefaultTimeoutDuration = 5 * 1000;
#else
    public const int DefaultTimeoutDuration = 30 * 1000;
#endif
 
    public static TimeSpan DefaultTimeoutTimeSpan { get; } = TimeSpan.FromMilliseconds(DefaultTimeoutDuration);
 
    public static Task DefaultTimeout(this Task task, int milliseconds = DefaultTimeoutDuration, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.TimeoutAfter(TimeSpan.FromMilliseconds(milliseconds), filePath, lineNumber);
    }
 
    public static Task DefaultTimeout(this Task task, TimeSpan timeout, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.TimeoutAfter(timeout, filePath, lineNumber);
    }
 
    public static Task DefaultTimeout(this ValueTask task, int milliseconds = DefaultTimeoutDuration, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.AsTask().TimeoutAfter(TimeSpan.FromMilliseconds(milliseconds), filePath, lineNumber);
    }
 
    public static Task DefaultTimeout(this ValueTask task, TimeSpan timeout, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.AsTask().TimeoutAfter(timeout, filePath, lineNumber);
    }
 
    public static Task<T> DefaultTimeout<T>(this Task<T> task, int milliseconds = DefaultTimeoutDuration, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.TimeoutAfter(TimeSpan.FromMilliseconds(milliseconds), filePath, lineNumber);
    }
 
    public static Task<T> DefaultTimeout<T>(this Task<T> task, TimeSpan timeout, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.TimeoutAfter(timeout, filePath, lineNumber);
    }
 
    public static Task<T> DefaultTimeout<T>(this ValueTask<T> task, int milliseconds = DefaultTimeoutDuration, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.AsTask().TimeoutAfter(TimeSpan.FromMilliseconds(milliseconds), filePath, lineNumber);
    }
 
    public static Task<T> DefaultTimeout<T>(this ValueTask<T> task, TimeSpan timeout, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = default)
    {
        return task.AsTask().TimeoutAfter(timeout, filePath, lineNumber);
    }
 
    [SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters", Justification = "Required to maintain compatibility")]
    public static async Task<T> TimeoutAfter<T>(this Task<T> task, TimeSpan timeout,
        [CallerFilePath] string filePath = null,
        [CallerLineNumber] int lineNumber = default)
    {
        // Don't create a timer if the task is already completed
        // or the debugger is attached
        if (task.IsCompleted || Debugger.IsAttached)
        {
            return await task.ConfigureAwait(false);
        }
#if NET6_0_OR_GREATER
        try
        {
            return await task.WaitAsync(timeout).ConfigureAwait(false);
        }
        catch (TimeoutException ex) when (ex.Source == typeof(TaskExtensions).Namespace)
        {
            throw new TimeoutException(CreateMessage(timeout, filePath, lineNumber));
        }
#else
        var cts = new CancellationTokenSource();
        if (task == await Task.WhenAny(task, Task.Delay(timeout, cts.Token)).ConfigureAwait(false))
        {
            cts.Cancel();
            return await task.ConfigureAwait(false);
        }
        else
        {
            throw new TimeoutException(CreateMessage(timeout, filePath, lineNumber));
        }
#endif
    }
 
    [SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters", Justification = "Required to maintain compatibility")]
    public static async Task TimeoutAfter(this Task task, TimeSpan timeout,
        [CallerFilePath] string filePath = null,
        [CallerLineNumber] int lineNumber = default)
    {
        // Don't create a timer if the task is already completed
        // or the debugger is attached
        if (task.IsCompleted || Debugger.IsAttached)
        {
            await task.ConfigureAwait(false);
            return;
        }
#if NET6_0_OR_GREATER
        try
        {
            await task.WaitAsync(timeout).ConfigureAwait(false);
        }
        catch (TimeoutException ex) when (ex.Source == typeof(TaskExtensions).Namespace)
        {
            throw new TimeoutException(CreateMessage(timeout, filePath, lineNumber));
        }
#else
        var cts = new CancellationTokenSource();
        if (task == await Task.WhenAny(task, Task.Delay(timeout, cts.Token)).ConfigureAwait(false))
        {
            cts.Cancel();
            await task.ConfigureAwait(false);
        }
        else
        {
            throw new TimeoutException(CreateMessage(timeout, filePath, lineNumber));
        }
#endif
    }
 
    private static string CreateMessage(TimeSpan timeout, string filePath, int lineNumber)
        => string.IsNullOrEmpty(filePath)
        ? $"The operation timed out after reaching the limit of {timeout.TotalMilliseconds}ms."
        : $"The operation at {filePath}:{lineNumber} timed out after reaching the limit of {timeout.TotalMilliseconds}ms.";
}