// 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.Net;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Xunit;
 
namespace Microsoft.AspNetCore.InternalTesting;
 
public class HttpClientSlimTest
{
    private static readonly byte[] _defaultResponse = Encoding.ASCII.GetBytes("test");
 
    [Fact]
    public async Task GetStringAsyncHttp()
    {
        using (var host = StartHost(out var address))
        {
            Assert.Equal("test", await HttpClientSlim.GetStringAsync(address));
        }
    }
 
    [Fact]
    public async Task GetStringAsyncThrowsForErrorResponse()
    {
        using (var host = StartHost(out var address, statusCode: 500))
        {
            await Assert.ThrowsAnyAsync<HttpRequestException>(() => HttpClientSlim.GetStringAsync(address));
        }
    }
 
    [Fact]
    public async Task PostAsyncHttp()
    {
        using (var host = StartHost(out var address, handler: context => context.Request.InputStream.CopyToAsync(context.Response.OutputStream)))
        {
            Assert.Equal("test post", await HttpClientSlim.PostAsync(address, new StringContent("test post")));
        }
    }
 
    [Fact]
    public async Task PostAsyncThrowsForErrorResponse()
    {
        using (var host = StartHost(out var address, statusCode: 500))
        {
            await Assert.ThrowsAnyAsync<HttpRequestException>(
                () => HttpClientSlim.PostAsync(address, new StringContent("")));
        }
    }
 
    [Fact]
    public void Ipv6ScopeIdsFilteredOut()
    {
        var requestUri = new Uri("http://[fe80::5d2a:d070:6fd6:1bac%7]:5003/");
        Assert.Equal("[fe80::5d2a:d070:6fd6:1bac]:5003", HttpClientSlim.GetHost(requestUri));
    }
 
    [Fact]
    public void GetHostExcludesDefaultPort()
    {
        var requestUri = new Uri("http://[fe80::5d2a:d070:6fd6:1bac%7]:80/");
        Assert.Equal("[fe80::5d2a:d070:6fd6:1bac]", HttpClientSlim.GetHost(requestUri));
    }
 
    private HttpListener StartHost(out string address, int statusCode = 200, Func<HttpListenerContext, Task> handler = null)
    {
        var listener = new HttpListener();
#if NET6_0_OR_GREATER
        var random = Random.Shared;
#else
        var random = new Random();
#endif
        address = null;
 
        for (var i = 0; i < 10; i++)
        {
            try
            {
                // HttpListener doesn't support requesting port 0 (dynamic).
                // Requesting port 0 from Sockets and then passing that to HttpListener is racy.
                // Just keep trying until we find a free one.
                address = $"http://localhost:{random.Next(1024, ushort.MaxValue)}/";
                listener.Prefixes.Add(address);
                listener.Start();
                break;
            }
            catch (HttpListenerException)
            {
                // Address in use
                listener.Close();
                listener = new HttpListener();
            }
        }
 
        Assert.True(listener.IsListening, "IsListening");
 
        _ = listener.GetContextAsync().ContinueWith(async task =>
        {
            var context = task.Result;
            context.Response.StatusCode = statusCode;
 
            if (handler == null)
            {
                await context.Response.OutputStream.WriteAsync(_defaultResponse, 0, _defaultResponse.Length);
            }
            else
            {
                await handler(context);
            }
 
            context.Response.Close();
        });
 
        return listener;
    }
}