// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http.Features;
using Microsoft.AspNetCore.Testing.xunit;
using Xunit;

namespace Microsoft.AspNetCore.Server.HttpSys
{
    public class RequestBodyLimitTests
    {
        [ConditionalFact]
        public async Task ContentLengthEqualsLimit_ReadSync_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                httpContext.Features.Get<IHttpBodyControlFeature>().AllowSynchronousIO = true;
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = httpContext.Request.Body.Read(input, 0, input.Length);
                httpContext.Response.ContentLength = read;
                httpContext.Response.Body.Write(input, 0, read);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World");
                Assert.Equal("Hello World", response);
            }
        }

        [ConditionalFact]
        public async Task ContentLengthEqualsLimit_ReadAsync_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, async httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = await httpContext.Request.Body.ReadAsync(input, 0, input.Length);
                httpContext.Response.ContentLength = read;
                await httpContext.Response.Body.WriteAsync(input, 0, read);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World");
                Assert.Equal("Hello World", response);
            }
        }

        [ConditionalFact]
        public async Task ContentLengthEqualsLimit_ReadBeginEnd_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = httpContext.Request.Body.EndRead(httpContext.Request.Body.BeginRead(input, 0, input.Length, null, null));
                httpContext.Response.ContentLength = read;
                httpContext.Response.Body.EndWrite(httpContext.Response.Body.BeginWrite(input, 0, read, null, null));
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World");
                Assert.Equal("Hello World", response);
            }
        }

        [ConditionalFact]
        public async Task ChunkedEqualsLimit_ReadSync_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                httpContext.Features.Get<IHttpBodyControlFeature>().AllowSynchronousIO = true;
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = httpContext.Request.Body.Read(input, 0, input.Length);
                httpContext.Response.ContentLength = read;
                httpContext.Response.Body.Write(input, 0, read);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World", chunked: true);
                Assert.Equal("Hello World", response);
            }
        }

        [ConditionalFact]
        public async Task ChunkedEqualsLimit_ReadAsync_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, async httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = await httpContext.Request.Body.ReadAsync(input, 0, input.Length);
                httpContext.Response.ContentLength = read;
                await httpContext.Response.Body.WriteAsync(input, 0, read);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World", chunked: true);
                Assert.Equal("Hello World", response);
            }
        }

        [ConditionalFact]
        public async Task ChunkedEqualsLimit_ReadBeginEnd_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = httpContext.Request.Body.EndRead(httpContext.Request.Body.BeginRead(input, 0, input.Length, null, null));
                httpContext.Response.ContentLength = read;
                httpContext.Response.Body.EndWrite(httpContext.Response.Body.BeginWrite(input, 0, read, null, null));
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World", chunked: true);
                Assert.Equal("Hello World", response);
            }
        }

        [ConditionalFact]
        public async Task ContentLengthExceedsLimit_ReadSync_ThrowsImmediately()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                httpContext.Features.Get<IHttpBodyControlFeature>().AllowSynchronousIO = true;
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                var ex = Assert.Throws<IOException>(() => httpContext.Request.Body.Read(input, 0, input.Length));
                Assert.Equal("The request's Content-Length 11 is larger than the request body size limit 10.", ex.Message);
                ex = Assert.Throws<IOException>(() => httpContext.Request.Body.Read(input, 0, input.Length));
                Assert.Equal("The request's Content-Length 11 is larger than the request body size limit 10.", ex.Message);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 10))
            {
                var response = await SendRequestAsync(address, "Hello World");
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task ContentLengthExceedsLimit_ReadAsync_ThrowsImmediately()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                var ex = Assert.Throws<IOException>(() => { var t = httpContext.Request.Body.ReadAsync(input, 0, input.Length); });
                Assert.Equal("The request's Content-Length 11 is larger than the request body size limit 10.", ex.Message);
                ex = Assert.Throws<IOException>(() => { var t = httpContext.Request.Body.ReadAsync(input, 0, input.Length); });
                Assert.Equal("The request's Content-Length 11 is larger than the request body size limit 10.", ex.Message);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 10))
            {
                var response = await SendRequestAsync(address, "Hello World");
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task ContentLengthExceedsLimit_ReadBeginEnd_ThrowsImmediately()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                var ex = Assert.Throws<IOException>(() => httpContext.Request.Body.BeginRead(input, 0, input.Length, null, null));
                Assert.Equal("The request's Content-Length 11 is larger than the request body size limit 10.", ex.Message);
                ex = Assert.Throws<IOException>(() => httpContext.Request.Body.BeginRead(input, 0, input.Length, null, null));
                Assert.Equal("The request's Content-Length 11 is larger than the request body size limit 10.", ex.Message);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 10))
            {
                var response = await SendRequestAsync(address, "Hello World");
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task ChunkedExceedsLimit_ReadSync_ThrowsAtLimit()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                httpContext.Features.Get<IHttpBodyControlFeature>().AllowSynchronousIO = true;
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                var ex = Assert.Throws<IOException>(() => httpContext.Request.Body.Read(input, 0, input.Length));
                Assert.Equal("The total number of bytes read 11 has exceeded the request body size limit 10.", ex.Message);
                ex = Assert.Throws<IOException>(() => httpContext.Request.Body.Read(input, 0, input.Length));
                Assert.Equal("The total number of bytes read 11 has exceeded the request body size limit 10.", ex.Message);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 10))
            {
                var response = await SendRequestAsync(address, "Hello World", chunked: true);
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task ChunkedExceedsLimit_ReadAsync_ThrowsAtLimit()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, async httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                var ex = await Assert.ThrowsAsync<IOException>(() => httpContext.Request.Body.ReadAsync(input, 0, input.Length));
                Assert.Equal("The total number of bytes read 11 has exceeded the request body size limit 10.", ex.Message);
                ex = await Assert.ThrowsAsync<IOException>(() => httpContext.Request.Body.ReadAsync(input, 0, input.Length));
                Assert.Equal("The total number of bytes read 11 has exceeded the request body size limit 10.", ex.Message);
            }, options => options.MaxRequestBodySize = 10))
            {
                var response = await SendRequestAsync(address, "Hello World", chunked: true);
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task ChunkedExceedsLimit_ReadBeginEnd_ThrowsAtLimit()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                var body = httpContext.Request.Body;
                var ex = Assert.Throws<IOException>(() => body.EndRead(body.BeginRead(input, 0, input.Length, null, null)));
                Assert.Equal("The total number of bytes read 11 has exceeded the request body size limit 10.", ex.Message);
                ex = Assert.Throws<IOException>(() => body.EndRead(body.BeginRead(input, 0, input.Length, null, null)));
                Assert.Equal("The total number of bytes read 11 has exceeded the request body size limit 10.", ex.Message);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 10))
            {
                var response = await SendRequestAsync(address, "Hello World", chunked: true);
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task Chunked_ReadSyncPartialBodyUnderLimit_ThrowsAfterLimit()
        {
            var content = new StaggardContent();
            string address;
            using (Utilities.CreateHttpServer(out address, httpContext =>
            {
                httpContext.Features.Get<IHttpBodyControlFeature>().AllowSynchronousIO = true;
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = httpContext.Request.Body.Read(input, 0, input.Length);
                Assert.Equal(10, read);
                content.Block.Release();
                var ex = Assert.Throws<IOException>(() => httpContext.Request.Body.Read(input, 0, input.Length));
                Assert.Equal("The total number of bytes read 20 has exceeded the request body size limit 10.", ex.Message);
                return Task.FromResult(0);
            }, options => options.MaxRequestBodySize = 10))
            {
                string response = await SendRequestAsync(address, content, chunked: true);
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task Chunked_ReadAsyncPartialBodyUnderLimit_ThrowsAfterLimit()
        {
            var content = new StaggardContent();
            string address;
            using (Utilities.CreateHttpServer(out address, async httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = await httpContext.Request.Body.ReadAsync(input, 0, input.Length);
                Assert.Equal(10, read);
                content.Block.Release();
                var ex = await Assert.ThrowsAsync<IOException>(() => httpContext.Request.Body.ReadAsync(input, 0, input.Length));
                Assert.Equal("The total number of bytes read 20 has exceeded the request body size limit 10.", ex.Message);
            }, options => options.MaxRequestBodySize = 10))
            {
                string response = await SendRequestAsync(address, content, chunked: true);
                Assert.Equal(string.Empty, response);
            }
        }

        [ConditionalFact]
        public async Task AdjustLimitPerRequest_ContentLength_ReadAsync_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, async httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, feature.MaxRequestBodySize);
                feature.MaxRequestBodySize = 12;
                Assert.Equal(12, httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = await httpContext.Request.Body.ReadAsync(input, 0, input.Length);
                Assert.True(feature.IsReadOnly);
                httpContext.Response.ContentLength = read;
                await httpContext.Response.Body.WriteAsync(input, 0, read);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World!");
                Assert.Equal("Hello World!", response);
            }
        }

        [ConditionalFact]
        public async Task AdjustLimitPerRequest_Chunked_ReadAsync_Success()
        {
            string address;
            using (Utilities.CreateHttpServer(out address, async httpContext =>
            {
                var feature = httpContext.Features.Get<IHttpMaxRequestBodySizeFeature>();
                Assert.NotNull(feature);
                Assert.False(feature.IsReadOnly);
                Assert.Equal(11, feature.MaxRequestBodySize);
                feature.MaxRequestBodySize = 12;
                Assert.Null(httpContext.Request.ContentLength);
                byte[] input = new byte[100];
                int read = await httpContext.Request.Body.ReadAsync(input, 0, input.Length);
                Assert.True(feature.IsReadOnly);
                httpContext.Response.ContentLength = read;
                await httpContext.Response.Body.WriteAsync(input, 0, read);
            }, options => options.MaxRequestBodySize = 11))
            {
                var response = await SendRequestAsync(address, "Hello World!", chunked: true);
                Assert.Equal("Hello World!", response);
            }
        }

        private Task<string> SendRequestAsync(string uri, string upload, bool chunked = false)
        {
            return SendRequestAsync(uri, new StringContent(upload), chunked);
        }

        private async Task<string> SendRequestAsync(string uri, HttpContent content, bool chunked = false)
        {
            using (HttpClient client = new HttpClient())
            {
                client.DefaultRequestHeaders.TransferEncodingChunked = chunked;
                HttpResponseMessage response = await client.PostAsync(uri, content);
                response.EnsureSuccessStatusCode();
                return await response.Content.ReadAsStringAsync();
            }
        }

        private class StaggardContent : HttpContent
        {
            public StaggardContent()
            {
                Block = new SemaphoreSlim(0, 1);
            }

            public SemaphoreSlim Block { get; private set; }

            protected async override Task SerializeToStreamAsync(Stream stream, TransportContext context)
            {
                await stream.WriteAsync(new byte[10], 0, 10);
                await stream.FlushAsync();
                Assert.True(await Block.WaitAsync(TimeSpan.FromSeconds(10)));
                await stream.WriteAsync(new byte[10], 0, 10);
            }

            protected override bool TryComputeLength(out long length)
            {
                length = 10;
                return true;
            }
        }
    }
}