// 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.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Features;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Net.Http.Headers;
using Xunit;

namespace Microsoft.AspNetCore.ResponseCaching.Tests
{
    public class ResponseCacheTests
    {
        [Fact]
        public async void ServesCachedContent_IfAvailable()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfNotAvailable()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("/different");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfVaryHeader_Matches()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.Response.Headers[HeaderNames.Vary] = HeaderNames.From;
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                client.DefaultRequestHeaders.From = "user@example.com";
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfVaryHeader_Mismatches()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.Response.Headers[HeaderNames.Vary] = HeaderNames.From;
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                client.DefaultRequestHeaders.From = "user@example.com";
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user2@example.com";
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfVaryParams_Matches()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = "param";
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?param=value");
                var subsequentResponse = await client.GetAsync("?param=value");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfVaryParamsExplicit_Matches_ParamNameCaseInsensitive()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = new[] { "ParamA", "paramb" };
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?parama=valuea&paramb=valueb");
                var subsequentResponse = await client.GetAsync("?ParamA=valuea&ParamB=valueb");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfVaryParamsStar_Matches_ParamNameCaseInsensitive()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = new[] { "*" };
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?parama=valuea&paramb=valueb");
                var subsequentResponse = await client.GetAsync("?ParamA=valuea&ParamB=valueb");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfVaryParamsExplicit_Matches_OrderInsensitive()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = new[] { "ParamB", "ParamA" };
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?ParamA=ValueA&ParamB=ValueB");
                var subsequentResponse = await client.GetAsync("?ParamB=ValueB&ParamA=ValueA");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfVaryParamsStar_Matches_OrderInsensitive()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = new[] { "*" };
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?ParamA=ValueA&ParamB=ValueB");
                var subsequentResponse = await client.GetAsync("?ParamB=ValueB&ParamA=ValueA");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfVaryParams_Mismatches()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = "param";
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?param=value");
                var subsequentResponse = await client.GetAsync("?param=value2");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfVaryParamsExplicit_Mismatch_ParamValueCaseSensitive()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = new[] { "ParamA", "ParamB" };
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?parama=valuea&paramb=valueb");
                var subsequentResponse = await client.GetAsync("?parama=ValueA&paramb=ValueB");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfVaryParamsStar_Mismatch_ParamValueCaseSensitive()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.GetResponseCacheFeature().VaryByParams = new[] { "*" };
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("?parama=valuea&paramb=valueb");
                var subsequentResponse = await client.GetAsync("?parama=ValueA&paramb=ValueB");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfRequestRequirements_NotMet()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.CacheControl = new System.Net.Http.Headers.CacheControlHeaderValue()
                {
                    MaxAge = TimeSpan.FromSeconds(0)
                };
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void Serves504_IfOnlyIfCachedHeader_IsSpecified()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.CacheControl = new System.Net.Http.Headers.CacheControlHeaderValue()
                {
                    OnlyIfCached = true
                };
                var subsequentResponse = await client.GetAsync("/different");

                initialResponse.EnsureSuccessStatusCode();
                Assert.Equal(System.Net.HttpStatusCode.GatewayTimeout, subsequentResponse.StatusCode);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfSetCookie_IsSpecified()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                var headers = context.Response.Headers[HeaderNames.SetCookie] = "cookieName=cookieValue";
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfIHttpSendFileFeature_NotUsed()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(app =>
            {
                app.Use(async (context, next) =>
                {
                    context.Features.Set<IHttpSendFileFeature>(new DummySendFileFeature());
                    await next.Invoke();
                });
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfIHttpSendFileFeature_Used()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(
                app =>
                {
                    app.Use(async (context, next) =>
                    {
                        context.Features.Set<IHttpSendFileFeature>(new DummySendFileFeature());
                        await next.Invoke();
                    });
                },
                requestDelegate: async (context) =>
                {
                    await context.Features.Get<IHttpSendFileFeature>().SendFileAsync("dummy", 0, 0, CancellationToken.None);
                    await TestUtils.TestRequestDelegate(context);
                });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfSubsequentRequest_ContainsNoStore()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.CacheControl = new System.Net.Http.Headers.CacheControlHeaderValue()
                {
                    NoStore = true
                };
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfInitialRequestContains_NoStore()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                client.DefaultRequestHeaders.CacheControl = new System.Net.Http.Headers.CacheControlHeaderValue()
                {
                    NoStore = true
                };
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void Serves304_IfIfModifiedSince_Satisfied()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.IfUnmodifiedSince = DateTimeOffset.MaxValue;
                var subsequentResponse = await client.GetAsync("");

                initialResponse.EnsureSuccessStatusCode();
                Assert.Equal(System.Net.HttpStatusCode.NotModified, subsequentResponse.StatusCode);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfIfModifiedSince_NotSatisfied()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache();

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.IfUnmodifiedSince = DateTimeOffset.MinValue;
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void Serves304_IfIfNoneMatch_Satisfied()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                var headers = context.Response.GetTypedHeaders().ETag = new EntityTagHeaderValue("\"E1\"");
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.IfNoneMatch.Add(new System.Net.Http.Headers.EntityTagHeaderValue("\"E1\""));
                var subsequentResponse = await client.GetAsync("");

                initialResponse.EnsureSuccessStatusCode();
                Assert.Equal(System.Net.HttpStatusCode.NotModified, subsequentResponse.StatusCode);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfIfNoneMatch_NotSatisfied()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                var headers = context.Response.GetTypedHeaders().ETag = new EntityTagHeaderValue("\"E1\"");
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.IfNoneMatch.Add(new System.Net.Http.Headers.EntityTagHeaderValue("\"E2\""));
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfBodySize_IsCacheable()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(options: new ResponseCacheOptions()
            {
                MaximumCachedBodySize = 100
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfBodySize_IsNotCacheable()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(options: new ResponseCacheOptions()
            {
                MaximumCachedBodySize = 1
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                var initialResponse = await client.GetAsync("");
                var subsequentResponse = await client.GetAsync("/different");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_WithoutReplacingCachedVaryBy_OnCacheMiss()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.Response.Headers[HeaderNames.Vary] = HeaderNames.From;
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                client.DefaultRequestHeaders.From = "user@example.com";
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user2@example.com";
                var otherResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user@example.com";
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesFreshContent_IfCachedVaryByUpdated_OnCacheMiss()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.Response.Headers[HeaderNames.Vary] = context.Request.Headers[HeaderNames.Pragma];
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                client.DefaultRequestHeaders.From = "user@example.com";
                client.DefaultRequestHeaders.Pragma.Clear();
                client.DefaultRequestHeaders.Pragma.Add(new System.Net.Http.Headers.NameValueHeaderValue("From"));
                client.DefaultRequestHeaders.MaxForwards = 1;
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user2@example.com";
                client.DefaultRequestHeaders.Pragma.Clear();
                client.DefaultRequestHeaders.Pragma.Add(new System.Net.Http.Headers.NameValueHeaderValue("Max-Forwards"));
                client.DefaultRequestHeaders.MaxForwards = 2;
                var otherResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user@example.com";
                client.DefaultRequestHeaders.Pragma.Clear();
                client.DefaultRequestHeaders.Pragma.Add(new System.Net.Http.Headers.NameValueHeaderValue("From"));
                client.DefaultRequestHeaders.MaxForwards = 1;
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseNotCachedAsync(initialResponse, subsequentResponse);
            }
        }

        [Fact]
        public async void ServesCachedContent_IfCachedVaryByNotUpdated_OnCacheMiss()
        {
            var builder = TestUtils.CreateBuilderWithResponseCache(requestDelegate: async (context) =>
            {
                context.Response.Headers[HeaderNames.Vary] = context.Request.Headers[HeaderNames.Pragma];
                await TestUtils.TestRequestDelegate(context);
            });

            using (var server = new TestServer(builder))
            {
                var client = server.CreateClient();
                client.DefaultRequestHeaders.From = "user@example.com";
                client.DefaultRequestHeaders.Pragma.Clear();
                client.DefaultRequestHeaders.Pragma.Add(new System.Net.Http.Headers.NameValueHeaderValue("From"));
                client.DefaultRequestHeaders.MaxForwards = 1;
                var initialResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user2@example.com";
                client.DefaultRequestHeaders.Pragma.Clear();
                client.DefaultRequestHeaders.Pragma.Add(new System.Net.Http.Headers.NameValueHeaderValue("From"));
                client.DefaultRequestHeaders.MaxForwards = 2;
                var otherResponse = await client.GetAsync("");
                client.DefaultRequestHeaders.From = "user@example.com";
                client.DefaultRequestHeaders.Pragma.Clear();
                client.DefaultRequestHeaders.Pragma.Add(new System.Net.Http.Headers.NameValueHeaderValue("From"));
                client.DefaultRequestHeaders.MaxForwards = 1;
                var subsequentResponse = await client.GetAsync("");

                await AssertResponseCachedAsync(initialResponse, subsequentResponse);
            }
        }

        private static async Task AssertResponseCachedAsync(HttpResponseMessage initialResponse, HttpResponseMessage subsequentResponse)
        {
            initialResponse.EnsureSuccessStatusCode();
            subsequentResponse.EnsureSuccessStatusCode();

            foreach (var header in initialResponse.Headers)
            {
                Assert.Equal(initialResponse.Headers.GetValues(header.Key), subsequentResponse.Headers.GetValues(header.Key));
            }
            Assert.True(subsequentResponse.Headers.Contains(HeaderNames.Age));
            Assert.Equal(await initialResponse.Content.ReadAsStringAsync(), await subsequentResponse.Content.ReadAsStringAsync());
        }

        private static async Task AssertResponseNotCachedAsync(HttpResponseMessage initialResponse, HttpResponseMessage subsequentResponse)
        {
            initialResponse.EnsureSuccessStatusCode();
            subsequentResponse.EnsureSuccessStatusCode();

            Assert.False(subsequentResponse.Headers.Contains(HeaderNames.Age));
            Assert.NotEqual(await initialResponse.Content.ReadAsStringAsync(), await subsequentResponse.Content.ReadAsStringAsync());
        }
    }
}