// 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.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.Razor.Internal;
using Microsoft.AspNetCore.Testing.xunit;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.FunctionalTests
{
    /// <summary>
    /// Functional test to verify the error reporting of Razor compilation by diagnostic middleware.
    /// </summary>
    public class ErrorPageTests : IClassFixture<MvcTestFixture<ErrorPageMiddlewareWebSite.Startup>>
    {
        private static readonly string PreserveCompilationContextMessage = HtmlEncoder.Default.Encode(
            "One or more compilation references are missing. Ensure that your project is referencing " +
            "'Microsoft.NET.Sdk.Web' and the 'PreserveCompilationContext' property is not set to false.");
        public ErrorPageTests(MvcTestFixture<ErrorPageMiddlewareWebSite.Startup> fixture)
        {
            Client = fixture.Client;
        }

        public HttpClient Client { get; }

        [Fact]
        public async Task CompilationFailuresAreListedByErrorPageMiddleware()
        {
            // Arrange
            var action = "CompilationFailure";
            var expected = "Cannot implicitly convert type &#x27;int&#x27; to &#x27;string&#x27;";
            var expectedMediaType = MediaTypeHeaderValue.Parse("text/html; charset=utf-8");

            // Act
            var response = await Client.GetAsync("http://localhost/" + action);

            // Assert
            Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
            Assert.Equal(expectedMediaType, response.Content.Headers.ContentType);
            var content = await response.Content.ReadAsStringAsync();
            Assert.Contains($"{action}.cshtml", content);
            Assert.Contains(expected, content);
            Assert.DoesNotContain(PreserveCompilationContextMessage, content);
        }

        [Fact]
        public async Task ParseFailuresAreListedByErrorPageMiddleware()
        {
            // Arrange
            var action = "ParserError";
            var expected = "The code block is missing a closing &quot;}&quot; character.  Make sure you " +
            "have a matching &quot;}&quot; character for all the &quot;{&quot; characters " +
            "within this block, and that none of the &quot;}&quot; characters are being " +
            "interpreted as markup.";
            var expectedMediaType = MediaTypeHeaderValue.Parse("text/html; charset=utf-8");

            // Act
            var response = await Client.GetAsync(action);

            // Assert
            Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
            Assert.Equal(expectedMediaType, response.Content.Headers.ContentType);
            var content = await response.Content.ReadAsStringAsync();
            Assert.Contains($"{action}.cshtml", content);
            Assert.Contains(expected, content);
        }

        [Fact]
        public async Task CompilationFailuresFromViewImportsAreListed()
        {
            // Arrange
            var expectedMessage = "The type or namespace name &#x27;NamespaceDoesNotExist&#x27; could not be found ("
                + "are you missing a using directive or an assembly reference?)";
            var expectedCompilationContent = "public class _Views_ErrorFromViewImports_Index_cshtml : "
                + "global::Microsoft.AspNetCore.Mvc.Razor.RazorPage&lt;dynamic&gt;";
            var expectedMediaType = MediaTypeHeaderValue.Parse("text/html; charset=utf-8");

            // Act
            var response = await Client.GetAsync("http://localhost/ErrorFromViewImports");

            // Assert
            Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
            Assert.Equal(expectedMediaType, response.Content.Headers.ContentType);
            var content = await response.Content.ReadAsStringAsync();
            Assert.Contains("_ViewImports.cshtml", content);
            Assert.Contains(expectedMessage, content);
            Assert.Contains(PreserveCompilationContextMessage, content);
            Assert.Contains(expectedCompilationContent, content);
        }

        [ConditionalFact]
        // MVC Generates portable PDBs when compiling Razor views. NET461 does not understand portable PDBs
        // so line and file information cannot be determined. This is blocked until one of these issues are fixed:
        // https://github.com/aspnet/Common/issues/235
        // https://github.com/aspnet/Mvc/issues/6356
        [FrameworkSkipCondition(RuntimeFrameworks.CLR)]
        public async Task RuntimeErrorAreListedByErrorPageMiddleware()
        {
            // Arrange
            var expectedMessage = HtmlEncoder.Default.Encode("throw new Exception(\"Error from view\");");
            var expectedMediaType = MediaTypeHeaderValue.Parse("text/html; charset=utf-8");

            // Act
            var response = await Client.GetAsync("http://localhost/RuntimeError");

            // Assert
            Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
            Assert.Equal(expectedMediaType, response.Content.Headers.ContentType);
            var content = await response.Content.ReadAsStringAsync();
            Assert.Contains("RuntimeError.cshtml", content);
            Assert.Contains(expectedMessage, content);
        }

        [Fact]
        public async Task LoaderExceptionsFromReflectionTypeLoadExceptionsAreListed()
        {
            // Arrange
            var expectedMessage = "Custom Loader Exception.";
            var expectedMediaType = MediaTypeHeaderValue.Parse("text/html; charset=utf-8");

            // Act
            var response = await Client.GetAsync("http://localhost/LoaderException");

            // Assert
            Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
            Assert.Equal(expectedMediaType, response.Content.Headers.ContentType);
            var content = await response.Content.ReadAsStringAsync();
            Assert.Contains("Loader Exceptions:", content);
            Assert.Contains(expectedMessage, content);
        }

        [Fact]
        public async void AggregateException_FlattensInnerExceptions()
        {
            // Arrange
            var aggregateException = "AggregateException: One or more errors occurred.";
            var nullReferenceException = "NullReferenceException: Foo cannot be null";
            var indexOutOfRangeException = "IndexOutOfRangeException: Index is out of range";

            // Act
            var response = await Client.GetAsync("http://localhost/AggregateException");
            var content = await response.Content.ReadAsStringAsync();

            // Assert
            Assert.Contains(aggregateException, content);
            Assert.Contains(nullReferenceException, content);
            Assert.Contains(indexOutOfRangeException, content);
        }
    }
}