// 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.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Features;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Routing;
using Moq;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
{
    public class SaveTempDataFilterTest
    {
        public static TheoryData<IActionResult> ActionResultsData
        {
            get
            {
                return new TheoryData<IActionResult>()
                {
                    new TestActionResult(),
                    new TestKeepTempDataActionResult()
                };
            }
        }

        [Fact]
        public async Task OnResultExecuting_DoesntThrowIfResponseStarted()
        {
            // Arrange
            var responseFeature = new TestResponseFeature(hasStarted: true);
            var httpContext = GetHttpContext(responseFeature);
            var tempDataFactory = new Mock<ITempDataDictionaryFactory>(MockBehavior.Loose);
            tempDataFactory
                .Setup(f => f.GetTempData(It.IsAny<HttpContext>()))
                .Verifiable();
            var filter = new SaveTempDataFilter(tempDataFactory.Object);
            var context = GetResultExecutingContext(httpContext);
            filter.OnResultExecuting(context);

            // Act
            // Checking it doesn't throw
            await responseFeature.FireOnSendingHeadersAsync();
        }

        [Fact]
        public void OnResourceExecuting_RegistersOnStartingCallback()
        {
            // Arrange
            var responseFeature = new Mock<IHttpResponseFeature>(MockBehavior.Strict);
            responseFeature
                .Setup(rf => rf.OnStarting(It.IsAny<Func<object, Task>>(), It.IsAny<object>()))
                .Verifiable();
            responseFeature
                .SetupGet(rf => rf.HasStarted)
                .Returns(false);

            var tempDataFactory = new Mock<ITempDataDictionaryFactory>(MockBehavior.Strict);
            tempDataFactory
                .Setup(f => f.GetTempData(It.IsAny<HttpContext>()))
                .Verifiable();
            var filter = new SaveTempDataFilter(tempDataFactory.Object);
            var httpContext = GetHttpContext(responseFeature.Object);
            var context = GetResourceExecutingContext(httpContext);

            // Act
            filter.OnResourceExecuting(context);

            // Assert
            responseFeature.Verify();
            tempDataFactory.Verify(tdf => tdf.GetTempData(It.IsAny<HttpContext>()), Times.Never());
        }

        [Fact]
        public void OnResultExecuted_CanBeCalledTwice()
        {
            // Arrange
            var responseFeature = new TestResponseFeature();
            var httpContext = GetHttpContext(responseFeature);
            var tempData = GetTempDataDictionary();
            var tempDataFactory = new Mock<ITempDataDictionaryFactory>(MockBehavior.Strict);
            tempDataFactory
                .Setup(f => f.GetTempData(It.IsAny<HttpContext>()))
                .Returns(tempData.Object)
                .Verifiable();
            var filter = new SaveTempDataFilter(tempDataFactory.Object);
            var context = GetResultExecutedContext(httpContext);

            // Act (No Assert)
            filter.OnResultExecuted(context);
            // Shouldn't have thrown
            filter.OnResultExecuted(context);
        }

        [Fact]
        public async Task OnResourceExecuting_DoesNotSaveTempData_WhenTempDataAlreadySaved()
        {
            // Arrange
            var responseFeature = new TestResponseFeature();
            var httpContext = GetHttpContext(responseFeature);
            httpContext.Items[SaveTempDataFilter.TempDataSavedKey] = true; // indicate that tempdata was already saved
            var tempDataFactory = new Mock<ITempDataDictionaryFactory>(MockBehavior.Strict);
            tempDataFactory
                .Setup(f => f.GetTempData(It.IsAny<HttpContext>()))
                .Verifiable();
            var filter = new SaveTempDataFilter(tempDataFactory.Object);
            var context = GetResourceExecutingContext(httpContext);
            filter.OnResourceExecuting(context); // registers callback

            // Act
            await responseFeature.FireOnSendingHeadersAsync();

            // Assert
            tempDataFactory.Verify(tdf => tdf.GetTempData(It.IsAny<HttpContext>()), Times.Never());
        }

        [Theory]
        [MemberData(nameof(ActionResultsData))]
        public async Task OnResultExecuting_SavesTempData_WhenTempData_NotSavedAlready(IActionResult result)
        {
            // Arrange
            var tempDataDictionary = GetTempDataDictionary();
            var filter = GetFilter(tempDataDictionary.Object);
            var responseFeature = new TestResponseFeature();
            var httpContext = GetHttpContext(responseFeature);
            var resourceContext = GetResourceExecutingContext(httpContext);
            var resultContext = GetResultExecutedContext(httpContext, result);

            filter.OnResourceExecuting(resourceContext); // registers callback
            filter.OnResultExecuted(resultContext);
            // Act
            await responseFeature.FireOnSendingHeadersAsync();

            // Assert
            tempDataDictionary.Verify(tdd => tdd.Save(), Times.Once());
        }

        [Fact]
        public async Task OnResourceExecuting_KeepsTempData_ForIKeepTempDataResult()
        {
            // Arrange
            var tempDataDictionary = GetTempDataDictionary();
            var filter = GetFilter(tempDataDictionary.Object);
            var responseFeature = new TestResponseFeature();
            var httpContext = GetHttpContext(responseFeature);
            var resourceContext = GetResourceExecutingContext(httpContext);
            var resultContext = GetResultExecutedContext(httpContext, new TestKeepTempDataActionResult());
            filter.OnResourceExecuting(resourceContext); // registers callback
            filter.OnResultExecuted(resultContext);

            // Act
            await responseFeature.FireOnSendingHeadersAsync();

            // Assert
            tempDataDictionary.Verify(tdf => tdf.Keep(), Times.Once());
            tempDataDictionary.Verify(tdf => tdf.Save(), Times.Once());
        }

        [Fact]
        public async Task OnResultExecuting_DoesNotKeepTempData_ForNonIKeepTempDataResult()
        {
            // Arrange
            var tempDataDictionary = GetTempDataDictionary();
            var filter = GetFilter(tempDataDictionary.Object);
            var responseFeature = new TestResponseFeature();
            var actionContext = GetHttpContext(responseFeature);
            var context = GetResourceExecutingContext(actionContext);
            filter.OnResourceExecuting(context); // registers callback

            // Act
            await responseFeature.FireOnSendingHeadersAsync();

            // Assert
            tempDataDictionary.Verify(tdf => tdf.Keep(), Times.Never());
            tempDataDictionary.Verify(tdf => tdf.Save(), Times.Once());
        }

        [Fact]
        public void OnResultExecuted_DoesNotSaveTempData_WhenResponseHas_AlreadyStarted()
        {
            // Arrange
            var tempDataFactory = new Mock<ITempDataDictionaryFactory>(MockBehavior.Strict);
            tempDataFactory
                .Setup(f => f.GetTempData(It.IsAny<HttpContext>()))
                .Verifiable();
            var filter = new SaveTempDataFilter(tempDataFactory.Object);
            var httpContext = GetHttpContext(new TestResponseFeature(hasStarted: true));
            var context = GetResultExecutedContext(httpContext);

            // Act
            filter.OnResultExecuted(context);

            // Assert
            tempDataFactory.Verify(tdf => tdf.GetTempData(It.IsAny<HttpContext>()), Times.Never());
        }

        [Theory]
        [MemberData(nameof(ActionResultsData))]
        public void OnResultExecuted_SavesTempData_WhenResponseHas_NotStarted(IActionResult result)
        {
            // Arrange
            var tempDataDictionary = GetTempDataDictionary();
            var filter = GetFilter(tempDataDictionary.Object);
            var context = GetResultExecutedContext(actionResult: result);

            // Act
            filter.OnResultExecuted(context);

            // Assert
            tempDataDictionary.Verify(tdf => tdf.Save(), Times.Once());
        }

        [Fact]
        public void OnResultExecuted_KeepsTempData_ForIKeepTempDataResult()
        {
            // Arrange
            var tempDataDictionary = GetTempDataDictionary();
            var filter = GetFilter(tempDataDictionary.Object);
            var context = GetResultExecutedContext(actionResult: new TestKeepTempDataActionResult());

            // Act
            filter.OnResultExecuted(context);

            // Assert
            tempDataDictionary.Verify(tdf => tdf.Keep(), Times.Once());
            tempDataDictionary.Verify(tdf => tdf.Save(), Times.Once());
        }

        [Fact]
        public void OnResultExecuted_DoesNotKeepTempData_ForNonIKeepTempDataResult()
        {
            // Arrange
            var tempDataDictionary = GetTempDataDictionary();
            var filter = GetFilter(tempDataDictionary.Object);
            var context = GetResultExecutedContext(actionResult: new TestActionResult());

            // Act
            filter.OnResultExecuted(context);

            // Assert
            tempDataDictionary.Verify(tdf => tdf.Keep(), Times.Never());
            tempDataDictionary.Verify(tdf => tdf.Save(), Times.Once());
        }

        private SaveTempDataFilter GetFilter(ITempDataDictionary tempDataDictionary)
        {
            var tempDataFactory = GetTempDataDictionaryFactory(tempDataDictionary);
            return new SaveTempDataFilter(tempDataFactory.Object);
        }

        private Mock<ITempDataDictionaryFactory> GetTempDataDictionaryFactory(ITempDataDictionary tempDataDictionary)
        {
            var tempDataFactory = new Mock<ITempDataDictionaryFactory>(MockBehavior.Strict);
            tempDataFactory
                .Setup(f => f.GetTempData(It.IsAny<HttpContext>()))
                .Returns(tempDataDictionary);
            return tempDataFactory;
        }

        private Mock<ITempDataDictionary> GetTempDataDictionary()
        {
            var tempDataDictionary = new Mock<ITempDataDictionary>(MockBehavior.Strict);
            tempDataDictionary
                .Setup(tdd => tdd.Keep())
                .Verifiable();
            tempDataDictionary
                .Setup(tdd => tdd.Save())
                .Verifiable();
            return tempDataDictionary;
        }

        private ResourceExecutingContext GetResourceExecutingContext(HttpContext httpContext)
        {
            if (httpContext == null)
            {
                httpContext = GetHttpContext();
            }
            var actionResult = new TestActionResult();

            var actionContext = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
            var filters = new IFilterMetadata[] { };
            var valueProviderFactories = new IValueProviderFactory[] { };

            return new ResourceExecutingContext(actionContext, filters, valueProviderFactories);
        }

        private ResultExecutedContext GetResultExecutedContext(HttpContext httpContext = null, IActionResult actionResult = null)
        {
            if (httpContext == null)
            {
                httpContext = GetHttpContext();
            }
            if (actionResult == null)
            {
                actionResult = new TestActionResult();
            }
            return new ResultExecutedContext(
                new ActionContext(httpContext, new RouteData(), new ActionDescriptor()),
                new IFilterMetadata[] { },
                actionResult,
                new TestController());
        }

        private ResultExecutingContext GetResultExecutingContext(ActionContext actionContext, IActionResult actionResult = null)
        {
            if (actionResult == null)
            {
                actionResult = new TestActionResult();
            }
            return new ResultExecutingContext(
                actionContext,
                new IFilterMetadata[] { },
                actionResult,
                new TestController());
        }

        private ResultExecutingContext GetResultExecutingContext(HttpContext httpContext = null, IActionResult actionResult = null)
        {
            if (httpContext == null)
            {
                httpContext = new DefaultHttpContext();
            }
            if (actionResult == null)
            {
                actionResult = new TestActionResult();
            }
            return new ResultExecutingContext(
                new ActionContext(httpContext, new RouteData(), new ActionDescriptor()),
                new IFilterMetadata[] { },
                new Mock<IActionResult>().Object,
                new TestController());
        }

        private HttpContext GetHttpContext(IHttpResponseFeature responseFeature = null)
        {
            if (responseFeature == null)
            {
                responseFeature = new TestResponseFeature();
            }
            var httpContext = new DefaultHttpContext();
            httpContext.Features.Set<IHttpResponseFeature>(responseFeature);
            return httpContext;
        }

        private ActionContext GetActionContext(HttpContext httpContext = null)
        {
            if (httpContext == null)
            {
                httpContext = GetHttpContext();
            }
            return new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
        }

        private class TestController : Controller
        {
        }

        private class TestActionResult : IActionResult
        {
            public Task ExecuteResultAsync(ActionContext context)
            {
                return context.HttpContext.Response.WriteAsync($"Hello from {nameof(TestActionResult)}");
            }
        }

        private class TestKeepTempDataActionResult : IActionResult, IKeepTempDataResult
        {
            public Task ExecuteResultAsync(ActionContext context)
            {
                return context.HttpContext.Response.WriteAsync($"Hello from {nameof(TestKeepTempDataActionResult)}");
            }
        }

        private class TestResponseFeature : HttpResponseFeature
        {
            private bool _hasStarted;
            private Func<Task> _responseStartingAsync = () => Task.FromResult(true);

            public TestResponseFeature(bool hasStarted = false)
            {
                _hasStarted = hasStarted;
            }

            public override bool HasStarted
            {
                get
                {
                    return _hasStarted;
                }
            }

            public override void OnStarting(Func<object, Task> callback, object state)
            {
                if (_hasStarted)
                {
                    throw new ArgumentException();
                }

                var prior = _responseStartingAsync;
                _responseStartingAsync = async () =>
                {
                    await callback(state);
                    await prior();
                };
            }

            public async Task FireOnSendingHeadersAsync()
            {
                await _responseStartingAsync();
                _hasStarted = true;
            }
        }
    }
}