// 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.Linq;
using Microsoft.AspNet.Http;
using Microsoft.AspNet.Routing;
using Moq;
using Xunit;

namespace Microsoft.AspNet.Mvc.Rendering
{
    public class CompositeViewEngineTest
    {
        [Fact]
        public void ViewEngines_ReturnsInstantiatedListOfViewEngines()
        {
            // Arrange
            var service = Mock.Of<ITestService>();
            var viewEngine = Mock.Of<IViewEngine>();
            var type = typeof(TestViewEngine);
            var serviceProvider = new Mock<IServiceProvider>();
            serviceProvider.Setup(p => p.GetService(typeof(ITestService)))
                           .Returns(service);
            var typeActivatorCache = new DefaultTypeActivatorCache();
            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(viewEngine);
            optionsAccessor.Options.ViewEngines.Add(type);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor, 
                typeActivatorCache, 
                serviceProvider.Object);

            // Act
            var result = compositeViewEngine.ViewEngines;

            // Assert
            Assert.Collection(result,
                actual => Assert.Same(viewEngine, actual),
                actual =>
                {
                    var testViewEngine = Assert.IsType<TestViewEngine>(actual);
                    Assert.Same(service, testViewEngine.Service);
                });
        }

        [Fact]
        public void FindView_ReturnsNotFoundResult_WhenNoViewEnginesAreRegistered()
        {
            // Arrange
            var viewName = "test-view";
            var actionContext = GetActionContext();
            var optionsAccessor = new MockMvcOptionsAccessor();
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindView(actionContext, viewName);

            // Assert
            Assert.False(result.Success);
            Assert.Empty(result.SearchedLocations);
        }


        [Fact]
        public void FindView_ReturnsNotFoundResult_WhenExactlyOneViewEngineIsRegisteredWhichReturnsNotFoundResult()
        {
            // Arrange
            var viewName = "test-view";
            var engine = new Mock<IViewEngine>();
            engine.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "controller/test-view" }));
            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindView(GetActionContext(), viewName);

            // Assert
            Assert.False(result.Success);
            Assert.Equal(new[] { "controller/test-view" }, result.SearchedLocations);
        }

        [Fact]
        public void FindView_ReturnsView_WhenExactlyOneViewEngineIsRegisteredWhichReturnsAFoundResult()
        {
            // Arrange
            var viewName = "test-view";
            var engine = new Mock<IViewEngine>();
            var view = Mock.Of<IView>();
            engine.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.Found(viewName, view));
            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindView(GetActionContext(), viewName);

            // Assert
            Assert.True(result.Success);
            Assert.Same(view, result.View);
        }

        [Fact]
        public void FindView_ReturnsViewFromFirstViewEngineWithFoundResult()
        {
            // Arrange
            var viewName = "foo";
            var engine1 = new Mock<IViewEngine>();
            var engine2 = new Mock<IViewEngine>();
            var engine3 = new Mock<IViewEngine>();
            var view2 = Mock.Of<IView>();
            var view3 = Mock.Of<IView>();
            engine1.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, Enumerable.Empty<string>()));
            engine2.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.Found(viewName, view2));
            engine3.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.Found(viewName, view3));

            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine1.Object);
            optionsAccessor.Options.ViewEngines.Add(engine2.Object);
            optionsAccessor.Options.ViewEngines.Add(engine3.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindView(GetActionContext(), viewName);

            // Assert
            Assert.True(result.Success);
            Assert.Same(view2, result.View);
            Assert.Equal(viewName, result.ViewName);
        }

        [Fact]
        public void FindView_ReturnsNotFound_IfAllViewEnginesReturnNotFound()
        {
            // Arrange
            var viewName = "foo";
            var engine1 = new Mock<IViewEngine>();
            var engine2 = new Mock<IViewEngine>();
            var engine3 = new Mock<IViewEngine>();
            engine1.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "1", "2" }));
            engine2.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "3" }));
            engine3.Setup(e => e.FindView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "4", "5" }));

            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine1.Object);
            optionsAccessor.Options.ViewEngines.Add(engine2.Object);
            optionsAccessor.Options.ViewEngines.Add(engine3.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindView(GetActionContext(), viewName);

            // Assert
            Assert.False(result.Success);
            Assert.Equal(new[] { "1", "2", "3", "4", "5" }, result.SearchedLocations);
        }

        [Fact]
        public void FindPartialView_ReturnsNotFoundResult_WhenNoViewEnginesAreRegistered()
        {
            // Arrange
            var viewName = "my-partial-view";
            var optionsAccessor = new MockMvcOptionsAccessor();
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindPartialView(GetActionContext(), viewName);

            // Assert
            Assert.False(result.Success);
            Assert.Empty(result.SearchedLocations);
        }

        [Fact]
        public void FindPartialView_ReturnsNotFoundResult_WhenExactlyOneViewEngineIsRegisteredWhichReturnsNotFoundResult()
        {
            // Arrange
            var viewName = "partial-view";
            var engine = new Mock<IViewEngine>();
            engine.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "Shared/partial-view" }));
            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindPartialView(GetActionContext(), viewName);

            // Assert
            Assert.False(result.Success);
            Assert.Equal(new[] { "Shared/partial-view" }, result.SearchedLocations);
        }

        [Fact]
        public void FindPartialView_ReturnsView_WhenExactlyOneViewEngineIsRegisteredWhichReturnsAFoundResult()
        {
            // Arrange
            var viewName = "test-view";
            var engine = new Mock<IViewEngine>();
            var view = Mock.Of<IView>();
            engine.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.Found(viewName, view));
            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindPartialView(GetActionContext(), viewName);

            // Assert
            Assert.True(result.Success);
            Assert.Same(view, result.View);
        }

        [Fact]
        public void FindPartialView_ReturnsViewFromFirstViewEngineWithFoundResult()
        {
            // Arrange
            var viewName = "bar";
            var engine1 = new Mock<IViewEngine>();
            var engine2 = new Mock<IViewEngine>();
            var engine3 = new Mock<IViewEngine>();
            var view2 = Mock.Of<IView>();
            var view3 = Mock.Of<IView>();
            engine1.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, Enumerable.Empty<string>()));
            engine2.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.Found(viewName, view2));
            engine3.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.Found(viewName, view3));

            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine1.Object);
            optionsAccessor.Options.ViewEngines.Add(engine2.Object);
            optionsAccessor.Options.ViewEngines.Add(engine3.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindPartialView(GetActionContext(), viewName);

            // Assert
            Assert.True(result.Success);
            Assert.Same(view2, result.View);
            Assert.Equal(viewName, result.ViewName);
        }

        [Fact]
        public void FindPartialView_ReturnsNotFound_IfAllViewEnginesReturnNotFound()
        {
            // Arrange
            var viewName = "foo";
            var engine1 = new Mock<IViewEngine>();
            var engine2 = new Mock<IViewEngine>();
            var engine3 = new Mock<IViewEngine>();
            engine1.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "1", "2" }));
            engine2.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "3" }));
            engine3.Setup(e => e.FindPartialView(It.IsAny<ActionContext>(), It.IsAny<string>()))
                   .Returns(ViewEngineResult.NotFound(viewName, new[] { "4", "5" }));

            var optionsAccessor = new MockMvcOptionsAccessor();
            optionsAccessor.Options.ViewEngines.Add(engine1.Object);
            optionsAccessor.Options.ViewEngines.Add(engine2.Object);
            optionsAccessor.Options.ViewEngines.Add(engine3.Object);
            var compositeViewEngine = new CompositeViewEngine(
                optionsAccessor,
                Mock.Of<ITypeActivatorCache>(),
                Mock.Of<IServiceProvider>());

            // Act
            var result = compositeViewEngine.FindPartialView(GetActionContext(), viewName);

            // Assert
            Assert.False(result.Success);
            Assert.Equal(new[] { "1", "2", "3", "4", "5" }, result.SearchedLocations);
        }

        private static ActionContext GetActionContext()
        {
            var httpContext = Mock.Of<HttpContext>();
            return new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
        }

        private class TestViewEngine : IViewEngine
        {
            public TestViewEngine(ITestService service)
            {
                Service = service;
            }

            public ITestService Service { get; private set; }

            public ViewEngineResult FindPartialView(ActionContext context, string partialViewName)
            {
                throw new NotImplementedException();
            }

            public ViewEngineResult FindView(ActionContext context, string viewName)
            {
                throw new NotImplementedException();
            }
        }

        public interface ITestService
        {
        }
    }
}