// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.Options;
using Moq;

namespace Microsoft.AspNetCore.Mvc.ViewEngines;

public class CompositeViewEngineTest
{
    [Fact]
    public void ViewEngines_UsesListOfViewEnginesFromOptions()
    {
        // Arrange
        var viewEngine1 = Mock.Of<IViewEngine>();
        var viewEngine2 = Mock.Of<IViewEngine>();
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(viewEngine1);
        optionsAccessor.Value.ViewEngines.Add(viewEngine2);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act
        var result = compositeViewEngine.ViewEngines;

        // Assert
        Assert.Equal(new[] { viewEngine1, viewEngine2 }, result);
    }

    [Fact]
    public void FindView_IsMainPage_Throws_WhenNoViewEnginesAreRegistered()
    {
        // Arrange
        var expected = $"'{typeof(MvcViewOptions).FullName}.{nameof(MvcViewOptions.ViewEngines)}' must not be " +
            $"empty. At least one '{typeof(IViewEngine).FullName}' is required to locate a view for rendering.";
        var viewName = "test-view";
        var actionContext = GetActionContext();
        var optionsAccessor = Options.Create(new MvcViewOptions());
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act & Assert
        var exception = Assert.Throws<InvalidOperationException>(
            () => compositeViewEngine.FindView(actionContext, viewName, isMainPage: true));
        Assert.Equal(expected, exception.Message);
    }

    [Fact]
    public void FindView_IsMainPage_ReturnsNotFoundResult_WhenExactlyOneViewEngineIsRegisteredWhichReturnsNotFoundResult()
    {
        // Arrange
        var viewName = "test-view";
        var engine = new Mock<IViewEngine>(MockBehavior.Strict);
        engine
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ true))
            .Returns(ViewEngineResult.NotFound(viewName, new[] { "controller/test-view" }));
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

    [Fact]
    public void FindView_IsMainPage_ReturnsView_WhenExactlyOneViewEngineIsRegisteredWhichReturnsAFoundResult()
    {
        // Arrange
        var viewName = "test-view";
        var engine = new Mock<IViewEngine>(MockBehavior.Strict);
        var view = Mock.Of<IView>();
        engine
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ true))
            .Returns(ViewEngineResult.Found(viewName, view));
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

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

        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine1.Object);
        optionsAccessor.Value.ViewEngines.Add(engine2.Object);
        optionsAccessor.Value.ViewEngines.Add(engine3.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

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

        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine1.Object);
        optionsAccessor.Value.ViewEngines.Add(engine2.Object);
        optionsAccessor.Value.ViewEngines.Add(engine3.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

    [Theory]
    [InlineData(false)]
    [InlineData(true)]
    public void GetView_ReturnsNotFoundResult_WhenNoViewEnginesAreRegistered(bool isMainPage)
    {
        // Arrange
        var expected = $"'{typeof(MvcViewOptions).FullName}.{nameof(MvcViewOptions.ViewEngines)}' must not be " +
            $"empty. At least one '{typeof(IViewEngine).FullName}' is required to locate a view for rendering.";
        var viewName = "test-view.cshtml";
        var optionsAccessor = Options.Create(new MvcViewOptions());
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act & Assert
        var exception = Assert.Throws<InvalidOperationException>(
            () => compositeViewEngine.GetView("~/Index.html", viewName, isMainPage));
        Assert.Equal(expected, exception.Message);
    }

    [Theory]
    [InlineData(false)]
    [InlineData(true)]
    public void GetView_ReturnsNotFoundResult_WhenExactlyOneViewEngineIsRegisteredWhichReturnsNotFoundResult(
        bool isMainPage)
    {
        // Arrange
        var viewName = "test-view.cshtml";
        var expectedViewName = "~/" + viewName;
        var engine = new Mock<IViewEngine>(MockBehavior.Strict);
        engine
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.NotFound(expectedViewName, new[] { expectedViewName }));
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act
        var result = compositeViewEngine.GetView("~/Index.html", viewName, isMainPage);

        // Assert
        Assert.False(result.Success);
        Assert.Equal(new[] { expectedViewName }, result.SearchedLocations);
    }

    [Theory]
    [InlineData(false)]
    [InlineData(true)]
    public void GetView_ReturnsView_WhenExactlyOneViewEngineIsRegisteredWhichReturnsAFoundResult(bool isMainPage)
    {
        // Arrange
        var viewName = "test-view.cshtml";
        var expectedViewName = "~/" + viewName;
        var engine = new Mock<IViewEngine>(MockBehavior.Strict);
        var view = Mock.Of<IView>();
        engine
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.Found(expectedViewName, view));
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act
        var result = compositeViewEngine.GetView("~/Index.html", viewName, isMainPage);

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

    [Theory]
    [InlineData(false)]
    [InlineData(true)]
    public void GetView_ReturnsViewFromFirstViewEngineWithFoundResult(bool isMainPage)
    {
        // Arrange
        var viewName = "foo.cshtml";
        var expectedViewName = "~/" + viewName;
        var engine1 = new Mock<IViewEngine>(MockBehavior.Strict);
        var engine2 = new Mock<IViewEngine>(MockBehavior.Strict);
        var engine3 = new Mock<IViewEngine>(MockBehavior.Strict);
        var view2 = Mock.Of<IView>();
        var view3 = Mock.Of<IView>();
        engine1
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.NotFound(expectedViewName, Enumerable.Empty<string>()));
        engine2
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.Found(expectedViewName, view2));
        engine3
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.Found(expectedViewName, view3));

        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine1.Object);
        optionsAccessor.Value.ViewEngines.Add(engine2.Object);
        optionsAccessor.Value.ViewEngines.Add(engine3.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act
        var result = compositeViewEngine.GetView("~/Index.html", viewName, isMainPage);

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

    [Theory]
    [InlineData(false)]
    [InlineData(true)]
    public void GetView_ReturnsNotFound_IfAllViewEnginesReturnNotFound(bool isMainPage)
    {
        // Arrange
        var viewName = "foo.cshtml";
        var expectedViewName = "~/" + viewName;
        var engine1 = new Mock<IViewEngine>(MockBehavior.Strict);
        var engine2 = new Mock<IViewEngine>(MockBehavior.Strict);
        var engine3 = new Mock<IViewEngine>(MockBehavior.Strict);
        engine1
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.NotFound(expectedViewName, new[] { "1", "2" }));
        engine2
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.NotFound(expectedViewName, new[] { "3" }));
        engine3
            .Setup(e => e.GetView("~/Index.html", viewName, isMainPage))
            .Returns(ViewEngineResult.NotFound(expectedViewName, new[] { "4", "5" }));

        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine1.Object);
        optionsAccessor.Value.ViewEngines.Add(engine2.Object);
        optionsAccessor.Value.ViewEngines.Add(engine3.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act
        var result = compositeViewEngine.GetView("~/Index.html", viewName, isMainPage);

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

    [Fact]
    public void FindView_ReturnsNotFoundResult_WhenNoViewEnginesAreRegistered()
    {
        // Arrange
        var expected = $"'{typeof(MvcViewOptions).FullName}.{nameof(MvcViewOptions.ViewEngines)}' must not be " +
            $"empty. At least one '{typeof(IViewEngine).FullName}' is required to locate a view for rendering.";
        var viewName = "my-partial-view";
        var optionsAccessor = Options.Create(new MvcViewOptions());
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

        // Act & AssertS
        var exception = Assert.Throws<InvalidOperationException>(
            () => compositeViewEngine.FindView(GetActionContext(), viewName, isMainPage: false));
        Assert.Equal(expected, exception.Message);
    }

    [Fact]
    public void FindView_ReturnsNotFoundResult_WhenExactlyOneViewEngineIsRegisteredWhichReturnsNotFoundResult()
    {
        // Arrange
        var viewName = "partial-view";
        var engine = new Mock<IViewEngine>(MockBehavior.Strict);
        engine
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ false))
            .Returns(ViewEngineResult.NotFound(viewName, new[] { "Shared/partial-view" }));
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

    [Fact]
    public void FindView_ReturnsView_WhenExactlyOneViewEngineIsRegisteredWhichReturnsAFoundResult()
    {
        // Arrange
        var viewName = "test-view";
        var engine = new Mock<IViewEngine>(MockBehavior.Strict);
        var view = Mock.Of<IView>();
        engine
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ false))
            .Returns(ViewEngineResult.Found(viewName, view));
        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

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

        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine1.Object);
        optionsAccessor.Value.ViewEngines.Add(engine2.Object);
        optionsAccessor.Value.ViewEngines.Add(engine3.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

        // 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>(MockBehavior.Strict);
        var engine2 = new Mock<IViewEngine>(MockBehavior.Strict);
        var engine3 = new Mock<IViewEngine>(MockBehavior.Strict);
        engine1
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ false))
            .Returns(ViewEngineResult.NotFound(viewName, new[] { "1", "2" }));
        engine2
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ false))
            .Returns(ViewEngineResult.NotFound(viewName, new[] { "3" }));
        engine3
            .Setup(e => e.FindView(It.IsAny<ActionContext>(), viewName, /*isMainPage*/ false))
            .Returns(ViewEngineResult.NotFound(viewName, new[] { "4", "5" }));

        var optionsAccessor = Options.Create(new MvcViewOptions());
        optionsAccessor.Value.ViewEngines.Add(engine1.Object);
        optionsAccessor.Value.ViewEngines.Add(engine2.Object);
        optionsAccessor.Value.ViewEngines.Add(engine3.Object);
        var compositeViewEngine = new CompositeViewEngine(optionsAccessor);

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

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

    private static ActionContext GetActionContext()
    {
        return new ActionContext(new DefaultHttpContext(), new RouteData(), new ActionDescriptor());
    }

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

        public ITestService Service { get; private set; }

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

        public ViewEngineResult GetView(string executingFilePath, string viewPath, bool isMainPage)
        {
            throw new NotImplementedException();
        }
    }

    public interface ITestService
    {
    }
}
