// 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.Reflection;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Testing;
using Moq;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure
{
    public class ServiceBasedPageModelActivatorProviderTest
    {
        [Fact]
        public void CreateActivator_ThrowsIfModelTypeInfoOnActionDescriptorIsNull()
        {
            // Arrange
            var activatorProvider = new ServiceBasedPageModelActivatorProvider();
            var descriptor = new CompiledPageActionDescriptor();

            // Act & Assert
            ExceptionAssert.ThrowsArgument(
                () => activatorProvider.CreateActivator(descriptor),
                "descriptor",
                "The 'ModelTypeInfo' property of 'descriptor' must not be null.");
        }

        [Fact]
        public void Create_GetsServicesFromServiceProvider()
        {
            // Arrange
            var simpleModel = new DISimpleModel();
            var serviceProvider = new Mock<IServiceProvider>(MockBehavior.Strict);  
            serviceProvider.Setup(s => s.GetService(typeof(DISimpleModel)))
                .Returns(simpleModel)
                .Verifiable();                         

            var activatorProvider = new ServiceBasedPageModelActivatorProvider();
            var pageContext = new PageContext
            {
                HttpContext = new DefaultHttpContext
                {
                    RequestServices = serviceProvider.Object,
                },
                ActionDescriptor = new CompiledPageActionDescriptor
                {
                    ModelTypeInfo = typeof(DISimpleModel).GetTypeInfo(),
                }
            };

            // Act
            var activator = activatorProvider.CreateActivator(pageContext.ActionDescriptor);
            var instance = activator(pageContext);

            // Assert
            Assert.Same(simpleModel, instance);
            serviceProvider.Verify();
        }

        [Fact]
        public void CreateActivator_CreatesModelInstance()
        {
            // Arrange
            var simpleModel = new DISimpleModel();
            var serviceProvider = new Mock<IServiceProvider>(MockBehavior.Strict);
            serviceProvider.Setup(s => s.GetService(typeof(DISimpleModel)))
                .Returns(simpleModel)
                .Verifiable();

            var activatorProvider = new ServiceBasedPageModelActivatorProvider();
            var pageContext = new PageContext
            {
                HttpContext = new DefaultHttpContext
                {
                    RequestServices = serviceProvider.Object,
                },
                ActionDescriptor = new CompiledPageActionDescriptor
                {
                    ModelTypeInfo = typeof(DISimpleModel).GetTypeInfo(),
                }
            };

            // Act
            var activator = activatorProvider.CreateActivator(pageContext.ActionDescriptor);
            var model = activator(pageContext);

            // Assert
            var simpleModel2 = Assert.IsType<DISimpleModel>(model);
            Assert.NotNull(simpleModel2);
        }

        [Fact]
        public void Create_ThrowsIfModelIsNotRegisteredInServiceProvider()
        {
            // Arrange
            var expected = "No service for type '" + typeof(DISimpleModel) + "' has been registered.";
            var model = new DISimpleModel();

            var httpContext = new DefaultHttpContext
            {
                RequestServices = Mock.Of<IServiceProvider>()
            };

            var activatorProvider = new ServiceBasedPageModelActivatorProvider();
            var context = new PageContext
            {
                HttpContext = httpContext,
                ActionDescriptor = new CompiledPageActionDescriptor
                {
                    ModelTypeInfo = typeof(DISimpleModel).GetTypeInfo(),
                }
            };

            // Act and Assert
            var activator = activatorProvider.CreateActivator(context.ActionDescriptor);
            var ex = Assert.Throws<InvalidOperationException>(
                () => activator(context));

            Assert.Equal(expected, ex.Message);
        }

        [Theory]
        [InlineData(typeof(SimpleModel))]
        [InlineData(typeof(object))]
        public void CreateReleaser_ReturnsNullForPageModels(Type pageType)
        {
            // Arrange
            var context = new PageContext();
            var activator = new ServiceBasedPageModelActivatorProvider();
            var actionDescriptor = new CompiledPageActionDescriptor
            {
                PageTypeInfo = pageType.GetTypeInfo(),
            };

            // Act
            var releaser = activator.CreateReleaser(actionDescriptor);

            // Assert
            Assert.Null(releaser);
        }

        private class SimpleModel
        {
        }

        private class DISimpleModel : SimpleModel
        {
        }
    }
}
