// 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.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.ActionConstraints;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.Extensions.DependencyInjection;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.Internal
{
    public class ActionConstraintCacheTest
    {
        [Fact]
        public void GetActionConstraints_CachesAllActionConstraints()
        {
            // Arrange
            var services = CreateServices();
            var cache = CreateCache(new DefaultActionConstraintProvider());

            var action = new ControllerActionDescriptor()
            {
                ActionConstraints = new[]
                {
                    new TestActionConstraint(),
                    new TestActionConstraint()
                },
            };
            var context = new DefaultHttpContext();

            // Act - 1
            var actionConstraints1 = cache.GetActionConstraints(context, action);

            // Assert - 1
            Assert.Collection(
                actionConstraints1,
                a => Assert.Same(action.ActionConstraints[0], a), // Copied by provider
                a => Assert.Same(action.ActionConstraints[1], a)); // Copied by provider

            // Act - 2
            var actionConstraints2 = cache.GetActionConstraints(context, action);

            Assert.Same(actionConstraints1, actionConstraints2);

            Assert.Collection(
                actionConstraints2,
                a => Assert.Same(actionConstraints1[0], a), // Cached
                a => Assert.Same(actionConstraints1[1], a)); // Cached
        }

        [Fact]
        public void GetActionConstraints_CachesActionConstraintFromFactory()
        {
            // Arrange
            var services = CreateServices();
            var cache = CreateCache(new DefaultActionConstraintProvider());

            var action = new ControllerActionDescriptor()
            {
                ActionConstraints = new[]
                {
                    new TestActionConstraintFactory() { IsReusable = true },
                    new TestActionConstraint() as IActionConstraintMetadata
                },
            };
            var context = new DefaultHttpContext();

            // Act - 1
            var actionConstraints1 = cache.GetActionConstraints(context, action);

            // Assert - 1
            Assert.Collection(
                actionConstraints1,
                a => Assert.NotSame(action.ActionConstraints[0], a), // Created by factory
                a => Assert.Same(action.ActionConstraints[1], a)); // Copied by provider

            // Act - 2
            var actionConstraints2 = cache.GetActionConstraints(context, action);

            Assert.Same(actionConstraints1, actionConstraints2);

            Assert.Collection(
                actionConstraints2,
                a => Assert.Same(actionConstraints1[0], a), // Cached
                a => Assert.Same(actionConstraints1[1], a)); // Cached
        }

        [Fact]
        public void GetActionConstraints_DoesNotCacheActionConstraintsWithIsReusableFalse()
        {
            // Arrange
            var services = CreateServices();
            var cache = CreateCache(new DefaultActionConstraintProvider());

            var action = new ControllerActionDescriptor()
            {
                ActionConstraints = new[]
                {
                    new TestActionConstraintFactory() { IsReusable = false },
                    new TestActionConstraint() as IActionConstraintMetadata
                },
            };
            var context = new DefaultHttpContext();

            // Act - 1
            var actionConstraints1 = cache.GetActionConstraints(context, action);

            // Assert - 1
            Assert.Collection(
                actionConstraints1,
                a => Assert.NotSame(action.ActionConstraints[0], a), // Created by factory
                a => Assert.Same(action.ActionConstraints[1], a)); // Copied by provider

            // Act - 2
            var actionConstraints2 = cache.GetActionConstraints(context, action);

            Assert.NotSame(actionConstraints1, actionConstraints2);

            Assert.Collection(
                actionConstraints2,
                a => Assert.NotSame(actionConstraints1[0], a), // Created by factory (again)
                a => Assert.Same(actionConstraints1[1], a)); // Cached
        }

        private class TestActionConstraint : IActionConstraint
        {
            public int Order
            {
                get
                {
                    throw new NotImplementedException();
                }
            }

            public bool Accept(ActionConstraintContext context)
            {
                throw new NotImplementedException();
            }
        }

        private class TestActionConstraintFactory : IActionConstraintFactory
        {
            public bool IsReusable { get; set; }

            public IActionConstraint CreateInstance(IServiceProvider serviceProvider)
            {
                return new TestActionConstraint();
            }
        }

        private static IServiceProvider CreateServices()
        {
            return new ServiceCollection().BuildServiceProvider();
        }

        private static ActionConstraintCache CreateCache(params IActionConstraintProvider[] providers)
        {
            var descriptorProvider = new ActionDescriptorCollectionProvider(
                Enumerable.Empty<IActionDescriptorProvider>(),
                Enumerable.Empty<IActionDescriptorChangeProvider>());
            return new ActionConstraintCache(descriptorProvider, providers);
        }
    }
}