using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNet.Abstractions;
using Microsoft.AspNet.DependencyInjection;
using Microsoft.AspNet.Routing;
using Moq;
using Xunit;

namespace Microsoft.AspNet.Mvc.Core.Test
{
    public class DefaultActionSelectorTest
    {
        [Fact]
        public void GetCandidateActions_Match_NonArea()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: null, controller: "Home", action: "Index");

            var selector = CreateSelector(actions);
            var context = CreateContext(new { controller = "Home", action = "Index" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }

        [Fact]
        public void GetCandidateActions_Match_AreaExplicit()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: "Admin", controller: "Home", action: "Index");

            var selector = CreateSelector(actions);
            var context = CreateContext(new { area = "Admin", controller = "Home", action = "Index" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }

        [Fact]
        public void GetCandidateActions_Match_AreaImplicit()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: "Admin", controller: "Home", action: "Index");

            var selector = CreateSelector(actions);
            var context = CreateContext(
                new { controller = "Home", action = "Index" },
                new { area = "Admin", controller = "Home", action = "Diagnostics" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }

        [Fact]
        public void GetCandidateActions_Match_NonAreaImplicit()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: null, controller: "Home", action: "Edit");

            var selector = CreateSelector(actions);
            var context = CreateContext(
                new { controller = "Home", action = "Edit" }, 
                new { area = "Admin", controller = "Home", action = "Diagnostics" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }

        [Fact]
        public void GetCandidateActions_Match_NonAreaExplicit()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: null, controller: "Home", action: "Index");

            var selector = CreateSelector(actions);
            var context = CreateContext(
                new { area = (string)null, controller = "Home", action = "Index" }, 
                new { area = "Admin", controller = "Home", action = "Diagnostics" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }

        [Fact]
        public void GetCandidateActions_Match_RestExplicit()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: null, controller: "Product", action: null);

            var selector = CreateSelector(actions);
            var context = CreateContext(
                new { controller = "Product", action = (string)null }, 
                new { controller = "Home", action = "Index" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }

        [Fact]
        public void GetCandidateActions_Match_RestImplicit()
        {
            // Arrange
            var actions = GetActions();
            var expected = GetActions(actions, area: null, controller: "Product", action: null);

            var selector = CreateSelector(actions);
            var context = CreateContext(
                new { controller = "Product" }, 
                new { controller = "Home", action = "Index" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Equal(expected, candidates);
        }


        [Fact]
        public void GetCandidateActions_NoMatch()
        {
            // Arrange
            var actions = GetActions();

            var selector = CreateSelector(actions);
            var context = CreateContext(
                new { area = "Admin", controller = "Home", action = "Edit" }, 
                new { area = "Admin", controller = "Home", action = "Index" });

            // Act
            var candidates = selector.GetCandidateActions(context);

            // Assert
            Assert.Empty(candidates);
        }

        [Fact]
        public void HasValidAction_Match()
        {
            // Arrange
            var actions = GetActions();

            var selector = CreateSelector(actions);
            var context = CreateContext(new { });
            context.ProvidedValues = new RouteValueDictionary(new { controller = "Home", action = "Index"});

            // Act
            var isValid = selector.HasValidAction(context);

            // Assert
            Assert.True(isValid);
        }

        [Fact]
        public void HasValidAction_NoMatch()
        {
            // Arrange
            var actions = GetActions();

            var selector = CreateSelector(actions);
            var context = CreateContext(new { });
            context.ProvidedValues = new RouteValueDictionary(new { controller = "Home", action = "FakeAction" });

            // Act
            var isValid = selector.HasValidAction(context);

            // Assert
            Assert.False(isValid);
        }

        private static ActionDescriptor[] GetActions()
        {
            return new ActionDescriptor[]
            {
                // Like a typical RPC controller
                CreateAction(area: null, controller: "Home", action: "Index"),
                CreateAction(area: null, controller: "Home", action: "Edit"),

                // Like a typical REST controller
                CreateAction(area: null, controller: "Product", action: null),
                CreateAction(area: null, controller: "Product", action: null),

                // RPC controller in an area with the same name as home
                CreateAction(area: "Admin", controller: "Home", action: "Index"),
                CreateAction(area: "Admin", controller: "Home", action: "Diagnostics"),
            };
        }

        private static IEnumerable<ActionDescriptor> GetActions(
            IEnumerable<ActionDescriptor> actions,
            string area,
            string controller,
            string action)
        {
            return
                actions
                .Where(a => a.RouteConstraints.Any(c => c.RouteKey == "area" && c.Comparer.Equals(c.RouteValue, area)))
                .Where(a => a.RouteConstraints.Any(c => c.RouteKey == "controller" && c.Comparer.Equals(c.RouteValue, controller)))
                .Where(a => a.RouteConstraints.Any(c => c.RouteKey == "action" && c.Comparer.Equals(c.RouteValue, action)));
        }

        private static DefaultActionSelector CreateSelector(IEnumerable<ActionDescriptor> actions)
        {
            var actionProvider = new Mock<INestedProviderManager<ActionDescriptorProviderContext>>(MockBehavior.Strict);
            actionProvider
                .Setup(p => p.Invoke(It.IsAny<ActionDescriptorProviderContext>()))
                .Callback<ActionDescriptorProviderContext>(c => c.Results.AddRange(actions));

            var bindingProvider = new Mock<IActionBindingContextProvider>(MockBehavior.Strict);

            return new DefaultActionSelector(actionProvider.Object, bindingProvider.Object);
        }

        private static VirtualPathContext CreateContext(object routeValues)
        {
            return CreateContext(routeValues, ambientValues: null);
        }

        private static VirtualPathContext CreateContext(object routeValues, object ambientValues)
        {
            var httpContext = new Mock<HttpContext>(MockBehavior.Strict);

            return new VirtualPathContext(
                httpContext.Object,
                new RouteValueDictionary(ambientValues),
                new RouteValueDictionary(routeValues));
        }

        private static ActionDescriptor CreateAction(string area, string controller, string action)
        {
            var actionDescriptor = new ActionDescriptor()
            {
                Name = string.Format("Area: {0}, Controller: {1}, Action: {2}", area, controller, action),
                RouteConstraints = new List<RouteDataActionConstraint>(),
            };

            actionDescriptor.RouteConstraints.Add(
                area == null ?
                new RouteDataActionConstraint("area", RouteKeyHandling.DenyKey) :
                new RouteDataActionConstraint("area", area));

            actionDescriptor.RouteConstraints.Add(
                controller == null ?
                new RouteDataActionConstraint("controller", RouteKeyHandling.DenyKey) :
                new RouteDataActionConstraint("controller", controller));

            actionDescriptor.RouteConstraints.Add(
                action == null ?
                new RouteDataActionConstraint("action", RouteKeyHandling.DenyKey) :
                new RouteDataActionConstraint("action", action));

            return actionDescriptor;
        }
    }
}