// 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.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.AspNetCore.Routing.Metadata;
using Microsoft.AspNetCore.Routing.Patterns;
using Xunit;

namespace Microsoft.AspNetCore.Routing.Matchers
{
    public class HttpMethodMatcherPolicyTest
    {
        [Fact]
        public void AppliesToNode_EndpointWithoutMetadata_ReturnsFalse()
        {
            // Arrange
            var endpoints = new[] { CreateEndpoint("/", null), };

            var policy = CreatePolicy();

            // Act
            var result = policy.AppliesToNode(endpoints);

            // Assert
            Assert.False(result);
        }

        [Fact]
        public void AppliesToNode_EndpointWithoutHttpMethods_ReturnsFalse()
        {
            // Arrange
            var endpoints = new[] { CreateEndpoint("/", Array.Empty<string>()), };

            var policy = CreatePolicy();

            // Act
            var result = policy.AppliesToNode(endpoints);

            // Assert
            Assert.False(result);
        }

        [Fact]
        public void AppliesToNode_EndpointHasHttpMethods_ReturnsTrue()
        {
            // Arrange
            var endpoints = new[] { CreateEndpoint("/", Array.Empty<string>()), CreateEndpoint("/", new[] { "GET", })};

            var policy = CreatePolicy();

            // Act
            var result = policy.AppliesToNode(endpoints);

            // Assert
            Assert.True(result);
        }

        [Fact]
        public void GetEdges_GroupsByHttpMethod()
        {
            // Arrange
            var endpoints = new[]
            {
                // These are arrange in an order that we won't actually see in a product scenario. It's done
                // this way so we can verify that ordering is preserved by GetEdges.
                CreateEndpoint("/", new[] { "GET", }),
                CreateEndpoint("/", Array.Empty<string>()),
                CreateEndpoint("/", new[] { "GET", "PUT", "POST" }),
                CreateEndpoint("/", new[] { "PUT", "POST" }),
                CreateEndpoint("/", Array.Empty<string>()),
            };

            var policy = CreatePolicy();

            // Act
            var edges = policy.GetEdges(endpoints);

            // Assert
            Assert.Collection(
                edges.OrderBy(e => e.State),
                e =>
                {
                    Assert.Equal(HttpMethodEndpointSelectorPolicy.AnyMethod, e.State);
                    Assert.Equal(new[] { endpoints[1], endpoints[4], }, e.Endpoints.ToArray());
                },
                e =>
                {
                    Assert.Equal("GET", e.State);
                    Assert.Equal(new[] { endpoints[0], endpoints[1], endpoints[2], endpoints[4], }, e.Endpoints.ToArray());
                },
                e =>
                {
                    Assert.Equal("POST", e.State);
                    Assert.Equal(new[] { endpoints[1], endpoints[2], endpoints[3], endpoints[4], }, e.Endpoints.ToArray());
                },
                e =>
                {
                    Assert.Equal("PUT", e.State);
                    Assert.Equal(new[] { endpoints[1], endpoints[2], endpoints[3], endpoints[4], }, e.Endpoints.ToArray());
                });
        }

        [Fact] // See explanation in GetEdges for how this case is different
        public void GetEdges_GroupsByHttpMethod_CreatesHttp405Endpoint()
        {
            // Arrange
            var endpoints = new[]
            {
                // These are arrange in an order that we won't actually see in a product scenario. It's done
                // this way so we can verify that ordering is preserved by GetEdges.
                CreateEndpoint("/", new[] { "GET", }),
                CreateEndpoint("/", new[] { "GET", "PUT", "POST" }),
                CreateEndpoint("/", new[] { "PUT", "POST" }),
            };

            var policy = CreatePolicy();

            // Act
            var edges = policy.GetEdges(endpoints);

            // Assert
            Assert.Collection(
                edges.OrderBy(e => e.State),
                e =>
                {
                    Assert.Equal(HttpMethodEndpointSelectorPolicy.AnyMethod, e.State);
                    Assert.Equal(HttpMethodEndpointSelectorPolicy.Http405EndpointDisplayName, e.Endpoints.Single().DisplayName);
                },
                e =>
                {
                    Assert.Equal("GET", e.State);
                    Assert.Equal(new[] { endpoints[0], endpoints[1], }, e.Endpoints.ToArray());
                },
                e =>
                {
                    Assert.Equal("POST", e.State);
                    Assert.Equal(new[] { endpoints[1], endpoints[2], }, e.Endpoints.ToArray());
                },
                e =>
                {
                    Assert.Equal("PUT", e.State);
                    Assert.Equal(new[] { endpoints[1], endpoints[2], }, e.Endpoints.ToArray());
                });
        }

        private static MatcherEndpoint CreateEndpoint(string template, string[] httpMethods)
        {
            var metadata = new List<object>();
            if (httpMethods != null)
            {
                metadata.Add(new HttpMethodMetadata(httpMethods));
            }

            return new MatcherEndpoint(
                MatcherEndpoint.EmptyInvoker,
                RoutePatternFactory.Parse(template),
                new RouteValueDictionary(),
                0,
                new EndpointMetadataCollection(metadata),
                $"test: {template}");
        }

        private static HttpMethodEndpointSelectorPolicy CreatePolicy()
        {
            return new HttpMethodEndpointSelectorPolicy();
        }
    }
}