// 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.Expressions;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Metadata;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Testing;
using Moq;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.Core
{
    /// <summary>
    /// Test the <see cref="HtmlHelperNameExtensions" /> class.
    /// </summary>
    public class HtmlHelperNameExtensionsTest
    {
        private static List<string> _staticCollection = new List<string>();
        private static int _staticIndex = 6;

        private List<string> _collection = new List<string>();
        private int _index = 7;
        private List<string[]> _nestedCollection = new List<string[]>();
        private string _string = string.Empty;

        private static List<string> StaticCollection { get; }

        private static int StaticIndex { get; } = 8;

        private List<string> Collection { get; }

        private int Index { get; } = 9;

        private List<string[]> NestedCollection { get; }

        private string StringProperty { get; }

        [Fact]
        public void IdAndNameHelpers_ReturnEmptyForModel()
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper();

            // Act
            var idResult = helper.Id(expression: string.Empty);
            var idNullResult = helper.Id(expression: null);   // null is another alias for current model
            var idForResult = helper.IdFor(m => m);
            var idForModelResult = helper.IdForModel();
            var nameResult = helper.Name(expression: string.Empty);
            var nameNullResult = helper.Name(expression: null);
            var nameForResult = helper.NameFor(m => m);
            var nameForModelResult = helper.NameForModel();

            // Assert
            Assert.Empty(idResult);
            Assert.Empty(idNullResult);
            Assert.Empty(idForResult);
            Assert.Empty(idForModelResult);
            Assert.Empty(nameResult);
            Assert.Empty(nameNullResult);
            Assert.Empty(nameForResult);
            Assert.Empty(nameForModelResult);
        }

        [Theory]
        [InlineData("", "")]
        [InlineData("A", "A")]
        [InlineData("A[23]", "A_23_")]
        [InlineData("A[0].B", "A_0__B")]
        [InlineData("A.B.C.D", "A_B_C_D")]
        public void IdAndNameHelpers_ReturnPrefixForModel(string prefix, string expectedId)
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper();
            helper.ViewData.TemplateInfo.HtmlFieldPrefix = prefix;

            // Act
            var idResult = helper.Id(expression: string.Empty);
            var idForResult = helper.IdFor(m => m);
            var idForModelResult = helper.IdForModel();
            var nameResult = helper.Name(expression: string.Empty);
            var nameForResult = helper.NameFor(m => m);
            var nameForModelResult = helper.NameForModel();

            // Assert
            Assert.Equal(expectedId, idResult);
            Assert.Equal(expectedId, idForResult);
            Assert.Equal(expectedId, idForModelResult);
            Assert.Equal(prefix, nameResult);
            Assert.Equal(prefix, nameForResult);
            Assert.Equal(prefix, nameForModelResult);
        }

        [Fact]
        public void IdAndNameHelpers_ReturnPropertyName()
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper();

            // Act
            var idResult = helper.Id("Property1");
            var idForResult = helper.IdFor(m => m.Property1);
            var nameResult = helper.Name("Property1");
            var nameForResult = helper.NameFor(m => m.Property1);

            // Assert
            Assert.Equal("Property1", idResult);
            Assert.Equal("Property1", idForResult);
            Assert.Equal("Property1", nameResult);
            Assert.Equal("Property1", nameForResult);
        }

        [Theory]
        [InlineData(null, "Property1", "Property1")]
        [InlineData("", "Property1", "Property1")]
        [InlineData("A", "A.Property1", "A_Property1")]
        [InlineData("A[23]", "A[23].Property1", "A_23__Property1")]
        [InlineData("A[0].B", "A[0].B.Property1", "A_0__B_Property1")]
        [InlineData("A.B.C.D", "A.B.C.D.Property1", "A_B_C_D_Property1")]
        public void IdAndNameHelpers_ReturnPrefixAndPropertyName(string prefix, string expectedName, string expectedId)
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper();
            helper.ViewData.TemplateInfo.HtmlFieldPrefix = prefix;

            // Act
            var idResult = helper.Id("Property1");
            var idForResult = helper.IdFor(m => m.Property1);
            var nameResult = helper.Name("Property1");
            var nameForResult = helper.NameFor(m => m.Property1);

            // Assert
            Assert.Equal(expectedId, idResult);
            Assert.Equal(expectedId, idForResult);
            Assert.Equal(expectedName, nameResult);
            Assert.Equal(expectedName, nameForResult);
        }

        [Fact]
        public void IdAndNameHelpers_ReturnPropertyPath_ForNestedProperty()
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper<OuterClass>(model: null);

            // Act
            var idResult = helper.Id("Inner.Id");
            var idForResult = helper.IdFor(m => m.Inner.Id);
            var nameResult = helper.Name("Inner.Id");
            var nameForResult = helper.NameFor(m => m.Inner.Id);

            // Assert
            Assert.Equal("Inner_Id", idResult);
            Assert.Equal("Inner_Id", idForResult);
            Assert.Equal("Inner.Id", nameResult);
            Assert.Equal("Inner.Id", nameForResult);
        }

        [Fact]
        public void IdAndNameHelpers_DoNotConsultMetadataOrMetadataProvider()
        {
            // Arrange
            var provider = new Mock<IModelMetadataProvider>(MockBehavior.Strict);
            var metadata = new Mock<ModelMetadata>(
                MockBehavior.Loose,
                ModelMetadataIdentity.ForType(typeof(DefaultTemplatesUtilities.ObjectTemplateModel)));
            provider
                .Setup(m => m.GetMetadataForType(typeof(DefaultTemplatesUtilities.ObjectTemplateModel)))
                .Returns(metadata.Object);

            var helper = DefaultTemplatesUtilities.GetHtmlHelper(provider.Object);

            // Act (do not throw)
            var idResult = helper.Id(expression: string.Empty);
            var idForResult = helper.IdFor(m => m);
            var idForModelResult = helper.IdForModel();
            var nameResult = helper.Name(expression: string.Empty);
            var nameForResult = helper.NameFor(m => m);
            var nameForModelResult = helper.NameForModel();

            // Assert
            // Only the ViewDataDictionary should do anything with metadata.
            provider.Verify(
                m => m.GetMetadataForType(typeof(DefaultTemplatesUtilities.ObjectTemplateModel)),
                Times.Exactly(1));
        }

        [Fact]
        public void IdAndNameHelpers_DoNotConsultMetadataOrMetadataProvider_ForProperty()
        {
            // Arrange
            var provider = new Mock<IModelMetadataProvider>(MockBehavior.Strict);
            var metadata = new Mock<ModelMetadata>(
                MockBehavior.Loose,
                ModelMetadataIdentity.ForType(typeof(DefaultTemplatesUtilities.ObjectTemplateModel)));
            provider
                .Setup(m => m.GetMetadataForType(typeof(DefaultTemplatesUtilities.ObjectTemplateModel)))
                .Returns(metadata.Object);

            var helper = DefaultTemplatesUtilities.GetHtmlHelper(provider.Object);

            // Act (do not throw)
            var idResult = helper.Id("Property1");
            var idForResult = helper.IdFor(m => m.Property1);
            var nameResult = helper.Name("Property1");
            var nameForResult = helper.NameFor(m => m.Property1);

            // Assert
            // Only the ViewDataDictionary should do anything with metadata.
            provider.Verify(
                m => m.GetMetadataForType(typeof(DefaultTemplatesUtilities.ObjectTemplateModel)),
                Times.Exactly(1));
        }

        [Theory]
        [InlineData("A", "A")]
        [InlineData("A[0].B", "A_0__B")]
        [InlineData("A.B.C.D", "A_B_C_D")]
        public void IdAndName_ReturnExpression_EvenIfExpressionNotFound(string expression, string expectedId)
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper();

            // Act
            var idResult = helper.Id(expression);
            var nameResult = helper.Name(expression);

            // Assert
            Assert.Equal(expectedId, idResult);
            Assert.Equal(expression, nameResult);
        }

        [Fact]
        public void IdForAndNameFor_ReturnEmpty_IfExpressionUnsupported()
        {
            // Arrange
            var helper = DefaultTemplatesUtilities.GetHtmlHelper();

            // Act
            var idResult = helper.IdFor(model => new { foo = "Bar" });
            var nameResult = helper.NameFor(model => new { foo = "Bar" });

            // Assert
            Assert.Empty(idResult);
            Assert.Empty(nameResult);
        }

        // expression, expected name, expected id
        public static TheoryData StaticExpressionNamesData
        {
            get
            {
                // Give expressions access to non-static fields and properties.
                var test = new HtmlHelperNameExtensionsTest();
                return test.ExpressionNamesData;
            }
        }

        // expression, expected name, expected id
        private TheoryData ExpressionNamesData
        {
            get
            {
                var collection = new List<string>();
                var nestedCollection = new List<string[]>();
                var index1 = 5;
                var index2 = 23;
                var unknownKey = "this is a dummy parameter value";

                return new TheoryData<Expression<Func<List<OuterClass>, string>>, string, string>
                {
                    { m => unknownKey, "unknownKey", "unknownKey" },
                    { m => collection[index1], "collection[5]", "collection_5_" },
                    { m => nestedCollection[index1][23], "nestedCollection[5][23]", "nestedCollection_5__23_" },
                    { m => nestedCollection[index1][index2], "nestedCollection[5][23]", "nestedCollection_5__23_" },
                    { m => nestedCollection[_index][Index], "nestedCollection[7][9]", "nestedCollection_7__9_" },
                    { m => nestedCollection[Index][StaticIndex], "nestedCollection[9][8]", "nestedCollection_9__8_" },
                    { m => _string, "_string", "zstring" },
                    { m => _collection[_index], "_collection[7]", "zcollection_7_" },
                    { m => _nestedCollection[_index][23], "_nestedCollection[7][23]", "znestedCollection_7__23_" },
                    { m => _nestedCollection[_index][index2], "_nestedCollection[7][23]", "znestedCollection_7__23_" },
                    { m => _nestedCollection[Index][_staticIndex], "_nestedCollection[9][6]", "znestedCollection_9__6_" },
                    { m => _nestedCollection[StaticIndex][_index], "_nestedCollection[8][7]", "znestedCollection_8__7_" },
                    { m => StringProperty, "StringProperty", "StringProperty" },
                    { m => Collection[Index], "Collection[9]", "Collection_9_" },
                    { m => NestedCollection[Index][23], "NestedCollection[9][23]", "NestedCollection_9__23_" },
                    { m => NestedCollection[Index][index2], "NestedCollection[9][23]", "NestedCollection_9__23_" },
                    { m => NestedCollection[_index][Index], "NestedCollection[7][9]", "NestedCollection_7__9_" },
                    { m => NestedCollection[Index][StaticIndex], "NestedCollection[9][8]", "NestedCollection_9__8_" },
                    { m => _staticCollection[_staticIndex], "_staticCollection[6]", "zstaticCollection_6_" },
                    { m => _staticCollection[Index], "_staticCollection[9]", "zstaticCollection_9_" },
                    { m => _staticCollection[_index], "_staticCollection[7]", "zstaticCollection_7_" },
                    { m => StaticCollection[StaticIndex], "StaticCollection[8]", "StaticCollection_8_" },
                    { m => StaticCollection[_staticIndex], "StaticCollection[6]", "StaticCollection_6_" },
                    { m => StaticCollection[index1], "StaticCollection[5]", "StaticCollection_5_" },
                    { m => m[index1].Inner.Name, "[5].Inner.Name", "z5__Inner_Name" },
                    { m => m[_staticIndex].Inner.Name, "[6].Inner.Name", "z6__Inner_Name" },
                    { m => m[_index].Inner.Name, "[7].Inner.Name", "z7__Inner_Name" },
                    { m => m[StaticIndex].Inner.Name, "[8].Inner.Name", "z8__Inner_Name" },
                    { m => m[Index].Inner.Name, "[9].Inner.Name", "z9__Inner_Name" },
                };
            }
        }

        [Theory]
        [MemberData(nameof(StaticExpressionNamesData))]
        public void IdForAndNameFor_ReturnExpectedValues_WithVariablesInExpression(
            Expression<Func<List<OuterClass>, string>> expression,
            string expectedName,
            string expectedId)
        {
            // Arrange
            var model = new List<OuterClass>();
            var helper = DefaultTemplatesUtilities.GetHtmlHelper(model);

            // Act
            var idResult = helper.IdFor(expression);
            var nameResult = helper.NameFor(expression);

            // Assert
            Assert.Equal(expectedId, idResult);
            Assert.Equal(expectedName, nameResult);
        }

        [Fact]
        public void IdForAndNameFor_Throws_WhenParameterUsedAsIndexer()
        {
            // Arrange
            var collection = new List<string>();
            var index = 24;
            var helper = DefaultTemplatesUtilities.GetHtmlHelper(index);
            var message = "The expression compiler was unable to evaluate the indexer expression 'm' because it " +
                "references the model parameter 'm' which is unavailable.";

            // Act & Assert
            ExceptionAssert.Throws<InvalidOperationException>(() => helper.IdFor(m => collection[m]), message);
            ExceptionAssert.Throws<InvalidOperationException>(() => helper.NameFor(m => collection[m]), message);
        }

        public sealed class InnerClass
        {
            public int Id { get; set; }

            public string Name { get; set; }
        }

        public sealed class OuterClass
        {
            public InnerClass Inner { get; set; }
        }
    }
}