// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CSharp;
using Xunit;
using VerifyCS = Test.Utilities.CSharpCodeFixVerifier<
    Roslyn.Diagnostics.Analyzers.DefaultableTypeShouldHaveDefaultableFieldsAnalyzer,
    Microsoft.CodeAnalysis.Testing.EmptyCodeFixProvider>;
 
namespace Roslyn.Diagnostics.Analyzers.UnitTests
{
    public class DefaultableTypeShouldHaveDefaultableFieldsTests
    {
        private const string NonDefaultableAttribute = """
            // <auto-generated/>
            using System;
 
            namespace Roslyn.Utilities {
                [AttributeUsage(AttributeTargets.Struct | AttributeTargets.GenericParameter)]
                sealed class NonDefaultableAttribute : Attribute { }
            }
            """;
 
        public static IEnumerable<object[]> DefaultableTypes
        {
            get
            {
                yield return new object[] { "int" };
                yield return new object[] { "int?" };
                yield return new object[] { "DateTime" };
                yield return new object[] { "object?" };
                yield return new object[] { "IFormattable?" };
                yield return new object[] { "EventHandler?" };
                yield return new object[] { "StringComparison" };
            }
        }
 
        public static IEnumerable<object[]> DefaultableTypesNullableDisableContext
        {
            get
            {
                yield return new object[] { "int" };
                yield return new object[] { "int?" };
                yield return new object[] { "DateTime" };
                yield return new object[] { "object" };
                yield return new object[] { "IFormattable" };
                yield return new object[] { "EventHandler" };
                yield return new object[] { "StringComparison" };
            }
        }
 
        public static IEnumerable<object[]> NonDefaultableTypes
        {
            get
            {
                yield return new object[] { "object" };
                yield return new object[] { "IFormattable" };
                yield return new object[] { "EventHandler" };
                yield return new object[] { "NonDefaultableStruct" };
            }
        }
 
        [Theory]
        [MemberData(nameof(NonDefaultableTypes))]
        public async Task TestNonDefaultableStructWithNonDefaultableTypeFieldAsync(string nonDefaultableType)
        {
            var code = $$"""
                #nullable enable
 
                using System;
                using Roslyn.Utilities;
 
                [NonDefaultable]
                struct NonDefaultableStruct { }
 
                [NonDefaultable]
                struct NonDefaultableTestStruct {
                    {{nonDefaultableType}} field;
                    {{nonDefaultableType}} Property { get; }
 
                    static {{nonDefaultableType}} staticField = default!;
                    static {{nonDefaultableType}} StaticProperty { get; } = default!;
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(NonDefaultableTypes))]
        public async Task TestNonDefaultableStructWithNonDefaultableTypeNullableDisableFieldAsync(string nonDefaultableType)
        {
            var code = $$"""
                #nullable disable
 
                using System;
                using Roslyn.Utilities;
 
                [NonDefaultable]
                struct NonDefaultableStruct { }
 
                [NonDefaultable]
                struct NonDefaultableTestStruct {
                    {{nonDefaultableType}} field;
                    {{nonDefaultableType}} Property { get; }
 
                    static {{nonDefaultableType}} staticField;
                    static {{nonDefaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(DefaultableTypes))]
        public async Task TestNonDefaultableStructWithDefaultableTypeFieldAsync(string defaultableType)
        {
            var code = $$"""
                #nullable enable
 
                using System;
                using Roslyn.Utilities;
 
                [NonDefaultable]
                struct NonDefaultableTestStruct {
                    {{defaultableType}} field;
                    {{defaultableType}} Property { get; }
 
                    static {{defaultableType}} staticField;
                    static {{defaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(DefaultableTypesNullableDisableContext))]
        public async Task TestNonDefaultableStructWithDefaultableTypeNullableDisableFieldAsync(string defaultableType)
        {
            var code = $$"""
                #nullable disable
 
                using System;
                using Roslyn.Utilities;
 
                [NonDefaultable]
                struct NonDefaultableTestStruct {
                    {{defaultableType}} field;
                    {{defaultableType}} Property { get; }
 
                    static {{defaultableType}} staticField;
                    static {{defaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(DefaultableTypes))]
        public async Task TestDefaultableStructWithDefaultableTypeFieldAsync(string defaultableType)
        {
            var code = $$"""
                #nullable enable
 
                using System;
 
                struct DefaultableStruct {
                    {{defaultableType}} field;
                    {{defaultableType}} Property { get; }
 
                    static {{defaultableType}} staticField;
                    static {{defaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(DefaultableTypes))]
        public async Task TestClassWithDefaultableTypeFieldAsync(string defaultableType)
        {
            var code = $$"""
                #nullable enable
 
                using System;
 
                class TestClass {
                    {{defaultableType}} field;
                    {{defaultableType}} Property { get; }
 
                    static {{defaultableType}} staticField;
                    static {{defaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(DefaultableTypesNullableDisableContext))]
        public async Task TestClassWithDefaultableTypeNullableDisableFieldAsync(string defaultableType)
        {
            var code = $$"""
                #nullable disable
 
                using System;
 
                class TestClass {
                    {{defaultableType}} field;
                    {{defaultableType}} Property { get; }
 
                    static {{defaultableType}} staticField;
                    static {{defaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(NonDefaultableTypes))]
        public async Task TestDefaultableStructWithNonDefaultableTypeFieldAsync(string nonDefaultableType)
        {
            var code = $$"""
                #nullable enable
 
                using System;
                using Roslyn.Utilities;
 
                [NonDefaultable]
                struct NonDefaultableStruct { }
 
                struct DefaultableStruct {
                    {{nonDefaultableType}} [|field|];
                    {{nonDefaultableType}} [|Property|] { get; }
 
                    static {{nonDefaultableType}} StaticField = default!;
                    static {{nonDefaultableType}} StaticProperty { get; } = default!;
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
 
        [Theory]
        [MemberData(nameof(NonDefaultableTypes))]
        public async Task TestDefaultableStructWithNonDefaultableTypeNullableDisableFieldAsync(string nonDefaultableType)
        {
            var code = $$"""
                #nullable disable
 
                using System;
                using Roslyn.Utilities;
 
                [NonDefaultable]
                struct NonDefaultableStruct { }
 
                struct DefaultableStruct {
                    {{nonDefaultableType}} field;
                    {{nonDefaultableType}} Property { get; }
 
                    static {{nonDefaultableType}} StaticField;
                    static {{nonDefaultableType}} StaticProperty { get; }
                }
                """;
 
            await new VerifyCS.Test
            {
                LanguageVersion = LanguageVersion.CSharp8,
                TestState = { Sources = { code, NonDefaultableAttribute } },
            }.RunAsync();
        }
    }
}