// 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.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp.UseCoalesceExpression;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Diagnostics;
using Microsoft.CodeAnalysis.Test.Utilities;
using Microsoft.CodeAnalysis.UseCoalesceExpression;
using Roslyn.Test.Utilities;
using Xunit;
using Xunit.Abstractions;

namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.UseCoalesceExpression
{
    [Trait(Traits.Feature, Traits.Features.CodeActionsUseCoalesceExpression)]
    public class UseCoalesceExpressionForNullableTernaryConditionalCheckTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest
    {
        public UseCoalesceExpressionForNullableTernaryConditionalCheckTests(ITestOutputHelper logger)
          : base(logger)
        {
        }

        internal override (DiagnosticAnalyzer, CodeFixProvider) CreateDiagnosticProviderAndFixer(Workspace workspace)
            => (new CSharpUseCoalesceExpressionForNullableTernaryConditionalCheckDiagnosticAnalyzer(),
                new UseCoalesceExpressionForNullableTernaryConditionalCheckCodeFixProvider());

        [Fact]
        public async Task TestOnLeft_Equals()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = [||]!x.HasValue ? y : x.Value;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = x ?? y ;
                    }
                }
                """);
        }

        [Fact]
        public async Task TestOnLeft_NotEquals()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = [||]x.HasValue ? x.Value : y;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = x ?? y;
                    }
                }
                """);
        }

        [Fact]
        public async Task TestComplexExpression()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = [||]!(x + y).HasValue ? y : (x + y).Value;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = (x + y) ?? y ;
                    }
                }
                """);
        }

        [Fact]
        public async Task TestParens1()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = [||](x.HasValue) ? x.Value : y;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z = x ?? y;
                    }
                }
                """);
        }

        [Fact]
        public async Task TestFixAll1()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z1 = {|FixAllInDocument:x|}.HasValue ? x.Value : y;
                        var z2 = !x.HasValue ? y : x.Value;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y)
                    {
                        var z1 = x ?? y;
                        var z2 = x ?? y ;
                    }
                }
                """);
        }

        [Fact]
        public async Task TestFixAll2()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y, int? z)
                    {
                        var w = {|FixAllInDocument:x|}.HasValue ? x.Value : y.ToString(z.HasValue ? z.Value : y);
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y, int? z)
                    {
                        var w = x ?? y.ToString(z ?? y);
                    }
                }
                """);
        }

        [Fact]
        public async Task TestFixAll3()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x, int? y, int? z)
                    {
                        var w = {|FixAllInDocument:x|}.HasValue ? x.Value : y.HasValue ? y.Value : z;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x, int? y, int? z)
                    {
                        var w = x ?? y ?? z;
                    }
                }
                """);
        }

        [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/17028")]
        public async Task TestInExpressionOfT()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;
                using System.Linq.Expressions;

                class C
                {
                    void M(int? x, int? y)
                    {
                        Expression<Func<int>> e = () => [||]!x.HasValue ? y : x.Value;
                    }
                }
                """,
                """
                using System;
                using System.Linq.Expressions;

                class C
                {
                    void M(int? x, int? y)
                    {
                        Expression<Func<int>> e = () => {|Warning:x ?? y|} ;
                    }
                }
                """);
        }

        [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/69087")]
        public async Task TestNotWithTargetTyping1()
        {
            await TestMissingInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x)
                    {
                        object z = [||]x.HasValue ? x.Value : "";
                    }
                }
                """);
        }

        [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/69087")]
        public async Task TestWithNonTargetTyping1()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M(int? x)
                    {
                        object z = [||]x.HasValue ? x.Value : 0;
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M(int? x)
                    {
                        object z = x ?? 0;
                    }
                }
                """);
        }

        [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/69087")]
        public async Task TestNotWithTargetTyping2()
        {
            await TestMissingInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    public int? Index { get; set; }

                    public string InterpolatedText => $"{([||]Index.HasValue ? Index.Value : "???")}: rest of the text";
                }
                """);
        }

        [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/69087")]
        public async Task TestWithNonTargetTyping2()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    public int? Index { get; set; }

                    public string InterpolatedText => $"{([||]Index.HasValue ? Index.Value : 0)}: rest of the text";
                }
                """,
                """
                using System;

                class C
                {
                    public int? Index { get; set; }

                    public string InterpolatedText => $"{(Index ?? 0)}: rest of the text";
                }
                """);
        }
    }
}
