// 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.CodeStyle;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.CodeStyle;
using Microsoft.CodeAnalysis.CSharp.MakeLocalFunctionStatic;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Diagnostics;
using Microsoft.CodeAnalysis.Test.Utilities;
using Roslyn.Test.Utilities;
using Xunit;
using Xunit.Abstractions;

namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.MakeLocalFunctionStatic
{
    public partial class MakeLocalFunctionStaticTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest
    {
        public MakeLocalFunctionStaticTests(ITestOutputHelper logger)
          : base(logger)
        {
        }

        internal override (DiagnosticAnalyzer, CodeFixProvider) CreateDiagnosticProviderAndFixer(Workspace workspace)
            => (new MakeLocalFunctionStaticDiagnosticAnalyzer(), new MakeLocalFunctionStaticCodeFixProvider());

        private static readonly ParseOptions CSharp72ParseOptions = CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.CSharp7_2);
        private static readonly ParseOptions CSharp8ParseOptions = CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.CSharp8);

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestAboveCSharp8()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M()
                    {
                        int [||]fibonacci(int n)
                        {
                            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """,
                """
                using System;

                class C
                {
                    void M()
                    {
                        static int fibonacci(int n)
                        {
                            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """,
parseOptions: CSharp8ParseOptions);
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseSimpleUsingStatement)]
        public async Task TestWithOptionOff()
        {
            await TestMissingInRegularAndScriptAsync(
                """
                using System;

                class C
                {
                    void M()
                    {
                        int [||]fibonacci(int n)
                        {
                            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """,
new TestParameters(
    parseOptions: CSharp8ParseOptions,
    options: Option(CSharpCodeStyleOptions.PreferStaticLocalFunction, CodeStyleOption2.FalseWithSilentEnforcement)));
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestMissingIfAlreadyStatic()
        {
            await TestMissingAsync(
                """
                using System;

                class C
                {
                    void M()
                    {
                        static int [||]fibonacci(int n)
                        {
                            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """, parameters: new TestParameters(parseOptions: CSharp8ParseOptions));
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestMissingPriorToCSharp8()
        {
            await TestMissingAsync(
                """
                using System;

                class C
                {
                    void M()
                    {
                        int [||]fibonacci(int n)
                        {
                            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """, parameters: new TestParameters(parseOptions: CSharp72ParseOptions));
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestMissingIfCapturesValue()
        {
            await TestMissingAsync(
                """
                using System;

                class C
                {
                    void M(int i)
                    {
                        int [||]fibonacci(int n)
                        {
                            return i <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """, parameters: new TestParameters(parseOptions: CSharp8ParseOptions));
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestMissingIfCapturesThis()
        {
            await TestMissingAsync(
                """
                using System;

                class C
                {
                    void M()
                    {
                        int [||]fibonacci(int n)
                        {
                            M();
                            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
                        }
                    }
                }
                """, parameters: new TestParameters(parseOptions: CSharp8ParseOptions));
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestAsyncFunction()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;
                using System.Threading.Tasks;

                class C
                {
                    void M()
                    {
                        async Task<int> [||]fibonacci(int n)
                        {
                            return n <= 1 ? n : await fibonacci(n - 1) + await fibonacci(n - 2);
                        }
                    }
                }
                """,
                """
                using System;
                using System.Threading.Tasks;

                class C
                {
                    void M()
                    {
                        static async Task<int> fibonacci(int n)
                        {
                            return n <= 1 ? n : await fibonacci(n - 1) + await fibonacci(n - 2);
                        }
                    }
                }
                """,
parseOptions: CSharp8ParseOptions);
        }

        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [InlineData("")]
        [InlineData("\r\n")]
        [InlineData("\r\n\r\n")]
        public async Task TestLeadingTriviaAfterSemicolon(string leadingTrivia)
        {
            await TestInRegularAndScriptAsync(
$@"using System;

class C
{{
    void M()
    {{
        int x;{leadingTrivia}
        int [||]fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
"""
using System;

class C
{
    void M()
    {
        int x;

        static int fibonacci(int n)
        {
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }
    }
}
""",
parseOptions: CSharp8ParseOptions);
        }

        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [InlineData("")]
        [InlineData("\r\n")]
        [InlineData("\r\n\r\n")]
        public async Task TestLeadingTriviaAfterOpenBrace(string leadingTrivia)
        {
            await TestInRegularAndScriptAsync(
$@"using System;

class C
{{
    void M()
    {{{leadingTrivia}
        int [||]fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
"""
using System;

class C
{
    void M()
    {
        static int fibonacci(int n)
        {
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }
    }
}
""",
parseOptions: CSharp8ParseOptions);
        }

        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [InlineData("")]
        [InlineData("\r\n")]
        [InlineData("\r\n\r\n")]
        public async Task TestLeadingTriviaAfterLocalFunction(string leadingTrivia)
        {
            await TestInRegularAndScriptAsync(
$@"using System;

class C
{{
    void M()
    {{
        bool otherFunction()
        {{
            return true;
        }}{leadingTrivia}
        int [||]fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
"""
using System;

class C
{
    void M()
    {
        bool otherFunction()
        {
            return true;
        }

        static int fibonacci(int n)
        {
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }
    }
}
""",
parseOptions: CSharp8ParseOptions);
        }

        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [InlineData("")]
        [InlineData("\r\n")]
        [InlineData("\r\n\r\n")]
        public async Task TestLeadingTriviaAfterExpressionBodyLocalFunction(string leadingTrivia)
        {
            await TestInRegularAndScriptAsync(
$@"using System;

class C
{{
    void M()
    {{
        bool otherFunction() => true;{leadingTrivia}
        int [||]fibonacci(int n) => n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
    }}
}}",
"""
using System;

class C
{
    void M()
    {
        bool otherFunction() => true;

        static int fibonacci(int n) => n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
    }
}
""",
parseOptions: CSharp8ParseOptions);
        }

        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [InlineData("")]
        [InlineData("\r\n")]
        [InlineData("\r\n\r\n")]
        public async Task TestLeadingTriviaAfterComment(string leadingTrivia)
        {
            await TestInRegularAndScriptAsync(
$@"using System;

class C
{{
    void M()
    {{
        //Local function comment{leadingTrivia}
        int [||]fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
$@"using System;

class C
{{
    void M()
    {{
        //Local function comment{leadingTrivia}
        static int fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
parseOptions: CSharp8ParseOptions);
        }

        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [InlineData("\r\n")]
        [InlineData("\r\n\r\n")]
        public async Task TestLeadingTriviaBeforeComment(string leadingTrivia)
        {
            await TestInRegularAndScriptAsync(
$@"using System;

class C
{{
    void M()
    {{{leadingTrivia}
        //Local function comment
        int [||]fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
$@"using System;

class C
{{
    void M()
    {{{leadingTrivia}
        //Local function comment
        static int fibonacci(int n)
        {{
            return n <= 1 ? n : fibonacci(n - 1) + fibonacci(n - 2);
        }}
    }}
}}",
parseOptions: CSharp8ParseOptions);
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [WorkItem("https://github.com/dotnet/roslyn/issues/46858")]
        public async Task TestMissingIfAnotherLocalFunctionCalled()
        {
            await TestMissingAsync(
                """
                using System;

                class C
                {
                    void M()
                    {
                        void [||]A()
                        {
                            B();
                        }

                        void B()
                        {
                        }
                    }
                }
                """, parameters: new TestParameters(parseOptions: CSharp8ParseOptions));
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestCallingStaticLocalFunction()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;
                using System.Threading.Tasks;

                class C
                {
                    void M()
                    {
                        void [||]A()
                        {
                            B();
                        }

                        static void B()
                        {
                        }
                    }
                }
                """,
                """
                using System;
                using System.Threading.Tasks;

                class C
                {
                    void M()
                    {
                        static void A()
                        {
                            B();
                        }

                        static void B()
                        {
                        }
                    }
                }
                """,
parseOptions: CSharp8ParseOptions);
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        public async Task TestCallingNestedLocalFunction()
        {
            await TestInRegularAndScriptAsync(
                """
                using System;
                using System.Threading.Tasks;

                class C
                {
                    void M()
                    {
                        void [||]A()
                        {
                            B();

                            void B()
                            {
                            }
                        }
                    }
                }
                """,
                """
                using System;
                using System.Threading.Tasks;

                class C
                {
                    void M()
                    {
                        static void A()
                        {
                            B();

                            void B()
                            {
                            }
                        }
                    }
                }
                """,
parseOptions: CSharp8ParseOptions);
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [WorkItem("https://github.com/dotnet/roslyn/issues/53179")]
        public async Task TestLocalFunctionAsTopLevelStatement()
        {
            await TestAsync("""
                void [||]A()
                {
                }
                """, """
                static void A()
                {
                }
                """,
parseOptions: CSharp8ParseOptions);
        }

        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeLocalFunctionStatic)]
        [WorkItem("https://github.com/dotnet/roslyn/issues/59286")]
        public async Task TestUnsafeLocalFunction()
        {
            await TestAsync("""
                unsafe void [||]A()
                {
                }
                """, """
                static unsafe void A()
                {
                }
                """,
parseOptions: CSharp8ParseOptions);
        }
    }
}
