// 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.
 
#nullable disable
 
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeGeneration;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Shared.Extensions;
 
namespace Microsoft.CodeAnalysis.GenerateMember.GenerateParameterizedMember;
 
internal partial class AbstractGenerateDeconstructMethodService<TService, TSimpleNameSyntax, TExpressionSyntax, TInvocationExpressionSyntax>
{
    internal new class State :
        AbstractGenerateParameterizedMemberService<TService, TSimpleNameSyntax, TExpressionSyntax, TInvocationExpressionSyntax>.State
    {
        /// <summary>
        /// Make a State instance representing the Deconstruct method we want to generate.
        /// The method will be called "Deconstruct". It will be a member of `typeToGenerateIn`.
        /// Its arguments will be based on `targetVariables`.
        /// </summary>
        public static async Task<State> GenerateDeconstructMethodStateAsync(
            TService service,
            SemanticDocument document,
            SyntaxNode targetVariables,
            INamedTypeSymbol typeToGenerateIn,
            CancellationToken cancellationToken)
        {
            var state = new State();
            if (!await state.TryInitializeMethodAsync(service, document, targetVariables, typeToGenerateIn, cancellationToken).ConfigureAwait(false))
            {
                return null;
            }
 
            return state;
        }
 
        private async Task<bool> TryInitializeMethodAsync(
            TService service,
            SemanticDocument document,
            SyntaxNode targetVariables,
            INamedTypeSymbol typeToGenerateIn,
            CancellationToken cancellationToken)
        {
            TypeToGenerateIn = typeToGenerateIn;
            IsStatic = false;
            var generator = document.Document.GetRequiredLanguageService<SyntaxGeneratorInternal>();
 
            IdentifierToken = generator.Identifier(WellKnownMemberNames.DeconstructMethodName);
            MethodGenerationKind = MethodGenerationKind.Member;
            MethodKind = MethodKind.Ordinary;
 
            cancellationToken.ThrowIfCancellationRequested();
 
            var semanticModel = document.SemanticModel;
            ContainingType = semanticModel.GetEnclosingNamedType(targetVariables.SpanStart, cancellationToken);
            if (ContainingType == null)
            {
                return false;
            }
 
            var parameters = service.TryMakeParameters(semanticModel, targetVariables, cancellationToken);
            if (parameters.IsDefault)
            {
                return false;
            }
 
            var methodSymbol = CodeGenerationSymbolFactory.CreateMethodSymbol(
                attributes: default,
                accessibility: default,
                modifiers: default,
                returnType: semanticModel.Compilation.GetSpecialType(SpecialType.System_Void),
                refKind: RefKind.None,
                explicitInterfaceImplementations: default,
                name: null,
                typeParameters: default,
                parameters);
 
            SignatureInfo = new MethodSignatureInfo(document, this, methodSymbol);
 
            return await TryFinishInitializingStateAsync(service, document, cancellationToken).ConfigureAwait(false);
        }
    }
}