// 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.Collections.Immutable;
using System.Runtime.CompilerServices;

namespace Microsoft.CodeAnalysis.CodeGeneration;

internal sealed class CodeGenerationDestructorInfo
{
    private static readonly ConditionalWeakTable<IMethodSymbol, CodeGenerationDestructorInfo> s_destructorToInfoMap = new();

    private readonly string _typeName;
    private readonly ImmutableArray<SyntaxNode> _statements;

    private CodeGenerationDestructorInfo(
        string typeName,
        ImmutableArray<SyntaxNode> statements)
    {
        _typeName = typeName;
        _statements = statements;
    }

    public static void Attach(
        IMethodSymbol destructor,
        string typeName,
        ImmutableArray<SyntaxNode> statements)
    {
        var info = new CodeGenerationDestructorInfo(typeName, statements);
        s_destructorToInfoMap.Add(destructor, info);
    }

    private static CodeGenerationDestructorInfo GetInfo(IMethodSymbol method)
    {
        s_destructorToInfoMap.TryGetValue(method, out var info);
        return info;
    }

    public static ImmutableArray<SyntaxNode> GetStatements(IMethodSymbol destructor)
        => GetStatements(GetInfo(destructor));

    public static string GetTypeName(IMethodSymbol destructor)
        => GetTypeName(GetInfo(destructor), destructor);

    private static ImmutableArray<SyntaxNode> GetStatements(CodeGenerationDestructorInfo info)
        => info?._statements ?? default;

    private static string GetTypeName(CodeGenerationDestructorInfo info, IMethodSymbol constructor)
        => info == null ? constructor.ContainingType.Name : info._typeName;
}