// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Microsoft.CodeAnalysis;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
 
namespace SourceGenerators
{
    internal static class TypeModelHelper
    {
        public static List<ITypeSymbol>? GetAllTypeArgumentsInScope(this INamedTypeSymbol type)
        {
            if (!type.IsGenericType)
            {
                return null;
            }
 
            List<ITypeSymbol>? args = null;
            TraverseContainingTypes(type);
            return args;
 
            void TraverseContainingTypes(INamedTypeSymbol current)
            {
                if (current.ContainingType is INamedTypeSymbol parent)
                {
                    TraverseContainingTypes(parent);
                }
 
                if (!current.TypeArguments.IsEmpty)
                {
                    (args ??= new()).AddRange(current.TypeArguments);
                }
            }
        }
 
        public static string GetFullyQualifiedName(this ITypeSymbol type) => type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
    }
}