// 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 Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis
{
    internal partial struct SymbolKey
    {
        private static class TypeParameterOrdinalSymbolKey
        {
            public static void Create(ITypeParameterSymbol symbol, int methodIndex, SymbolKeyWriter visitor)
            {
                Contract.ThrowIfFalse(symbol.TypeParameterKind == TypeParameterKind.Method);
                visitor.WriteInteger(methodIndex);
                visitor.WriteInteger(symbol.Ordinal);
            }
 
            public static SymbolKeyResolution Resolve(SymbolKeyReader reader, out string? failureReason)
            {
                var methodIndex = reader.ReadInteger();
                var ordinal = reader.ReadInteger();
                var method = reader.ResolveMethod(methodIndex);
 
                var typeParameter = method?.TypeParameters[ordinal];
                if (typeParameter == null)
                {
                    failureReason = $"({nameof(TypeParameterOrdinalSymbolKey)} failed)";
                    return default;
                }
 
                failureReason = null;
                return new SymbolKeyResolution(typeParameter);
            }
        }
    }
}