// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using Microsoft.CSharp.RuntimeBinder.Syntax;
 
namespace Microsoft.CSharp.RuntimeBinder.Semantics
{
    /////////////////////////////////////////////////////////////////////////////////
 
    internal sealed class TypeParameterType : CType
    {
        public TypeParameterType(TypeParameterSymbol symbol)
            : base(TypeKind.TK_TypeParameterType)
        {
            Debug.Assert(symbol.GetTypeParameterType() == null);
            Symbol = symbol;
            symbol.SetTypeParameterType(this);
        }
 
        public TypeParameterSymbol Symbol { get; }
 
        // Forward calls into the symbol.
 
        public ParentSymbol OwningSymbol => Symbol.parent;
 
        public Name Name => Symbol.name;
 
        public bool Covariant => Symbol.Covariant;
 
        public bool Invariant => Symbol.Invariant;
 
        public bool Contravariant => Symbol.Contravariant;
 
        public override bool IsValueType => Symbol.IsValueType();
 
        public override bool IsReferenceType => Symbol.IsReferenceType();
 
        public override bool IsNonNullableValueType => Symbol.IsNonNullableValueType();
 
        public bool HasNewConstraint => Symbol.HasNewConstraint();
 
        public bool HasRefConstraint => Symbol.HasRefConstraint();
 
        public bool HasValConstraint => Symbol.HasValConstraint();
 
        public bool IsMethodTypeParameter => Symbol.IsMethodTypeParameter();
 
        public int IndexInOwnParameters => Symbol.GetIndexInOwnParameters();
 
        public int IndexInTotalParameters => Symbol.GetIndexInTotalParameters();
 
        public TypeArray Bounds => Symbol.GetBounds();
 
        public override Type AssociatedSystemType
        {
            [RequiresUnreferencedCode(Binder.TrimmerWarning)]
            get =>
                (IsMethodTypeParameter
                    ? ((MethodInfo)((MethodSymbol)OwningSymbol).AssociatedMemberInfo).GetGenericArguments()
                    : ((AggregateSymbol)OwningSymbol).AssociatedSystemType.GetGenericArguments()
                )[IndexInOwnParameters];
        }
 
        public override FUNDTYPE FundamentalType => FUNDTYPE.FT_VAR;
    }
}