// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
 
namespace Microsoft.Extensions.DependencyInjection.ServiceLookup
{
    internal sealed class ConstantCallSite : ServiceCallSite
    {
        private readonly Type _serviceType;
        internal object? DefaultValue => Value;
 
        public ConstantCallSite(Type serviceType, object? defaultValue) : base(ResultCache.None(serviceType))
        {
            _serviceType = serviceType ?? throw new ArgumentNullException(nameof(serviceType));
            if (defaultValue != null && !serviceType.IsInstanceOfType(defaultValue))
            {
                throw new ArgumentException(SR.Format(SR.ConstantCantBeConvertedToServiceType, defaultValue.GetType(), serviceType));
            }
 
            Value = defaultValue;
        }
 
        public override Type ServiceType => _serviceType;
        public override Type ImplementationType => DefaultValue?.GetType() ?? _serviceType;
        public override CallSiteKind Kind { get; } = CallSiteKind.Constant;
    }
}