// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System.Collections.Immutable;

// This is needed due to NativeAOT which doesn't enable nullable globally yet
#nullable enable

namespace ILLink.Shared.TypeSystemProxy
{
    internal readonly partial struct MethodProxy : IMemberProxy
    {
        // Currently this only needs to work on non-nested, non-generic types.
        // The format of the fullTypeName parameter is 'namespace.typename', so for example 'System.Reflection.Assembly'
        internal partial bool IsDeclaredOnType(string fullTypeName);

        /// <summary>
        /// Returns the number of the parameters in the 'parameters' metadata section. This should map directly to the number of parameters in the C# source declaration as well.
        /// </summary>
        internal partial int GetMetadataParametersCount();

        /// <summary>
        /// Returns true if the method has parameters in the 'parameters' metadata section (i.e. has parameters besides the implicit 'this' parameter)
        /// </summary>
        internal partial bool HasMetadataParameters();

        /// <summary>
        /// Returns the number of parameters that are passed to the method in IL (including the implicit 'this' parameter).
        /// In pseudocode: <code>method.HasImplicitThis() ? 1 + MetadataParametersCount : MetadataParametersCount;</code>
        /// </summary>
        internal partial int GetParametersCount();

        /// <summary>
        /// Returns a List of <see cref="ParameterProxy"/> representing the parameters the method takes, including the implicit 'this' parameters.
        /// </summary>
        internal partial ParameterProxyEnumerable GetParameters();

        /// <summary>
        /// Returns the ParameterProxy corresponding to the parameter at <paramref name="index"/>, and throws if the index is out of bounds for the method.
        /// <paramref name="index"/> is the index of the parameters as they are passed to the method, with 0 being the implicit this parameter if it exists.
        /// See <see cref="ParameterIndex"/> for more info.
        /// </summary>
        internal partial ParameterProxy GetParameter(ParameterIndex index);

        /// <summary>
        /// Returns true if the 'parameters' metadata section has <paramref name="parameterCount"/> number of parameters.
        /// Metadata parameters count maps directly to the number of parameters in C# source code.
        /// Metadata parameters count excludes the implicit 'this' parameter.
        /// </summary>
        internal bool HasMetadataParametersCount(int parameterCount) => GetMetadataParametersCount() == parameterCount;

        // Currently this only needs to work on non-nested, non-generic types.
        // The format of the fullTypeName parameter is 'namespace.typename', so for example 'System.Reflection.Assembly'
        internal bool HasParameterOfType(ParameterIndex parameterIndex, string fullTypeName)
            => (int)parameterIndex < GetParametersCount() && GetParameter(parameterIndex).IsTypeOf(fullTypeName);
        internal partial bool HasGenericParameters();
        internal partial ImmutableArray<GenericParameterProxy> GetGenericParameters();
        internal partial bool HasGenericArgumentsCount(int genericArgumentCount);
        internal partial bool IsConstructor();
        internal partial bool IsStatic();
        internal partial bool HasImplicitThis();
        internal partial bool ReturnsVoid();
    }
}