//  Copyright 2018 Google Inc. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

using System;
using System.Reflection;

namespace NtApiDotNet.Utilities.Memory
{
    internal class CrossBitnessTypeAttribute : Attribute
    {
        private Lazy<MethodInfo> _base_method;
        public Type CrossBitnessType { get; }

        private static MethodInfo GetMethodInfo(Type cross_bitness_type)
        {
            Func<long, int> read_memory = NtProcess.Current.ReadMemory<int>;
            return read_memory.Method.GetGenericMethodDefinition().MakeGenericMethod(cross_bitness_type);
        }

        public CrossBitnessTypeAttribute(Type cross_bitness_type)
        {
            CrossBitnessType = cross_bitness_type;
            _base_method = new Lazy<MethodInfo>(() => GetMethodInfo(cross_bitness_type));
        }

        public T ReadType<T>(NtProcess process, long base_address) where T : struct
        {
            IConvertToNative<T> converter = (IConvertToNative<T>)_base_method.Value.Invoke(process, new object[] { base_address });
            return converter.Convert();
        }

        public int GetSize()
        {
            return System.Runtime.InteropServices.Marshal.SizeOf(CrossBitnessType);
        }
    }
}
