//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="Numa"
// Project: StgSharp
// AuthorGroup: Nitload
// Copyright (c) Nitload. All rights reserved.
//     
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//     
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Common.HighPerformance.ProcessorAbstraction
{
    public static partial class Numa
    {

        private static NumaNode[] _numaNodes;

        public static int NumaNodeCount { get; private set; }

        public static ReadOnlySpan<NumaNode> AllNumaNode => _numaNodes;

        [LibraryImport(Native.LibName, EntryPoint = "sn_get_numa_each")]
        [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
        [DefaultDllImportSearchPaths(DllImportSearchPath.AssemblyDirectory)]
        public static partial int GetNumaEach(
                                  uint numaId,
                                  Span<ulong> CpuIndexInNuma,
                                  Span<uint> globalCpuIdInNuma
        );

        [LibraryImport(Native.LibName, EntryPoint = "sn_get_numa_overall")]
        [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
        [DefaultDllImportSearchPaths(DllImportSearchPath.AssemblyDirectory)]
        public static partial int GetNumaOverall(
                                  ref int count,
                                  Span<int> coreCountInNuma
        );

        internal static void Initialize()
        {
            Span<int> coreCountInNuma = stackalloc int[(Environment.ProcessorCount / 32) + 1];
            int numaNodeCount = 0;
            if (0 == GetNumaOverall(ref numaNodeCount, coreCountInNuma)) {
                throw new InvalidOperationException("Failed to get NUMA overall information.");
            }
            _numaNodes = new NumaNode[numaNodeCount];
            for (uint i = 0; i < numaNodeCount; i++) {
                _numaNodes[i] = InitNumaNode(i, coreCountInNuma[(int)i]);
            }
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private static NumaNode InitNumaNode(
                                uint numaId,
                                int count
        )
        {
            Span<uint> globalIndex = stackalloc uint[count];
            Span<ulong> groupIndex = stackalloc ulong[count];
            _ = GetNumaEach(numaId, groupIndex, globalIndex);
            return new(numaId, count, globalIndex);
        }

    }
}