using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using Vanara.Extensions;

namespace Vanara.PInvoke
{
	public static partial class Kernel32
	{
		/// <summary>Retrieves the node that currently has the highest number.</summary>
		/// <param name="HighestNodeNumber">The number of the highest node.</param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
		/// </returns>
		// BOOL WINAPI GetNumaHighestNodeNumber( _Out_ PULONG HighestNodeNumber); https://msdn.microsoft.com/en-us/library/windows/desktop/ms683203(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("systemtopology.h", MSDNShortId = "ms683203")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool GetNumaHighestNodeNumber(out uint HighestNodeNumber);

		/// <summary>Retrieves the multi-group processor mask of the specified node.</summary>
		/// <param name="NodeNumber">Supplies the zero-based node number for the node of interest.</param>
		/// <param name="ProcessorMasks">
		/// <para>An array of GROUP_AFFINITY structures, which upon successful return describes the processor mask of the specified node.</para>
		/// <para>
		/// Each element in the array describes a set of processors that belong to the node within a single processor group. There will be
		/// one element in the resulting array for each processor group this node has active processors in.
		/// </para>
		/// </param>
		/// <param name="ProcessorMaskCount">Specifies the size of the ProcessorMasks array, in elements.</param>
		/// <param name="RequiredMaskCount">
		/// <para>On successful return, specifies the number of affinity structures written to the array.</para>
		/// <para>
		/// If the input array was too small, the function fails with <c>ERROR_INSUFFICIENT_BUFFER</c> and sets the RequiredMaskCount
		/// parameter to the number of elements required.
		/// </para>
		/// <para>The number of required elements is always less than or equal to the maximum group count returned by GetMaximumProcessorGroupCount.</para>
		/// </param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero and extended error information can be retrieved by calling GetLastError.</para>
		/// <para>
		/// If the array supplied is too small, the error value is <c>ERROR_INSUFFICIENT_BUFFER</c> and the RequiredMaskCount parameter is
		/// set to the number of elements required.
		/// </para>
		/// <para>
		/// If the NodeNumber supplied is invalid (i.e. greater than the value returned by GetNumaHighestNodeNumber), the error value is <c>ERROR_INVALID_PARAMETER</c>.
		/// </para>
		/// </returns>
		/// <remarks>
		/// If the node specified does not have any processors associated with it (i.e. it only contains memory or peripherals), then the
		/// RequiredMaskCount returned will be 0 and no structures will be written to the array.
		/// </remarks>
		// https://docs.microsoft.com/en-us/windows/win32/api/systemtopologyapi/nf-systemtopologyapi-getnumanodeprocessormask2
		// BOOL GetNumaNodeProcessorMask2( USHORT NodeNumber, PGROUP_AFFINITY ProcessorMasks, USHORT ProcessorMaskCount, PUSHORT RequiredMaskCount );
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("systemtopologyapi.h", MSDNShortId = "NF:systemtopologyapi.GetNumaNodeProcessorMask2")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool GetNumaNodeProcessorMask2(ushort NodeNumber,
			[In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] GROUP_AFFINITY[] ProcessorMasks, ushort ProcessorMaskCount,
			out ushort RequiredMaskCount);

		/// <summary>Retrieves the processor mask for a node regardless of the processor group the node belongs to.</summary>
		/// <param name="Node">The node number.</param>
		/// <param name="ProcessorMask">
		/// <para>
		/// A pointer to a <c>GROUP_AFFINITY</c> structure that receives the processor mask for the specified node. A processor mask is a bit
		/// vector in which each bit represents a processor and whether it is in the node.
		/// </para>
		/// <para>If the specified node has no processors configured, the <c>Mask</c> member is zero and the <c>Group</c> member is undefined.</para>
		/// </param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero.</para>
		/// </returns>
		// BOOL GetNumaNodeProcessorMaskEx( _In_ USHORT Node, _Out_ PGROUP_AFFINITY ProcessorMask); https://msdn.microsoft.com/en-us/library/windows/desktop/dd405493(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = false, ExactSpelling = true)]
		[PInvokeData("systemtopology.h", MSDNShortId = "dd405493")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool GetNumaNodeProcessorMaskEx(ushort Node, out GROUP_AFFINITY ProcessorMask);

		/// <summary>Retrieves the NUMA node number that corresponds to the specified proximity identifier as a <c>USHORT</c> value.</summary>
		/// <param name="ProximityId">The proximity identifier of the node.</param>
		/// <param name="NodeNumber">Points to a variable to receive the node number for the specified proximity identifier.</param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero.</para>
		/// </returns>
		// BOOL GetNumaProximityNodeEx( _In_ ULONG ProximityId, _Out_ PUSHORT NodeNumber); https://msdn.microsoft.com/en-us/library/windows/desktop/dd405495(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = false, ExactSpelling = true)]
		[PInvokeData("systemtopology.h", MSDNShortId = "dd405495")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool GetNumaProximityNodeEx(uint ProximityId, out ushort NodeNumber);

		/// <summary>Represents a processor group-specific affinity, such as the affinity of a thread.</summary>
		// typedef struct _GROUP_AFFINITY { KAFFINITY Mask; WORD Group; WORD Reserved[3];} GROUP_AFFINITY, *PGROUP_AFFINITY; https://msdn.microsoft.com/en-us/library/windows/desktop/dd405500(v=vs.85).aspx
		[PInvokeData("WinNT.h", MSDNShortId = "dd405500")]
		[StructLayout(LayoutKind.Sequential, Pack = 4)]
		public struct GROUP_AFFINITY
		{
			/// <summary>A bitmap that specifies the affinity for zero or more processors within the specified group.</summary>
			public UIntPtr Mask;

			/// <summary>The processor group number.</summary>
			public ushort Group;

			/// <summary>This member is reserved.</summary>
			private ushort Reserved1;

			/// <summary>This member is reserved.</summary>
			private ushort Reserved2;

			/// <summary>This member is reserved.</summary>
			private ushort Reserved3;

			/// <summary>Gets or sets the affinitized processors in the <see cref="Mask"/> field as their indexed values.</summary>
			/// <value>The affinitized processors.</value>
			public IEnumerable<uint> AffinitizedProcessors
			{
				get
				{
					var v = Mask.ToUInt64();
					for (uint i = 0; i < UIntPtr.Size * 8; i++)
					{
						if ((v & 0x1UL) == 1)
							yield return i;
						v = v >> 1;
					}
				}
				set
				{
					var v = 0UL;
					foreach (var i in value)
						v |= 1UL << (int)i;
					Mask = (UIntPtr)v;
				}
			}
		}
	}
}