//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="MatrixMetadata"
// 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 StgSharp.HighPerformance;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Mathematics.Numeric
{
    public enum MatrixLayout
    {

        DenseSquare,
        UpperTriangle,
        LowerTriangle,

    }

    [StructLayout(LayoutKind.Sequential)]
    public unsafe struct MatrixKernelEnumeration
    {

        public readonly delegate* unmanaged[Cdecl]
            <int, int, MatrixKernelEnumerator*, long> GetIndexOffset;

        public readonly delegate* unmanaged[Cdecl]<int, int, MatrixKernelEnumerator*, bool> IsInBuffer;

        [Obsolete("Do not use constructor, use static method instead", true)]
        public MatrixKernelEnumeration() { }

        public MatrixKernelEnumeration(
               delegate* unmanaged[Cdecl]
           <int, int, MatrixKernelEnumerator*, long> getOffset,
               delegate* unmanaged[Cdecl]<int, int, MatrixKernelEnumerator*, bool> inBuffer)
        {
            GetIndexOffset = getOffset;
            IsInBuffer = inBuffer;
        }

        private static delegate* unmanaged[Cdecl]<int, int, MatrixKernelEnumerator*, bool> IsInBufferDenseSquarePtr { get; } = (delegate* unmanaged[Cdecl]<int, int, MatrixKernelEnumerator*, bool>)&IsInBufferDenseSquare;

        public static MatrixKernelEnumeration Create(MatrixLayout layout)
        {
            return layout switch
            {
                MatrixLayout.DenseSquare => new MatrixKernelEnumeration(null, IsInBufferDenseSquarePtr),

                MatrixLayout.UpperTriangle => throw new NotImplementedException(),
            };
        }

        private static bool IsInBufferDenseSquare(
                            int col,
                            int row,
                            MatrixKernelEnumerator* enumerator)
        {
            return true;
        }

    }

    [StructLayout(LayoutKind.Explicit)]
    public struct MatrixSize
    {

        [FieldOffset(0)] public readonly int ElementColumnLength;
        [FieldOffset(4)] public readonly int ElementRowLength;

        [FieldOffset(8)] public readonly int KernelColumnLength;
        [FieldOffset(12)] public readonly int KernelRowLength;

    }

    [StructLayout(LayoutKind.Explicit)]
    public struct MatrixKernelEnumerator
    {

        [FieldOffset(0)] public int CurrentColumn;
        [FieldOffset(4)] public int CurrentRow;

        [FieldOffset(8)] public  readonly int KernelColumnLength;
        [FieldOffset(12)] public readonly int KernelRowLength;

    }
}