using System;
using System.Runtime.InteropServices;

namespace XCEngine
{
    [StructLayout(LayoutKind.Sequential)]
    public struct Matrix4x4
    {
        public float M00;
        public float M01;
        public float M02;
        public float M03;
        public float M10;
        public float M11;
        public float M12;
        public float M13;
        public float M20;
        public float M21;
        public float M22;
        public float M23;
        public float M30;
        public float M31;
        public float M32;
        public float M33;

        public static Matrix4x4 Identity =>
            new Matrix4x4
            {
                M00 = 1.0f,
                M11 = 1.0f,
                M22 = 1.0f,
                M33 = 1.0f
            };

        public float this[int row, int column]
        {
            get
            {
                switch (row)
                {
                    case 0:
                        switch (column)
                        {
                            case 0:
                                return M00;
                            case 1:
                                return M01;
                            case 2:
                                return M02;
                            case 3:
                                return M03;
                            default:
                                throw new ArgumentOutOfRangeException(
                                    nameof(column));
                        }
                    case 1:
                        switch (column)
                        {
                            case 0:
                                return M10;
                            case 1:
                                return M11;
                            case 2:
                                return M12;
                            case 3:
                                return M13;
                            default:
                                throw new ArgumentOutOfRangeException(
                                    nameof(column));
                        }
                    case 2:
                        switch (column)
                        {
                            case 0:
                                return M20;
                            case 1:
                                return M21;
                            case 2:
                                return M22;
                            case 3:
                                return M23;
                            default:
                                throw new ArgumentOutOfRangeException(
                                    nameof(column));
                        }
                    case 3:
                        switch (column)
                        {
                            case 0:
                                return M30;
                            case 1:
                                return M31;
                            case 2:
                                return M32;
                            case 3:
                                return M33;
                            default:
                                throw new ArgumentOutOfRangeException(
                                    nameof(column));
                        }
                    default:
                        throw new ArgumentOutOfRangeException(nameof(row));
                }
            }
            set
            {
                switch (row)
                {
                    case 0:
                        switch (column)
                        {
                            case 0:
                                M00 = value;
                                return;
                            case 1:
                                M01 = value;
                                return;
                            case 2:
                                M02 = value;
                                return;
                            case 3:
                                M03 = value;
                                return;
                        }
                        break;
                    case 1:
                        switch (column)
                        {
                            case 0:
                                M10 = value;
                                return;
                            case 1:
                                M11 = value;
                                return;
                            case 2:
                                M12 = value;
                                return;
                            case 3:
                                M13 = value;
                                return;
                        }
                        break;
                    case 2:
                        switch (column)
                        {
                            case 0:
                                M20 = value;
                                return;
                            case 1:
                                M21 = value;
                                return;
                            case 2:
                                M22 = value;
                                return;
                            case 3:
                                M23 = value;
                                return;
                        }
                        break;
                    case 3:
                        switch (column)
                        {
                            case 0:
                                M30 = value;
                                return;
                            case 1:
                                M31 = value;
                                return;
                            case 2:
                                M32 = value;
                                return;
                            case 3:
                                M33 = value;
                                return;
                        }
                        break;
                }

                throw new ArgumentOutOfRangeException(
                    row < 0 || row > 3
                        ? nameof(row)
                        : nameof(column));
            }
        }

        public Vector4 GetRow(int row)
        {
            switch (row)
            {
                case 0:
                    return new Vector4(M00, M01, M02, M03);
                case 1:
                    return new Vector4(M10, M11, M12, M13);
                case 2:
                    return new Vector4(M20, M21, M22, M23);
                case 3:
                    return new Vector4(M30, M31, M32, M33);
                default:
                    throw new ArgumentOutOfRangeException(nameof(row));
            }
        }

        public Vector4 GetColumn(int column)
        {
            switch (column)
            {
                case 0:
                    return new Vector4(M00, M10, M20, M30);
                case 1:
                    return new Vector4(M01, M11, M21, M31);
                case 2:
                    return new Vector4(M02, M12, M22, M32);
                case 3:
                    return new Vector4(M03, M13, M23, M33);
                default:
                    throw new ArgumentOutOfRangeException(
                        nameof(column));
            }
        }
    }
}