using Skeleton.Algebra.FixableObjects;
using Skeleton.Algebra.ScalarFieldStructure;

namespace Skeleton.Algebra;

public partial class CategoryOf<TDimension>
{
    public static partial class OnField<TScalar>
    {
        /// <inheritdoc />
        public class FDiagonalMatrix : FNormalMatrix
        {
            /// <inheritdoc />
            public FDiagonalMatrix()
            {
                U = One;
                D = AsMatrix;
            }

            /// <inheritdoc />
            public FDiagonalMatrix(IEnumerable<FVector> es, bool row = true) : base(es, row) =>
                this.PostConstructionFix();
            
            /// <inheritdoc />
            public FDiagonalMatrix(params TScalar[] es)
            {
                U = One;
                if (es.Length == FDim)
                    for (int i = 1; i <= FDim; i++)
                        this[i, i] = es[i - 1];
                else
                    for (int i = 1; i <= FDim; i++)
                    for (int j = 1; j <= FDim; j++)
                        this[i, j] = es[i - 1 + (j - 1) * FDim];
                this.PostConstructionFix();
            }
            internal override bool NeedFix => base.NeedFix || !Property.IsDiagonal;
            internal override void Fix()
            {
                for (int i = 1; i <= Dim; i++)
                {
                    for (int j = i + 1; j <= Dim; j++)
                    {
                        this[i, j] = StaticAccess<TScalar>.AdditionUnit;
                        this[j, i] = StaticAccess<TScalar>.AdditionUnit;
                    }
                }
                base.Fix();
            }

            /// <summary>
            /// log of the normal matrix
            /// </summary>
            /// <returns></returns>
            public FDiagonalMatrix Log()
            {
                FDiagonalMatrix res = new();
                for (int i = 1; i <= Dim; i++)
                    res[i, i] = FieldStructure.Log(this[i, i]);
                return res;
            }

            /// <summary>
            /// exp of the normal matrix
            /// </summary>
            /// <returns></returns>
            public FDiagonalMatrix Exp()
            {
                FDiagonalMatrix res = new();
                for (int i = 1; i <= Dim; i++)
                    res[i, i] = FieldStructure.Exp(this[i, i]);
                return res;
            }

            internal override void UnitaryFix(FMatrix a) { }

        }
    }
}