using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static System.Math;

namespace Geo
{
    [Serializable]
    public class Vector3d : IVector
    {
        double[] arr;
        int n = 3;

        public double this[int i] { get => arr[i]; set => arr[i] = value; }
        public double Vx { get => arr[0]; set => arr[0] = value; }
        public double Vy { get => arr[1]; set => arr[1] = value; }
        public double Vz { get => arr[2]; set => arr[2] = value; }
        public double Norma { get => Sqrt(Pow(Vx, 2) + Pow(Vy, 2) + Pow(Vz, 2)); }
        public double[] Unit { get => new double[] { Vx / Norma, Vy / Norma, Vz / Norma }; }
        public int N { get => n; }

        public Vector3d()
        {
            arr = new double[3];
        }

        public Vector3d(Vector3d source)
        {
            arr = new double[3];
            arr = (double[])source.arr.Clone();
        }

        public Vector3d(Point3d source)
        {
            arr = new double[3];
            arr[0] = source.X; arr[1] = source.Y; arr[2] = source.Z;
        }

        public Vector3d(Vector source)
        {
            arr = new double[3];
            if (source.N >= 3)
            {
                arr[0] = source[0]; arr[1] = source[1]; arr[2] = source[2];
            }
        }

        public Vector3d(Vector2d source)
        {
            arr = new double[3];
            arr[0] = source.Vx;
            arr[1] = source.Vy;
            arr[2] = 0;
        }

        public Vector3d(double[] source)
        {
            arr = new double[3];
            if (source.Length >= 3)
            {
                arr[0] = source[0]; arr[1] = source[1]; arr[2] = source[2];
            }  
        }

        public static double CosAngleBetVectors(Vector3d v1, Vector3d v2)
        {
            return (v1.Vx * v2.Vx + v1.Vy * v2.Vy + v1.Vz * v2.Vz) / (Sqrt(v1.Vx* v1.Vx + v1.Vy* v1.Vy+ v1.Vz * v1.Vz) * Sqrt(v2.Vx * v2.Vx + v2.Vy * v2.Vy + v2.Vz * v2.Vz));
        }

        public double[] ToArray()
        {
            return arr;
        }

        public Vector2d ToVector2d()
        {
            return new Vector2d() { Vx = Vx, Vy = Vy };
        }

        public Vector ToVector()
        {
            return new Vector(arr);
        }

        public static Vector3d operator ^(Vector3d v1, Vector3d v2)
        {
            return new Vector3d
            {
                Vx = v1.Vy * v2.Vz - v1.Vz * v2.Vy,
                Vy = v1.Vz * v2.Vx - v1.Vx * v2.Vz,
                Vz = v1.Vx * v2.Vy - v1.Vy * v2.Vx
            };
        }

        public static Vector3d operator *(Vector3d v1, Vector3d v2)
        {
            return new Vector3d
            {
                Vx = v1.Vx * v2.Vx,
                Vy = v1.Vy * v2.Vy,
                Vz = v1.Vz * v2.Vz
            };
        }
    }
}