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

namespace YKMoon.Math
{
    /// <summary>
    /// Custom long mask like unity layoutmask.
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public struct LongMask
    {
        public const int MAX_LAYER = 64;
        private long m_Mask;

        public static implicit operator long(LongMask mask)
        {
            return mask.m_Mask;
        }
        public static implicit operator LongMask(long intVal)
        {
            LongMask mask;
            mask.m_Mask = intVal;
            return mask;
        }

        public long value {
            get {
                return this.m_Mask;
            }
            set {
                this.m_Mask = value;
            }
        }

        public void Set(int pos, bool value)
        {
            if(value) {
                m_Mask |= ((long)1) << pos;
            } else {
                m_Mask &= ~(((long)1) << pos);
            }
        }

        public static long GetMask(params int[] values)
        {
            if(values == null) {
                throw new ArgumentNullException("values");
            }
            long num = 0;
            for(int i = 0; i < values.Length; i++) {
                int intval = values[i];
                if(intval != -1) {
                    num |= ((long)1) << intval;
                }
            }
            return num;
        }
        public static long GetMask(List<int> values)
        {
            if(values == null) {
                throw new ArgumentNullException("values");
            }
            long num = 0;
            for(int i = 0; i < values.Count; i++) {
                int intval = values[i];
                if(intval != -1) {
                    num |= ((long)1) << intval;
                }
            }
            return num;
        }

        public bool Contains(int layer)
        {
            return ((m_Mask & ((long)1 << layer)) > 0);
        }

        public List<int> Split()
        {
            List<int> result = new List<int>();

            for(int i=0; i< MAX_LAYER; i++) {
                if (Contains(i)) {
                    result.Add(i);
                }
            }
            return result;
        }
    }
}