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

namespace YKMoon.Math
{
    /// <summary>
    /// Custom int mask like unity layoutmask.
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public struct IntMask
    {
        private int m_Mask;

        public static implicit operator int(IntMask mask)
        {
            return mask.m_Mask;
        }
        public static implicit operator IntMask(int intVal)
        {
            IntMask mask;
            mask.m_Mask = intVal;
            return mask;
        }

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

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

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

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

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