using System;
using System.Collections.Generic;

namespace ZeroLevel.Services.Async.Internal
{
	internal struct BitArray32 : IEquatable<BitArray32>
	{
		public const int BitCapacity = sizeof(uint) * 8;
		public static readonly BitArray32 Empty = new BitArray32();

		private readonly uint _value;

		public BitArray32(uint value)
		{
			_value = value;
		}

		public BitArray32 WithBitSet(int index) => new BitArray32(_value | GetMask(index));

		public bool IsBitSet(int index)
		{
			uint mask = GetMask(index);
			return (_value & mask) == mask;
		}

		public override string ToString()
		{
			char[] chars = new char[BitCapacity];

			for (int index = 0; index < BitCapacity; index++)
			{
				char bitChar = IsBitSet(index) ? '1' : '0';
				chars[index] = bitChar;
			}

			return new string(chars);
		}

		private static uint GetMask(int index) => (1u << index);

		#region IEquatable<BitArray32>

		public override int GetHashCode() => EqualityComparer<uint>.Default.GetHashCode(_value);
		public bool Equals(BitArray32 other) => EqualityComparer<uint>.Default.Equals(_value, other._value);
		public override bool Equals(object obj) => obj is BitArray32 && Equals((BitArray32)obj);

		public static bool operator ==(BitArray32 x, BitArray32 y) => x.Equals(y);
		public static bool operator !=(BitArray32 x, BitArray32 y) => !x.Equals(y);

		#endregion
	}
}