using System;
using WIDESEAWCS_S7Simulator.Core.Interfaces;

namespace WIDESEAWCS_S7Simulator.Core.Memory
{
    /// <summary>
    /// I区（输入区/Input）实现
    /// 用于模拟西门子S7 PLC的输入过程映像区
    /// </summary>
    public class IRegion : MemoryRegion, IMemoryRegion
    {
        /// <summary>
        /// 区域类型
        /// </summary>
        public override string RegionType => "I";

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="size">区域大小（字节）</param>
        public IRegion(int size) : base(size)
        {
        }

        /// <summary>
        /// 读取位
        /// </summary>
        /// <param name="byteOffset">字节偏移量</param>
        /// <param name="bitOffset">位偏移量（0-7）</param>
        /// <returns>位状态（true/false）</returns>
        public bool ReadBit(ushort byteOffset, byte bitOffset)
        {
            if (bitOffset > 7)
                throw new ArgumentOutOfRangeException(nameof(bitOffset), "位偏移必须在0-7之间");

            _lock.EnterReadLock();
            try
            {
                if (byteOffset >= Size)
                    throw new ArgumentOutOfRangeException(nameof(byteOffset), "字节偏移超出I区范围");

                return (_memory[byteOffset] & (1 << bitOffset)) != 0;
            }
            finally
            {
                _lock.ExitReadLock();
            }
        }

        /// <summary>
        /// 写入位
        /// </summary>
        /// <param name="byteOffset">字节偏移量</param>
        /// <param name="bitOffset">位偏移量（0-7）</param>
        /// <param name="value">位值（true/false）</param>
        public void WriteBit(ushort byteOffset, byte bitOffset, bool value)
        {
            if (bitOffset > 7)
                throw new ArgumentOutOfRangeException(nameof(bitOffset), "位偏移必须在0-7之间");

            _lock.EnterWriteLock();
            try
            {
                if (byteOffset >= Size)
                    throw new ArgumentOutOfRangeException(nameof(byteOffset), "字节偏移超出I区范围");

                if (value)
                    _memory[byteOffset] |= (byte)(1 << bitOffset);
                else
                    _memory[byteOffset] &= (byte)~(1 << bitOffset);
            }
            finally
            {
                _lock.ExitWriteLock();
            }
        }
    }
}