using System;
using WIDESEAWCS_S7Simulator.Core.Interfaces;

namespace WIDESEAWCS_S7Simulator.Core.Memory
{
    /// <summary>
    /// M区（位存储器/Merker）实现
    /// </summary>
    public class MRegion : MemoryRegion, IMemoryRegion
    {
        /// <summary>
        /// 区域类型
        /// </summary>
        public override string RegionType => "M";

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

        /// <summary>
        /// 读取位
        /// </summary>
        /// <param name="byteOffset">字节偏移</param>
        /// <param name="bitOffset">位偏移（0-7）</param>
        /// <returns>位值</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), "字节偏移超出范围");

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

        /// <summary>
        /// 写入位
        /// </summary>
        /// <param name="byteOffset">字节偏移</param>
        /// <param name="bitOffset">位偏移（0-7）</param>
        /// <param name="value">位值</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), "字节偏移超出范围");

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

        /// <summary>
        /// 读取字（Word，2字节）
        /// </summary>
        public ushort ReadWord(ushort byteOffset)
        {
            var data = Read(byteOffset, 2);
            return (ushort)((data[0] << 8) | data[1]);
        }

        /// <summary>
        /// 写入字（Word，2字节）
        /// </summary>
        public void WriteWord(ushort byteOffset, ushort value)
        {
            var data = new byte[] { (byte)(value >> 8), (byte)(value & 0xFF) };
            Write(byteOffset, data);
        }

        /// <summary>
        /// 读取双字（DWord，4字节）
        /// </summary>
        public uint ReadDWord(ushort byteOffset)
        {
            var data = Read(byteOffset, 4);
            return (uint)((data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3]);
        }

        /// <summary>
        /// 写入双字（DWord，4字节）
        /// </summary>
        public void WriteDWord(ushort byteOffset, uint value)
        {
            var data = new byte[] {
                (byte)(value >> 24),
                (byte)((value >> 16) & 0xFF),
                (byte)((value >> 8) & 0xFF),
                (byte)(value & 0xFF)
            };
            Write(byteOffset, data);
        }

        /// <summary>
        /// 读取整数（Int，2字节，有符号）
        /// </summary>
        public short ReadInt(ushort byteOffset)
        {
            return (short)ReadWord(byteOffset);
        }

        /// <summary>
        /// 写入整数（Int，2字节，有符号）
        /// </summary>
        public void WriteInt(ushort byteOffset, short value)
        {
            WriteWord(byteOffset, (ushort)value);
        }

        /// <summary>
        /// 读取双整数（DInt，4字节，有符号）
        /// </summary>
        public int ReadDInt(ushort byteOffset)
        {
            return (int)ReadDWord(byteOffset);
        }

        /// <summary>
        /// 写入双整数（DInt，4字节，有符号）
        /// </summary>
        public void WriteDInt(ushort byteOffset, int value)
        {
            WriteDWord(byteOffset, (uint)value);
        }

        /// <summary>
        /// 读取浮点数（Real，4字节）
        /// </summary>
        public float ReadReal(ushort byteOffset)
        {
            var bytes = Read(byteOffset, 4);
            return BitConverter.ToSingle(bytes, 0);
        }

        /// <summary>
        /// 写入浮点数（Real，4字节）
        /// </summary>
        public void WriteReal(ushort byteOffset, float value)
        {
            var bytes = BitConverter.GetBytes(value);
            Write(byteOffset, bytes);
        }
    }
}