using Modbus.Net;
using Modbus.Net.Modbus;
using MultipleMachinesJobScheduler = Modbus.Net.MultipleMachinesJobScheduler<Modbus.Net.IMachineMethodDatas, string, double>;

namespace SampleModbusRtuServer.Service
{
    /// <summary>
    /// Modbus RTU 服务器后台工作服务
    /// 监听串口，响应 Modbus RTU 读写请求
    /// </summary>
    public class Worker : BackgroundService
    {
        private readonly ILogger<Worker> _logger;

        // 线圈数据数组（0X 区，10000 点）
        private bool[] zerox = new bool[10000];
        
        // 保持寄存器数据数组（4X 区，20000 字节=10000 个寄存器）
        private byte[] threex = new byte[20000];

        // 数据更新标志
        private bool _isUpdate = false;

        // 最后更新时间
        private DateTime _updateTime = DateTime.MinValue;

        public Worker(ILogger<Worker> logger)
        {
            _logger = logger;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            // 创建 Modbus RTU 协议接收器，监听 COM2 端口，从站地址 1
            ModbusRtuProtocolReceiver receiver = new ModbusRtuProtocolReceiver("COM2", 1);
            
            // 设置数据处理回调
            receiver.DataProcess = receiveContent =>
            {
                byte[]? returnBytes = null;
                // 读取内容缓冲区（每个寄存器 2 字节）
                var readContent = new byte[receiveContent.Count * 2];
                // 写入内容
                var values = receiveContent.WriteContent;
                // 值字典（未使用）
                var valueDic = new Dictionary<string, double>();
                // Redis 值字典（未使用）
                var redisValues = new Dictionary<string, ReturnUnit<double>>();
                
                // 处理写操作
                if (values != null)
                {
                    try
                    {
                        // 如果处于更新模式且距离上次更新超过 9.5 秒，记录日志
                        if (_isUpdate && DateTime.Now - _updateTime > TimeSpan.FromSeconds(9.5))
                        {
                            _logger.LogDebug($"receive content { String.Concat(receiveContent.WriteContent.Select(p => " " + p.ToString("X2")))}");
                        }
                    }
                    catch (Exception ex)
                    {
                        _logger.LogError(ex, "Error");
                    }
                    
                    // 根据功能码处理不同的写操作
                    switch (receiveContent.FunctionCode)
                    {
                        case (byte)ModbusProtocolFunctionCode.WriteMultiRegister:
                            {
                                // 写多个寄存器（功能码 16）
                                // 将写入的数据复制到保持寄存器数组
                                Array.Copy(receiveContent.WriteContent, 0, threex, receiveContent.StartAddress * 2, receiveContent.WriteContent.Length);
                                // 生成响应帧
                                returnBytes = new WriteDataModbusProtocol().Format(receiveContent.SlaveAddress, receiveContent.FunctionCode, receiveContent.StartAddress, receiveContent.Count);
                                _isUpdate = true;
                                break;
                            }
                        case (byte)ModbusProtocolFunctionCode.WriteSingleCoil:
                            {
                                // 写单个线圈（功能码 5）
                                // 255=ON, 0=OFF
                                if (receiveContent.WriteContent[0] == 255)
                                {
                                    zerox[receiveContent.StartAddress] = true;
                                }
                                else
                                {
                                    zerox[receiveContent.StartAddress] = false;
                                }
                                // 生成响应帧
                                returnBytes = new WriteDataModbusProtocol().Format(receiveContent.SlaveAddress, receiveContent.FunctionCode, receiveContent.StartAddress, receiveContent.WriteContent);
                                _isUpdate = true;
                                break;
                            }
                        case (byte)ModbusProtocolFunctionCode.WriteMultiCoil:
                            {
                                // 写多个线圈（功能码 15）
                                var pos = 0;
                                List<bool> bitList = new List<bool>();
                                // 将字节数组转换为位列表
                                for (int i = 0; i < receiveContent.WriteByteCount; i++)
                                {
                                    var bitArray = BigEndianLsbValueHelper.Instance.GetBits(receiveContent.WriteContent, ref pos);
                                    bitList.AddRange(bitArray.ToList());
                                }
                                // 将位列表复制到线圈数组
                                Array.Copy(bitList.ToArray(), 0, zerox, receiveContent.StartAddress, bitList.Count);
                                // 生成响应帧
                                returnBytes = new WriteDataModbusProtocol().Format(receiveContent.SlaveAddress, receiveContent.FunctionCode, receiveContent.StartAddress, receiveContent.Count);
                                _isUpdate = true;
                                break;
                            }
                        case (byte)ModbusProtocolFunctionCode.WriteSingleRegister:
                            {
                                // 写单个寄存器（功能码 6）
                                // 将写入的数据复制到保持寄存器数组
                                Array.Copy(receiveContent.WriteContent, 0, threex, receiveContent.StartAddress * 2, receiveContent.Count * 2);
                                // 生成响应帧
                                returnBytes = new WriteDataModbusProtocol().Format(receiveContent.SlaveAddress, receiveContent.FunctionCode, receiveContent.StartAddress, receiveContent.Count);
                                _isUpdate = true;
                                break;
                            }
                    }
                }
                // 处理读操作
                else
                {
                    switch (receiveContent.FunctionCode)
                    {
                        case (byte)ModbusProtocolFunctionCode.ReadHoldRegister:
                            {
                                // 读保持寄存器（功能码 3）
                                // 从保持寄存器数组复制数据到读取缓冲区
                                Array.Copy(threex, receiveContent.StartAddress, readContent, 0, readContent.Length);
                                // 生成响应帧
                                returnBytes = new ReadDataModbusProtocol().Format(receiveContent.SlaveAddress, receiveContent.FunctionCode, (byte)receiveContent.Count, readContent);
                                break;
                            }
                        case (byte)ModbusProtocolFunctionCode.ReadCoilStatus:
                            {
                                // 读线圈状态（功能码 1）
                                // 计算需要读取的位数
                                var bitCount = receiveContent.WriteByteCount * 8;
                                var boolContent = new bool[bitCount];
                                // 从线圈数组复制数据
                                Array.Copy(zerox, receiveContent.StartAddress, boolContent, 0, bitCount);
                                
                                // 将位数组打包为字节数组
                                var byteList = new List<byte>();
                                for (int i = 0; i < receiveContent.WriteByteCount; i++)
                                {
                                    byte result = 0;
                                    for (int j = i; j < i + 8; j++)
                                    {
                                        // 将布尔值转换为位（1 或 0）
                                        byte bit = boolContent[j] ? (byte)1 : (byte)0;

                                        // 使用位移运算将位合并为字节
                                        result = (byte)((result << 1) | bit);
                                    }
                                    byteList.Add(result);
                                }
                                readContent = byteList.ToArray();
                                // 生成响应帧
                                returnBytes = new ReadDataModbusProtocol().Format(receiveContent.SlaveAddress, receiveContent.FunctionCode, receiveContent.WriteByteCount, readContent);
                                break;
                            }
                    }
                }
                
                // 返回响应帧，如果无法处理则返回 null
                if (returnBytes != null) return returnBytes;
                else return null;
            };
           
            // 连接接收器（打开串口）
            await receiver.ConnectAsync();
        }

        public override Task StopAsync(CancellationToken cancellationToken)
        {
            // 停止所有作业调度
            return Task.Run(() => MultipleMachinesJobScheduler.CancelJob());
        }
    }
}