using System;
using System.Collections.Generic;

namespace AutoFocusTool.Serial
{
    /// <summary>
    /// 下位机串口协议帧构造 + 校验。完全依据原工程 Commander.cs 实测确证：
    ///   帧: [0]帧头0x5E [1]命令码 [2]序号0x00 [3]整帧长 [4..n-2]辅助码+参数 [n-1]累加和校验
    ///   校验 = 前 n-1 字节逐字节相加(byte溢出截断)放末字节。无独立帧尾。
    ///   电机绝对运动脉冲值: 32位int, 大端写入帧(高字节在前)。
    /// </summary>
    public static class Protocol
    {
        public const byte ST = 0x5E;       // 帧头
        public const byte CMD_MOTOR = 0x05; // 电机控制
        public const byte CMD_IO = 0x09;    // 设IO（含LED）
        public const byte CMD_READ_MOTOR = 0x18; // 读电机位置
        public const byte CMD_SHAKE = 0x01; // 握手
        public const byte CMD_READ_EEPROM = 0x11; // 读EEPROM（回复10字节）

        /// <summary>累加和校验：前 n-1 字节求和写入末字节</summary>
        public static byte[] WithChecksum(byte[] frame)
        {
            byte sum = 0;
            for (int i = 0; i < frame.Length - 1; i++) sum += frame[i];
            frame[frame.Length - 1] = sum;
            return frame;
        }

        /// <summary>校验回复帧（末字节==前面累加和）</summary>
        public static bool CheckChecksum(byte[] frame)
        {
            if (frame == null || frame.Length < 2) return false;
            byte sum = 0;
            for (int i = 0; i < frame.Length - 1; i++) sum += frame[i];
            return frame[frame.Length - 1] == sum;
        }

        /// <summary>
        /// 根据命令码返回下位机回复的固定字节数（依据 Commander.CustomProtocolLength）。
        /// 接收端按这个长度收帧，不靠帧尾。
        /// </summary>
        public static int ReplyLength(byte cmd)
        {
            switch (cmd)
            {
                case 0x01: return 6;   // 握手
                case 0x02: return 6;   // 自检
                case 0x04: return 7;   // 设目标温度
                case 0x05: return 6;   // 电机控制
                case 0x06: return 9;   // 读传感器
                case 0x08: return 9;
                case 0x09: return 6;   // 设IO（LED开关）
                case 0x10: return 7;
                case 0x11: return 10;  // 读EEPROM
                case 0x12: return 6;
                case 0x18: return 10;  // 读电机位置
                case 0x19: return 6;
                case 0x20: return 12;
                default: return 6;
            }
        }

        // ── 握手：5E 01 00 05 00 + 校验 ──
        public static byte[] ShakeHands()
            => WithChecksum(new byte[] { ST, 0x01, 0x00, 0x05, 0x00 });

        // ── 读舱室绑定的相机序列号 CCDSN（读EEPROM，原工程 GetModule）──
        // 5E 11 00 09 00 00 10 04 00 + 校验，回复10字节，[4..7]拼int32
        public static byte[] GetCCDSN()
            => WithChecksum(new byte[] { ST, 0x11, 0x00, 0x09, 0x00, 0x00, 0x10, 0x04, 0x00 });

        // ── 读EEPROM灯光亮度（只读，无写命令）──
        // 5E 11 00 09 00 05 34 04 00 + 校验
        public static byte[] ReadLightBrightness()
            => WithChecksum(new byte[] { ST, 0x11, 0x00, 0x09, 0x00, 0x05, 0x34, 0x04, 0x00 });

        /// <summary>
        /// 读第 wellNum(1-16) 个well的水平电机位置（旋转脉冲，存EEPROM）。
        /// 培养皿16个well圆形布局，转动培养皿让well对准相机。地址表来自原工程 Commander.cs:284。
        /// 命令: 5E 11 00 09 00 04 [地址低] 04 00 + 校验，回复10字节，位置在[4..7]。
        /// </summary>
        public static byte[] ReadWellHorizontalPos(int wellNum)
        {
            // wellNum → EEPROM 地址低字节（确证自源码）
            byte addr;
            switch (wellNum)
            {
                case 1: addr = 0x00; break;
                case 2: addr = 0x50; break;
                case 3: addr = 0x54; break;
                case 4: addr = 0x58; break;
                case 5: addr = 0x5C; break;
                case 6: addr = 0x60; break;
                case 7: addr = 0x64; break;
                case 8: addr = 0x68; break;
                case 9: addr = 0x6C; break;
                case 10: addr = 0x70; break;
                case 11: addr = 0x74; break;
                case 12: addr = 0x78; break;
                case 13: addr = 0x7C; break;
                case 14: addr = 0x80; break;
                case 15: addr = 0x84; break;
                case 16: addr = 0x04; break;
                default: addr = 0x00; break;
            }
            return WithChecksum(new byte[] { ST, 0x11, 0x00, 0x09, 0x00, 0x04, addr, 0x04, 0x00 });
        }

        /// <summary>
        /// 读第 wellNum(1-16) 个well的垂直电机焦准脉冲数（Z对焦零点，存EEPROM）。
        /// 地址表来自原工程 Commander.cs:530。well1=0x08, 步进4, well16=0x44。
        /// </summary>
        public static byte[] ReadWellFocusZero(int wellNum)
        {
            byte addr;
            switch (wellNum)
            {
                case 1: addr = 0x08; break;
                case 2: addr = 0x0C; break;
                case 3: addr = 0x10; break;
                case 4: addr = 0x14; break;
                case 5: addr = 0x18; break;
                case 6: addr = 0x1C; break;
                case 7: addr = 0x20; break;
                case 8: addr = 0x24; break;
                case 9: addr = 0x28; break;
                case 10: addr = 0x2C; break;
                case 11: addr = 0x30; break;
                case 12: addr = 0x34; break;
                case 13: addr = 0x38; break;
                case 14: addr = 0x3C; break;
                case 15: addr = 0x40; break;
                case 16: addr = 0x44; break;
                default: addr = 0x08; break;
            }
            return WithChecksum(new byte[] { ST, 0x11, 0x00, 0x09, 0x00, 0x04, addr, 0x04, 0x00 });
        }

        /// <summary>读垂直电机扫描间隔脉冲（每层Z步距，存EEPROM）。Commander.cs:668。</summary>
        public static byte[] ReadScanStep()
            => WithChecksum(new byte[] { ST, 0x11, 0x00, 0x09, 0x00, 0x04, 0x48, 0x04, 0x00 });

        // ── LED 开/关（固定字节，原工程实测）──
        public static byte[] OpenLED()
            => new byte[] { 0x5E, 0x09, 0x00, 0x07, 0x00, 0x01, 0x6F };
        public static byte[] CloseLED()
            => new byte[] { 0x5E, 0x09, 0x00, 0x07, 0x00, 0x00, 0x6E };

        // ── 读电机位置：5E 18 00 06 [轴] 00 + 校验。轴: 0x01水平 0x02垂直 ──
        public static byte[] ReadHorizontalMotor()
            => WithChecksum(new byte[] { ST, 0x18, 0x00, 0x06, 0x01, 0x00 });
        public static byte[] ReadVerticalMotor()
            => WithChecksum(new byte[] { ST, 0x18, 0x00, 0x06, 0x02, 0x00 });

        // ── 电机复位（固定字节，原工程实测）──
        // 水平复位 5E 05 00 0B 13 00 00 00 0B B8 44
        public static byte[] HorizontalReset()
            => new byte[] { 0x5E, 0x05, 0x00, 0x0B, 0x13, 0x00, 0x00, 0x00, 0x0B, 0xB8, 0x44 };
        // 垂直复位 5E 05 00 0B 23 00 00 00 07 D0 68
        public static byte[] VerticalReset()
            => new byte[] { 0x5E, 0x05, 0x00, 0x0B, 0x23, 0x00, 0x00, 0x00, 0x07, 0xD0, 0x68 };

        // ── 电机绝对运动：11字节帧，辅助码 0x14水平 0x24垂直，脉冲32位大端 ──
        public static byte[] HorizontalAbsolute(int pulse) => MotorAbsolute(0x14, pulse);
        public static byte[] VerticalAbsolute(int pulse) => MotorAbsolute(0x24, pulse);

        // ── 电机相对正/反转：辅助码 水平0x10/0x11，垂直0x20/0x21 ──
        public static byte[] HorizontalForward(int pulse) => MotorAbsolute(0x10, pulse);
        public static byte[] HorizontalBackward(int pulse) => MotorAbsolute(0x11, pulse);
        public static byte[] VerticalForward(int pulse) => MotorAbsolute(0x20, pulse);
        public static byte[] VerticalBackward(int pulse) => MotorAbsolute(0x21, pulse);

        /// <summary>
        /// 构造电机运动帧：5E 05 00 0B [辅助码] [p3 p2 p1 p0 大端] 00 [校验]
        /// </summary>
        private static byte[] MotorAbsolute(byte auxCode, int pulse)
        {
            byte[] p = BitConverter.GetBytes(pulse); // 小端: p[0]低..p[3]高
            var cmd = new List<byte>
            {
                ST, CMD_MOTOR, 0x00, 0x0B, auxCode,
                p[3], p[2], p[1], p[0], // 大端写入：高字节在前
                0x00, // 参数5
                0x00  // 校验占位
            };
            return WithChecksum(cmd.ToArray());
        }

        /// <summary>解析读电机位置回复：字节[4..7]拼 int32（帧内大端）。失败 -1。</summary>
        public static int ParseMotorPosition(byte[] reply)
        {
            if (reply == null || reply.Length < 8) return -1;
            byte[] t = { reply[7], reply[6], reply[5], reply[4] };
            if (!BitConverter.IsLittleEndian) Array.Reverse(t);
            return BitConverter.ToInt32(t, 0);
        }

        /// <summary>解析握手回复：字节[2]即模块号/houseSn。</summary>
        public static int ParseShakeHands(byte[] reply)
        {
            if (reply == null || reply.Length < 3) return -1;
            return reply[2];
        }

        /// <summary>解析读EEPROM回复：字节[4..7]拼 int32（用于 CCDSN / 亮度）。失败 -1。</summary>
        public static int ParseEepromInt(byte[] reply)
        {
            if (reply == null || reply.Length < 8) return -1;
            byte[] t = { reply[4], reply[5], reply[6], reply[7] };
            if (!BitConverter.IsLittleEndian) Array.Reverse(t);
            return BitConverter.ToInt32(t, 0);
        }
    }
}