package plc

import (
	"encoding/hex"
	"errors"
	"fmt"
	"io"
	"strings"
	"time"

	"github.com/jacobsa/go-serial/serial"
)

/*
定义串口客户端
*/

type SerialClient struct {
	readWriter io.ReadWriteCloser
	OutBuffer  chan string
	PortName   string
	baudRate   uint
}

func NewSerialClient(portName string, baudRate uint) (*SerialClient, error) {
	c := &SerialClient{
		readWriter: nil,
		OutBuffer:  make(chan string, 1024),
		PortName:   portName,
		baudRate:   baudRate,
	}
	r, err := c.open(portName, baudRate)
	if err != nil {
		return nil, err
	}

	c.readWriter = r
	return c, nil
}

func (c *SerialClient) Start() {
	for {
		buf := make([]byte, 1024)
		n, err := c.readWriter.Read(buf)
		if err != nil {
			if err != io.EOF {
				//尝试重新打开
				r, err := c.open(c.PortName, c.baudRate)
				if err != nil {
					time.Sleep(2 * time.Second)
					continue
				}
				c.readWriter = r
			}
			continue
		}

		buf = buf[:n]
		res := hex.EncodeToString(buf)
		if strings.TrimSpace(res) == "" {
			continue
		}
		fmt.Printf("Rx: %s\n", res)
		c.OutBuffer <- res
	}
}

func (c *SerialClient) open(portName string, baudRate uint) (io.ReadWriteCloser, error) {
	options := serial.OpenOptions{
		PortName:        portName,
		BaudRate:        baudRate,
		DataBits:        7,
		StopBits:        1,
		MinimumReadSize: 4,
		ParityMode:      serial.PARITY_EVEN,
	}

	r, err := serial.Open(options)
	if err != nil {
		return nil, err
	}

	c.readWriter = r

	return r, err
}

func (c *SerialClient) Close() {
	if c.readWriter != nil {
		c.readWriter.Close()
	}
}

func (c *SerialClient) SendMsg(data string) (int, error) {
	if c.readWriter == nil {
		return 0, errors.New("serial port is closed")
	}

	bytes, err := hex.DecodeString(data)
	if err != nil {
		return 0, err
	}

	return c.readWriter.Write(bytes)
}

func (c *SerialClient) ReadHoldRegister(addr string) (int, error) {
	if c.readWriter == nil {
		return 0, errors.New("serial port is closed")
	}

	// 三菱fn系列串口协议
	// 02 表示开始 + 30 表示读数据 + 4位地址位 + 02 数据长度 + 03 停止 + 偶校验

	// 先组装数据
	// 读取的地址
	dataBytes := append([]byte{0x30}, []byte(addr)...)

	// 读取的长度
	dataBytes = append(dataBytes, []byte("02")...)

	// 停止
	dataBytes = append(dataBytes, []byte{0x03}...)

	// 计算校验码, 30 + 地址编码 + 数据长度 + 03 , 十六进制结果取后两位.
	var sum uint8
	for _, d := range dataBytes {
		sum += d
	}

	sumStr := fmt.Sprintf("%x", sum)

	fmt.Printf("sumStr: %s\n", sumStr)

	var checkCode string
	if len(sumStr) < 2 {
		checkCode = "0" + sumStr
	} else {
		checkCode = sumStr[len(sumStr)-2:]
	}

	var bytes = []byte{0x02}
	// 添加数据
	bytes = append(bytes, dataBytes...)
	// 添加校验
	bytes = append(bytes, []byte(checkCode)...)

	fmt.Printf("Tx: %X \n", bytes)

	// 写
	if n, err := c.readWriter.Write(bytes); err != nil {
		return n, err
	} else {
		fmt.Printf("Tx:len:%d\n", n)
	}

	// 读
	buf := make([]byte, 1024)
	n, err := c.readWriter.Read(buf)
	if err != nil {
		return n, err
	}

	buf = buf[:n]

	fmt.Printf("Rx: %X\nRx len:%d", buf, n)
	fmt.Printf("value: %d\n", buf[2:6])

	return n, nil
}

func (c *SerialClient) WriteHoldRegister(addr string) (int, error) {
	if c.readWriter == nil {
		return 0, errors.New("serial port is closed")
	}

	// 三菱fn系列串口协议
	// 02 表示开始 + 31 表示写数据 + 4位地址位 + 02 数据长度 + 03 停止 + 偶校验

	// 先组装数据
	// 读取的地址
	dataBytes := append([]byte{0x31}, []byte(addr)...)

	// 读取的长度
	dataBytes = append(dataBytes, []byte("02")...)

	// 停止
	dataBytes = append(dataBytes, []byte{0x03}...)

	// 计算校验码, 30 + 地址编码 + 数据长度 + 03 , 十六进制结果取后两位.
	var sum uint8
	for _, d := range dataBytes {
		sum += d
	}

	sumStr := fmt.Sprintf("%x", sum)

	fmt.Printf("sumStr: %s\n", sumStr)

	var checkCode string
	if len(sumStr) < 2 {
		checkCode = "0" + sumStr
	} else {
		checkCode = sumStr[len(sumStr)-2:]
	}

	var bytes = []byte{0x02}
	// 添加数据
	bytes = append(bytes, dataBytes...)
	// 添加校验
	bytes = append(bytes, []byte(checkCode)...)

	fmt.Printf("Tx: %X \n", bytes)

	// 写
	if n, err := c.readWriter.Write(bytes); err != nil {
		return n, err
	} else {
		fmt.Printf("Tx:len:%d\n", n)
	}

	// 读
	buf := make([]byte, 1024)
	n, err := c.readWriter.Read(buf)
	if err != nil {
		return n, err
	}

	buf = buf[:n]

	fmt.Printf("Rx: %X\nRx len:%d", buf, n)
	fmt.Printf("value: %d\n", buf[2:6])

	return n, nil
}