package tools

import (
	"context"
	"io"
	"log"
	"strings"

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

type VusartSct struct {
	portName string
	baudRate uint
}

func (vu *VusartSct) Initial(portName string, baudRate uint) {

	vu.portName = portName
	vu.baudRate = baudRate

}

func (vu *VusartSct) open() (io.ReadWriteCloser, error) {
	options := serial.OpenOptions{
		PortName:        vu.portName,
		BaudRate:        vu.baudRate,
		DataBits:        8,
		StopBits:        1,
		ParityMode:      serial.PARITY_NONE,
		MinimumReadSize: 4,
	}

	return serial.Open(options)
}

func (vu *VusartSct) Write(buf string) error {
	// 写入数据
	port, err := vu.open()
	if err != nil {
		return err
	}
	defer port.Close()

	_, err = port.Write([]byte(buf))
	return err
}

func (vu *VusartSct) Read(ctx context.Context) (chan string, error) {
	ch := make(chan string, 128)

	go func(ctx context.Context) {
		port, err := vu.open()
		if err != nil {
			log.Println(err)
			goto label_return
		}
		defer port.Close()

		for {
			select {
			case <-ctx.Done():
				goto label_return
			default:
				// 读取数据
				buf := make([]byte, 1024)
				n, err := port.Read(buf)
				if err != nil {
					log.Println(err)
					break
				}
				ch <- string(buf[:n])
			}
		}
	label_return:
		close(ch)
	}(ctx)

	return ch, nil
}

func (vu *VusartSct) ReadSplit(ctx context.Context, sep string) (chan string, error) {

	strs, err := vu.Read(ctx)
	if err != nil {
		return nil, err
	}

	ch := make(chan string)

	go func() {
		var tmpStr string = ""
		for str := range strs {
			if len(str) > 0 {
				tmpStr += str
			}
			for {
				crlf := strings.Index(tmpStr, sep)
				if crlf >= 0 {
					ch <- tmpStr[:crlf]

					if len(tmpStr) > crlf+2 {
						tmpStr = tmpStr[crlf+2:]
					} else {
						tmpStr = ""
					}
				} else {
					break
				}
			}
		}
		close(ch)
	}()

	return ch, nil
}