Potencially working.

api/modem/at/at.go

@@ -0,0 +1,154 @@
+package at
+
+import (
+	"fmt"
+	"log"
+	"strings"
+	"time"
+
+	"go.bug.st/serial"
+)
+
+// Some constants
+const (
+	ReadTimeout  = time.Second
+	InputBufSize = 128
+)
+
+// Command types
+type CmdType byte
+
+// Command types base on request/answer semantic:
+const (
+	CmdTest CmdType = iota
+	// AT\r\n
+	// OK
+	CmdCheck
+	// AT+<CMD>\r\n
+	// OK
+	CmdGet
+	// AT+<CMD>\r\n
+	// +<CMD>: <ANS>
+	CmdQuestion
+	// AT+<CMD>?\r\n
+	// +<CMD>: <ANS>
+)
+
+type atPort struct {
+	baudrate int
+	portName string
+	port     serial.Port
+	inputBuf []byte
+}
+
+type Port interface {
+	Connect() error
+	Disconnect() error
+	Request(cmdType CmdType, cmd string) (string, error)
+	GetName() string
+	IsConnected() bool
+	GetSerialPort() serial.Port // For extra need
+}
+
+func New(portName string, baudrate int) Port {
+	return &atPort{
+		portName: portName,
+		baudrate: baudrate,
+		inputBuf: make([]byte, InputBufSize),
+	}
+}
+
+func (p *atPort) Connect() error {
+	log.Println("Connecting to", p.portName, "...")
+	s, err := serial.Open(p.portName, &serial.Mode{BaudRate: p.baudrate})
+	if err != nil {
+		return fmt.Errorf("open port: %w", err)
+	}
+	// s.Close() There is no open f
+	// s.Open()
+	p.port = s
+	p.port.SetReadTimeout(ReadTimeout)
+	p.port.ResetInputBuffer()
+	p.port.ResetOutputBuffer()
+	return nil
+}
+
+func (p *atPort) Disconnect() error {
+	defer func() {
+		p.port = nil
+	}()
+	if err := p.port.Close(); err != nil {
+		return fmt.Errorf("close port: %w", err)
+	}
+	return nil
+}
+
+// Low level write/read function
+func (p *atPort) makeReq(msg string) (string, error) {
+	// Write
+	p.port.ResetInputBuffer()
+	log.Println("Write...") // DEBUG
+	if written, err := p.port.Write([]byte(msg)); err != nil {
+		return "", fmt.Errorf("serial port write: %w", err)
+	} else {
+		log.Println("Written:", written) // DEBUG
+	}
+	// Read
+	log.Println("Read...") // DEBUG
+	readLen, err := p.port.Read(p.inputBuf)
+	if err != nil {
+		return "", fmt.Errorf("port read: %w", err)
+	}
+
+	log.Println("Read: ", readLen, string(p.inputBuf[:readLen])) // DEBUG
+	return string(p.inputBuf[:readLen]), nil
+}
+
+func (p *atPort) Request(cmdType CmdType, cmd string) (string, error) {
+	msg := "AT"
+	// Make command
+	// By default it just will be AT check cmd
+	switch cmdType {
+	case CmdGet, CmdCheck:
+		msg += cmd
+	case CmdQuestion:
+		msg += cmd + "?"
+	}
+	msg += "\r\n"
+	rawResp, err := p.makeReq(msg)
+	log.Println("Got")
+	if err != nil {
+		return "", fmt.Errorf("make at request: %w", err)
+	}
+	if len(rawResp) == 0 {
+		return "", fmt.Errorf("read nothing")
+	}
+	resp := strings.Split(rawResp, "\n")
+	switch cmdType {
+	case CmdTest, CmdCheck:
+		// Check and test cmds do not suppose anything but OK
+		if len(resp[1]) >= 2 && resp[1][:2] == "OK" {
+			return "", nil
+		}
+		return "", fmt.Errorf("connection lost")
+	case CmdGet, CmdQuestion:
+		checkL := len(cmd) + 1
+		if len(resp[1]) >= checkL && resp[1][:checkL] != "+"+cmd {
+			return "", fmt.Errorf("connetion lost")
+		}
+		return strings.Split(resp[1], ":")[1], nil
+	}
+	return "", fmt.Errorf("undefined command type")
+}
+
+func (p *atPort) GetName() string {
+	return p.portName
+}
+
+func (p *atPort) IsConnected() bool {
+	return p.port != nil
+}
+
+func (p *atPort) GetSerialPort() serial.Port {
+	return p.port
+}