package main

import (
	"fmt"
	"github.com/tarm/serial"
	"log"
	"math/rand"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func RandomEUI64() string {
	r := rand.New(rand.NewSource(time.Now().UnixNano()))

	var letter = []rune("ABCDEF0123456789")

	b := make([]rune, 16+7)
	for i := range b {
		if (i+1)%3 == 0 {
			b[i] = '-'
		} else {
			b[i] = letter[r.Intn(len(letter))]
		}
	}
	return string(b)
}

func sendCommand(p *serial.Port, command string, waitForOk bool) string {
	fmt.Print(command)
	var status string = ""
	p.Flush()
	_, err := p.Write([]byte(command))
	if err != nil {
		log.Fatal(err)
	}
	buf := make([]byte, 32)
	var loop int = 1
	if waitForOk {
		loop = 10
	}

	time.Sleep(200 * time.Millisecond)

	for i := 0; i < loop; i++ {
		// ignoring error as EOF raises error on Linux
		n, _ := p.Read(buf)
		if n > 0 {
			status = string(buf[:n])
			fmt.Print(status)
			if strings.Contains(status, "OK") || strings.Contains(status, "?") {
				break
			}
		}
	}
	return status
}

func main() {
	if len(os.Args) != 3 {
		fmt.Println("usage: " + filepath.Base(os.Args[0]) + " <SerialDevice> <DevEUI>")
		os.Exit(1)
	}

	serialdev := os.Args[1]
	deveui := os.Args[2]

	c := &serial.Config{Name: serialdev, Baud: 115200, ReadTimeout: time.Second * 1}
	s, err := serial.OpenPort(c)
	if err != nil {
		log.Fatal("Problem mit Serial Interface")
	}

	sendCommand(s, "system configure syseui "+RandomEUI64()+"\n", true)
	sendCommand(s, "system configure platformguid 53ca094b-b888-465e-aa0e-e3064ec56d21\n", true)
	sendCommand(s, "system configure operatingflags 0\n", true)
	sendCommand(s, "lorawan configure deveui "+deveui+"\n", true)
	sendCommand(s, "lorawan configure appeui "+deveui+"\n", true)
	sendCommand(s, "lorawan configure appkey "+deveui+"-"+deveui+"\n", true)
	sendCommand(s, "lorawan configure join 1\n", true)
}