package system

import (
	"bytes"
	"errors"
	"fmt"
	"hash/fnv"
	"net"
	"os/exec"
	"strings"
)

// this package serves to add in wrappers for system commands to get hwinfo from the board
// this package does not actually use the hwinfo command, but rather gathers hardware info from a variety of commands

// command for model :
// lshw -C system 2>/dev/null | head -n 1
// command for ip && mac address :
// ifconfig eth0 | awk '/inet |ether / {print $2}'

// can combine and dump into file using
// lshw -C system 2>/dev/null | head -n 1 > hwinfo.txt && ifconfig eth0 | awk '/inet |ether / {print $2}' >> hwinfo.txt
// *** will just replace info in file everytime

func GetId(eth string) (int, error) {
	maccmd := fmt.Sprintf("ifconfig %v | awk '/ether / {print $2}'", eth)
	var stderr bytes.Buffer
	var out bytes.Buffer
	cmd := exec.Command("bash", "-c", maccmd)
	cmd.Stdout = &out
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		return 0, err
	}
	hash := fnv.New32a()
	hash.Write(out.Bytes())
	id := hash.Sum32()
	return int(id), nil
}

func GetIp(eth string) (string, error) {
	ipcmd := fmt.Sprintf("ifconfig %v | awk '/inet / {print $2}'", eth)
	var stderr bytes.Buffer
	var out bytes.Buffer
	cmd := exec.Command("bash", "-c", ipcmd)
	cmd.Stdout = &out
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		return "", err
	}
	ip := strings.Trim(out.String(), " \n")
	return ip, nil

}

func GetPort() (int, error) {
	if addr, err := net.ResolveTCPAddr("tcp", ":0"); err != nil {
		return 0, err
	} else if lis, err := net.ListenTCP("tcp", addr); err != nil {
		return 0, err
	} else {
		defer lis.Close()
		return lis.Addr().(*net.TCPAddr).Port, nil
	}
}

func GetBus() (int, error) {
	bus := map[string]int{"raspberrypi": 1, "beaglebone": 2}
	devname := "lshw -C system 2>/dev/null | head -n 1"
	var stderr, out bytes.Buffer
	cmd := exec.Command("bash", "-c", devname)
	cmd.Stdout = &out
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		return 0, err
	}
	b := out.String()
	b = strings.Trim(b, " \n")
	if bs, ok := bus[b]; !ok {
		return 0, errors.New(fmt.Sprintf("No bus for dev %v", b))
	} else {
		return bs, nil
	}
}

func GetModel() (string, error) {
	devname := "lshw -C system 2>/dev/null | head -n 1"
	var stderr, out bytes.Buffer
	cmd := exec.Command("bash", "-c", devname)
	cmd.Stdout = &out
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		return "", err
	}
	b := out.String()
	b = strings.Trim(b, " \n")
	return b, nil
}

func Get() error {
	// responsible for filling out struct
	//bus := map[string]int{"raspberrypi":1,"beaglebone":2} // eventually will replace this with a config file

	ipcmd := "ifconfig eth0 | awk '/inet / {print $2}'"
	maccmd := "ifconfig eth0 | awk '/ether / {print $2}'"
	devcmd := "lshw -C system 2>/dev/null | head -n 1"

	res := [3]bytes.Buffer{}
	var stderr bytes.Buffer
	cmds := []string{ipcmd, maccmd, devcmd}
	for i, c := range cmds {
		cmd := exec.Command("bash", "-c", c)
		cmd.Stdout = &res[i]
		cmd.Stderr = &stderr
		err := cmd.Run()
		if err != nil {
			return err
		}
	}
	// formatting
	ip := res[0].String()
	ip = strings.Trim(ip, " \n")

	hash := fnv.New32a()
	hash.Write(res[1].Bytes())

	b := res[2].String()
	b = strings.Trim(b, " \n")
	return nil
}