package main

import (
	"fmt"
	"os"
	"os/exec"
	"runtime"
	"strings"
)

func GetOsInfo() string {
	var osInfo string
	osInfoByte, err := os.ReadFile("/etc/os-release")
	if err != nil {
		fmt.Println(err)
	}
	osInfoStr := string(osInfoByte)
	for _, envStr := range strings.Split(osInfoStr, "\n") {
		envStrArr := strings.Split(envStr, "=")
		if envStrArr[0] == "PRETTY_NAME" {
			osInfo = envStrArr[1]
			break
		}
	}
	return osInfo
}

func GetUser() string {
	var user string
	for _, envStr := range os.Environ() {
		envStrArr := strings.Split(envStr, "=")
		if envStrArr[0] == "USER" {
			user = envStrArr[1]
			break
		}
	}
	return user
}

func GetShell() string {
	var shell string
	for _, envStr := range os.Environ() {
		envStrArr := strings.Split(envStr, "=")
		if envStrArr[0] == "SHELL" {
			shell = envStrArr[1]
			break
		}
	}
	return shell
}

func GetKernelVersion() string {
	var out strings.Builder
	cmd := exec.Command("uname", "-r")
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		fmt.Println(err)
	}
	return out.String()
}

func GetHostname() string {
	hostnameByte, err := os.ReadFile("/etc/hostname")
	if err != nil {
		fmt.Println(err)
	}
	hostname := string(hostnameByte)
	return strings.Fields(hostname)[0]
}

func GetUptime() string {
	hostnameByte, err := os.ReadFile("/proc/uptime")
	if err != nil {
		fmt.Println(err)
	}
	hostname := string(hostnameByte)
	return strings.Fields(hostname)[0]
}
func GetAnsiColor() string {
	var ansiColor string
	ansiColorByte, err := os.ReadFile("/etc/os-release")
	if err != nil {
		fmt.Println(err)
	}
	ansiColorStr := string(ansiColorByte)
	for _, envStr := range strings.Split(ansiColorStr, "\n") {
		envStrArr := strings.Split(envStr, "=")
		if envStrArr[0] == "ANSI_COLOR" {
			ansiColor = strings.Split(envStrArr[1], "\"")[1]
			break
		}
	}
	return ansiColor
}

func GenBreaker(user string, hostname string) string {
	var breaker strings.Builder
	for i := 0; i < (len(user) + len(hostname) + 1); i++ {
		fmt.Fprintf(&breaker, "=")
	}
	return breaker.String()
}

func main() {
	if runtime.GOOS != "linux" {
		fmt.Println("OS not support")
		os.Exit(0)
	}

	user := GetUser()
	hostname := GetHostname()
	ansiColor := GetAnsiColor()

	fmt.Printf("%v@%v\n", user, hostname)
	fmt.Printf("\033[%vm%v\033[0m\n", ansiColor, GenBreaker(user, hostname))
	fmt.Printf("\033[%vmOS\033[0m:\t%v\n", ansiColor, GetOsInfo())
	fmt.Printf("\033[%vmKERNEL\033[0m:\t%v", ansiColor, GetKernelVersion())
	fmt.Printf("\033[%vmSHELL\033[0m:\t%v\n", ansiColor, GetShell())
	fmt.Printf("\033[%vmUPTIME\033[0m:\t%v\n", ansiColor, GetUptime())
}