package main

import (
	_ "embed"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/smtp"
	"os"
	"strings"
	"time"

	"github.com/joho/godotenv"
)

//go:embed .env
var env string
var envvar map[string]string

var Error *log.Logger

func init() {
	log.SetFlags(log.Lmicroseconds | log.Ldate)
	// logFile, err := os.Create("main.log")
	// if err != nil {
	// 	log.Printf("Error creating log file: %v", err)
	// 	os.Exit(1)
	// }
	logger := io.MultiWriter(os.Stdout)
	log.SetOutput(logger)

	Error = log.New(io.MultiWriter(os.Stderr, os.Stdout),
		fmt.Sprintf("%sERROR:%s ", "\033[0;101m", "\033[0m"),
		log.Lmicroseconds|log.Lshortfile)
}

var oldIP, newIP string

const REMOTE_URL = "http://141.147.53.95:5000"
const IP_FILE = "ip"

var ipFile *os.File
var lastMailed time.Time

func main() {
	var err error
	envvar, err = godotenv.Parse(strings.NewReader(env))
	if err != nil {
		Error.Fatalf("Error parsing .env file: %v", err)
		os.Exit(1)
	}
	ipFile, err = os.OpenFile(IP_FILE, os.O_RDWR|os.O_CREATE, 0644)
	if err != nil {
		Error.Fatalf("Error opening IP file: %v", err)
		os.Exit(1)
	}

	fileIP, err := io.ReadAll(ipFile)
	if err != nil {
		Error.Fatalf("Error reading IP file: %v", err)
		os.Exit(1)
	}
	oldIP = string(fileIP)

	for {
		newIP = checkIP()
		if newIP != oldIP {
			err := doNotify()
			if err != nil {
				Error.Fatalf("Error sending email: %v", err)
			}

			oldIP = newIP
			ipFile.Truncate(0)
			ipFile.Seek(0, 0)
			_, err = ipFile.WriteString(newIP)
			if err != nil {
				Error.Fatalf("Error writing to IP file: %v", err)
			}
		} else {
			log.Println("ips same")
		}
		time.Sleep(1 * time.Second)
	}
}

func checkIP() string {
	http.NewRequest("GET", REMOTE_URL, nil)
	resp, err := http.Get(REMOTE_URL)
	if err != nil {
		Error.Fatalf("Error getting IP: %v", err)
		return ""
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		Error.Fatalf("Error reading response body: %v", err)
		return ""
	}

	return string(body)
}

func doNotify() error {
	if time.Since(lastMailed) < 30*time.Minute {
		return nil
	}

	smtpHost, ok := envvar["SMTP_HOST"]
	if !ok {
		return fmt.Errorf("error getting env var SMTP_HOST")
	}
	smtpPort, ok := envvar["SMTP_PORT"]
	if !ok {
		return fmt.Errorf("error getting env var SMTP_PORT")
	}
	smtpUser, ok := envvar["SMTP_USER"]
	if !ok {
		return fmt.Errorf("error getting env var SMTP_USER")
	}
	smtpPass, ok := envvar["SMTP_PASSWORD"]
	if !ok {
		return fmt.Errorf("error getting env var SMTP_PASSWORD")
	}

	from := "admin@quack-lab.dev"
	to := []string{"david.majdandzic@hotmail.com"}
	subject := "IP Changed!"
	body := fmt.Sprintf("Old IP: %s; New IP: %s", oldIP, newIP)

	msg := []byte(fmt.Sprintf("Subject: %s\nFrom: %s\nTo: %s\n\n%s", subject, from, strings.Join(to, ","), body))

	auth := smtp.PlainAuth("", smtpUser, smtpPass, smtpHost)
	err := smtp.SendMail(smtpHost+":"+smtpPort, auth, from, to, msg)
	if err != nil {
		return err
	}
	log.Println("Sent mail")
	lastMailed = time.Now()
	return nil
}