package main

import (
	"fmt"
	"log"
	"net/smtp"
	"os"
	"strconv"

	"github.com/emersion/go-imap"
	"github.com/emersion/go-imap/client"
	"github.com/joho/godotenv"
)

func main() {
	var username string
	var password string
	var fetchServer string
	var sendServer string

	err := godotenv.Load()
	if err != nil {
		log.Fatalf("unable to load env: %s", err)
	}

	username = os.Getenv("USERNAME")
	password = os.Getenv("PASSWORD")
	fetchServer = os.Getenv("IMAP_SERVER")
	sendServer = os.Getenv("SMTP_SERVER")
	port := 993

	if len(username) == 0 || len(password) == 0 || len(fetchServer) == 0 || len(sendServer) == 0 {
		log.Fatal("missing configuration variables")
	}

	imapClient, err := connectToServer(username, password, fetchServer, port)
	if err != nil {
		log.Fatal(err)
	}
	defer imapClient.Logout()

	if err := fetchEmails(imapClient); err != nil {
		log.Fatal(err)
	}

	/*
	   to := "harry@culpan.org"
	   subject := "Test Email"
	   body := "This is a test email sent from a Go-based email client."

	   	if err := sendEmail(username, password, sendServer, 587, to, subject, body); err != nil {
	   		log.Fatal(err)
	   	}
	*/
}

func fetchEmails(imapClient *client.Client) error {
	// Select the mailbox you want to read
	_, err := imapClient.Select("INBOX", false)
	if err != nil {
		return err
	}

	criteria := imap.NewSearchCriteria()
	criteria.WithoutFlags = []string{"\\Seen"}
	uids, err := imapClient.Search(criteria)
	if err != nil {
		log.Printf("Search error: %s\n", err)
	}

	if len(uids) > 0 {
		// Define the range of emails to fetch
		seqSet := new(imap.SeqSet)
		seqSet.AddNum(uids...)

		// Fetch the required message attributes
		messages := make(chan *imap.Message, 10)
		section := &imap.BodySectionName{}
		items := []imap.FetchItem{section.FetchItem(), imap.FetchEnvelope}

		go func() {
			if err := imapClient.Fetch(seqSet, items, messages); err != nil {
				log.Fatal("Fetch error: " + err.Error())
			}
		}()

		for msg := range messages {
			fmt.Println("Subject:", msg.Envelope.Subject)
		}
	}

	return nil
}

func sendEmail(username, password, server string, port int, to, subject, body string) error {
	auth := smtp.PlainAuth("", username, password, server)

	msg := "From: " + username + "\r\n" +
		"To: " + to + "\r\n" +
		"Subject: " + subject + "\r\n" +
		"\r\n" +
		body

	err := smtp.SendMail(server+":"+strconv.Itoa(port), auth, username, []string{to}, []byte(msg))
	if err != nil {
		return err
	}

	return nil
}

func connectToServer(username, password, server string, port int) (*client.Client, error) {
	c, err := client.DialTLS(fmt.Sprintf("%s:%d", server, port), nil)
	if err != nil {
		return nil, err
	}

	if err := c.Login(username, password); err != nil {
		return nil, err
	}

	return c, nil
}