// Package mail - SMTP email sender.
package mail

import (
	"crypto/tls"
	"fmt"
	"net/smtp"
)

type SMTPConfig struct {
	Host     string // e.g., "smtp.gmail.com"
	Port     int    // e.g., 587 for TLS, 465 for SSL
	Username string // SMTP auth username
	Password string // SMTP auth password
	From     string // From address for emails
}

type SMTPSender struct {
	config SMTPConfig
}

func NewSMTPSender(config SMTPConfig) *SMTPSender {
	return &SMTPSender{config: config}
}

func (s *SMTPSender) Send(email, subject, body string) error {

	message := fmt.Sprintf("From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n%s",
		s.config.From, email, subject, body)

	addr := fmt.Sprintf("%s:%d", s.config.Host, s.config.Port)
	auth := smtp.PlainAuth("", s.config.Username, s.config.Password, s.config.Host)

	// Use TLS
	tlsConfig := &tls.Config{
		ServerName: s.config.Host,
	}

	conn, err := tls.Dial("tcp", addr, tlsConfig)
	if err != nil {
		return fmt.Errorf("dial: %w", err)
	}
	defer conn.Close()

	client, err := smtp.NewClient(conn, s.config.Host)
	if err != nil {
		return fmt.Errorf("create client: %w", err)
	}
	defer client.Quit()

	if err := client.Auth(auth); err != nil {
		return fmt.Errorf("auth: %w", err)
	}

	if err := client.Mail(s.config.From); err != nil {
		return fmt.Errorf("mail from: %w", err)
	}

	if err := client.Rcpt(email); err != nil {
		return fmt.Errorf("rcpt to: %w", err)
	}

	w, err := client.Data()
	if err != nil {
		return fmt.Errorf("data: %w", err)
	}

	_, err = w.Write([]byte(message))
	if err != nil {
		return fmt.Errorf("write: %w", err)
	}

	if err := w.Close(); err != nil {
		return fmt.Errorf("close: %w", err)
	}

	return nil
}