package mailer

import (
	"bytes"
	"fmt"
	"net/smtp"
	"text/template"

	"github.com/jordan-wright/email"
)

const (
	smtpAuthAddress   = "smtp.gmail.com"
	smtpServerAddress = "smtp.gmail.com:587"
)

type GmailSender struct {
	name              string
	fromEmailAddress  string
	fromEmailPassword string
}

func NewGmailSender(name, fromEmailAddress, fromEmailPassword string) MailSender {
	return &GmailSender{
		name:              name,
		fromEmailAddress:  fromEmailAddress,
		fromEmailPassword: fromEmailPassword,
	}
}

func (s *GmailSender) Send(
	mailTemplate string,
	vars any,
	to []string,
	cc []string,
	bcc []string,
	attachFiles []string,
) error {
	e := email.NewEmail()
	e.From = fmt.Sprintf("%s <%s>", s.name, s.fromEmailAddress)
	e.To = to
	e.Cc = cc
	e.Bcc = bcc

	tmpl, err := template.ParseFS(FS, "templates/"+mailTemplate)
	if err != nil {
		return fmt.Errorf("failed to parse email template: %w", err)
	}

	subject := new(bytes.Buffer)
	if err := tmpl.ExecuteTemplate(subject, "subject", vars); err != nil {
		return fmt.Errorf("failed to execute subject template: %w", err)
	}

	body := new(bytes.Buffer)
	if err := tmpl.ExecuteTemplate(body, "body", vars); err != nil {
		return fmt.Errorf("failed to execute body template: %w", err)
	}

	e.Subject = subject.String()
	e.HTML = body.Bytes()

	for _, file := range attachFiles {
		_, err := e.AttachFile(file)
		if err != nil {
			return fmt.Errorf("failed to attach file %s: %w", file, err)
		}
	}

	smtpAuth := smtp.PlainAuth("", s.fromEmailAddress, s.fromEmailPassword, smtpAuthAddress)
	return e.Send(smtpServerAddress, smtpAuth)
}