package mailer

import (
	domain "RenewCMS/internal/domain/mail"
	"RenewCMS/internal/infrastructure/config"
	"bytes"
	"embed"
	"html/template"
	"log"

	"gopkg.in/gomail.v2"
)

type MailRepository struct {
	smtp config.SmtpSettings
}

//go:embed templates/*
var mailTemplateFiles embed.FS

func NewMailRepository(smtp config.SmtpSettings) *MailRepository {
	return &MailRepository{smtp: smtp}
}

const defaultSubject = "RenewCMS | Action required"

type subjectProvider interface {
	Subject() string
}

func subjectFor(templateName string, data any) string {
	if provider, ok := data.(subjectProvider); ok {
		return provider.Subject()
	}
	switch templateName {
	case "verification":
		return "Verify your RenewCMS account"
	case "password-reset":
		return "Reset your RenewCMS password"
	}
	return defaultSubject
}

func (m MailRepository) Render(templateName string, data any) (string, string, error) {
	subject := subjectFor(templateName, data)

	tmpl, err := template.ParseFS(mailTemplateFiles, "templates/"+templateName+".html")
	if err != nil {
		log.Println("error when template.ParseFS:", err)
		return subject, "", err
	}

	var body bytes.Buffer
	if err := tmpl.Execute(&body, data); err != nil {
		log.Println("error when tmpl.Execute:", err)
		return subject, "", err
	}

	return subject, body.String(), nil
}

func (m MailRepository) Send(receiverAddress string, templateName string, data any) error {
	login := m.smtp.Login
	sender := m.smtp.Sender
	password := m.smtp.Password
	smtpHost := m.smtp.Host
	smtpPort := m.smtp.Port

	d := gomail.NewDialer(smtpHost, smtpPort, login, password)

	subject, body, err := m.Render(templateName, data)
	if err != nil {
		return err
	}

	msg := gomail.NewMessage()
	msg.SetHeaders(map[string][]string{
		"From":    {"RenewCMS <" + sender + ">"},
		"To":      {receiverAddress},
		"Subject": {subject},
	})
	msg.SetBody("text/html", body)

	if err := d.DialAndSend(msg); err != nil {
		log.Println("error when sending email:", err)
		return err
	}

	return nil
}

var _ domain.Repository = &MailRepository{}