package smtpclient

import (
	"bytes"
	"embed"
	"fmt"
	"html/template"
	"strings"

	"git.keks.cloud/kekskurse/miniauth/pkg/utils"
	"github.com/go-gomail/gomail"
	"github.com/rs/zerolog"
)

type SMTPConfig struct {
	Server   string `env:"SERVER"`
	Port     int    `env:"PORT, default=587"`
	Username string `env:"USERNAME"`
	Password string `env:"PASSWORD"`
	From     string `env:"FROM"`
}

type SMTPClient struct {
	log    zerolog.Logger
	config SMTPConfig
}

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

func (s SMTPClient) SendMail(templateName string, to string, data any) error {
	log := s.log.With().Str("templateName", templateName).Str("to", to).Any("data", data).Str("func", "SendMail").Logger()
	if to == "error@error.error" {
		return ErrCantSendMailToErrorMail
	}

	if s.config.Server == "test" {
		return nil
	}

	subject, txt, html, err := s.renderTemplates(templateName, data)
	if err != nil {
		return utils.WrapError(ErrCantRenderTemplate, err, log)
	}

	m := gomail.NewMessage()
	m.SetHeader("From", s.config.From)
	m.SetHeader("To", to)
	m.SetHeader("Subject", subject)
	m.SetBody("text/plain", txt)
	m.AddAlternative("text/html", html)

	d := gomail.NewDialer(s.config.Server, s.config.Port, s.config.Username, s.config.Password)

	err = d.DialAndSend(m)
	if err != nil {
		return utils.WrapError(ErrCantSendMail, err, log)
	}

	return nil
}

func NewDummySMTPClient() SMTPClient {
	s := SMTPClient{}
	s.config.Server = "test"
	return s
}

func (s SMTPClient) renderTemplates(templateName string, data any) (string, string, string, error) {
	subject, err := s.renderFile(fmt.Sprintf("%v.subject", templateName), data)
	if err != nil {
		return "", "", "", err
	}
	txt, err := s.renderFile(fmt.Sprintf("%v.txt", templateName), data)
	if err != nil {
		return "", "", "", err
	}

	html, err := s.renderFile(fmt.Sprintf("%v.html", templateName), data)
	if err != nil {
		return "", "", "", err
	}

	return subject, txt, html, nil
}

func (s SMTPClient) renderFile(filename string, data any) (string, error) {
	tmpl, err := template.ParseFS(templates, "template/"+filename)
	if err != nil {
		return "", err
	}

	var buf bytes.Buffer
	err = tmpl.Execute(&buf, data)
	if err != nil {
		return "", err
	}

	renderedString := buf.String()
	return strings.Trim(renderedString, "\n"), nil
}