package email

import (
	"crypto/tls"
	"errors"
	"strings"
	"time"

	"github.com/spf13/viper"
	gomail "gopkg.in/gomail.v2"
)

type Client struct {
	dialer *gomail.Dialer
	from   string
}

func NewSMTPClient() (*Client, error) {
	host := viper.GetString("email.host")
	port := viper.GetInt("email.port")
	user := viper.GetString("email.username")
	pass := viper.GetString("email.password")
	from := viper.GetString("email.from")

	security := strings.ToLower(viper.GetString("email.security"))
	insecure := viper.GetBool("email.insecure_skip_verify")

	if host == "" || port == 0 || user == "" || pass == "" {
		return nil, errors.New("SMTP config not set")
	}

	dialer := gomail.NewDialer(host, port, user, pass)

	dialer.TLSConfig = &tls.Config{
		ServerName:         host,
		InsecureSkipVerify: insecure,
	}

	switch security {
	case "ssl":
		dialer.SSL = true
	case "starttls":
		dialer.SSL = false
	case "plain", "":
		dialer.SSL = false
		dialer.TLSConfig = nil
	default:
		return nil, errors.New("unknown smtp security mode: " + security)
	}

	return &Client{
		dialer: dialer,
		from:   from,
	}, nil
}

func (c *Client) Send(to, subject, html string) (string, error) {
	m := gomail.NewMessage()

	m.SetHeader("From", c.from)
	m.SetHeader("To", to)
	m.SetHeader("Subject", subject)
	m.SetBody("text/html", html)

	if err := c.dialer.DialAndSend(m); err != nil {
		return "", err
	}

	return time.Now().Format(time.RFC3339Nano), nil
}