package scsusers

import (
	"bytes"
	"crypto/rand"
	"database/sql"
	"encoding/base32"
	"fmt"
	"log"
	"net/smtp"
	"strings"
	"time"
)

func RecoverByUsername(username string) {
	var email string
	username = strings.ToLower(username)

	q := fmt.Sprintf("select email from %s_auth where username = ?", c.TablePrefix)
	err := c.db.Get(&email, q, username)
	if err != sql.ErrNoRows {
		recoverycode := randBytes(16)
		qq := fmt.Sprintf("update %s_auth set recoverycode=?, recoverytime=NOW() where username = ?", c.TablePrefix)
		_, err := c.db.Exec(qq, recoverycode, username)
		if err == nil {
			SendRecoveryEmail(email, username, string(recoverycode))
		}
	}
}

func RecoverByEmail(e string) {
	var username, email string
	q := fmt.Sprintf("select username from %s_auth where email = ?", c.TablePrefix)
	err := c.db.Get(&username, q, e)
	if err != sql.ErrNoRows {
		recoverycode := randBytes(16)
		qq := fmt.Sprintf("update %s_auth set recoverycode=?, recoverytime=NOW() where username = ?", c.TablePrefix)
		_, err := c.db.Exec(qq, recoverycode, username)
		if err == nil {
			SendRecoveryEmail(email, username, string(recoverycode))
		}
	}
}

func randBytes(n int) []byte {
	randomBytes := make([]byte, 32)
	_, err := rand.Read(randomBytes)
	if err != nil {
		panic(err)
	}
	return []byte(base32.StdEncoding.EncodeToString(randomBytes)[:n])
}

func SendRegistrationEmail(recipient, username, password string) bool {
	data := struct {
		SiteName  string
		FromEmail string
		UserName  string
		Pass      string
	}{
		SiteName:  c.SiteName,
		FromEmail: c.FromEmail,
		UserName:  username,
		Pass:      password,
	}
	var body bytes.Buffer
	err := c.Templates.Registration.Execute(&body, data)
	if err != nil {
		log.Printf("scsusers.sendRegistrationEmail: Registration template failed to execute: %v returned %s\n", data, err.Error())
		return false
	}
	subject := fmt.Sprintf("Welcome to %s", c.SiteName)
	err = SendMail(c.SMTPServer, c.FromEmail, subject, body.String(), recipient)
	if err != nil {
		log.Printf("scsusers.SendRegistrationEmail: Error sending mail to %s: %s\n", recipient, err.Error())
		return false
	}
	return true
}

func SendAlertEmail(username, recipient, message string) bool {
	data := struct {
		SiteName  string
		FromEmail string
		UserName  string
		Activity  string
	}{
		SiteName:  c.SiteName,
		FromEmail: c.FromEmail,
		UserName:  username,
		Activity:  message,
	}
	var body bytes.Buffer
	err := c.Templates.Alert.Execute(&body, data)
	if err != nil {
		log.Printf("scsusers.sendAlertEmail: Alert template failed to execute: %v returned %s\n", data, err.Error())
		return false
	}

	subject := fmt.Sprintf("new Activity Notification on %s", c.SiteName)
	err = SendMail(c.SMTPServer, c.FromEmail, subject, body.String(), recipient)
	if err != nil {
		log.Printf("scsusers.sendAlertEmail: Error sending mail to %s: %s\n", recipient, err.Error())
		return false
	}
	return true
}

func SendRecoveryEmail(recipient, username, code string) bool {
	data := struct {
		SiteName     string
		FromEmail    string
		UserName     string
		RecoveryCode string
	}{
		SiteName:     c.SiteName,
		FromEmail:    c.FromEmail,
		UserName:     username,
		RecoveryCode: code,
	}
	var body bytes.Buffer
	err := c.Templates.Registration.Execute(&body, data)
	if err != nil {
		log.Printf("scsusers.sendRecoveryEmail: Recovery template failed to execute: %v returned %s\n", data, err.Error())
		return false
	}
	subject := fmt.Sprintf("Account recovery at %s", c.SiteName)
	err = SendMail(c.SMTPServer, c.FromEmail, subject, body.String(), recipient)
	if err != nil {
		log.Printf("scsusers.sendRecoveryEmail: Error sending mail to %s: %s\n", recipient, err.Error())
		return false
	}
	return true
}

func Send2faEmail(recipient, fullname, code string) error {
	data := struct {
		SiteName     string
		FromEmail    string
		FullName     string
		Code string
	}{
		SiteName:     c.SiteName,
		FromEmail:    c.FromEmail,
		FullName:     fullname,
		Code: code,
	}
	var body bytes.Buffer
	err := c.Templates.TwoFA.Execute(&body, data)
	if err != nil {
		return fmt.Errorf("scsusers.send2fayEmail: 2fa template failed to execute: %v returned %s", data, err.Error())
	}
	subject := fmt.Sprintf("Two Factor Authentication Code at %s", c.SiteName)
	err = SendMail(c.SMTPServer, c.FromEmail, subject, body.String(), recipient)
	return err
}

func SendMail(addr, from, subject, body string, to string) error {
	r := strings.NewReplacer("\r\n", "", "\r", "", "\n", "", "%0a", "", "%0d", "")

	c, err := smtp.Dial(addr)
	if err != nil {
		return err
	}
	defer c.Close()
	if err = c.Mail(r.Replace(from)); err != nil {
		return err
	}
	to = r.Replace(to)
	if err = c.Rcpt(to); err != nil {
		return err
	}

	w, err := c.Data()
	if err != nil {
		return err
	}

	date := time.Now()
	msg := "To: " + to + "\r\n" +
		"From: " + from + "\r\n" +
		"Subject: " + subject + "\r\n" +
		"Content-Type: text/html; charset=\"UTF-8\"\r\n" +
		"Date: " + date.Format(time.RFC1123Z) + "\r\n" +
		"\r\n" + body

	_, err = w.Write([]byte(msg))
	if err != nil {
		return err
	}
	err = w.Close()
	if err != nil {
		return err
	}
	return c.Quit()
}