// Copyright or © or Copr. happyDNS (2020)
//
// contact@happydomain.org
//
// This software is a computer program whose purpose is to provide a modern
// interface to interact with DNS systems.
//
// This software is governed by the CeCILL license under French law and abiding
// by the rules of distribution of free software.  You can use, modify and/or
// redistribute the software under the terms of the CeCILL license as
// circulated by CEA, CNRS and INRIA at the following URL
// "http://www.cecill.info".
//
// As a counterpart to the access to the source code and rights to copy, modify
// and redistribute granted by the license, users are provided only with a
// limited warranty and the software's author, the holder of the economic
// rights, and the successive licensors have only limited liability.
//
// In this respect, the user's attention is drawn to the risks associated with
// loading, using, modifying and/or developing or reproducing the software by
// the user in light of its specific status of free software, that may mean
// that it is complicated to manipulate, and that also therefore means that it
// is reserved for developers and experienced professionals having in-depth
// computer knowledge. Users are therefore encouraged to load and test the
// software's suitability as regards their requirements in conditions enabling
// the security of their systems and/or data to be ensured and, more generally,
// to use and operate it in the same conditions as regards security.
//
// The fact that you are presently reading this means that you have had
// knowledge of the CeCILL license and that you accept its terms.

package utils

import (
	"io"
	"os"
	"os/exec"

	gomail "github.com/go-mail/mail"
)

// sendmail contains the path to the sendmail command
const sendmail = "/usr/sbin/sendmail"

// SystemSendmail uses the sendmail command to send message
type SystemSendmail struct{}

func (t *SystemSendmail) Send(from string, to []string, msg io.WriterTo) error {
	cmd := exec.Command(sendmail, "-t")
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	pw, err := cmd.StdinPipe()
	if err != nil {
		return err
	}

	err = cmd.Start()
	if err != nil {
		return err
	}

	if _, err = msg.WriteTo(pw); err != nil {
		return err
	}

	if err = pw.Close(); err != nil {
		return err
	}

	if err = cmd.Wait(); err != nil {
		return err
	}

	return nil
}

// Send sends an e-mail to the given recipients using the sendmail command.
func (t *SystemSendmail) PrepareAndSend(m ...*gomail.Message) (err error) {
	err = gomail.Send(t, m...)
	return
}