<?php
/**
 * This example shows how to send via Google's Gmail servers using XOAUTH2 authentication.
 */

//Import PHPMailer classes into the global namespace
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\OAuth;

// Alias the League Google OAuth2 provider class
use League\OAuth2\Client\Provider\Google;

//SMTP needs accurate times, and the PHP time zone MUST be set
//This should be done in your php.ini, but this is how to do it if you don't have access to that
date_default_timezone_set('Etc/UTC');

//Load dependencies from composer
//If this causes an error, run 'composer install'
require '../vendor/autoload.php';

//Create a new PHPMailer instance
$mail = new PHPMailer;

//Tell PHPMailer to use SMTP
$mail->isSMTP();

//Enable SMTP debugging
// 0 = off (for production use)
// 1 = client messages
// 2 = client and server messages
$mail->SMTPDebug = 2;

//Set the hostname of the mail server
$mail->Host = 'smtp.gmail.com';

//Set the SMTP port number - 587 for authenticated TLS, a.k.a. RFC4409 SMTP submission
$mail->Port = 587;

//Set the encryption system to use - ssl (deprecated) or tls
$mail->SMTPSecure = 'tls';

//Whether to use SMTP authentication
$mail->SMTPAuth = true;

//Set AuthType to use XOAUTH2
$mail->AuthType = 'XOAUTH2';

//Fill in authentication details here
$email = 'someone@gmail.com';
$clientId = 'RANDOMCHARS-----duv1n2.apps.googleusercontent.com';
$clientSecret = 'RANDOMCHARS-----lGyjPcRtvP';

//Obtained by configuring and running get_oauth_token.php
//after setting up an app in Google Developer Console.
$refreshToken = 'RANDOMCHARS-----DWxgOvPT003r-yFUV49TQYag7_Aod7y0';

//Create a new OAuth2 provider instance
$provider = new Google([
    'clientId' => $clientId,
    'clientSecret' => $clientSecret
]);

//Pass the OAuth provider instance to PHPMailer
$mail->setOAuth(
    new OAuth([
        'provider' => $provider,
        'clientId' => $clientId,
        'clientSecret' => $clientSecret,
        'refreshToken' => $refreshToken,
        'userName' => $email
    ])
);

//Set who the message is to be sent from
//For gmail, this generally needs to be the same as the user you logged in as
$mail->setFrom($email, 'First Last');

//Set who the message is to be sent to
$mail->addAddress('someone@gmail.com', 'John Doe');

//Set the subject line
$mail->Subject = 'PHPMailer GMail XOAUTH2 SMTP test';

//Read an HTML message body from an external file, convert referenced images to embedded,
//convert HTML into a basic plain-text alternative body
$mail->CharSet = 'utf-8';
$mail->msgHTML(file_get_contents('contentsutf8.html'), dirname(__FILE__));

//Replace the plain text body with one created manually
$mail->AltBody = 'This is a plain-text message body';

//Attach an image file
$mail->addAttachment('images/phpmailer_mini.png');

//send the message, check for errors
if (!$mail->send()) {
    echo "Mailer Error: " . $mail->ErrorInfo;
} else {
    echo "Message sent!";
}