<?php

session_start();

require_once 'Google/Client.php';
require_once 'Google/Service/Gmail.php';

// Replace this with your Google Client ID
$client_id     = 'apps.googleusercontent.com';
$client_secret = 'Your Google Client Secret';
$redirect_uri  = 'http://ctrlq.org/'; // Change this

$client = new Google_Client();
$client->setClientId($client_id);
$client->setClientSecret($client_secret);
$client->setRedirectUri($redirect_uri);

// We only need permissions to compose and send emails
$client->addScope("https://www.googleapis.com/auth/gmail.compose");
$service = new Google_Service_Gmail($client);

// Redirect the URL after OAuth
if (isset($_GET['code'])) {
  $client->authenticate($_GET['code']);
  $_SESSION['access_token'] = $client->getAccessToken();
  $redirect = 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'];
  header('Location: ' . filter_var($redirect, FILTER_SANITIZE_URL));
}

// If Access Toket is not set, show the OAuth URL
if (isset($_SESSION['access_token']) && $_SESSION['access_token']) {
  $client->setAccessToken($_SESSION['access_token']);
} else {
  $authUrl = $client->createAuthUrl();
}

if ($client->getAccessToken() && isset($_POST['message'])) {

  $_SESSION['access_token'] = $client->getAccessToken();

  // Prepare the message in message/rfc822
  try {

      // The message needs to be encoded in Base64URL
      $mime = rtrim(strtr(base64_encode($_POST["message"]), '+/', '-_'), '=');
      $msg = new Google_Service_Gmail_Message();
      $msg->setRaw($mime);
      $service->users_messages->send("me", $msg);

  } catch (Exception $e) {
      print($e->getMessage());
      unset($_SESSION['access_token']);
  }

} ?>

<? if ( isset ( $authUrl ) ) { ?>
<a href="<?= $authUrl; ?>"><img src="google.png" title="Sign-in with Google" /></a>
<? } else { ?>
<form method="POST" action="">
  <textarea name="message" required></textarea>
  <input type="email" required name="to">
  <input type="text"  required name="subject">
  <a href="#" onclick="document.forms.htmlmail.submit();return false;">Send Mail</a>
</form>
<? } ?>