<?php

    require_once 'php-google-api-client/src/Google_Client.php';
    require_once 'php-google-api-client/src/Google_YouTubeService.php';

    session_start();

    $OAUTH2_CLIENT_ID = 'apps.googleusercontent.com';
    $OAUTH2_CLIENT_SECRET = 'labnol';

    $redirect = "http://ctrlq.org/youtube/playlists/";

    $client = new Google_Client();
    $client->setClientId($OAUTH2_CLIENT_ID);
    $client->setClientSecret($OAUTH2_CLIENT_SECRET);
    $client->setRedirectUri($redirect);

    $youtube = new Google_YoutubeService($client);

    if (isset($_GET['code'])) {

        if (strval($_SESSION['state']) !== strval($_GET['state'])) {
            die('The session state did not match.');
        }

        $client->authenticate();
        $_SESSION['token'] = $client->getAccessToken();
        header('Location: ' . $redirect);

    }

    if (isset($_SESSION['token'])) {
        $client->setAccessToken($_SESSION['token']);
    }

    if ($client->getAccessToken()) {

            try {

                if ( preg_match('/(PL[A-Za-z0-9_-]+)/', $_POST["url"], $match) ) {

                    $plID = $match[0];
                    $pl_options = array ("id" => $plID, "maxResults" => 1);
                    $playlistDetails = $youtube->playlists->listPlaylists("snippet", $pl_options);

                    if ( $playlistDetails["pageInfo"]["totalResults"] == 1 ) {

                        $options = array ("playlistId" => $plID, "maxResults" => 50);
                        $videos = "";

                        do {

                            $playlist = $youtube->playlistItems->listPlaylistItems("snippet", $options);
                            $nextPageToken = $playlist["nextPageToken"];
                            $options["pageToken"] = $nextPageToken;

                            foreach ($playlist["items"] as $playlistItem) {
                                $videos .=  $playlistItem["snippet"]["resourceId"]["videoId"] . "#";
                            }

                        } while ($nextPageToken);

                        $playlistSnippet = new Google_PlaylistSnippet();
                        $playlistSnippet->setTitle($playlistDetails["items"][0]["snippet"]["title"]);

                        $playlistStatus = new Google_PlaylistStatus();
                        $playlistStatus->setPrivacyStatus('private');

                        $youTubePlaylist = new Google_Playlist();
                        $youTubePlaylist->setSnippet($playlistSnippet);
                        $youTubePlaylist->setStatus($playlistStatus);

                        $playlistResponse = $youtube->playlists->insert('snippet,status', $youTubePlaylist, array());

                        $ids = explode ( "#", $videos ) ;

                        for ($i=0; $i<count($ids); $i++) {

                            $resourceId = new Google_ResourceId();
                            $resourceId->setVideoId($ids[$i]);
                            $resourceId->setKind('youtube#video');

                            $playlistItemSnippet = new Google_PlaylistItemSnippet();
                            $playlistItemSnippet->setPlaylistId($playlistResponse['id']);
                            $playlistItemSnippet->setResourceId($resourceId);

                            $playlistItem = new Google_PlaylistItem();
                            $playlistItem->setSnippet($playlistItemSnippet);

                            $playlistItemResponse = $youtube->playlistItems->insert('snippet,contentDetails', $playlistItem, array());

                        }

                    }

                }

            } catch (Google_ServiceException $e) {
                $htmlBody .= sprintf('<p>A service error occurred: <code>%s</code></p>',
                htmlspecialchars($e->getMessage()));
            } catch (Google_Exception $e) {
                $htmlBody .= sprintf('<p>An client error occurred: <code>%s</code></p>',
                htmlspecialchars($e->getMessage()));
            }

        } else {

            $htmlBody = <<<END
    <form method="post">
      <input type="text" name="url" id="url">
      <button type="submit">Copy Playlist to YouTube</button>
    </form>
END;

        }

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

    } else {

        $state = mt_rand();
        $client->setState($state);
        $_SESSION['state'] = $state;

        $authUrl = $client->createAuthUrl();
        $htmlBody = <<<END
                <p><a href="$authUrl">Step 1: Sign-in with YouTube</a></p>
END;
    }
?>

<?= $htmlBody; ?>