AlbumsBackend.php

<?php

declare(strict_types=1);

/**
 * @copyright Copyright (c) 2022 Varun Patil <radialapps@gmail.com>
 * @author Varun Patil <radialapps@gmail.com>
 * @license AGPL-3.0-or-later
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

namespace OCA\Memories\ClustersBackend;

use OCA\Memories\Db\AlbumsQuery;
use OCA\Memories\Db\SQL;
use OCA\Memories\Db\TimelineQuery;
use OCA\Memories\Exceptions;
use OCA\Memories\Util;
use OCP\DB\QueryBuilder\IQueryBuilder;
use OCP\IRequest;

class AlbumsBackend extends Backend
{
    public function __construct(
        protected AlbumsQuery $albumsQuery,
        protected IRequest $request,
        protected TimelineQuery $tq,
    ) {}

    public static function appName(): string
    {
        return 'Albums';
    }

    public static function clusterType(): string
    {
        return 'albums';
    }

    public function isEnabled(): bool
    {
        return Util::albumsIsEnabled();
    }

    public function clusterName(string $name): string
    {
        return explode('/', $name)[1];
    }

    public function transformDayQuery(IQueryBuilder &$query, bool $aggregate): void
    {
        $albumId = (string) $this->request->getParam(self::clusterType());

        // Get album object
        $album = $this->albumsQuery->getIfAllowed($this->getUID(), $albumId);

        // Check permission
        if (null === $album) {
            throw new \Exception("Album {$albumId} not found");
        }

        // WHERE these are items with this album
        $query->innerJoin('m', 'photos_albums_files', 'paf', $query->expr()->andX(
            $query->expr()->eq('paf.album_id', $query->createNamedParameter($album['album_id'])),
            $query->expr()->eq('paf.file_id', 'm.fileid'),
        ));

        // Since we joined to the album, otherwise this is unsafe
        $this->tq->allowEmptyRoot();
    }

    public function getClustersInternal(int $fileid = 0): array
    {
        // Materialize the query
        $materialize = static fn (IQueryBuilder &$query): IQueryBuilder => SQL::materialize($query, 'pa');

        // Function to add etag
        $etag = static fn (string $name): \Closure => static function (IQueryBuilder &$query) use ($name): void {
            TimelineQuery::selectEtag($query, "pa.{$name}", "{$name}_etag");
        };

        // Add cover from self user
        $ownCover = static function (IQueryBuilder &$query): void {
            Covers::selectCover(
                query: $query,
                type: self::clusterType(),
                clusterTable: 'pa',
                clusterTableId: 'album_id',
                objectTable: 'photos_albums_files',
                objectTableObjectId: 'file_id',
                objectTableClusterId: 'album_id',
                validateFilecache: false,
            );
        };

        // Transformation for shared albums
        $shareCover = static function (IQueryBuilder &$query): void {
            Covers::selectCover(
                query: $query,
                type: self::clusterType(),
                clusterTable: 'pa',
                clusterTableId: 'album_id',
                objectTable: 'photos_albums_files',
                objectTableObjectId: 'file_id',
                objectTableClusterId: 'album_id',
                validateFilecache: false,
                field: 'cover_owner',
                user: 'pa.user',
            );
        };

        // Transformation to select the shared flag
        $sharedFlag = function (IQueryBuilder &$query): void {
            $this->albumsQuery->transformSharedFlag($query);
        };

        // Transformation to get the date range of photos in the album
        $dateRange = function (IQueryBuilder &$query): void {
            $this->albumsQuery->transformDateRange($query);
        };

        // Transformations to apply to own albums
        $transformOwned = [
            $sharedFlag,
            $dateRange,
            $materialize, $ownCover,
            $materialize, $etag('last_added_photo'), $etag('cover'),
        ];

        // Transformations to apply to shared albums
        $transformShared = [
            $dateRange,
            $materialize, $ownCover, $shareCover,
            $materialize, $etag('last_added_photo'), $etag('cover'), $etag('cover_owner'),
        ];

        // Get personal and shared albums
        $list = array_merge(
            $this->albumsQuery->getList(Util::getUID(), false, $fileid, $transformOwned),
            $this->albumsQuery->getList(Util::getUID(), true, $fileid, $transformShared),
        );

        // Remove elements with duplicate album_id
        $seenIds = [];
        $list = array_filter($list, static function ($item) use (&$seenIds) {
            if (\in_array($item['album_id'], $seenIds, true)) {
                return false;
            }
            $seenIds[] = $item['album_id'];

            return true;
        });

        $userManager = \OC::$server->get(\OCP\IUserManager::class);

        array_walk($list, static function (array &$item) use ($userManager) {
            // Fall back cover to cover_owner if available
            if (empty($item['cover']) && !empty($item['cover_owner'] ?? null)) {
                $item['cover'] = $item['cover_owner'];
                $item['cover_etag'] = $item['cover_owner_etag'];
            }
            unset($item['cover_owner'], $item['cover_owner_etag']);

            // Add display names for users
            $user = $userManager->get($item['user']);
            $item['user_display'] = $user ? $user->getDisplayName() : null;
        });

        // Convert $list to sequential array
        return array_values($list);
    }

    public static function getClusterId(array $cluster): int|string
    {
        return $cluster['cluster_id'];
    }

    public function getPhotos(string $name, ?int $limit = null, ?int $fileid = null): array
    {
        // Get album
        $album = $this->albumsQuery->getIfAllowed($this->getUID(), $name);
        if (null === $album) {
            throw Exceptions::NotFound("album {$name}");
        }

        // Get files
        $id = (int) $album['album_id'];

        return $this->albumsQuery->getAlbumPhotos($id, $limit, $fileid);
    }

    public function sortPhotosForPreview(array &$photos): void
    {
        // Do nothing, the photos are already sorted by added date desc
    }

    public function getClusterIdFrom(array $photo): int
    {
        return (int) $photo['album_id'];
    }

    private function getUID(): string
    {
        return Util::isLoggedIn() ? Util::getUID() : '---';
    }
}