<?php

declare(strict_types=1);

/**
 * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * 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\Mail\IMAP;

use Horde_Imap_Client_Exception;
use OCA\Mail\Account;
use OCA\Mail\Db\Mailbox;
use OCA\Mail\Db\Message;
use OCA\Mail\Db\MessageMapper as DbMapper;
use OCA\Mail\IMAP\MessageMapper as ImapMapper;
use Psr\Log\LoggerInterface;
use function array_key_exists;
use function array_map;
use function array_merge;
use function array_reduce;

class PreviewEnhancer {
	/** @var IMAPClientFactory */
	private $clientFactory;

	/** @var ImapMapper */
	private $imapMapper;

	/** @var DbMapper */
	private $mapper;

	/** @var LoggerInterface */
	private $logger;

	public function __construct(IMAPClientFactory $clientFactory,
								ImapMapper $imapMapper,
								DbMapper $dbMapper,
								LoggerInterface $logger) {
		$this->clientFactory = $clientFactory;
		$this->imapMapper = $imapMapper;
		$this->mapper = $dbMapper;
		$this->logger = $logger;
	}

	/**
	 * @param Message[] $messages
	 *
	 * @return Message[]
	 */
	public function process(Account $account, Mailbox $mailbox, array $messages): array {
		$needAnalyze = array_reduce($messages, function (array $carry, Message $message) {
			if ($message->getStructureAnalyzed()) {
				// Nothing to do
				return $carry;
			}

			return array_merge($carry, [$message->getUid()]);
		}, []);

		if (empty($needAnalyze)) {
			// Nothing to enhance
			return $messages;
		}

		$client = $this->clientFactory->getClient($account);
		try {
			$data = $this->imapMapper->getBodyStructureData(
				$client,
				$mailbox->getName(),
				$needAnalyze
			);
		} catch (Horde_Imap_Client_Exception $e) {
			// Ignore for now, but log
			$this->logger->warning('Could not fetch structure detail data to enhance message previews: ' . $e->getMessage(), [
				'exception' => $e,
			]);

			return $messages;
		} finally {
			$client->logout();
		}

		return $this->mapper->updatePreviewDataBulk(...array_map(function (Message $message) use ($data) {
			if (!array_key_exists($message->getUid(), $data)) {
				// Nothing to do
				return $message;
			}

			/** @var MessageStructureData $structureData */
			$structureData = $data[$message->getUid()];
			$message->setFlagAttachments($structureData->hasAttachments());
			$message->setPreviewText($structureData->getPreviewText());
			$message->setStructureAnalyzed(true);
			$message->setImipMessage($structureData->isImipMessage());

			return $message;
		}, $messages));
	}
}
