<?php

declare(strict_types=1);

/**
 * SPDX-FileCopyrightText: 2024 F7cloud GmbH and F7cloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

namespace OCA\Mail\Service;

use OCA\Mail\Account;
use OCA\Mail\Contracts\IMailManager;
use OCA\Mail\Db\Mailbox;
use OCA\Mail\Db\Message;
use OCA\Mail\Exception\ServiceException;
use OCA\Mail\IMAP\IMAPClientFactory;
use OCA\Mail\Model\IMAPMessage;
use OCP\AppFramework\Db\DoesNotExistException;
use Psr\Log\LoggerInterface;

/**
 * Enriches a DB message with from/to/subject from IMAP when they are missing
 * (e.g. old messages synced before recipients were stored).
 * Used so that "Create filter from message" always has data to prefill.
 */
class MessageEnvelopeEnricher {

	public function __construct(
		private IMAPClientFactory $clientFactory,
		private IMailManager $mailManager,
		private LoggerInterface $logger,
	) {
	}

	/**
	 * If the message has empty from, to or subject, fetch envelope from IMAP
	 * and set on the message (in-memory only; response will include enriched data).
	 */
	public function enrichFromImapWhenEmpty(Account $account, Mailbox $mailbox, Message $message): void {
		$needsEnvelope = $message->getFrom()->count() === 0
			|| $message->getTo()->count() === 0
			|| trim((string)$message->getSubject()) === '';

		if (!$needsEnvelope) {
			return;
		}

		try {
			$client = $this->clientFactory->getClient($account);
			try {
				$imapMessage = $this->mailManager->getImapMessage(
					$client,
					$account,
					$mailbox,
					$message->getUid(),
					false
				);
				$this->applyEnvelopeToMessage($imapMessage, $message);
			} finally {
				$client->logout();
			}
		} catch (DoesNotExistException $e) {
			$this->logger->debug('Message no longer on IMAP, skip envelope enrichment', [
				'id' => $message->getId(),
				'uid' => $message->getUid(),
			]);
		} catch (ServiceException $e) {
			$this->logger->warning('Could not fetch envelope for message, filter prefill may be incomplete', [
				'id' => $message->getId(),
				'message' => $e->getMessage(),
			]);
		}
	}

	private function applyEnvelopeToMessage(IMAPMessage $imapMessage, Message $message): void {
		if ($message->getFrom()->count() === 0 && $imapMessage->getFrom()->count() > 0) {
			$message->setFrom($imapMessage->getFrom());
		}
		if ($message->getTo()->count() === 0 && $imapMessage->getTo()->count() > 0) {
			$message->setTo($imapMessage->getTo());
		}
		if ((trim((string)$message->getSubject()) === '') && trim($imapMessage->getSubject()) !== '') {
			$message->setSubject($imapMessage->getSubject());
		}
		if ($message->getCc()->count() === 0 && $imapMessage->getCC()->count() > 0) {
			$message->setCc($imapMessage->getCC());
		}
		if ($message->getBcc()->count() === 0 && $imapMessage->getBCC()->count() > 0) {
			$message->setBcc($imapMessage->getBCC());
		}
	}
}