<?php

/**
 * @package     MokoSuiteBackup
 * @subpackage  com_mokosuitebackup
 * @author      Moko Consulting <hello@mokoconsulting.tech>
 * @copyright   Copyright (C) 2026 Moko Consulting. All rights reserved.
 * @license     GNU General Public License version 3 or later; see LICENSE
 */

namespace Joomla\Component\MokoSuiteBackup\Administrator\Engine;

defined('_JEXEC') or die;

use Joomla\Component\MokoSuiteBackup\Administrator\Utility\BackupDirectory;

/**
 * Enforces per-profile backup retention — the single retention authority.
 *
 * A profile may cap retained backups by age (retention_days) and/or by
 * number of copies (retention_count). When a profile leaves a rule at 0 the
 * caller-supplied global default is used instead. A backup is pruned when
 * EITHER rule matches: it is older than the effective days OR it falls outside
 * the newest effective count of copies.
 *
 * Pruning a record removes, in this order:
 *   1. the DB row (#__mokosuitebackup_records),
 *   2. the local archive + its .log file, and
 *   3. the archive copy on every enabled remote destination for the profile.
 *
 * The standalone restore script (restore.php) is intentionally NOT deleted
 * from remotes: it is a single, fixed-name file that every backup overwrites,
 * so newer backups still depend on it — removing it while pruning an old
 * archive would break restore for the copies that remain.
 *
 * Because records do not store which destinations they were uploaded to,
 * remote deletion targets the profile's *currently enabled* remotes. Remote
 * deletes are idempotent (an already-absent file counts as success) and
 * best-effort: a failing remote is logged but never blocks local pruning.
 */
final class RetentionManager
{
	/**
	 * Prune old backups for a profile according to its retention settings.
	 *
	 * Called after a backup completes and from the periodic admin-side cleanup.
	 * Only 'complete' and 'warning' records are considered — pending/running/
	 * failed records are never pruned here.
	 *
	 * @param   object  $db           Database driver
	 * @param   object  $profile      Profile row (needs id, retention_days, retention_count)
	 * @param   int     $globalDays   Fallback max age (days) when the profile's is 0
	 * @param   int     $globalCount  Fallback max copies when the profile's is 0
	 *
	 * @return  int  Number of backup records deleted
	 */
	public static function prune(object $db, object $profile, int $globalDays = 0, int $globalCount = 0): int
	{
		$days  = (int) ($profile->retention_days ?? 0);
		$count = (int) ($profile->retention_count ?? 0);

		// A profile value of 0 means "use the global default".
		$days  = $days > 0 ? $days : $globalDays;
		$count = $count > 0 ? $count : $globalCount;

		// No retention configured — nothing to do.
		if ($days <= 0 && $count <= 0) {
			return 0;
		}

		// Newest first, so the index is the copy's position from the top.
		$query = $db->getQuery(true)
			->select($db->quoteName(['id', 'archivename', 'absolute_path', 'backupstart']))
			->from($db->quoteName('#__mokosuitebackup_records'))
			->where($db->quoteName('profile_id') . ' = ' . (int) $profile->id)
			->where($db->quoteName('status') . ' IN (' . implode(',', array_map([$db, 'quote'], ['complete', 'warning'])) . ')')
			->order($db->quoteName('backupstart') . ' DESC');
		$db->setQuery($query);
		$records = $db->loadObjectList() ?: [];

		if (empty($records)) {
			return 0;
		}

		$cutoffTs = $days > 0 ? (time() - ($days * 86400)) : null;
		$remotes  = self::loadEnabledRemotes($db, (int) $profile->id);
		$deleted  = 0;

		foreach ($records as $index => $record) {
			$tooOld    = $cutoffTs !== null && strtotime((string) $record->backupstart) < $cutoffTs;
			$overCount = $count > 0 && $index >= $count;

			// Delete-if-either: prune when age OR count rule is exceeded.
			if (!$tooOld && !$overCount) {
				continue;
			}

			if (self::deleteRecord($db, $record, $remotes)) {
				$deleted++;
			}
		}

		return $deleted;
	}

	/**
	 * Delete backup records whose profile no longer exists.
	 *
	 * Orphans have no owning profile and therefore no remote destinations to
	 * reconcile, so only the local archive/log and DB row are removed.
	 *
	 * @param   object  $db  Database driver
	 *
	 * @return  int  Number of orphaned records deleted
	 */
	public static function pruneOrphans(object $db): int
	{
		$query = $db->getQuery(true)
			->select($db->quoteName(['r.id', 'r.archivename', 'r.absolute_path'], ['id', 'archivename', 'absolute_path']))
			->from($db->quoteName('#__mokosuitebackup_records', 'r'))
			->join(
				'LEFT',
				$db->quoteName('#__mokosuitebackup_profiles', 'p')
				. ' ON ' . $db->quoteName('p.id') . ' = ' . $db->quoteName('r.profile_id')
			)
			->where($db->quoteName('p.id') . ' IS NULL')
			->where($db->quoteName('r.status') . ' IN (' . implode(',', array_map([$db, 'quote'], ['complete', 'warning'])) . ')');
		$db->setQuery($query);
		$orphans = $db->loadObjectList() ?: [];

		$deleted = 0;

		foreach ($orphans as $record) {
			if (self::deleteRecord($db, $record, [])) {
				$deleted++;
			}
		}

		return $deleted;
	}

	/**
	 * Delete a single backup record, its on-disk archive + log file, and the
	 * archive copy on each enabled remote destination.
	 *
	 * The DB row is removed first; the local files are only unlinked if that
	 * succeeds, so a failed delete never orphans the record from its files.
	 * Remote deletion is best-effort and runs regardless.
	 *
	 * @param   object    $db       Database driver
	 * @param   object    $record   Record row (needs id, archivename, absolute_path)
	 * @param   object[]  $remotes  Enabled remote rows (type, params) for the profile
	 */
	private static function deleteRecord(object $db, object $record, array $remotes): bool
	{
		$query = $db->getQuery(true)
			->delete($db->quoteName('#__mokosuitebackup_records'))
			->where($db->quoteName('id') . ' = ' . (int) $record->id);
		$db->setQuery($query);

		try {
			$db->execute();
		} catch (\Throwable $e) {
			error_log('MokoSuiteBackup: retention could not delete record ' . $record->id . ': ' . $e->getMessage());

			return false;
		}

		$archivePath = (string) ($record->absolute_path ?? '');

		if ($archivePath !== '' && is_file($archivePath)) {
			@unlink($archivePath);

			$logPath = BackupDirectory::logPathFromArchive($archivePath);

			if (is_file($logPath)) {
				@unlink($logPath);
			}
		}

		self::deleteFromRemotes($record, $remotes);

		return true;
	}

	/**
	 * Remove the record's archive from every enabled remote destination.
	 *
	 * Best-effort: each remote is tried independently and failures are logged,
	 * never thrown, so one unreachable destination can't stall retention.
	 *
	 * @param   object    $record   Record row (needs archivename)
	 * @param   object[]  $remotes  Enabled remote rows (type, params)
	 */
	private static function deleteFromRemotes(object $record, array $remotes): void
	{
		$archiveName = (string) ($record->archivename ?? '');

		if ($archiveName === '' || empty($remotes)) {
			return;
		}

		foreach ($remotes as $remote) {
			try {
				$params   = json_decode((string) ($remote->params ?? ''), true) ?: [];
				$uploader = RemoteUploaderFactory::create((string) $remote->type, $params);
				$result   = $uploader->delete($archiveName);

				if (empty($result['success'])) {
					error_log(
						'MokoSuiteBackup: retention could not delete ' . $archiveName
						. ' from ' . $remote->type . ' remote: ' . ($result['message'] ?? 'unknown error')
					);
				}
			} catch (\Throwable $e) {
				error_log(
					'MokoSuiteBackup: retention remote-delete error for ' . $archiveName
					. ' (' . ($remote->type ?? '?') . '): ' . $e->getMessage()
				);
			}
		}
	}

	/**
	 * Load the profile's enabled remote destinations (type + params only).
	 *
	 * Returns an empty array if the remotes table is missing (very old installs)
	 * or the profile has none, so callers can iterate unconditionally.
	 */
	private static function loadEnabledRemotes(object $db, int $profileId): array
	{
		try {
			$query = $db->getQuery(true)
				->select($db->quoteName(['type', 'params']))
				->from($db->quoteName('#__mokosuitebackup_remotes'))
				->where($db->quoteName('profile_id') . ' = ' . $profileId)
				->where($db->quoteName('enabled') . ' = 1')
				->order($db->quoteName('ordering') . ' ASC');
			$db->setQuery($query);

			return $db->loadObjectList() ?: [];
		} catch (\Throwable $e) {
			return [];
		}
	}
}