<?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
 *
 * Restores content from a snapshot JSON file.
 *
 * Two restore modes:
 *   - replace: Truncates target tables then inserts all snapshot rows (clean slate)
 *   - merge:   Upserts by primary key — updates existing rows, inserts new ones
 */

namespace Joomla\Component\MokoSuiteBackup\Administrator\Engine;

defined('_JEXEC') or die;

use Joomla\CMS\Factory;
use Joomla\Event\Event;

class SnapshotRestoreEngine
{
	private array $log = [];

	/** Primary key columns for each table */
	private const PRIMARY_KEYS = [
		'#__content'                 => 'id',
		'#__content_frontpage'       => 'content_id',
		'#__categories'              => 'id',
		'#__workflow_associations'   => 'item_id',
		'#__contentitem_tag_map'     => null,  // composite key, handled specially
		'#__modules'                 => 'id',
		'#__modules_menu'            => null,  // composite key, handled specially
		'#__tags'                    => 'id',
		'#__fields'                  => 'id',
		'#__fields_values'           => null,  // composite key, handled specially
		'#__fields_categories'       => null,  // composite key, handled specially
	];

	/**
	 * Restore from a snapshot record.
	 *
	 * @param   int     $snapshotId    Snapshot record ID
	 * @param   string  $mode          'replace' or 'merge'
	 * @param   array   $contentTypes  Which types to restore (empty = all from snapshot)
	 *
	 * @return  array{success: bool, message: string, log?: string}
	 */
	public function restore(int $snapshotId, string $mode = 'replace', array $contentTypes = []): array
	{
		if (!@set_time_limit(0)) {
			$this->log('WARNING: Could not disable time limit — large restores may timeout');
		}

		if (!@ini_set('memory_limit', '512M')) {
			$this->log('WARNING: Could not increase memory limit to 512M');
		}

		$mode = $this->normaliseMode($mode);

		if (!in_array($mode, ['replace', 'merge', 'create', 'duplicate'], true)) {
			return ['success' => false, 'message' => 'Invalid restore mode: ' . $mode];
		}

		$db = Factory::getDbo();

		// Load snapshot record
		$query = $db->getQuery(true)
			->select('*')
			->from($db->quoteName('#__mokosuitebackup_snapshots'))
			->where($db->quoteName('id') . ' = ' . $snapshotId);
		$db->setQuery($query);
		$record = $db->loadObject();

		if (!$record) {
			return ['success' => false, 'message' => 'Snapshot not found: ' . $snapshotId];
		}

		if ($record->status !== 'complete') {
			return ['success' => false, 'message' => 'Cannot restore from failed snapshot'];
		}

		if (!is_file($record->data_file) || !is_readable($record->data_file)) {
			return ['success' => false, 'message' => 'Snapshot file not found: ' . $record->data_file];
		}

		$this->log('Loading snapshot file: ' . basename($record->data_file));

		$json = file_get_contents($record->data_file);

		if ($json === false) {
			return ['success' => false, 'message' => 'Cannot read snapshot file'];
		}

		$data = json_decode($json, true);

		if (json_last_error() !== JSON_ERROR_NONE) {
			return ['success' => false, 'message' => 'Snapshot file contains invalid JSON: ' . json_last_error_msg()];
		}

		if (!is_array($data) || empty($data['tables'])) {
			return ['success' => false, 'message' => 'Invalid snapshot data format: missing tables key'];
		}

		$snapshotTypes = $data['content_types'] ?? [];
		$this->log('Snapshot contains: ' . implode(', ', $snapshotTypes));
		$this->log('Restore mode: ' . $mode);

		// Determine which types to restore
		if (!empty($contentTypes)) {
			$restoreTypes = array_intersect($contentTypes, $snapshotTypes);
		} else {
			$restoreTypes = $snapshotTypes;
		}

		if (empty($restoreTypes)) {
			return ['success' => false, 'message' => 'No matching content types to restore'];
		}

		$this->log('Restoring types: ' . implode(', ', $restoreTypes));

		$prefix = $db->getPrefix();
		$totalRows = 0;

		// Build list of tables to restore based on selected types
		$tablesToRestore = $this->getTablesToRestore($restoreTypes);

		/* Duplicate mode inserts brand-new records through Joomla's Table API,
		   whose Nested tables (categories, tags) issue LOCK TABLES — which
		   implicitly COMMITS any open transaction in MySQL/InnoDB. Wrapping it
		   in transactionStart()/Rollback() would be a false atomicity promise:
		   the first category/tag store would commit and defeat the rollback.
		   Duplicate mode is therefore best-effort and per-item defensive (a bad
		   item is skipped and logged, never fatal) rather than all-or-nothing.
		   The raw-DB modes (replace/create/merge) remain fully transactional. */
		$useTransaction = ($mode !== 'duplicate');

		try {
			if ($useTransaction) {
				$db->transactionStart();
			}

			if ($mode === 'duplicate') {
				$totalRows = $this->restoreDuplicate($data, $restoreTypes);
			} else {
			foreach ($tablesToRestore as $abstractTable) {
				if (!isset($data['tables'][$abstractTable])) {
					$this->log('  Skipping ' . $abstractTable . ' (not in snapshot)');
					continue;
				}

				$rows = $data['tables'][$abstractTable];
				$realTable = str_replace('#__', $prefix, $abstractTable);

				if ($mode === 'replace') {
					$rowCount = $this->restoreReplace($db, $realTable, $abstractTable, $rows);
				} elseif ($mode === 'create') {
					$rowCount = $this->restoreCreate($db, $realTable, $abstractTable, $rows);
				} else {
					$rowCount = $this->restoreMerge($db, $realTable, $abstractTable, $rows);
				}

				$totalRows += $rowCount;
				$this->log('  ' . $abstractTable . ': ' . $rowCount . ' rows restored');
			}
			}

			if ($useTransaction) {
				$db->transactionCommit();
			}

			$this->log('Restore complete: ' . $totalRows . ' total rows');

			// Send snapshot restore notification
			try {
				$profile = NotificationSender::getDefaultProfile();

				if ($profile) {
					$userName  = Factory::getApplication()->getIdentity()->username ?? 'Unknown';
					$userIdVal = Factory::getApplication()->getIdentity()->id ?? 0;

					NotificationSender::sendRestoreNotification($profile, 'snapshot_restore', [
						'mode'          => $mode,
						'content_types' => $restoreTypes,
						'row_count'     => $totalRows,
						'user'          => $userName . ' (ID: ' . $userIdVal . ')',
					], implode("\n", $this->log));
				}
			} catch (\Throwable $e) {
				error_log('MokoSuiteBackup: Snapshot restore notification failed: ' . $e->getMessage());
			}

			// Dispatch event for actionlog and other listeners
			$this->dispatchAfterSnapshotRestore(true, $snapshotId, $mode);

			return [
				'success' => true,
				'message' => sprintf('Snapshot restored (%s mode): %d rows across %d tables', $mode, $totalRows, count($tablesToRestore)),
				'log'     => implode("\n", $this->log),
			];
		} catch (\Throwable $e) {
			if ($useTransaction) {
				try {
					$db->transactionRollback();
					$this->log('Transaction rolled back');
				} catch (\Exception $rollbackEx) {
					$this->log('Rollback failed: ' . $rollbackEx->getMessage());
				}
			} else {
				$this->log('Duplicate mode is not transactional; records already inserted are left in place.');
			}

			$this->log('FATAL: ' . $e->getMessage());

			// Dispatch event for actionlog and other listeners
			$this->dispatchAfterSnapshotRestore(false, $snapshotId, $mode);

			return [
				'success' => false,
				'message' => 'Restore failed: ' . $e->getMessage(),
				'log'     => implode("\n", $this->log),
			];
		}
	}

	/**
	 * Replace mode: delete existing rows, then insert all snapshot rows.
	 */
	private function restoreReplace(object $db, string $realTable, string $abstractTable, array $rows): int
	{
		// Use DELETE instead of TRUNCATE to stay within transaction
		$this->truncateFiltered($db, $realTable, $abstractTable, $rows);

		$count = 0;

		foreach ($rows as $row) {
			$obj = (object) $row;
			$db->insertObject($realTable, $obj);
			$count++;
		}

		return $count;
	}

	/**
	 * Merge mode: upsert rows by primary key.
	 */
	private function restoreMerge(object $db, string $realTable, string $abstractTable, array $rows): int
	{
		$pk = self::PRIMARY_KEYS[$abstractTable] ?? null;
		$count = 0;

		foreach ($rows as $row) {
			$obj = (object) $row;

			if ($pk !== null && isset($row[$pk])) {
				// Check if row exists
				$exists = $db->setQuery(
					$db->getQuery(true)
						->select('COUNT(*)')
						->from($db->quoteName($realTable))
						->where($db->quoteName($pk) . ' = ' . $db->quote($row[$pk]))
				)->loadResult();

				if ($exists) {
					$db->updateObject($realTable, $obj, $pk);
				} else {
					$db->insertObject($realTable, $obj);
				}
			} else {
				// Composite key tables — insert, skip genuine duplicates
				try {
					$db->insertObject($realTable, $obj);
				} catch (\Exception $e) {
					if (str_contains($e->getMessage(), 'Duplicate entry') || $e->getCode() === 1062) {
						$this->log('  Skipped duplicate in ' . $abstractTable);
						continue;
					}

					throw $e;
				}
			}

			$count++;
		}

		return $count;
	}

	/**
	 * Create mode: insert only rows that don't already exist; never overwrite.
	 * Non-destructive — existing content on the target is left untouched. Used
	 * by master→slave injection when the master must not clobber local edits.
	 */
	private function restoreCreate(object $db, string $realTable, string $abstractTable, array $rows): int
	{
		$pk    = self::PRIMARY_KEYS[$abstractTable] ?? null;
		$count = 0;

		foreach ($rows as $row) {
			$obj = (object) $row;

			if ($pk !== null && isset($row[$pk])) {
				$exists = $db->setQuery(
					$db->getQuery(true)
						->select('COUNT(*)')
						->from($db->quoteName($realTable))
						->where($db->quoteName($pk) . ' = ' . $db->quote($row[$pk]))
				)->loadResult();

				if ($exists) {
					continue;
				}

				$db->insertObject($realTable, $obj);
			} else {
				// Composite-key tables: insert, skip genuine duplicates.
				try {
					$db->insertObject($realTable, $obj);
				} catch (\Exception $e) {
					if (str_contains($e->getMessage(), 'Duplicate entry') || $e->getCode() === 1062) {
						continue;
					}

					throw $e;
				}
			}

			$count++;
		}

		return $count;
	}

	/**
	 * Normalise external mode names to the engine's internal modes.
	 * overwrite→replace, skip/new→create, copy→duplicate; passthrough otherwise.
	 */
	private function normaliseMode(string $mode): string
	{
		$map = [
			'overwrite' => 'replace',
			'replace'   => 'replace',
			'update'    => 'merge',
			'merge'     => 'merge',
			'skip'      => 'create',
			'new'       => 'create',
			'create'    => 'create',
			'copy'      => 'duplicate',
			'duplicate' => 'duplicate',
		];

		return $map[strtolower(trim($mode))] ?? strtolower(trim($mode));
	}

	/**
	 * Duplicate mode: insert snapshot content as BRAND-NEW records (new IDs),
	 * leaving existing content untouched. Uses Joomla's Table API so assets,
	 * UCM entries, category/tag nested-sets and alias uniqueness are handled by
	 * core. Every item is wrapped in try/catch — a bad item is skipped + logged,
	 * never fatal — so a partial import degrades gracefully rather than corrupting.
	 *
	 * Known limits: workflow stage is left to the article table's default;
	 * references to content NOT included in the snapshot keep their original IDs.
	 *
	 * @return  int  Number of new records created
	 */
	private function restoreDuplicate(array $data, array $types): int
	{
		$app    = Factory::getApplication();
		$db     = Factory::getDbo();
		$tables = $data['tables'] ?? [];
		$count  = 0;

		$catMap     = [];
		$articleMap = [];
		$moduleMap  = [];

		// --- Categories (parents before children so the remap resolves) ---
		if (in_array('categories', $types, true) && !empty($tables['#__categories'])) {
			$factory = $app->bootComponent('com_categories')->getMVCFactory();
			$cats    = $tables['#__categories'];
			usort($cats, static fn ($a, $b) => ((int) ($a['level'] ?? 0)) <=> ((int) ($b['level'] ?? 0)));

			foreach ($cats as $row) {
				$oldId     = (int) ($row['id'] ?? 0);
				$oldParent = (int) ($row['parent_id'] ?? 1);
				$newParent = $catMap[$oldParent] ?? ($oldParent > 1 ? $oldParent : 1);

				unset($row['id'], $row['asset_id'], $row['lft'], $row['rgt'], $row['level'], $row['path']);
				$row['extension'] = 'com_content';
				$row['parent_id'] = $newParent;
				$row['alias']     = $this->uniqueAlias($db, '#__categories', (string) ($row['alias'] ?? ''), ['extension' => 'com_content']);

				try {
					$table = $factory->createTable('Category', 'Administrator');
					$table->setLocation($newParent, 'last-child');

					if ($table->bind($row) && $table->check() && $table->store()) {
						$catMap[$oldId] = (int) $table->id;
						$count++;
					} else {
						$this->log('  Category skipped: ' . $table->getError());
					}
				} catch (\Throwable $e) {
					$this->log('  Category "' . ($row['title'] ?? '?') . '" skipped: ' . $e->getMessage());
				}
			}
		}

		// --- Articles ---
		if (in_array('articles', $types, true) && !empty($tables['#__content'])) {
			$factory  = $app->bootComponent('com_content')->getMVCFactory();
			$featured = [];

			foreach ($tables['#__content_frontpage'] ?? [] as $fp) {
				$featured[(int) ($fp['content_id'] ?? 0)] = true;
			}

			$tagTitles = $this->buildArticleTagTitles($tables);

			foreach ($tables['#__content'] as $row) {
				$oldId  = (int) ($row['id'] ?? 0);
				$oldCat = (int) ($row['catid'] ?? 0);

				unset($row['id'], $row['asset_id']);

				if (isset($catMap[$oldCat])) {
					$row['catid'] = $catMap[$oldCat];
				}

				$row['alias'] = $this->uniqueAlias($db, '#__content', (string) ($row['alias'] ?? ''), ['catid' => (int) ($row['catid'] ?? 0)]);

				try {
					$table  = $factory->createTable('Article', 'Administrator');
					$tagIds = $this->resolveTagIds($db, $app, $tagTitles[$oldId] ?? []);

					if ($tagIds) {
						$table->newTags = $tagIds;
					}

					if ($table->bind($row) && $table->check() && $table->store()) {
						$newId              = (int) $table->id;
						$articleMap[$oldId] = $newId;
						$count++;

						if (!empty($featured[$oldId])) {
							try {
								$db->insertObject($db->getPrefix() . 'content_frontpage', (object) ['content_id' => $newId, 'ordering' => 0]);
							} catch (\Throwable $e) {
								// featured-ordering row is non-critical
							}
						}
					} else {
						$this->log('  Article skipped: ' . $table->getError());
					}
				} catch (\Throwable $e) {
					$this->log('  Article "' . ($row['title'] ?? '?') . '" skipped: ' . $e->getMessage());
				}
			}

			// Custom-field values for the duplicated articles.
			foreach ($tables['#__fields_values'] ?? [] as $fv) {
				$oldItem = (int) ($fv['item_id'] ?? 0);

				if (!isset($articleMap[$oldItem])) {
					continue;
				}

				$fv['item_id'] = (string) $articleMap[$oldItem];

				try {
					$db->insertObject($db->getPrefix() . 'fields_values', (object) $fv);
				} catch (\Throwable $e) {
					// duplicate/invalid field value — skip
				}
			}
		}

		// --- Modules ---
		if (in_array('modules', $types, true) && !empty($tables['#__modules'])) {
			$factory = $app->bootComponent('com_modules')->getMVCFactory();

			foreach ($tables['#__modules'] as $row) {
				$oldId = (int) ($row['id'] ?? 0);
				unset($row['id'], $row['asset_id']);

				try {
					$table = $factory->createTable('Module', 'Administrator');

					if ($table->bind($row) && $table->check() && $table->store()) {
						$moduleMap[$oldId] = (int) $table->id;
						$count++;
					} else {
						$this->log('  Module skipped: ' . $table->getError());
					}
				} catch (\Throwable $e) {
					$this->log('  Module "' . ($row['title'] ?? '?') . '" skipped: ' . $e->getMessage());
				}
			}

			foreach ($tables['#__modules_menu'] ?? [] as $mm) {
				$oldMod = (int) ($mm['moduleid'] ?? 0);

				if (!isset($moduleMap[$oldMod])) {
					continue;
				}

				try {
					$db->insertObject($db->getPrefix() . 'modules_menu', (object) ['moduleid' => $moduleMap[$oldMod], 'menuid' => (int) ($mm['menuid'] ?? 0)]);
				} catch (\Throwable $e) {
					// duplicate assignment — skip
				}
			}
		}

		$this->log('Duplicated ' . $count . ' new records (categories: ' . count($catMap) . ', articles: ' . count($articleMap) . ', modules: ' . count($moduleMap) . ')');

		return $count;
	}

	/**
	 * Make an alias unique within a scope by appending -2, -3, … if needed.
	 */
	private function uniqueAlias(object $db, string $abstractTable, string $alias, array $scope): string
	{
		$alias = $alias !== '' ? $alias : 'item';
		$table = str_replace('#__', $db->getPrefix(), $abstractTable);
		$base  = $alias;
		$n     = 1;

		while (true) {
			$query = $db->getQuery(true)
				->select('COUNT(*)')
				->from($db->quoteName($table))
				->where($db->quoteName('alias') . ' = ' . $db->quote($alias));

			foreach ($scope as $col => $val) {
				$query->where($db->quoteName($col) . ' = ' . $db->quote($val));
			}

			if ((int) $db->setQuery($query)->loadResult() === 0) {
				return $alias;
			}

			$n++;
			$alias = $base . '-' . $n;

			if ($n > 100) {
				return $base . '-' . substr(md5((string) mt_rand()), 0, 6);
			}
		}
	}

	/**
	 * Map old article id → its tag titles, from the snapshot's tag map + tags.
	 *
	 * @return  array<int,string[]>
	 */
	private function buildArticleTagTitles(array $tables): array
	{
		$tagTitle = [];

		foreach ($tables['#__tags'] ?? [] as $tag) {
			$tagTitle[(int) ($tag['id'] ?? 0)] = (string) ($tag['title'] ?? '');
		}

		$byArticle = [];

		foreach ($tables['#__contentitem_tag_map'] ?? [] as $map) {
			if (strpos((string) ($map['type_alias'] ?? ''), 'com_content.article') !== 0) {
				continue;
			}

			$articleId = (int) ($map['content_item_id'] ?? 0);
			$title     = $tagTitle[(int) ($map['tag_id'] ?? 0)] ?? '';

			if ($articleId && $title !== '') {
				$byArticle[$articleId][] = $title;
			}
		}

		return $byArticle;
	}

	/**
	 * Resolve tag titles to target tag IDs, creating any that don't exist.
	 *
	 * @return  int[]
	 */
	private function resolveTagIds(object $db, object $app, array $titles): array
	{
		$ids = [];

		foreach (array_unique($titles) as $title) {
			try {
				$existing = $db->setQuery(
					$db->getQuery(true)
						->select($db->quoteName('id'))
						->from($db->quoteName('#__tags'))
						->where($db->quoteName('title') . ' = ' . $db->quote($title))
				)->loadResult();

				if ($existing) {
					$ids[] = (int) $existing;
					continue;
				}

				$table = $app->bootComponent('com_tags')->getMVCFactory()->createTable('Tag', 'Administrator');
				$table->setLocation(1, 'last-child');

				if ($table->bind(['title' => $title, 'alias' => '', 'published' => 1, 'parent_id' => 1])
					&& $table->check() && $table->store()) {
					$ids[] = (int) $table->id;
				}
			} catch (\Throwable $e) {
				// tag resolution is best-effort
			}
		}

		return $ids;
	}

	/**
	 * Delete rows from a table, scoping to relevant content only.
	 *
	 * Shared tables (#__categories, #__modules, etc.) are filtered so
	 * only the rows belonging to our content types are deleted — never
	 * the entire table.
	 */
	private function truncateFiltered(object $db, string $realTable, string $abstractTable, array $rows): void
	{
		$query = $db->getQuery(true)->delete($db->quoteName($realTable));

		switch ($abstractTable) {
			case '#__categories':
				$query->where($db->quoteName('extension') . ' = ' . $db->quote('com_content'));
				break;

			case '#__workflow_associations':
				$query->where($db->quoteName('extension') . ' = ' . $db->quote('com_content.article'));
				break;

			case '#__contentitem_tag_map':
				$query->where($db->quoteName('type_alias') . ' LIKE ' . $db->quote('com_content.%'));
				break;

			case '#__modules':
				// Only delete modules that exist in the snapshot — never wipe all site modules
				$ids = array_filter(array_column($rows, 'id'));

				if (empty($ids)) {
					return;
				}

				$ids = array_map('intval', $ids);
				$query->where($db->quoteName('id') . ' IN (' . implode(',', $ids) . ')');
				break;

			case '#__modules_menu':
				// Only delete menu assignments for modules in the snapshot
				$moduleIds = array_filter(array_column($rows, 'moduleid'));

				if (empty($moduleIds)) {
					return;
				}

				$moduleIds = array_map('intval', array_unique($moduleIds));
				$query->where($db->quoteName('moduleid') . ' IN (' . implode(',', $moduleIds) . ')');
				break;

			case '#__tags':
				// Only delete tags that exist in the snapshot — never wipe all tags
				$ids = array_filter(array_column($rows, 'id'));

				if (empty($ids)) {
					return;
				}

				$ids = array_map('intval', $ids);
				$query->where($db->quoteName('id') . ' IN (' . implode(',', $ids) . ')');
				break;

			case '#__fields':
				// Only delete custom fields scoped to com_content.article
				$query->where($db->quoteName('context') . ' = ' . $db->quote('com_content.article'));
				break;

			case '#__fields_values':
				// Only delete field values for com_content.article fields
				$prefix = $db->getPrefix();
				$fTable = $prefix . 'fields';

				$subQuery = $db->getQuery(true)
					->select($db->quoteName('id'))
					->from($db->quoteName($fTable))
					->where($db->quoteName('context') . ' = ' . $db->quote('com_content.article'));
				$query->where($db->quoteName('field_id') . ' IN (' . $subQuery . ')');
				break;

			case '#__fields_categories':
				// Delete field-category mappings for com_content.article fields only
				$prefix = $db->getPrefix();
				$fTable = $prefix . 'fields';

				$subQuery = $db->getQuery(true)
					->select($db->quoteName('id'))
					->from($db->quoteName($fTable))
					->where($db->quoteName('context') . ' = ' . $db->quote('com_content.article'));

				$query->where($db->quoteName('field_id') . ' IN (' . $subQuery . ')');
				break;

			// #__content and #__content_frontpage are fully owned by com_content
			default:
				break;
		}

		$db->setQuery($query);
		$db->execute();
	}

	/**
	 * Build list of abstract table names for the given content types.
	 */
	private function getTablesToRestore(array $types): array
	{
		$tables = [];

		if (in_array('articles', $types)) {
			$tables[] = '#__content';
			$tables[] = '#__content_frontpage';
			$tables[] = '#__workflow_associations';
			$tables[] = '#__contentitem_tag_map';
			$tables[] = '#__tags';
			$tables[] = '#__fields';
			$tables[] = '#__fields_values';
			$tables[] = '#__fields_categories';
		}

		if (in_array('categories', $types)) {
			$tables[] = '#__categories';
		}

		if (in_array('modules', $types)) {
			$tables[] = '#__modules';
			$tables[] = '#__modules_menu';
		}

		return array_unique($tables);
	}

	/**
	 * Restore only selected articles (and their related rows) from a snapshot.
	 *
	 * Uses merge/upsert mode: updates existing rows by ID, inserts missing ones.
	 *
	 * @param   int    $snapshotId  Snapshot record ID
	 * @param   array  $articleIds  Article IDs to restore
	 *
	 * @return  array{success: bool, message: string, restored?: int, log?: string}
	 */
	public function restoreSelectedArticles(int $snapshotId, array $articleIds): array
	{
		if (empty($articleIds)) {
			return ['success' => false, 'message' => 'No article IDs provided'];
		}

		$articleIds = array_map('intval', $articleIds);
		$articleIds = array_filter($articleIds, fn($id) => $id > 0);

		if (empty($articleIds)) {
			return ['success' => false, 'message' => 'No valid article IDs provided'];
		}

		$db = Factory::getDbo();

		// Load snapshot record
		$query = $db->getQuery(true)
			->select('*')
			->from($db->quoteName('#__mokosuitebackup_snapshots'))
			->where($db->quoteName('id') . ' = ' . $snapshotId);
		$db->setQuery($query);
		$record = $db->loadObject();

		if (!$record) {
			return ['success' => false, 'message' => 'Snapshot not found: ' . $snapshotId];
		}

		if ($record->status !== 'complete') {
			return ['success' => false, 'message' => 'Cannot restore from failed snapshot'];
		}

		if (!is_file($record->data_file) || !is_readable($record->data_file)) {
			return ['success' => false, 'message' => 'Snapshot file not found: ' . $record->data_file];
		}

		$this->log('Loading snapshot file: ' . basename($record->data_file));

		$json = file_get_contents($record->data_file);

		if ($json === false) {
			return ['success' => false, 'message' => 'Cannot read snapshot file'];
		}

		$data = json_decode($json, true);

		if (json_last_error() !== JSON_ERROR_NONE) {
			return ['success' => false, 'message' => 'Snapshot file contains invalid JSON: ' . json_last_error_msg()];
		}

		if (!is_array($data) || empty($data['tables'])) {
			return ['success' => false, 'message' => 'Invalid snapshot data format: missing tables key'];
		}

		$contentTable = $data['tables']['#__content'] ?? [];

		if (empty($contentTable)) {
			return ['success' => false, 'message' => 'Snapshot does not contain articles'];
		}

		// Filter #__content rows to only selected article IDs
		$selectedRows = array_filter($contentTable, fn($row) => in_array((int) ($row['id'] ?? 0), $articleIds, true));

		if (empty($selectedRows)) {
			return ['success' => false, 'message' => 'None of the selected article IDs exist in this snapshot'];
		}

		$foundIds = array_map(fn($row) => (int) $row['id'], $selectedRows);
		$this->log('Restoring ' . count($selectedRows) . ' articles: IDs ' . implode(', ', $foundIds));

		// Filter workflow_associations for selected articles
		$workflowRows = [];

		if (!empty($data['tables']['#__workflow_associations'])) {
			$workflowRows = array_filter(
				$data['tables']['#__workflow_associations'],
				fn($row) => in_array((int) ($row['item_id'] ?? 0), $foundIds, true)
			);
		}

		// Filter tag_map entries for selected articles
		$tagMapRows = [];

		if (!empty($data['tables']['#__contentitem_tag_map'])) {
			$tagMapRows = array_filter(
				$data['tables']['#__contentitem_tag_map'],
				fn($row) => in_array((int) ($row['content_item_id'] ?? 0), $foundIds, true)
					&& str_starts_with($row['type_alias'] ?? '', 'com_content.')
			);
		}

		$prefix    = $db->getPrefix();
		$totalRows = 0;

		try {
			$db->transactionStart();

			// Restore articles using merge/upsert
			$realTable = str_replace('#__', $prefix, '#__content');
			$rowCount  = $this->restoreMerge($db, $realTable, '#__content', array_values($selectedRows));
			$totalRows += $rowCount;
			$this->log('  #__content: ' . $rowCount . ' rows restored');

			// Restore workflow associations
			if (!empty($workflowRows)) {
				$realTable = str_replace('#__', $prefix, '#__workflow_associations');
				$rowCount  = $this->restoreMerge($db, $realTable, '#__workflow_associations', array_values($workflowRows));
				$totalRows += $rowCount;
				$this->log('  #__workflow_associations: ' . $rowCount . ' rows restored');
			}

			// Restore tag map entries
			if (!empty($tagMapRows)) {
				$realTable = str_replace('#__', $prefix, '#__contentitem_tag_map');
				$rowCount  = $this->restoreMerge($db, $realTable, '#__contentitem_tag_map', array_values($tagMapRows));
				$totalRows += $rowCount;
				$this->log('  #__contentitem_tag_map: ' . $rowCount . ' rows restored');
			}

			$db->transactionCommit();

			$this->log('Selective restore complete: ' . $totalRows . ' total rows');

			// Send notification
			try {
				$profile = NotificationSender::getDefaultProfile();

				if ($profile) {
					$userName  = Factory::getApplication()->getIdentity()->username ?? 'Unknown';
					$userIdVal = Factory::getApplication()->getIdentity()->id ?? 0;

					NotificationSender::sendRestoreNotification($profile, 'snapshot_selective_restore', [
						'mode'        => 'selective',
						'article_ids' => $foundIds,
						'row_count'   => $totalRows,
						'user'        => $userName . ' (ID: ' . $userIdVal . ')',
					], implode("\n", $this->log));
				}
			} catch (\Throwable $e) {
				error_log('MokoSuiteBackup: Selective restore notification failed: ' . $e->getMessage());
			}

			// Dispatch event for actionlog and other listeners
			$this->dispatchAfterSnapshotRestore(true, $snapshotId, 'selective');

			return [
				'success'  => true,
				'message'  => sprintf('Restored %d articles (%d total rows)', count($selectedRows), $totalRows),
				'restored' => count($selectedRows),
				'log'      => implode("\n", $this->log),
			];
		} catch (\Throwable $e) {
			try {
				$db->transactionRollback();
				$this->log('Transaction rolled back');
			} catch (\Exception $rollbackEx) {
				$this->log('Rollback failed: ' . $rollbackEx->getMessage());
			}

			$this->log('FATAL: ' . $e->getMessage());

			// Dispatch event for actionlog and other listeners
			$this->dispatchAfterSnapshotRestore(false, $snapshotId, 'selective');

			return [
				'success' => false,
				'message' => 'Selective restore failed: ' . $e->getMessage(),
				'log'     => implode("\n", $this->log),
			];
		}
	}

	/**
	 * Dispatch the onMokoSuiteBackupAfterSnapshotRestore event so plugins (actionlog, etc.) can react.
	 */
	private function dispatchAfterSnapshotRestore(bool $success, int $snapshotId, string $mode): void
	{
		try {
			$app = Factory::getApplication();

			$event = new Event('onMokoSuiteBackupAfterSnapshotRestore', [
				'success'     => $success,
				'snapshot_id' => $snapshotId,
				'mode'        => $mode,
			]);

			$app->getDispatcher()->dispatch('onMokoSuiteBackupAfterSnapshotRestore', $event);
		} catch (\Throwable $e) {
			// Never let a listener failure break the restore result, but log it
			error_log('MokoSuiteBackup: onAfterSnapshotRestore listener error: ' . $e->getMessage());
		}
	}

	private function log(string $message): void
	{
		$this->log[] = '[' . date('H:i:s') . '] ' . $message;
	}
}