<?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
 *
 * Snapshot engine — creates lightweight JSON snapshots of specific content
 * types (articles, categories, modules) without touching the filesystem.
 */

namespace Joomla\Component\MokoSuiteBackup\Administrator\Engine;

defined('_JEXEC') or die;

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

class SnapshotEngine
{
	private array $log = [];

	/** Content type => tables mapping */
	private const TYPE_TABLES = [
		'articles' => [
			'#__content',
			'#__content_frontpage',
		],
		'categories' => [
			'#__categories',
		],
		'modules' => [
			'#__modules',
			'#__modules_menu',
		],
	];

	/** Related tables always captured when articles are included */
	private const ARTICLE_RELATED = [
		'#__workflow_associations',
		'#__contentitem_tag_map',
	];

	/**
	 * Create a snapshot of selected content types.
	 *
	 * @param   array   $contentTypes  Types to snapshot: articles, categories, modules
	 * @param   string  $description   User-provided description
	 *
	 * @return  array{success: bool, message: string, id?: int}
	 */
	public function create(array $contentTypes, string $description = ''): array
	{
		$db = Factory::getDbo();
		$prefix = $db->getPrefix();

		if (empty($contentTypes)) {
			return ['success' => false, 'message' => 'No content types selected'];
		}

		$validTypes = array_intersect($contentTypes, ['articles', 'categories', 'modules']);

		if (empty($validTypes)) {
			return ['success' => false, 'message' => 'No valid content types selected'];
		}

		$this->log('Starting snapshot: ' . implode(', ', $validTypes));

		try {
			$data = [
				'version'       => 1,
				'created'       => date('Y-m-d H:i:s'),
				'content_types' => array_values($validTypes),
				'tables'        => [],
			];

			$counts = [
				'articles'   => 0,
				'categories' => 0,
				'modules'    => 0,
			];

			// Dump each selected content type
			foreach ($validTypes as $type) {
				foreach (self::TYPE_TABLES[$type] as $abstractTable) {
					$realTable = str_replace('#__', $prefix, $abstractTable);
					$rows = $this->dumpTable($db, $realTable, $abstractTable, $type);
					$data['tables'][$abstractTable] = $rows;
					$this->log('  ' . $abstractTable . ': ' . count($rows) . ' rows');
				}
			}

			// Capture related tables for articles
			if (in_array('articles', $validTypes)) {
				$rows = $this->dumpFilteredTable(
					$db,
					str_replace('#__', $prefix, '#__workflow_associations'),
					'#__workflow_associations',
					'extension',
					'com_content.article'
				);
				$data['tables']['#__workflow_associations'] = $rows;
				$this->log('  #__workflow_associations: ' . count($rows) . ' rows');

				$rows = $this->dumpTagMap($db, $prefix);
				$data['tables']['#__contentitem_tag_map'] = $rows;
				$this->log('  #__contentitem_tag_map: ' . count($rows) . ' rows');
			}

			// Count items
			if (in_array('articles', $validTypes)) {
				$counts['articles'] = count($data['tables']['#__content'] ?? []);
			}

			if (in_array('categories', $validTypes)) {
				$counts['categories'] = count($data['tables']['#__categories'] ?? []);
			}

			if (in_array('modules', $validTypes)) {
				$counts['modules'] = count($data['tables']['#__modules'] ?? []);
			}

			// Write JSON file to backup directory
			$backupDir = BackupDirectory::getDefaultAbsolute();
			BackupDirectory::ensureReady($backupDir);

			$filename = 'snapshot_' . date('Ymd_His') . '_' . implode('-', $validTypes) . '.json';
			$filePath = $backupDir . '/' . $filename;

			$json = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);

			if ($json === false) {
				throw new \RuntimeException('Failed to encode snapshot data as JSON');
			}

			if (file_put_contents($filePath, $json) === false) {
				throw new \RuntimeException('Failed to write snapshot file: ' . $filePath);
			}

			$fileSize = strlen($json);
			$this->log('Snapshot saved: ' . $filename . ' (' . number_format($fileSize) . ' bytes)');

			// Create database record
			$now = Factory::getDate()->toSql();
			$userId = Factory::getApplication()->getIdentity()->id ?? 0;

			$record = (object) [
				'description'      => $description ?: 'Snapshot: ' . implode(', ', $validTypes),
				'content_types'    => json_encode(array_values($validTypes)),
				'status'           => 'complete',
				'articles_count'   => $counts['articles'],
				'categories_count' => $counts['categories'],
				'modules_count'    => $counts['modules'],
				'data_file'        => $filePath,
				'data_size'        => $fileSize,
				'log'              => implode("\n", $this->log),
				'created'          => $now,
				'created_by'       => $userId,
			];

			$db->insertObject('#__mokosuitebackup_snapshots', $record, 'id');

			$this->log('Snapshot record created: ID ' . $record->id);

			return [
				'success' => true,
				'message' => sprintf(
					'Snapshot created: %d articles, %d categories, %d modules',
					$counts['articles'],
					$counts['categories'],
					$counts['modules']
				),
				'id' => $record->id,
			];
		} catch (\Exception $e) {
			$this->log('FATAL: ' . $e->getMessage());

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

	/**
	 * Dump all rows from a table.
	 */
	private function dumpTable(object $db, string $realTable, string $abstractTable, string $type): array
	{
		$query = $db->getQuery(true)->select('*')->from($db->quoteName($realTable));

		// Filter categories to com_content only
		if ($abstractTable === '#__categories' && $type === 'categories') {
			$query->where($db->quoteName('extension') . ' = ' . $db->quote('com_content'));
		}

		$db->setQuery($query);

		return $db->loadAssocList() ?: [];
	}

	/**
	 * Dump rows from a table filtered by a column value.
	 */
	private function dumpFilteredTable(object $db, string $realTable, string $abstractTable, string $column, string $value): array
	{
		$query = $db->getQuery(true)
			->select('*')
			->from($db->quoteName($realTable))
			->where($db->quoteName($column) . ' = ' . $db->quote($value));
		$db->setQuery($query);

		return $db->loadAssocList() ?: [];
	}

	/**
	 * Dump tag map entries for com_content items.
	 */
	private function dumpTagMap(object $db, string $prefix): array
	{
		$table = $prefix . 'contentitem_tag_map';
		$query = $db->getQuery(true)
			->select('*')
			->from($db->quoteName($table))
			->where($db->quoteName('type_alias') . ' LIKE ' . $db->quote('com_content.%'));
		$db->setQuery($query);

		return $db->loadAssocList() ?: [];
	}

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