<?php

/**
 * @package     MokoJoomBackup
 * @subpackage  com_mokojoombackup
 * @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
 *
 * Manages state for AJAX step-based backups.
 *
 * On shared hosting where max_execution_time cannot be overridden,
 * the backup runs as a series of small AJAX requests. Each request
 * loads the session, does one chunk of work, saves state, and returns.
 * The browser JS fires the next step automatically.
 *
 * Phases: init → database → files → finalize → upload → complete
 */

namespace Joomla\Component\MokoJoomBackup\Administrator\Engine;

defined('_JEXEC') or die;

class SteppedSession
{
	public string $sessionId;
	public string $phase = 'init';
	public int $recordId = 0;
	public int $profileId = 0;
	public string $archivePath = '';
	public string $archiveName = '';
	public string $description = '';
	public string $origin = 'backend';

	// Database phase tracking
	public array $tables = [];
	public int $tableIndex = 0;
	public int $tablesCount = 0;
	public int $dbSize = 0;

	// Files phase tracking
	public array $fileBatches = [];
	public int $batchIndex = 0;
	public int $filesCount = 0;
	public int $batchSize = 200;

	// Profile settings (cached so we don't re-query each step)
	public string $backupType = 'full';
	public string $backupDir = '';
	public array $excludeDirs = [];
	public array $excludeFiles = [];
	public array $excludeTables = [];
	public string $remoteStorage = 'none';
	public bool $includeMokoRestore = false;
	public bool $remoteKeepLocal = true;

	// Progress
	public int $totalSteps = 0;
	public int $currentStep = 0;
	public string $statusMessage = '';
	public array $log = [];

	private static function getSessionDir(): string
	{
		$dir = JPATH_ROOT . '/tmp/mokojoombackup-sessions';

		if (!is_dir($dir)) {
			if (!mkdir($dir, 0755, true)) {
				throw new \RuntimeException('Cannot create session directory: ' . $dir);
			}
		}

		return $dir;
	}

	private static function getSessionPath(string $sessionId): string
	{
		// Sanitize session ID to prevent path traversal
		$safe = preg_replace('/[^a-zA-Z0-9_-]/', '', $sessionId);

		return self::getSessionDir() . '/' . $safe . '.json';
	}

	/**
	 * Create a new session.
	 */
	public static function create(): self
	{
		$session = new self();
		$session->sessionId = 'mb_' . bin2hex(random_bytes(8));

		return $session;
	}

	/**
	 * Load an existing session from disk.
	 */
	public static function load(string $sessionId): ?self
	{
		$path = self::getSessionPath($sessionId);

		if (!is_file($path)) {
			return null;
		}

		$data = json_decode(file_get_contents($path), true);

		if (!$data) {
			return null;
		}

		$session = new self();

		foreach ($data as $key => $value) {
			if (property_exists($session, $key)) {
				$session->$key = $value;
			}
		}

		return $session;
	}

	/**
	 * Save session state to disk.
	 */
	public function save(): void
	{
		$path = self::getSessionPath($this->sessionId);
		if (file_put_contents($path, json_encode(get_object_vars($this), JSON_PRETTY_PRINT)) === false) {
			throw new \RuntimeException('Cannot save backup session: ' . $path);
		}
	}

	/**
	 * Delete session file.
	 */
	public function destroy(): void
	{
		$path = self::getSessionPath($this->sessionId);

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

	/**
	 * Add a log entry.
	 */
	public function log(string $message): void
	{
		$this->log[] = '[' . date('H:i:s') . '] ' . $message;
	}

	/**
	 * Calculate progress percentage.
	 */
	public function getProgress(): int
	{
		if ($this->totalSteps <= 0) {
			return 0;
		}

		return min(100, (int) round(($this->currentStep / $this->totalSteps) * 100));
	}

	/**
	 * Clean up old session files (older than 24 hours).
	 */
	public static function cleanupOldSessions(): void
	{
		$dir = self::getSessionDir();

		if (!is_dir($dir)) {
			return;
		}

		$cutoff = time() - 86400;

		foreach (glob($dir . '/mb_*.json') as $file) {
			if (filemtime($file) < $cutoff) {
				@unlink($file);
			}
		}
	}
}