<?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
 *
 * Imports a SQL dump file created by DatabaseDumper.
 * Handles #__ prefix replacement, multi-statement execution,
 * and DROP TABLE before CREATE TABLE for clean restores.
 */

namespace Joomla\Component\MokoSuiteBackup\Administrator\Engine;

defined('_JEXEC') or die;

use Joomla\CMS\Factory;

class DatabaseImporter
{
	/**
	 * Import a SQL dump file into the database.
	 *
	 * @param   string  $sqlFile  Absolute path to the SQL dump file
	 *
	 * @return  int  Number of statements executed
	 *
	 * @throws  \RuntimeException  On import failure
	 */
	public function import(string $sqlFile): int
	{
		if (!is_file($sqlFile) || !is_readable($sqlFile)) {
			throw new \RuntimeException('SQL file not readable: ' . $sqlFile);
		}

		$db     = Factory::getDbo();
		$prefix = $db->getPrefix();

		$handle = fopen($sqlFile, 'r');

		if ($handle === false) {
			throw new \RuntimeException('Cannot open SQL file: ' . $sqlFile);
		}

		$statementsExecuted = 0;
		$currentStatement   = '';
		$inMultiLineComment = false;

		try {
			while (($line = fgets($handle)) !== false) {
				$trimmed = trim($line);

				// Skip empty lines
				if ($trimmed === '') {
					continue;
				}

				// Skip single-line comments
				if (str_starts_with($trimmed, '--') || str_starts_with($trimmed, '#')) {
					continue;
				}

				// Handle multi-line comments
				if (str_starts_with($trimmed, '/*')) {
					$inMultiLineComment = true;
				}

				if ($inMultiLineComment) {
					if (str_contains($trimmed, '*/')) {
						$inMultiLineComment = false;
					}

					continue;
				}

				// Accumulate the statement
				$currentStatement .= $line;

				// Check if statement is complete (ends with semicolon)
				if (str_ends_with($trimmed, ';')) {
					$statement = trim($currentStatement);
					$currentStatement = '';

					if (empty($statement)) {
						continue;
					}

					// Replace abstract #__ prefix with the current site's prefix
					$statement = str_replace('#__', $prefix, $statement);

					try {
						$db->setQuery($statement);
						$db->execute();
						$statementsExecuted++;
					} catch (\Exception $e) {
						// Log but don't abort — some statements may fail on
						// different MySQL versions (e.g. charset differences)
						// but the overall restore should continue.
						error_log('MokoSuiteBackup SQL import warning: ' . $e->getMessage());
					}
				}
			}

			// Execute any remaining statement without trailing semicolon
			$remaining = trim($currentStatement);

			if (!empty($remaining)) {
				$remaining = str_replace('#__', $prefix, $remaining);

				try {
					$db->setQuery($remaining);
					$db->execute();
					$statementsExecuted++;
				} catch (\Exception $e) {
					error_log('MokoSuiteBackup SQL import warning (final): ' . $e->getMessage());
				}
			}
		} finally {
			fclose($handle);
		}

		return $statementsExecuted;
	}
}