<?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\CMS\Factory;

class DatabaseDumper
{
	/** @var array Tables to exclude entirely (both structure and data) */
	private array $excludeBoth = [];

	/** @var array Tables to exclude data only (structure is kept) */
	private array $excludeDataOnly = [];

	/** @var array Tables to exclude structure only (data is kept — unusual) */
	private array $excludeStructureOnly = [];

	private int $tablesCount = 0;

	/**
	 * @param   array  $excludeTables  Table names to exclude (with #__ prefix).
	 *                                 Supports suffixes: :data-only, :structure-only.
	 *                                 No suffix = exclude both (backward compatible).
	 */
	public function __construct(array $excludeTables = [])
	{
		foreach ($excludeTables as $entry) {
			if (str_ends_with($entry, ':data-only')) {
				$this->excludeDataOnly[] = substr($entry, 0, -10);
			} elseif (str_ends_with($entry, ':structure-only')) {
				$this->excludeStructureOnly[] = substr($entry, 0, -15);
			} else {
				$this->excludeBoth[] = $entry;
			}
		}
	}

	/**
	 * Dump all database tables to SQL.
	 *
	 * @return  string  The SQL dump
	 */
	public function dump(): string
	{
		$db     = Factory::getDbo();
		$prefix = $db->getPrefix();
		$output = [];

		$output[] = '-- MokoSuiteBackup Database Dump';
		$output[] = '-- Generated: ' . date('Y-m-d H:i:s');
		$output[] = '-- Server: ' . $db->getServerType();
		$output[] = '-- Database: ' . $db->getName();
		$output[] = '-- Original Prefix: ' . $prefix;
		$output[] = '-- Abstract Prefix: #__';
		$output[] = '-- Note: Table names use #__ placeholder. Replace with your prefix on restore.';
		$output[] = '';
		$output[] = 'SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";';
		$output[] = 'SET time_zone = "+00:00";';
		$output[] = '';

		// Get all tables with the site prefix
		$tables = $db->getTableList();
		$siteTables = [];

		foreach ($tables as $table) {
			if (str_starts_with($table, $prefix)) {
				$siteTables[] = $table;
			}
		}

		foreach ($siteTables as $table) {
			// Check if excluded
			$abstractName = '#__' . substr($table, strlen($prefix));

			if ($this->isExcludedBoth($abstractName, $table)) {
				continue;
			}

			$skipData      = $this->isExcludedDataOnly($abstractName, $table);
			$skipStructure = $this->isExcludedStructureOnly($abstractName, $table);

			$this->tablesCount++;

			$output[] = '-- --------------------------------------------------------';
			$output[] = '-- Table: ' . $abstractName;

			if ($skipData) {
				$output[] = '-- (data excluded)';
			}

			if ($skipStructure) {
				$output[] = '-- (structure excluded)';
			}

			$output[] = '-- --------------------------------------------------------';
			$output[] = '';

			// Get CREATE TABLE statement (unless structure is excluded)
			if (!$skipStructure) {
				$db->setQuery('SHOW CREATE TABLE ' . $db->quoteName($table));
				$createRow = $db->loadRow();

				if (!$createRow || empty($createRow[1])) {
					continue;
				}

				// Replace all occurrences of the live prefix with #__ in CREATE TABLE
				// output — covers the table itself and FK REFERENCES to other tables
				$createSql = str_replace('`' . $prefix, '`#__', $createRow[1]);
				$output[] = 'DROP TABLE IF EXISTS `' . $abstractName . '`;';
				$output[] = $createSql . ';';
				$output[] = '';
			}

			// Dump data (unless data is excluded)
			if ($skipData) {
				$output[] = '';
				continue;
			}

			$db->setQuery('SELECT COUNT(*) FROM ' . $db->quoteName($table));
			$rowCount = (int) $db->loadResult();

			if ($rowCount === 0) {
				$output[] = '-- (empty table)';
				$output[] = '';
				continue;
			}

			$chunkSize = 500;

			for ($offset = 0; $offset < $rowCount; $offset += $chunkSize) {
				$db->setQuery(
					$db->getQuery(true)
						->select('*')
						->from($db->quoteName($table)),
					$offset,
					$chunkSize
				);
				$rows = $db->loadAssocList();

				if (empty($rows)) {
					break;
				}

				foreach ($rows as $row) {
					$values = [];

					foreach ($row as $value) {
						if ($value === null) {
							$values[] = 'NULL';
						} else {
							$values[] = $db->quote($value);
						}
					}

					$columns = array_map([$db, 'quoteName'], array_keys($row));
					$output[] = 'INSERT INTO `' . $abstractName . '`'
						. ' (' . implode(', ', $columns) . ')'
						. ' VALUES (' . implode(', ', $values) . ');';
				}
			}

			$output[] = '';
		}

		return implode("\n", $output);
	}

	/**
	 * Check if a table is fully excluded (both data and structure).
	 */
	private function isExcludedBoth(string $abstractName, string $realName): bool
	{
		foreach ($this->excludeBoth as $pattern) {
			if ($pattern === $abstractName || $pattern === $realName) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Check if a table's data is excluded (structure only).
	 */
	private function isExcludedDataOnly(string $abstractName, string $realName): bool
	{
		foreach ($this->excludeDataOnly as $pattern) {
			if ($pattern === $abstractName || $pattern === $realName) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Check if a table's structure is excluded (data only).
	 */
	private function isExcludedStructureOnly(string $abstractName, string $realName): bool
	{
		foreach ($this->excludeStructureOnly as $pattern) {
			if ($pattern === $abstractName || $pattern === $realName) {
				return true;
			}
		}

		return false;
	}

	public function getTablesCount(): int
	{
		return $this->tablesCount;
	}
}