<?php

declare(strict_types=1);

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

namespace TYPO3\CMS\ContentBlocks\Generator;

use TYPO3\CMS\ContentBlocks\Definition\Factory\TableDefinitionCollectionFactory;
use TYPO3\CMS\ContentBlocks\Definition\TableDefinition;
use TYPO3\CMS\ContentBlocks\FieldType\FieldTypeRegistry;
use TYPO3\CMS\ContentBlocks\Loader\ContentBlockLoader;
use TYPO3\CMS\ContentBlocks\Schema\SimpleTcaSchemaFactory;
use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Core\Database\Event\AlterTableDefinitionStatementsEvent;

/**
 * @internal Not part of TYPO3's public API.
 */
#[AsEventListener(identifier: 'content-blocks-sql')]
readonly class SqlGenerator
{
    public function __construct(
        protected ContentBlockLoader $contentBlockLoader,
        protected TableDefinitionCollectionFactory $tableDefinitionCollectionFactory,
        protected SimpleTcaSchemaFactory $simpleTcaSchemaFactory,
        protected FieldTypeRegistry $fieldTypeRegistry,
    ) {}

    public function __invoke(AlterTableDefinitionStatementsEvent $event): void
    {
        $contentBlocksSqlData = $this->generate();
        $mergedSqlData = array_merge($contentBlocksSqlData, $event->getSqlData());
        $event->setSqlData($mergedSqlData);
    }

    public function generate(): array
    {
        $contentBlockRegistry = $this->contentBlockLoader->loadUncached();
        $tableDefinitionCollection = $this->tableDefinitionCollectionFactory->createUncached(
            $contentBlockRegistry,
            $this->fieldTypeRegistry,
            $this->simpleTcaSchemaFactory
        );
        $sql = [];
        foreach ($tableDefinitionCollection as $tableDefinition) {
            foreach ($tableDefinition->sqlColumnDefinitionCollection as $column) {
                if ($column->getSql() === '') {
                    continue;
                }
                // Add SQL specific for that field. Note: Core field type definitions are ALL handled in Core already.
                $sql[] = 'CREATE TABLE `' . $tableDefinition->table . '`' . '(' . $column->getSql() . ');';
            }
            $resultSql = $this->handleParentReferences($tableDefinition);
            $sql = array_merge($sql, $resultSql);
        }
        return $sql;
    }

    protected function handleParentReferences(TableDefinition $tableDefinition): array
    {
        $indexes = [];
        $fields = [];
        $table = $tableDefinition->table;
        foreach ($tableDefinition->parentReferences as $parentReference) {
            $index = [];
            $parentTcaConfig = $parentReference->getTca()['config'];
            if (isset($parentTcaConfig['foreign_table_field'])) {
                $foreignTableName = $parentTcaConfig['foreign_table_field'];
                $index[] = $foreignTableName;
            }
            // The foreign_match_fields fields are automatically added, so that feature "shareAcrossFields" works.
            foreach ($parentTcaConfig['foreign_match_fields'] ?? [] as $foreignMatchField => $foreignMatchValue) {
                $index[] = $foreignMatchField;
                $fields[] = $foreignMatchField;
            }
            // Generate indexes for the parent uid field for better performance.
            if (isset($parentTcaConfig['foreign_field'])) {
                $foreignField = $parentTcaConfig['foreign_field'];
                $index[] = $foreignField;
            }
            $indexes[] = $index;
        }
        $sql = [];
        foreach ($fields as $fieldName) {
            $sqlStatement = 'CREATE TABLE `' . $table . '` (`' . $fieldName . '` varchar(255) DEFAULT \'\' NOT NULL);';
            if (!in_array($sqlStatement, $sql, true)) {
                $sql[] = $sqlStatement;
            }
        }
        $indexes = array_map(fn(array $index): string => implode(', ', $index), $indexes);
        $indexes = array_unique($indexes);
        $indexes = array_values($indexes);
        foreach ($indexes as $counter => $index) {
            $key = 'parent_uid';
            if ($counter > 0) {
                $key .= '_' . ($counter + 1);
            }
            $sqlStatement = 'CREATE TABLE `' . $table . '` (KEY ' . $key . ' (' . $index . '));';
            $sql[] = $sqlStatement;
        }
        return $sql;
    }
}