<?php

/*
 * 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\Install\Service;

use TYPO3\CMS\Core\Cache\CacheManager;
use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
use TYPO3\CMS\Core\DependencyInjection\Cache\ContainerBackend;

/**
 * Basic service to clear caches within the install tool.
 * @internal This is NOT an API class, it is for internal use in the install tool only.
 */
readonly class ClearCacheService
{
    public function __construct(
        private LateBootService $lateBootService,
        private FrontendInterface $dependencyInjectionCache
    ) {}

    /**
     * This clear cache implementation follows a pretty brutal approach.
     * Goal is to reliably get rid of cache entries, even if some broken
     * extension is loaded that would kill the backend 'clear cache' action.
     *
     * Therefore, this method "knows" implementation details of the cache
     * framework and uses them to clear all file based cache (typo3temp/Cache)
     * and database caches (tables prefixed with cf_) manually.
     *
     * After that ext_localconf of extensions are loaded, those
     * may register additional caches in the caching framework with different
     * backend, and will then clear them with the usual flush() method.
     */
    public function clearAll(): void
    {
        // Flush all caches defined in TYPO3_CONF_VARS, but not the ones defined by extensions in ext_localconf.php
        $baseCaches = $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations'] ?? [];

        // Remove DI container cache (will be renewed in next step)
        if ($this->dependencyInjectionCache->getBackend() instanceof ContainerBackend) {
            /** @var ContainerBackend $diCacheBackend */
            $diCacheBackend = $this->dependencyInjectionCache->getBackend();
            // We need to remove using the forceFlush method because the DI cache backend disables the flush method
            $diCacheBackend->forceFlush();
        }

        // The cache manager is already instantiated in the install tool
        // * (both in the failsafe and the late boot container), but
        // * with settings to disable caching (all caches using NullBackend).
        // Obtain a real instance
        $this->lateBootService->unsetInternalContainerInstance();
        $container = $this->lateBootService->getContainer(true);
        $this->lateBootService->makeCurrent($container);
        $cacheManager = $container->get(CacheManager::class);

        $cacheManager->flushCaches();

        // From this point on, the code may fatal, if some broken extension is loaded.
        $this->lateBootService->loadExtLocalconfDatabase();

        $extensionCaches = $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations'] ?? [];
        // Loose comparison on purpose to allow changed ordering of the array
        if ($baseCaches != $extensionCaches) {
            // When configuration has changed during loading of extensions (due to ext_localconf.php), flush all caches again
            $cacheManager->setCacheConfigurations($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']);
            $cacheManager->flushCaches();
        }
    }
}