<?php
/************************************************************************
 * This file is part of EspoCRM.
 *
 * EspoCRM – Open Source CRM application.
 * Copyright (C) 2014-2026 EspoCRM, Inc.
 * Website: https://www.espocrm.com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License version 3.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License version 3,
 * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
 ************************************************************************/

namespace Espo\Core\Utils\Cache;

use Closure;
use Espo\Core\Utils\Cache\Exceptions\ReadError;
use Espo\Core\Utils\Config\SystemConfig;
use Espo\Core\Utils\DataCache;
use Espo\Core\Utils\Log;
use LogicException;
use stdClass;

/**
 * @internal
 * @since 10.1.0
 * @template T of array<int|string, mixed> | stdClass = array<int|string, mixed> | stdClass
 * @todo Test.
 */
class DataCacheAccess
{
    /** @var T|null  */
    private mixed $data = null;

    private ?string $key = null;

    /** @var (Closure(): T)|null  */
    private ?Closure $loader = null;

    /** @var (Closure(T): bool)|null  */
    private ?Closure $validityChecker = null;

    public function __construct(
        private DataCache $dataCache,
        private SystemConfig $systemConfig,
        private Log $log,
    ) {}

    /**
     * @param Closure(): T $loader
     * @param (Closure(T): bool)|null $validityChecker
     */
    public function init(string $key, Closure $loader, ?Closure $validityChecker = null): void
    {
        $this->key = $key;
        $this->loader = $loader;
        $this->validityChecker = $validityChecker;

        $this->data = null;
    }

    public function reset(): void
    {
        $this->data = null;
    }

    /**
     * @param T $data
     */
    public function set(mixed $data): void
    {
        $this->data = $data;
    }

    public function store(): void
    {
        if (!$this->key) {
            throw new LogicException("Not initialized.");
        }

        if ($this->data === null) {
            throw new LogicException("Data not set.");
        }

        if ($this->systemConfig->useCache()) {
            $this->dataCache->store($this->key, $this->data);
        }
    }

    /**
     * @return T
     */
    public function get(): mixed
    {
        if ($this->data && $this->validityChecker && !($this->validityChecker)($this->data)) {
            $this->data = null;
        }

        if ($this->data !== null) {
            return $this->data;
        }

        $key = $this->key;
        $loader = $this->loader;

        if (!$key || !$loader) {
            throw new LogicException("Not initialized.");
        }

        if ($this->systemConfig->useCache() && $this->dataCache->has($key)) {
            $this->loadFromCache();
        }

        if ($this->data === null) {
            $this->data = $loader();

            if ($this->systemConfig->useCache()) {
                $this->dataCache->store($key, $this->data);
            }
        }

        return $this->data;
    }

    private function loadFromCache(): void
    {
        $key = $this->key ?? throw new LogicException();

        try {
            $data = $this->dataCache->get($key);
        } catch (ReadError $e) {
            $this->log->warning("Corrupted cache data by key '{key}'.", [
                'exception' => $e,
                'key' => $key,
            ]);

            $this->dataCache->clear($key);

            return;
        }

        if ($data === null) {
            return;
        }

        /** @var T $data */

        if ($this->validityChecker && !($this->validityChecker)($data)) {
            $this->data = null;

            return;
        }

        $this->data = $data;
    }
}