<?php

declare(strict_types=1);

/**
 * This file is part of CodeIgniter 4 framework.
 *
 * (c) CodeIgniter Foundation <admin@codeigniter.com>
 *
 * For the full copyright and license information, please view
 * the LICENSE file that was distributed with this source code.
 */

namespace CodeIgniter\Cache;

use CodeIgniter\Exceptions\RuntimeException;
use CodeIgniter\HTTP\CLIRequest;
use CodeIgniter\HTTP\Header;
use CodeIgniter\HTTP\IncomingRequest;
use CodeIgniter\HTTP\ResponseInterface;
use Config\Cache as CacheConfig;

/**
 * Web Page Caching
 *
 * @see \CodeIgniter\Cache\ResponseCacheTest
 */
final class ResponseCache
{
 /**
 * Whether to take the URL query string into consideration when generating
 * output cache files. Valid options are:
 *
 * false = Disabled
 * true = Enabled, take all query parameters into account.
 * Please be aware that this may result in numerous cache
 * files generated for the same page over and over again.
 * array('q') = Enabled, but only take into account the specified list
 * of query parameters.
 *
 * @var bool|list<string>
 */
 private array|bool $cacheQueryString = false;

 /**
 * Cache time to live (TTL) in seconds.
 */
 private int $ttl = 0;

 public function __construct(CacheConfig $config, private readonly CacheInterface $cache)
 {
 $this->cacheQueryString = $config->cacheQueryString;
 }

 public function setTtl(int $ttl): self
 {
 $this->ttl = $ttl;

 return $this;
 }

 /**
 * Generates the cache key to use from the current request.
 *
 * @internal for testing purposes only
 */
 public function generateCacheKey(CLIRequest|IncomingRequest $request): string
 {
 if ($request instanceof CLIRequest) {
 return md5($request->getPath());
 }

 $uri = clone $request->getUri();

 $query = (bool) $this->cacheQueryString
 ? $uri->getQuery(is_array($this->cacheQueryString) ? ['only' => $this->cacheQueryString] : [])
 : '';

 return md5($request->getMethod() . ':' . $uri->setFragment('')->setQuery($query));
 }

 /**
 * Caches the response.
 */
 public function make(CLIRequest|IncomingRequest $request, ResponseInterface $response): bool
 {
 if ($this->ttl === 0) {
 return true;
 }

 $headers = [];

 foreach ($response->headers() as $name => $value) {
 if ($value instanceof Header) {
 $headers[$name] = $value->getValueLine();
 } else {
 foreach ($value as $header) {
 $headers[$name][] = $header->getValueLine();
 }
 }
 }

 return $this->cache->save(
 $this->generateCacheKey($request),
 serialize([
 'headers' => $headers,
 'output' => $response->getBody(),
 'status' => $response->getStatusCode(),
 'reason' => $response->getReasonPhrase(),
 ]),
 $this->ttl,
 );
 }

 /**
 * Gets the cached response for the request.
 */
 public function get(CLIRequest|IncomingRequest $request, ResponseInterface $response): ?ResponseInterface
 {
 $cachedResponse = $this->cache->get($this->generateCacheKey($request));

 if (is_string($cachedResponse) && $cachedResponse !== '') {
 $cachedResponse = unserialize($cachedResponse);

 if (
 ! is_array($cachedResponse)
 || ! isset($cachedResponse['output'])
 || ! isset($cachedResponse['headers'])
 ) {
 throw new RuntimeException('Error unserializing page cache');
 }

 $headers = $cachedResponse['headers'];
 $output = $cachedResponse['output'];
 $status = $cachedResponse['status'] ?? 200;
 $reason = $cachedResponse['reason'] ?? '';

 // Clear all default headers
 foreach (array_keys($response->headers()) as $key) {
 $response->removeHeader($key);
 }

 // Set cached headers
 foreach ($headers as $name => $value) {
 $response->setHeader($name, $value);
 }

 $response->setBody($output);

 $response->setStatusCode($status, $reason);

 return $response;
 }

 return null;
 }
}