<?php

namespace Kirby\Cms;

use Kirby\Cache\Cache;
use Kirby\Cache\NullCache;
use Kirby\Exception\InvalidArgumentException;

/**
 * AppCaches
 *
 * @package   Kirby Cms
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://getkirby.com/license
 */
trait AppCaches
{
	protected array $caches = [];

	/**
	 * Returns a cache instance by key
	 */
	public function cache(string $key): Cache
	{
		if (isset($this->caches[$key]) === true) {
			return $this->caches[$key];
		}

		// get the options for this cache type
		$options = $this->cacheOptions($key);

		if ($options['active'] === false) {
			// use a dummy cache that does nothing
			return $this->caches[$key] = new NullCache();
		}

		$type  = strtolower($options['type']);
		$types = $this->extensions['cacheTypes'] ?? [];

		if (array_key_exists($type, $types) === false) {
			throw new InvalidArgumentException([
				'key'  => 'cache.type.invalid',
				'data' => ['type' => $type]
			]);
		}

		$className = $types[$type];

		// initialize the cache class
		$cache = new $className($options);

		// check if it is a usable cache object
		if ($cache instanceof Cache === false) {
			throw new InvalidArgumentException([
				'key'  => 'cache.type.invalid',
				'data' => ['type' => $type]
			]);
		}

		return $this->caches[$key] = $cache;
	}

	/**
	 * Returns the cache options by key
	 */
	protected function cacheOptions(string $key): array
	{
		$options   = $this->option($this->cacheOptionsKey($key), null);
		$options ??= $this->core()->caches()[$key] ?? false;

		if ($options === false) {
			return [
				'active' => false
			];
		}

		$prefix =
			str_replace(['/', ':'], '_', $this->system()->indexUrl()) .
			'/' .
			str_replace(['/', '.'], ['_', '/'], $key);

		$defaults = [
			'active'    => true,
			'type'      => 'file',
			'extension' => 'cache',
			'root'      => $this->root('cache'),
			'prefix'    => $prefix
		];

		if ($options === true) {
			return $defaults;
		}

		return array_merge($defaults, $options);
	}

	/**
	 * Takes care of converting prefixed plugin cache setups
	 * to the right cache key, while leaving regular cache
	 * setups untouched.
	 */
	protected function cacheOptionsKey(string $key): string
	{
		$prefixedKey = 'cache.' . $key;

		if (isset($this->options[$prefixedKey])) {
			return $prefixedKey;
		}

		// plain keys without dots don't need further investigation
		// since they can never be from a plugin.
		if (strpos($key, '.') === false) {
			return $prefixedKey;
		}

		// try to extract the plugin name
		$parts        = explode('.', $key);
		$pluginName   = implode('/', array_slice($parts, 0, 2));
		$pluginPrefix = implode('.', array_slice($parts, 0, 2));
		$cacheName    = implode('.', array_slice($parts, 2));

		// check if such a plugin exists
		if ($this->plugin($pluginName)) {
			return empty($cacheName) === true ? $pluginPrefix . '.cache' : $pluginPrefix . '.cache.' . $cacheName;
		}

		return $prefixedKey;
	}
}