<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Cache\Traits;

use Symfony\Component\Cache\Exception\InvalidArgumentException;

/**
 * @author Nicolas Grekas <p@tchwork.com>
 *
 * @internal
 */
trait FilesystemCommonTrait
{
    private $directory;
    private $tmp;

    private function init(string $namespace, ?string $directory)
    {
        if (!isset($directory[0])) {
            $directory = sys_get_temp_dir().\DIRECTORY_SEPARATOR.'symfony-cache';
        } else {
            $directory = realpath($directory) ?: $directory;
        }
        if (isset($namespace[0])) {
            if (preg_match('#[^-+_.A-Za-z0-9]#', $namespace, $match)) {
                throw new InvalidArgumentException(sprintf('Namespace contains "%s" but only characters in [-+_.A-Za-z0-9] are allowed.', $match[0]));
            }
            $directory .= \DIRECTORY_SEPARATOR.$namespace;
        } else {
            $directory .= \DIRECTORY_SEPARATOR.'@';
        }
        if (!is_dir($directory)) {
            @mkdir($directory, 0777, true);
        }
        $directory .= \DIRECTORY_SEPARATOR;
        // On Windows the whole path is limited to 258 chars
        if ('\\' === \DIRECTORY_SEPARATOR && \strlen($directory) > 234) {
            throw new InvalidArgumentException(sprintf('Cache directory too long (%s).', $directory));
        }

        $this->directory = $directory;
    }

    /**
     * {@inheritdoc}
     */
    protected function doClear(string $namespace)
    {
        $ok = true;

        foreach ($this->scanHashDir($this->directory) as $file) {
            if ('' !== $namespace && 0 !== strpos($this->getFileKey($file), $namespace)) {
                continue;
            }

            $ok = ($this->doUnlink($file) || !file_exists($file)) && $ok;
        }

        return $ok;
    }

    /**
     * {@inheritdoc}
     */
    protected function doDelete(array $ids)
    {
        $ok = true;

        foreach ($ids as $id) {
            $file = $this->getFile($id);
            $ok = (!is_file($file) || $this->doUnlink($file) || !file_exists($file)) && $ok;
        }

        return $ok;
    }

    protected function doUnlink($file)
    {
        return @unlink($file);
    }

    private function write(string $file, string $data, int $expiresAt = null)
    {
        set_error_handler(__CLASS__.'::throwError');
        try {
            if (null === $this->tmp) {
                $this->tmp = $this->directory.bin2hex(random_bytes(6));
            }
            try {
                $h = fopen($this->tmp, 'x');
            } catch (\ErrorException $e) {
                if (false === strpos($e->getMessage(), 'File exists')) {
                    throw $e;
                }

                $this->tmp = $this->directory.bin2hex(random_bytes(6));
                $h = fopen($this->tmp, 'x');
            }
            fwrite($h, $data);
            fclose($h);

            if (null !== $expiresAt) {
                touch($this->tmp, $expiresAt);
            }

            return rename($this->tmp, $file);
        } finally {
            restore_error_handler();
        }
    }

    private function getFile(string $id, bool $mkdir = false, string $directory = null)
    {
        // Use MD5 to favor speed over security, which is not an issue here
        $hash = str_replace('/', '-', base64_encode(hash('md5', static::class.$id, true)));
        $dir = ($directory ?? $this->directory).strtoupper($hash[0].\DIRECTORY_SEPARATOR.$hash[1].\DIRECTORY_SEPARATOR);

        if ($mkdir && !is_dir($dir)) {
            @mkdir($dir, 0777, true);
        }

        return $dir.substr($hash, 2, 20);
    }

    private function getFileKey(string $file): string
    {
        return '';
    }

    private function scanHashDir(string $directory): \Generator
    {
        if (!is_dir($directory)) {
            return;
        }

        $chars = '+-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';

        for ($i = 0; $i < 38; ++$i) {
            if (!is_dir($directory.$chars[$i])) {
                continue;
            }

            for ($j = 0; $j < 38; ++$j) {
                if (!is_dir($dir = $directory.$chars[$i].\DIRECTORY_SEPARATOR.$chars[$j])) {
                    continue;
                }

                foreach (@scandir($dir, \SCANDIR_SORT_NONE) ?: [] as $file) {
                    if ('.' !== $file && '..' !== $file) {
                        yield $dir.\DIRECTORY_SEPARATOR.$file;
                    }
                }
            }
        }
    }

    /**
     * @internal
     */
    public static function throwError($type, $message, $file, $line)
    {
        throw new \ErrorException($message, 0, $type, $file, $line);
    }

    /**
     * @return array
     */
    public function __sleep()
    {
        throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
    }

    public function __wakeup()
    {
        throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
    }

    public function __destruct()
    {
        if (method_exists(parent::class, '__destruct')) {
            parent::__destruct();
        }
        if (null !== $this->tmp && is_file($this->tmp)) {
            unlink($this->tmp);
        }
    }
}