<?php

namespace sacy;

class FileCache
{
    private $cache_dir;

    public function __construct()
    {
        $this->cache_dir = implode(DIRECTORY_SEPARATOR, [
            ASSET_COMPILE_OUTPUT_DIR,
            'fragments',
        ]);
        if (!is_dir($this->cache_dir)) {
            if (!@mkdir($this->cache_dir, 0755, true)) {
                throw new Exception('Failed to create fragments cache directory');
            }
        }
    }

    public function key2file($key)
    {
        if (!preg_match('#^[0-9a-z]+$#', $key)) {
            throw new Exception('Invalid cache key');
        }

        return implode(DIRECTORY_SEPARATOR, [
            $this->cache_dir,
            preg_replace('#^([0-9a-f]{2})([0-9a-f]{2})(.*)$#u', '\1/\2/\3', $key),
        ]);
    }

    public function get($key)
    {
        return null;
        $p = $this->key2file($key);

        return file_exists($p) ? @file_get_contents($p) : null;
    }

    public function set($key, $value)
    {
        return true;
        $p = $this->key2file($key);
        if (!@mkdir(dirname($p), 0755, true)) {
            throw new Exception("Failed to create fragment cache dir: {$p}");
        }

        return @file_put_contents($p, $value);
    }
}