<?php

/** DomFramework
  * @package domframework
  * @author Dominique Fournier <dominique@fournier38.fr>
  * @license BSD
  */

namespace Domframework;

/** This class permit to cache the ouptut of a code. If the cache is already
  * available, use it.
  * It resend the headers as the ouptut send them
  * Use it by :
  *    $c = new Cacheoutput ("URL");
  * Don't forget to define a variable or the cache saved is always empty
  */
class Cacheoutput
{
    /** Record if the saving of pages is on going */
    private $saving = false;
    /** The called id */
    private $id = null;
    /** The called ttl */
    private $ttl = null;
    /** The cache object */
    private $cache = null;
    /** Current path at start due to lack of information in __destruct*/
    private $cacheCWD = null;

    /**
        @param string $id The cache identifier
        @param integer|null $ttl The cache Time to Leave in seconds (60s by
                                 default)
        @param string|null $method The cache method to use */
    public function __construct($id, $ttl = 60, $method = "file")
    {
        $res = @include("domframework/cache$method.php");
        if ($res === false) {
            throw new \Exception(
                sprintf(dgettext(
                    "domframework",
                    "Unkwnown cache method : "
                ), $method),
                500
            );
        }
        $this->id = $id;
        $this->ttl = $ttl;
        $this->cacheCWD = getcwd();
        $cachemethod = "Cache$method";
        $this->cache = new $cachemethod();
        if ($ttl === 0) {
            $this->cache->nocache = 1;
        }
        $res = $this->cache->read($id);
        // If there is a cache : display it
        if ($res !== false) {
            foreach ($res["headers"] as $header) {
                @header($header);
            }
            echo $res["content"];
            exit;
        }

        ob_start();
        $this->saving = true;
        // The data are sent automatically
    }

    /** End of saving the data in cache */
    public function __destruct()
    {
        // Force the path because it return to / in the destructor
        chdir($this->cacheCWD);
        if ($this->saving === true) {
            // Do the saving of the data
            $data = array("content" => ob_get_contents(),
                      "headers" => headers_list());
            $this->cache->write($this->id, $data, $this->ttl);
        }
    }
}