<?php

// (c) Copyright by authors of the Tiki Wiki CMS Groupware Project
//
// All Rights Reserved. See copyright.txt for details and a complete list of authors.
// Licensed under the GNU LESSER GENERAL PUBLIC LICENSE. See license.txt for details.
// $Id$

class Tiki_PageCache
{
    private $cacheData = [];
    private $key;
    private $meta = null;
    private $headerLibCopy = null;

    public static function create()
    {
        return new self();
    }

    public function disableForRegistered()
    {
        global $user;

        if ($user) {
            $this->cacheData = null;
        }

        return $this;
    }

    public function onlyForGet()
    {
        if ($_SERVER['REQUEST_METHOD'] != 'GET') {
            $this->cacheData = null;
        }

        return $this;
    }

    public function requiresPreference($preference)
    {
        global $prefs;

        if ($prefs[$preference] != 'y') {
            $this->cacheData = null;
        }

        return $this;
    }

    public function addKeys($array, $keys)
    {
        if (is_array($this->cacheData)) {
            foreach ($keys as $k) {
                if (! isset($this->cacheData[$k])) {
                    $this->cacheData[$k] = isset($array[$k]) ? $array[$k] : null;
                }
            }
        }

        return $this;
    }

    public function addArray($array)
    {
        if (is_array($this->cacheData)) {
            $this->cacheData = array_merge($this->cacheData, $array);
        }

        return $this;
    }

    public function addValue($key, $value)
    {
        if (is_array($this->cacheData)) {
            $this->cacheData[$key] = $value;
        }

        return $this;
    }

    public function checkMeta($role, $data)
    {
        $this->meta = array_merge([ 'role' => $role ], $data);

        return $this;
    }

    public function applyCache()
    {
        if (is_array($this->cacheData)) {
            $memcachelib = TikiLib::lib("memcache");

            if (TikiLib::lib("memcache")->isEnabled()) {
                $this->key = $memcachelib->buildKey($this->cacheData);

                if ($this->meta) {
                    list($cachedOutput, $metaTime) = $memcachelib->getMulti(
                        [
                            $this->key,
                            $this->meta,
                        ]
                    );

                    if ($cachedOutput && $metaTime && $metaTime > $cachedOutput['timestamp']) {
                        $cachedOutput = null;
                    }
                } else {
                    $cachedOutput = $memcachelib->get($this->key);
                }

                if ($cachedOutput && $cachedOutput['output']) {
                    $headerlib = TikiLib::lib('header');
                    if (is_array($cachedOutput['jsfiles'])) {
                        foreach ($cachedOutput['jsfiles'] as $rank => $files) {
                            foreach ($files as $file) {
                                $skip_minify = isset($cachedOutput['skip_minify']) ? true : false;
                                $headerlib->add_jsfile_by_rank($file, $rank, $skip_minify);
                            }
                        }
                    }
                    if (is_array($cachedOutput['js'])) {
                        foreach ($cachedOutput['js'] as $rank => $js) {
                            foreach ($js as $j) {
                                $headerlib->add_js($j, $rank);
                            }
                        }
                    }
                    if (is_array($cachedOutput['jq_onready'])) {
                        foreach ($cachedOutput['jq_onready'] as $rank => $js) {
                            foreach ($js as $j) {
                                $headerlib->add_jq_onready($j, $rank);
                            }
                        }
                    }
                    if (is_array($cachedOutput['css'])) {
                        foreach ($cachedOutput['css'] as $rank => $css) {
                            foreach ($css as $c) {
                                $headerlib->add_css($c, $rank);
                            }
                        }
                    }
                    if (is_array($cachedOutput['cssfile'])) {
                        foreach ($cachedOutput['cssfile'] as $rank => $css) {
                            foreach ($css as $c) {
                                $headerlib->add_cssfile($c, $rank);
                            }
                        }
                    }


                    echo $cachedOutput['output'];
                    echo "\n<!-- memcache " . htmlspecialchars($this->key) . "-->";
                    exit;
                }

                // save state of headerlib
                $this->headerLibCopy = unserialize(serialize(TikiLib::lib('header')));

                // Start caching, automatically gather at destruction
                ob_start();
            }
        }

        return $this;
    }

    public function cleanUp()
    {
        if ($this->key) {
            $cachedOutput = [
                'timestamp' => time(),
                'output'    => ob_get_contents()
            ];

            if ($this->headerLibCopy) {
                $headerlib = TikiLib::lib('header');
                $cachedOutput['jsfiles']    = array_diff($headerlib->jsfiles, $this->headerLibCopy->jsfiles);
                $cachedOutput['skip_minify'] = array_diff($headerlib->skip_minify, $this->headerLibCopy->skip_minify);
                $cachedOutput['jq_onready'] = array_diff($headerlib->jq_onready, $this->headerLibCopy->jq_onready);
                $cachedOutput['js']         = array_diff($headerlib->js, $this->headerLibCopy->js);
                $cachedOutput['css']        = array_diff($headerlib->css, $this->headerLibCopy->css);
                $cachedOutput['cssfiles']   = array_diff($headerlib->cssfiles, $this->headerLibCopy->cssfiles);
            }

            if ($cachedOutput['output']) {
                TikiLib::lib("memcache")->set($this->key, $cachedOutput);
            }

            ob_end_flush();
        }

        $this->cacheData = [];
        $this->key = null;
        $this->meta = null;
    }

    public function invalidate()
    {
        if ($this->meta) {
            TikiLib::lib("memcache")->set($this->meta, time());
        }
    }

    public function __destruct()
    {
        $this->cleanUp();
    }
}