<?php
/**
 * Event_Handler_Blog2Facebook
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage base
 */

WBClass::load('WBEvent_Handler'
    , 'WBString'
    , 'WBBlog'
    , 'WBBlog_Tool'
    );

/**
 * Event_Handler_Blog2Facebook
 *
 * Post blog article on facebook
 *
 * @version 0.1.0
 * @package WB
 * @subpackage base
 */
class WBEvent_Handler_Blog2Facebook extends WBEvent_Handler
{
    /**
     * configuration parameter
     * @var array
     */
    protected $config  = array(
                                'msgindex'      =>  'title',
                                'titleindex'    =>  'title'
                                // 'actions'   =>  array('Like')
                                );
    /**
     * blog tool
     * @vart WBBlog_Tool
     */
    private $blog;

    /**
     * facebook connection
     * @var WBFacebook
     */
    private $fb;

    /**
     * dict
     * @var WBDatasource_URLReference
     */
    private $ref;

    /**
     * file
     * @var WBVFS_File
     */
    private $file;

    /**
     * process event
     *
     * just say OK
     *
     * @see isRecoverable()
     * @param WBEvent $e
     * @return bool true to continue, false to stop processing
     * @throws Exception in case of error
     */
    public function process(WBEvent $e)
    {
        $change =   $e->get('change');
        if ('public' != $change[1]) {
            return true;
        }

        $new    =   $e->get('new');
        if (!$new && 'public' == $change[0]) {
            return true;
        }

        $msg    =   $e->get($this->config['msgindex'], '');
        if (empty($msg)) {
            $msg    =   $e->get('title');
        }

        // check for timed records
        $ts =   strtotime($e->get('created', '1970-01-01 00:00:00'));
        if (time() < $ts) {
            $this->retry();
            return true;
        }

        $url    =   $this->getBlogUrl($e);
        $data   =   array(
                            'message'   =>  $msg
                            );
        $this->addPicture($data, $url);
        $this->postOnWall($data, $url);
        return true;
    }

    /**
     * add picture URL
     *
     * Find vfsfile references and add first file as picture.
     *
     * @param array $data
     * @param string $url
     */
    private function addPicture(&$data, $url)
    {
        $this->file =   WBClass::create('WBVFS_File');
        $this->ref  =   WBClass::create('WBDatasource_URLReference');

        $files      =   $this->ref->get($url, array('vfsfile'));
        if (empty($files)) {
            return;
        }

        foreach ($files as $f) {
            $file   =   $this->file->loadById($f['xid']);
            if (!$file->isOK()) {
                continue;
            }
            $data['picture']    =   WBString::replaceSuperPlaceholders($file->getUrl('image'));
            return;
        }
    }

    /**
     * post record on wall
     *
     * @todo do something with the post id?
     * @param array $data
     * @param string $link
     */
    private function postOnWall($data, $link)
    {
        if (!$this->fb) {
            $this->fb   =   WBClass::create('WBFacebook');
        }
        $data['link']   =   $link;
        $actions        =   array(
                                array(
                                    'name'  =>  'Like',
                                    'link'  =>  $link
                                    )
                            );
        $id     =   $this->fb->postOnWall($data, $actions);
    }

    /**
     * get blog's article URL
     *
     * @param WBEvent $e
     * @return string $url
     */
    private function getBlogUrl(WBEvent $e)
    {
        if (!$this->blog) {
            $this->blog =   WBClass::create('WBBlog_Tool');
        }
        $this->blog->loadArticleByData($e->get());
        $url        =   $this->blog->getArticleUrl();
        $url        =   WBString::replaceSuperPlaceholders($url);
        return $url;
    }

    /**
     * throw recoverable execption
     *
     * @throws WBException_Trylater
     */
    private function retry()
    {
        $this->recoverable  =   true;
        WBClass::load('WBException_Trylater');
        throw new WBException_Trylater('It is too early to publish the article at facebook, try again later.', 1, __CLASS__);
    }
}
?>