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

WBClass::load('WBObserver'
        , 'WBObserver_Observable'
        );

/**
 * Datasource Sitemap
 *
 * @version 0.3.0
 * @package WB
 * @subpackage datasource
 */
abstract class WBDatasource_Sitemap extends WBStdClass implements WBObserver_Observable
{
    /**
     * current priority
     * @var float
     */
    private $priority   =   1.0;

    /**
     * current path
     * @var float
     */
    private $path   =   '/';

    /**
     * sitemap snippet XML chunk, usually empty
     * @var string
     */
    private $snippet = '';

    /**
     * Date of modification
     * @var string
     */
    private $modified = '';

    /**
     * Change Frequency
     * @var string
     */
    private $changeFreq = '';

    const CHANGE_FREQ_ALWAYS    =   'always';
    const CHANGE_FREQ_DAILY     =   'daily';
    const CHANGE_FREQ_WEEKLY    =   'weekly';
    const CHANGE_FREQ_MONTHLY   =   'monthly';
    const CHANGE_FREQ_YEARLY    =   'yeaarly';
    const CHANGE_FREQ_NEVER     =   'never';

    /**
     * list of observers
     * @var array
     */
    private $observers = array();

    /**
     * datasource config
     * @var array
     */
    protected $config   =   array();

    /**
     * Configure datasource object
     *
     * Merge given config with default configuration
     *
     * @see $config
     * @param array $config
     */
    final public function configure($config)
    {
        if (!is_array($config)) {
            $config =   array();
        }
        $this->config   =   array_merge($this->config, $config);
    }

    /**
     * attach observer
     *
     * @param WBObserver $observer
     */
    final public function attach(WBObserver $observer)
    {
        $this->observers[$observer->getObjectId()]  =   $observer;
    }

    /**
     * detach observer
     *
     * @param WBObserver $observer
     */
    final public function detach(WBObserver $observer)
    {
        unset($this->observers[$observer->getObjectId()]);
    }

    /**
     * notify observer
     *
     */
    final public function notify()
    {
        foreach ($this->observers as $o) {
            $o->update($this);
        }
    }

    /**
     * Set current path
     *
     * @param string $path
     * @param string $snippet, usually empty
     */
    final protected function setPath($path, $snippet = '')
    {
        $this->path     =   $path;
        $this->snippet  =   $snippet;
    }

    /**
     * Set current priority
     *
     * @param float $priority
     */
    final protected function setPriority($priority)
    {
        $this->priority =   $priority;
    }

    /**
     * Set Last Modifed Date
     *
     * @param string $timestamp
     */
    final protected function setModified($timestamp = null)
    {
        if (empty($timestamp)) {
            $this->modified =   '';
        }
        if (10 < strlen($timestamp)) {
            $timestamp  =   substr($timestamp, 0, 10);
        }
        $this->modified =   $timestamp;
    }

    /**
     * Set Current Change Frequency
     *
     * @see CHANGE_FREQ_DAILY
     * @param string $freq
     */
    final protected function setChangeFreq($freq = null)
    {
        if (empty($freq)) {
            $this->changeFreq   =   '';
        }
        $this->changeFreq   =   $freq;
    }

    /**
     * Get current path
     *
     * Usually called by observer
     *
     * @return string
     */
    final public function getPath()
    {
        return $this->path;
    }

    /**
     * Get current priority
     *
     * Usually called by observer
     *
     * @return float
     */
    final public function getPriority()
    {
        return $this->priority;
    }

    /**
     * Get current snippet
     *
     * Usually called by observer. Snippet is usually empty, still modification day and changefreq may be there
     *
     * @return float
     */
    final public function getSnippet()
    {
        return $this->snippet;
    }

    /**
     * Get Current Modifed Date
     *
     * @return string
     */
    final public function getModified()
    {
        return $this->modified;
    }

    /**
     * Get Current Change Frequency
     *
     * @return string
     */
    final public function getChangedFreq()
    {
        return $this->changeFreq;
    }

    /**
     * Find all the URLs
     *
     * Walk through all the pages etc. to find all URLs to be added to the sitemap.
     */
    abstract public function find();
}