<?php

namespace Providers;

abstract class Provider {

    protected $_options = [];
    protected $_feed = NULL;
    protected $_cacheTimeout = '15 minutes';
    protected $_cacheTime;

    public function __construct($feed, $options=[]) {
        $this->_feed = $feed;
        $this->_options = $options;
    }

    abstract protected function _getCachePath();

    protected function _getCache($path) {
        return file_get_contents($path);
    }

    abstract protected function _fetchItems();

    abstract protected function _spamFilter($items);

    abstract protected function _mapItems($content);

    abstract protected function _sortContent($content);

    protected function _getItems() {
        $cacheFile = sprintf($this->_getCachePath(), $this->_feed);
        $this->_cacheTime = file_exists($cacheFile) ? filemtime($cacheFile) : 0;
        if ($this->_cacheTime > strtotime('-' . $this->_cacheTimeout)) {
            return unserialize($this->_getCache($cacheFile));
        } else {
            $content = $this->_fetchItems();
            file_put_contents($cacheFile, serialize($content));
            $this->_cacheTime = time();
            return $content;
        }
    }

    public function get() {
        $items = $this->_getItems();
        if (isset($this->_options['spamfilter'])) {
            $items = $this->_spamFilter($items);
        }
        return $this->_sortContent($this->_mapItems($items));
    }

    public function cacheTime() {
        return $this->_cacheTime;
    }

    abstract public function title();

}

?>