<?php

class FilterMoreBridge extends FeedExpander {

	const MAINTAINER = 'boyska';
	const NAME = 'FilterMore';
	const CACHE_TIMEOUT = 2;
	const DESCRIPTION = 'Filters a feed of your choice';
	const URI = 'https://git.lattuta.net/boyska/rss-bridge';

	const PARAMETERS = array(array(
		'url' => array(
			'name' => 'Feed URL',
			'required' => true,
		),
		'conj_type' => array(
			'name' => 'Conjunction type type',
			'type' => 'list',
			'required' => false,
			'values' => array(
				'All conditions must be met' => 'and',
				'Any condition must be met' => 'or',
			),
			'defaultValue' => 'permit',
		),

		'title_re' => array(
			'name' => 'Filter item title (regular expression, see php.net/pcre_match for details)',
			'required' => false,
            'exampleValue' => '/breaking\ news/i',
		),
		'body_re' => array(
			'name' => 'Filter body (regular expression)',
			'required' => false,
		),
		'author_re' => array(
			'name' => 'Filter author (regular expression)',
			'required' => false,
            'exampleValue' => '/(technology|politics)/i',
		),
		'newer_than' => array(
			'name' => 'Filter date: ok if newer than the value (see php.net/strtotime for details)',
			'required' => false,
            'exampleValue' => '-14 days',
		),
		'older_than' => array(
			'name' => 'Filter date: ok if older than the value (see php.net/strtotime for details)',
			'required' => false,
            'exampleValue' => '-1 hour',
		),

		'invert_filter' => array(
			'name' => 'Invert filter result',
			'type' => 'checkbox',
			'required' => false,
			'defaultValue' => false,
		),
	));

	protected function parseItem($newItem){
		$item = parent::parseItem($newItem);
        $item['enclosures'] = [];
        if(isset($newItem->enclosure)) {
            foreach($newItem->enclosure as $encl) {
                $serialized = [];
                foreach($encl->attributes() as $key => $value) {
                    $serialized[$key] = (string)$value;
                }
                $serialized["length"] = intval($serialized["length"]);
                $item['enclosures'][] = $serialized;
            }
        }
        if(isset($newItem->link)) {
            foreach($newItem->link as $el) {
                if(((string)$el['rel']) !== 'enclosure') continue;
                $serialized = [];
                $serialized['url'] = (string)$el['href'];

                $item['enclosures'][] = $serialized;
            }
        }

        $filters = ['filterByTitle', 'filterByBody', 'filterByAuthor', 'filterByDateNewer', 'filterByDateOlder'];
        $results = [];

        foreach($filters as $filter) {
            $filter_res = $this->$filter($item);
            if($filter_res === null) continue;
            $results[] = $filter_res;
        }

        $old_enclosures = $item['enclosures'];
        $item['enclosures'] = [];
        foreach($old_enclosures as $e) {
            $item['enclosures'][] = $e['url'];
        }
        if(count($results) === 0) {
            return $item;
        }
        if($this->getConjType() === 'and') {
            $result = !in_array(false, $results);
        } else { // or
            $result = in_array(true, $results);
        }
        if($this->getInvertResult()) {
            $result = !$result;
        }
        if($result)
            return $item;
        else
            return null;
	}

    private function cmp($a, $b) {
        if($a > $b) return 1;
        if($a < $b) return -1;
        return 0;
    }
	private function filterByFieldRegexp($field, $re){
        if($re === "") return null;
        if(preg_match($re, $field)) {
            return true;
        }
        return false;
	}
	protected function filterByTitle($item){
		$re = $this->getInput('title_re');
        return $this->filterByFieldRegexp($item['title'], $re);
	}
	protected function filterByBody($item){
		$re = $this->getInput('body_re');
        return $this->filterByFieldRegexp($item['content'], $re);
	}
	protected function filterByAuthor($item){
		$re = $this->getInput('author_re');
        return $this->filterByFieldRegexp($item['author'], $re);
	}
	private function filterByDate($item, $input, $expected){
		$val = $this->getInput($input);
        if($val === "") return null;
        $ts = strtotime($val);
        if($ts === false) {
            throw new Exception("Invalid time specification: " . $val);
        }
        $cmp =  $this->cmp($item['timestamp'], $ts); // 1 if newer, -1 if older
        return $cmp === $expected;
	}
	protected function filterByDateNewer($item){
        return $this->filterByDate($item, 'newer_than', 1);
	}
	protected function filterByDateOlder($item){
        return $this->filterByDate($item, 'older_than', -1);
	}

	protected function getConjType(){
		return $this->getInput('conj_type');
	}
	protected function getInvertResult(){
		return $this->getInput('invert_filter');
	}

	public function getURI(){
		$url = $this->getInput('url');

		if(empty($url)) {
			$url = parent::getURI();
		}
		return $url;
	}

	public function collectData(){
		if($this->getInput('url') && substr($this->getInput('url'), 0, strlen('http')) !== 'http') {
			// just in case someone find a way to access local files by playing with the url
			returnClientError('The url parameter must either refer to http or https protocol.');
		}
		try{
			$this->collectExpandableDatas($this->getURI());
		} catch (HttpException $e) {
			$this->collectExpandableDatas($this->getURI());
		}
	}
}