<?php

namespace Scraping;

use \Goutte\Client;

class Scraper
{
    public $results = [];
    public $allowedMimetypes;
    public $link_rules;
    public $debug = false;

    /**
     * Scrapes specified URLs
     * 
     * @param array     $urls
     * @param int       $level
     */
    public function scrape(array $urls, int $level){
        $client = new Client();

        $sub_urls = [];

        foreach ($urls as $url) {
            $crawler = $client->request('GET', $url);

            if ($this->debug) {
                print '['.$level.'] '.$url."\n";
            }

            $scraped_obj[$url]['content-type'] = $this->getContentType($client);
            $scraped_obj[$url]['is-downloadable'] = $this->isDownloadable($client);
            $scraped_obj[$url]['filename'] = ( $scraped_obj[$url]['is-downloadable'] ? $this->getFilename($client) : '' );

            $this->results = array_merge( $this->results, $scraped_obj );

            $new_urls = $crawler->filterXPath($this->link_rules[$level])->each(function ($node) {
                return $node->link()->getUri();
            });

            $sub_urls = array_merge( $sub_urls, $new_urls );
        }

        if ($level++ < count($this->link_rules) && !empty($sub_urls)) {
            $this->scrape($sub_urls, $level);
        }
    }

    /**
     * Returns if URL is downloadable
     * 
     * @return boolean
     * 
     * @param Client    $client
     */
    public function isDownloadable(Client $client){
        foreach ($this->allowedMimetypes as $mimetype) {
            if (isset($client->getResponse()->getHeaders()['content-type'][0])) {
                if (strstr($client->getResponse()->getHeaders()['content-type'][0], $mimetype)) {
                    return true;
                }
            }
        }

        return false;
    }

    /**
     * Get filename of http response based on URL or content-disposition header
     * 
     * @return string
     * 
     * @param Client    $client
     */
    public function getFilename(Client $client){
        $filename = basename( $client->getRequest()->getUri() );

        // Try to get filename from content-disposition
        if (isset($client->getResponse()->getHeaders()['content-disposition'][0])) {
            $content_disposition = $client->getResponse()->getHeaders()['content-disposition'][0];
            
            if (preg_match('/filename="([^"]+)"/', $content_disposition, $m)) {
                $filename = $m[1].'-'.$this->allowedMimetypes[ $this->getContentType($client) ];
            } else {
                $filename = time();
            }
        }

        return $filename;
    }

    /**
     * Get content type of http response
     * 
     * @return string
     * 
     * @param Client    $client
     */
    public static function getContentType(Client $client){
        $content_type = '';

        if (isset($client->getResponse()->getHeaders()['content-type'][0])) {
            $content_type = $client->getResponse()->getHeaders()['content-type'][0];
        }

        return $content_type;
    }
}