function price_book($book)
{
    global $SELLERS_URL;
    $best_book_price = 1000;
    $best_book_ship = 2.99;
    $best_book_ISBN = "";
    $best_book_url = NULL;
    $best_book_price_amazon = 0;
    // replace entites quote
    $book = str_replace("’", "'", $book);
    $book = urlencode($book);
    // 0. parse all books from pmba reading list
    foreach ($SELLERS_URL as $seller_url) {
        // 1. Parse all sellers and save best price + url
        $seller_price = price_book_sellers($seller_url, $book);
        if (isset($seller_price)) {
            $price = $seller_price[0];
            $url = $seller_price[1];
            // test best price
            if ($price < $best_book_price) {
                $best_book_price = $price;
                $best_book_url = $url;
            }
        }
    }
    // 2. from best book price url, get price, ship price, ISBN
    if (!isset($best_book_url)) {
        return;
    }
    $ISBN = get_ISBN($best_book_url);
    $best_book_price_amazon = get_amazon_price($book);
    return array($best_book_price_amazon, $best_book_price, $best_book_ship, $best_book_ISBN, $best_book_url);
}
function price_book($book)
{
    $amazon_url = "http://www.amazon.fr/gp/search/ref=sr_adv_b/?search-alias=stripbooks&__mk_fr_FR=%C5M%C5Z%D5%D1&unfiltered=1&field-author=&field-title=&field-isbn=&field-publisher=&field-collection=&node=&field-binding_browse-bin=492481011&field-dateop=&field-datemod=&field-dateyear=&sort=relevancerank&Adv-Srch-Books-Submit.x=0&Adv-Srch-Books-Submit.y=0";
    $amazon_url .= "&field-keywords=" . $book;
    $snoopy = new Snoopy();
    $snoopy->fetch($amazon_url);
    $html = $snoopy->results;
    $html = str_get_html($html);
    $prices = null;
    $results = $html->find('#atfResults', 0);
    if (isset($results)) {
        // book url
        $book_url = $results->find('.productTitle', 0);
        $book_url = $book_url->find('a', 0)->href;
        $ISBN = get_ISBN($book_url);
        $prices = get_best_price($ISBN);
    } else {
        $prices[0] = 0;
        $prices[1] = 0;
        $ISBN = -1;
        $book_url = 'http://www.amazon.fr';
    }
    $html->clear();
    unset($html);
    return array($prices[0], $prices[1], '2.99', $ISBN, $book_url);
}
                        $array[$i]['name'] = $name;
                        $array[$i]['link'] = $baseurl . $link;
                        $array[$i]['old-price'] = 'N/A';
                        $array[$i]['new-price'] = text_prepare(pq($item)->find('span[id^="itemPrice_"]')->html());
                        $array[$i]['date-added'] = text_prepare(str_replace('Added', '', pq($item)->find('div[id^="itemAction_"] .a-size-small')->html()));
                        $array[$i]['priority'] = text_prepare(pq($item)->find('span[id^="itemPriorityLabel_"]')->html());
                        $array[$i]['rating'] = 'N/A';
                        $array[$i]['total-ratings'] = $total_ratings;
                        $array[$i]['comment'] = text_prepare(pq($item)->find('span[id^="itemComment_"]')->html());
                        $array[$i]['picture'] = pq($item)->find('div[id^="itemImage_"] img')->attr('src');
                        $array[$i]['page'] = $page_num;
                        $array[$i]['ASIN'] = get_ASIN($array[$i]['link']);
                        $array[$i]['large-ssl-image'] = get_large_ssl_image($array[$i]['picture']);
                        $array[$i]['affiliate-url'] = get_affiliate_link($array[$i]['ASIN']);
                        if ($_GET['isbn'] == true) {
                            $array[$i]['isbn'] = get_ISBN($array[$i]['link']);
                        }
                        if ($_GET['author'] == true) {
                            $array[$i]['author'] = pq($item)->find('div[id^="itemInfo_"] .a-row.a-size-small:has(h5 a[id^="itemName_"])');
                            $array[$i]['author']->find('h5')->remove();
                            $array[$i]['author'] = trim(preg_replace('/\\([\\ \\w]+\\)/', '', str_replace('by', '', $array[$i]['author']->text())));
                        }
                        $i++;
                    }
                }
            }
        }
    }
}
//go to product details page for isbn
function get_ISBN($url)