<?php
/**
 * DB helper file.
 *
 * Provides a helper to perform database operations.
 *
 * @author Iñigo Valentin <i@inigovalentin.com>
 * @license https://www.gnu.org/licenses/gpl-3.0.en.html GNU General Public License V3
 * @package IV
 */

require_once(__DIR__ . "/Helper.php");


/**
 * Text helper.
 *
 * Contains utilities to show and manipulate texts.
 *
 * @category Helper.
 */
final class TEXT extends Helper{

    /**
     * Selects the language the page will be displayed on.
     * 
     * First, it tries to read the language cookie in the client. If none is set, get the browser
     * language preference list. If none is provided or they are not supported, it will use the
     * default language.
     * 
     * @return string Lowercase, two-letter language code.
     * @todo Refactor to use user definced languages.
     */
    function select_language(){
        // Get available languages from db
        $available_languages = array();
        $q_lang = mysqli_query($db, "SELECT code FROM lang WHERE active = 1;");
        while ($r_lang = mysqli_fetch_array($q_lang))
            array_push($available_languages, $r_lang["code"]);
        // Is there a language cookie installed on the client?.
        header("Cache-control: private");
        if (isSet($_COOKIE["lang"])){
            $lang = $_COOKIE["lang"];
            if (in_array($lang, $available_languages)) return $lang;
        }
        // If no cookie, select from client browser preferences.
        $lang = prefered_language($available_languages, $_SERVER["HTTP_ACCEPT_LANGUAGE"]);
        if (in_array($lang, $available_languages)) return $lang;
        // If no method was succesfull, default language
        $lang = $available_languages[0];
        return $lang;
    }


    /**
     * Parses the language prefrences of the client broser, comparing them to the languages
     * offered by the site and selects the prefered one among the ones supported.
     * 
     * @param string[] available_languages List of lowercase, two-letter language codes allowed by
     * the site.
     * @param string http_accept_language Raw header with info about client language preferences.
     * @return string Lowercase, two-letter code of the prefered available language.
     * @todo Refactor to user user defined languages.
     */
    function prefered_language(array $available_languages, $http_accept_language) {

        $available_languages = array_flip($available_languages);
        $langs = [];
        preg_match_all(
          "~([\w-]+)(?:[^,\d]+([\d.]+))?~", strtolower($http_accept_language),
          $matches, PREG_SET_ORDER
        );
        foreach($matches as $match) {
            list($a, $b) = explode("-", $match[1]) + array("", "");
            $value = isset($match[2]) ? (float) $match[2] : 1.0;
            if(isset($available_languages[$match[1]])) {
                $langs[$match[1]] = $value;
                continue;
            }
            if(isset($available_languages[$a])) $langs[$a] = $value - 0.1;
        }
        if (count($langs) > 0){
            arsort($langs);
            //return $langs[0];
            return array_values($langs)[0];
        }
        else return 'en';
    }


    /**
     * Returns a date string into a human readable string on the specified language. Only works
     * for spanish, basque and english.
     * 
     * @param string $str_date Date string ('yyyy-mm-dd' or 'yyyy-mm-dd HH:MM:SS')
     * @param string $lang Language code (es, en, eu).
     * @param string $time Append the time at the end.
     * @return string Formatted date string.
     */
    function format_date($str_date, $lang, $time = true){
        $date = strtotime($str_date);
        $year = date("o", $date);
        $month = date("n", $date);
        $month --;
        $day = date("j", $date);
        $wday = date("N", $date);
        $wday --;
        $hour = date("H", $date);
        $minute = date("i", $date);
        switch ($lang){
            case "en":
                $week = [
                  "Monday", "Tuesday", "Wednesday", "Thursday",
                  "Friday", "Saturday", "Sunday"
                ];
                $months = [
                  "January", "February", "March", "April", "May", "June",
                  "July", "August", "September", "October", "November", "December"
                ];
                if ($time) $str = "$week[$wday], $months[$month] $day, $year at $hour:$minute";
                else $str = "$week[$wday], $months[$month] $day, $year";
                break;
            case "eu":
                $week = [
                  "astelehena", "asteartea", "asteazkena", "osteguna",
                  "ostirala", "larumbata", "igandea"
                ];
                $months = [
                  "urtarrilaren", "otsailaren", "martxoaren", "apirilaren",
                  "maiatzaren","ekainaren", "uztailaren", "abuztuaren",
                  "irailaren", "urriaren", "azaroaren", "abenduaren"
                ];
                if ($time)
                    $str = $year . "ko $months[$month] $day" . "an, $week[$wday], $hour:$minute";
                else $str = $year . "ko $months[$month] $day" . "an, $week[$wday]";
                break;
            default:
                $week = [
                  "Lunes", "Martes", "Mi&eacute;rcoles", "Jueves",
                  "Viernes", "S&aacute;bado", "Domingo"
                ];
                $months = [
                  "enero", " febrero", "marzo", "abril", "mayo", "junio",
                  "julio", "agosto", "septiembre", "octubre", "noviembre", "diciembre"
                ];
                if ($time)
                    $str = "$week[$wday] $day de $months[$month] de $year a las $hour:$minute";
                else $str = "$week[$wday] $day de $months[$month] de $year";
        }
        return $str;
    }


    /**
     * Retrieves a text fragment from the database.
     * 
     * @param string $id Text identifier.
     * @param bool $html True to decode for HTML.
     * @returns string The text, or an empty string if it's not found.
     */
    public static function get($id, $html = true){
        $statement = get_context()->get_db()->prepare(
          "SELECT text, file FROM text WHERE id = :id AND lang = :lang"
        );
        $statement->bindValue(':id', $id, PDO::PARAM_STR);
        $statement->bindValue(':lang', get_context()->get_lang(), PDO::PARAM_STR);
        $statement->execute();
        $row = $statement->fetch(PDO::FETCH_ASSOC);
        if ($row !== false){
            $text = "";
            if (strlen($row["file"]) > 0) $text = file_get_contents(PATH::TEXT . $row["file"]);
            else $text = $row["text"];
            //$text = utf8_decode($text);
            if ($html === true) $text = htmlentities($text, ENT_QUOTES | ENT_SUBSTITUTE);
            return $text;
        }
        else{
            Log::error("Text resource with id '$id' not found.");
            return "";
        }
    }

    /**
     * Retrieves and formats  atext fragment from the database.
     *
     * @param string $id Text identifier.
     * @param string[] $fragments Texts to replace each "#" character with.
     * @param bool $html True to decode for HTML.
     * @returns string The text.
     */
    public static function compose($id, $fragments, $html = true){
        $text = Text::get($id, $html);
        foreach ($fragments as $fragment){
            $pos = strpos($text, "$");
            if ($pos !== false)
                $text = substr($text, 0, $pos) . $fragment . substr($text, $pos + 1);
        }
        return $text;
    }


    /**
     * This function closes all the opened HTML tags in a given string.
     * 
     * @param string html The string with HTML tags.
     * @return string HTML with closed tags.
     */
    function close_tags($html) {
        $result = [];
        preg_match_all(
          "#<(?!meta|img|br|hr|input\b)\b([a-z]+)(?: .*)?(?<![/|/ ])>#iU", $html, $result
        );
        $openedtags = $result[1];
        preg_match_all("#</([a-z]+)>#iU", $html, $result);
        $closedtags = $result[1];
        $len_opened = count($openedtags);
        if (count($closedtags) == $len_opened) return $html;
        $openedtags = array_reverse($openedtags);
        for ($i=0; $i < $len_opened; $i++) {
            if (!in_array($openedtags[$i], $closedtags)) $html .= "</".$openedtags[$i].">";
            else unset($closedtags[array_search($openedtags[$i], $closedtags)]);
        }
        return $html;
    }


    /**
     * Text shortener. Given a string, it trims in the proximity of the desired string, up to the
     * next white character. If indicated, it will append a link to the full text.
     * 
     * @param string $text The text to shorten.
     * @param int $length The desired length.
     * @param string $link_text Text for the link. Optional.
     * @param string $link URI of the link.
     * @return string Shortened text.
     */
     function cut_text($text, $length, $link_text = "", $link = ""){
        if (strlen($text) < $length) return $text;
        $cut = substr($text, 0, strpos($text, " ", $length));
        $cut = close_tags($cut);
        if (strlen($cut) == 0) $cut = $text;
        if (strlen($text) != strlen($cut) && strlen($link) > 0 && strlen($link_text) > 0)
            $cut = $cut . "... <a href='$link'>$link_text</a>";
        return $cut;
    }

    /**
     * Creates the srcset attribute for content images.
     *
     * Creates 9 different resolutions, from 100px to 900px.
     * 
     * @param string $file Path to the file, relative to $path["img"]["content"]).
     * @return string srcset atttribute content.
     */
    public static function srcset($file){
        global $static;
        $srcset = "";
        $dir = dirname($file);
        $name = basename($file);
        foreach (range(1, 9) as $d)
            $srcset .= $static["content"] . $dir . "/x" . $d . "00/" . $name . " " . $d . "00px, ";
        $srcset = rtrim($srcset, ", ");
        return $srcset;
    }

}