<?php
namespace ContingentParser\Parser;

use DOMDocument;
use DOMXPath;

class ContingentParser
{
    private ?DOMXPath $xpath;
    private DOMDocument $dom;
    private const TEMPLATE = '//tr[@itemprop="eduChislen"]//';
    private const ENCODING = "UTF-8"; 
    private const FIELDS = [
        "eduCode" => "td",
        "eduName" => "td",
        "eduLevel" => "td",
        "eduForm" => "td",
        "numberAll" => ["th", "td"]
    ];

    public function __construct(string $html)
    {
        libxml_use_internal_errors(true);
        $this->dom = new DOMDocument(
            encoding: self::ENCODING
        );
        if (empty($html)) {
            $this->xpath = null;
        } else {
            $this->setEncoding($html);
            $this->dom->loadHTML($html);
            $this->xpath = new DOMXPath($this->dom);
        }
    }
    
    private function setEncoding(string &$html) : void
    {
        $encoding = mb_detect_encoding($html, 'UTF-8, windows-1251');
        if ($encoding != self::ENCODING) {
            $html = mb_convert_encoding(
                $html,
                self::ENCODING,
                $encoding
            );
            $html = str_replace('windows-1251',self::ENCODING, $html); 
        }
        $html = mb_convert_encoding($html,'HTML-ENTITIES','UTF-8');
    }
    public function getDataTable() : array
    {
        if (empty($this->xpath)) return [];
        
        $data = $this->parseContingent();
        $records = [];
        if ($data == null) return [];

        $equal = $data['eduName']->length;
        foreach ($data as $field) {
            if ($field->length == 0) {
                return [];
            }
            if ($field->length != $equal) {
                return [];
            }
        }

        for ($i = 0; $i < $data['eduCode']->length; $i++) { 
            $contingentRow = new ContingentRow(
                $data['eduCode']->item($i)->textContent,
                $data['eduName']->item($i)->textContent,
                $data['eduLevel']->item($i)->textContent,
                $data['eduForm']->item($i)->textContent,
                (int)$data['numberAll']->item($i)->textContent
            );
            $records[] = $contingentRow->getData();
        }
        return $records;
    }

    private function parseContingent() : array
    {
        $data = [];
        foreach (self::FIELDS as $field => $tag) {
            if (!is_array($tag)) {
                $data[$field] = $this->xpath->query(
                    self::TEMPLATE . $tag . "[@itemprop=\"$field\"]"
                );
            } else {
                $th = $this->xpath->query(
                    self::TEMPLATE . $tag[0] . "[@itemprop=\"$field\"]"
                );
                $td = $this->xpath->query(
                    self::TEMPLATE . $tag[1] . "[@itemprop=\"$field\"]"
                );
                $data[$field] = $th->length > $td->length ? $th : $td;
            }
        }
        return $data;
    }

    public function getLink(): string
    {
        $data = $this->dom->getElementsByTagName('a');
        var_dump($data->item(0)->getAttribute('href'));
        return '';
    }
}