<?php

declare(strict_types=1);

namespace App\Model;

use Nette\Database\Explorer;
use Nette\Utils\Json;
use Nette\Utils\JsonException;
use SimpleXMLElement;

/**
 * Hranice sboru. V tabulce je jeden záznam, nový KML ho nahradí.
 */
final class SborFacade
{
    public function __construct(
        private Explorer $database,
    ) {
    }

    /**
     * @return array{nazev: string, bodu: int}|null
     */
    public function getSbor(): ?array
    {
        $radek = $this->database->fetch('SELECT TOP 1 NAZEV, GEO FROM SBOR ORDER BY ID');
        if ($radek === null) {
            return null;
        }

        try {
            $geo = Json::decode((string) $radek->GEO, forceArrays: true);
        } catch (JsonException) {
            $geo = [];
        }

        return [
            'nazev' => (string) $radek->NAZEV,
            'bodu' => is_array($geo) ? $this->pocetBodu($geo) : 0,
        ];
    }

    /**
     * GeoJSON geometrie jediné uložené hranice sboru.
     */
    public function getGeoJson(): ?string
    {
        $geo = $this->database->fetchField('SELECT TOP 1 GEO FROM SBOR ORDER BY ID');
        if (!is_string($geo) || trim($geo) === '') {
            return null;
        }

        return $geo;
    }

    public function nahradZKml(string $kml): void
    {
        $nazev = $this->nazevZKml($kml);
        $geo = Json::encode($this->geometrieZKml($kml));

        $id = $this->database->fetchField('SELECT TOP 1 ID FROM SBOR ORDER BY ID');
        if ($id === null) {
            $this->database->query('INSERT INTO SBOR (NAZEV, GEO) VALUES (?, ?)', $nazev, $geo);
            return;
        }

        $this->database->query('UPDATE SBOR SET NAZEV = ?, GEO = ? WHERE ID = ?', $nazev, $geo, $id);
        $this->database->query('DELETE FROM SBOR WHERE ID <> ?', $id);
    }

    private function nazevZKml(string $kml): string
    {
        $xml = $this->nactiKml($kml);
        $nazvy = $xml->xpath('//k:Document/k:name');
        if ($nazvy === false || $nazvy === []) {
            $nazvy = $xml->xpath('//k:Placemark/k:name');
        }
        $nazev = trim((string) ($nazvy[0] ?? ''));
        if ($nazev === '') {
            throw new \InvalidArgumentException('V souboru KML chybí název sboru.');
        }
        if (mb_strlen($nazev) > 50) {
            throw new \InvalidArgumentException('Název sboru v souboru je delší než 50 znaků.');
        }

        return $nazev;
    }

    /**
     * @return array{type: string, coordinates: array<int, mixed>}
     */
    private function geometrieZKml(string $kml): array
    {
        $xml = $this->nactiKml($kml);
        $uzly = $xml->xpath('//k:Polygon/k:outerBoundaryIs/k:LinearRing/k:coordinates');
        if ($uzly === false || $uzly === []) {
            throw new \InvalidArgumentException('V souboru KML není polygon s hranicí.');
        }

        $prstence = [];
        foreach ($uzly as $uzel) {
            $prstence[] = $this->prstenec((string) $uzel);
        }

        if (count($prstence) === 1) {
            return [
                'type' => 'Polygon',
                'coordinates' => [$prstence[0]],
            ];
        }

        return [
            'type' => 'MultiPolygon',
            'coordinates' => array_map(
                static fn(array $prstenec): array => [$prstenec],
                $prstence,
            ),
        ];
    }

    private function nactiKml(string $kml): SimpleXMLElement
    {
        $kml = trim($kml);
        if ($kml === '' || !str_contains($kml, '<kml')) {
            throw new \InvalidArgumentException('Soubor není ve formátu KML.');
        }

        $predchozi = libxml_use_internal_errors(true);
        try {
            $xml = simplexml_load_string($kml, SimpleXMLElement::class, LIBXML_NONET);
        } finally {
            libxml_clear_errors();
            libxml_use_internal_errors($predchozi);
        }
        if (!$xml instanceof SimpleXMLElement) {
            throw new \InvalidArgumentException('Soubor KML se nepodařilo přečíst.');
        }

        $xml->registerXPathNamespace('k', 'http://www.opengis.net/kml/2.2');
        return $xml;
    }

    /**
     * @return list<array{0: float, 1: float}>
     */
    private function prstenec(string $text): array
    {
        $kruh = [];
        foreach (preg_split('/\s+/', trim($text)) ?: [] as $token) {
            if ($token === '') {
                continue;
            }
            $casti = explode(',', $token);
            if (count($casti) < 2 || !is_numeric($casti[0]) || !is_numeric($casti[1])) {
                throw new \InvalidArgumentException('Bod hranice v KML nemá souřadnice.');
            }
            $lng = round((float) $casti[0], 7);
            $lat = round((float) $casti[1], 7);
            if ($lng < 12.0 || $lng > 19.0 || $lat < 48.0 || $lat > 52.0) {
                throw new \InvalidArgumentException('Bod hranice sboru je mimo oblast obvodů.');
            }
            $kruh[] = [$lng, $lat];
        }

        if (count($kruh) > 1 && $kruh[0] === $kruh[count($kruh) - 1]) {
            array_pop($kruh);
        }
        if (count($kruh) < 3) {
            throw new \InvalidArgumentException('Hranice sboru musí mít aspoň tři body.');
        }
        if (count($kruh) > 50000) {
            throw new \InvalidArgumentException('Hranice sboru má příliš mnoho bodů.');
        }

        $kruh[] = $kruh[0];
        return $kruh;
    }

    /**
     * @param array<string, mixed> $geo
     */
    private function pocetBodu(array $geo): int
    {
        $prstence = [];
        if (($geo['type'] ?? '') === 'Polygon') {
            $prstence[] = $geo['coordinates'][0] ?? [];
        } elseif (($geo['type'] ?? '') === 'MultiPolygon') {
            foreach ($geo['coordinates'] ?? [] as $polygon) {
                $prstence[] = $polygon[0] ?? [];
            }
        }

        $pocet = 0;
        foreach ($prstence as $kruh) {
            if (!is_array($kruh)) {
                continue;
            }
            $delka = count($kruh);
            if ($delka > 1 && $kruh[0] === $kruh[$delka - 1]) {
                $delka--;
            }
            $pocet += $delka;
        }

        return $pocet;
    }
}