<?php

declare(strict_types=1);

namespace CrocoAI\DataBridge\Domain;

final class CategoryLanguageMatch
{
    /**
     * Pick an existing category under the walked parent.
     *
     * A same-name term at another parent is not a match. Croco must not reuse
     * a root duplicate when the payload walks a nested path.
     *
     * @param list<array{
     *   id:int,
     *   parent:int,
     *   language:string,
     *   translated_id:?int,
     *   translated_parent:?int
     * }> $candidates
     */
    public static function pick(array $candidates, int $parent, string $language): ?int
    {
        $underParent = [];
        foreach ($candidates as $row) {
            if ((int) $row['parent'] === $parent) {
                $underParent[] = $row;
            }
        }
        if ($underParent === []) {
            return null;
        }
        if ($language === '') {
            return (int) $underParent[0]['id'];
        }
        foreach ($underParent as $row) {
            $termLanguage = (string) $row['language'];
            if ($termLanguage === '' || $termLanguage === $language) {
                return (int) $row['id'];
            }
        }
        foreach ($underParent as $row) {
            $translatedId = (int) ($row['translated_id'] ?? 0);
            $translatedParent = $row['translated_parent'] ?? null;
            if ($translatedId > 0 && $translatedParent !== null && (int) $translatedParent === $parent) {
                return $translatedId;
            }
        }
        return (int) $underParent[0]['id'];
    }
}