<?php

namespace App\Models;

use CodeIgniter\Model;

class CategoryModel extends Model
{
    protected $table            = 'categories';
    protected $primaryKey       = 'id';
    protected $returnType       = 'array';
    protected $useTimestamps    = true;
    protected $allowedFields    = ['name', 'type', 'parent_id'];

    protected $validationRules = [
        'name'      => 'required|max_length[100]',
        'type'      => 'required|in_list[income,expense]',
        'parent_id' => 'permit_empty|is_natural_no_zero',
    ];

    /**
     * Plaska lista kategorii, opcjonalnie filtrowana typem.
     */
    public function flatList(?string $type = null): array
    {
        $builder = $this->orderBy('type', 'ASC')->orderBy('name', 'ASC');
        if ($type !== null && $type !== '') {
            $builder = $builder->where('type', $type);
        }

        return $builder->findAll();
    }

    /**
     * Czy kategoria jest uzywana przez jakies operacje.
     */
    public function usedByOperations(int $id): bool
    {
        return (bool) model(OperationModel::class)->where('category_id', $id)->countAllResults();
    }

    /**
     * Kategorie w porzadku drzewa, posortowane po nazwie na kazdym poziomie.
     * Kazdy element dostaje 'depth' oraz 'indent_label' (nazwa z wcieciem) do list i selectow.
     */
    public function tree(?string $type = null): array
    {
        $builder = $this->orderBy('name', 'ASC');
        if ($type !== null && $type !== '') {
            $builder->where('type', $type);
        }
        $all = $builder->findAll();

        // Grupowanie dzieci wg rodzica (0 = korzen)
        $childrenByParent = [];
        foreach ($all as $c) {
            $childrenByParent[(int) ($c['parent_id'] ?: 0)][] = $c;
        }

        $indent = "\u{00A0}\u{00A0}\u{00A0}\u{00A0}"; // 4x twarda spacja na poziom
        $out    = [];

        $walk = static function (int $parentId, int $depth, string $parentPath) use (&$walk, &$out, $childrenByParent, $indent): void {
            foreach ($childrenByParent[$parentId] ?? [] as $c) {
                $c['depth']        = $depth;
                $c['indent_label'] = str_repeat($indent, $depth) . $c['name'];
                // Pelna sciezka "Nadrzedna → Podrzedna" — jednoznaczna nawet gdy JS uciasnie wciecia.
                $c['path_label']   = $parentPath === '' ? $c['name'] : $parentPath . ' → ' . $c['name'];
                $out[]             = $c;
                $walk((int) $c['id'], $depth + 1, $c['path_label']);
            }
        };
        $walk(0, 0, '');

        // Sieroty (np. rodzic odfiltrowany typem) — dopnij na koncu bez wciecia
        $seen = array_column($out, null, 'id');
        foreach ($all as $c) {
            if (! isset($seen[$c['id']])) {
                $c['depth']        = 0;
                $c['indent_label'] = $c['name'];
                $c['path_label']   = $c['name'];
                $out[]             = $c;
            }
        }

        return $out;
    }
}