<?php

namespace App\Services;

use App\Models\NavItemModel;
use App\Models\RoleNavItemModel;
use CodeIgniter\Cache\CacheInterface;

class NavbarService
{
    public function __construct(
        protected NavItemModel $navModel = new NavItemModel(),
        protected RoleNavItemModel $mapModel = new RoleNavItemModel(),
        protected ?CacheInterface $cache = null
    ){
        $this->cache ??= cache();
    }

    public function getMenuForRoles(array $roles): array
    {
        $roles = array_map(fn($r)=>strtolower(trim((string)$r)), $roles);
        $cacheKey = 'navbar_' . md5(json_encode($roles));

        if ($menu = $this->cache->get($cacheKey)) {
            return $menu;
        }

        // Which items this user can see
        $allowedIds = $this->mapModel->getNavItemIdsForRoles($roles);
        if (empty($allowedIds)) return [];

        // Load all enabled items, then filter. The builder controls this order.
        $rows = $this->navModel->where('is_enabled', 1)
            ->orderBy('sort_order', 'ASC')
            ->orderBy('label', 'ASC')
            ->orderBy('id', 'ASC')
            ->findAll();

        // index by id
        $byId = [];
        foreach ($rows as $r) {
            if (in_array($r['id'], $allowedIds, true)) {
                $r['children'] = [];
                $byId[$r['id']] = $r;
            }
        }

        // Build tree
        $tree = [];
        foreach ($byId as $id => &$node) {
            $pid = $node['menu_parent_id'];
            if ($pid && isset($byId[$pid])) {
                $byId[$pid]['children'][] = &$node;
            } else {
                $tree[] = &$node;
            }
        }
        unset($node);

        $this->sortTreeByOrder($tree);

        $this->cache->save($cacheKey, $tree, 300); // 5 minutes
        return $tree;
    }

    private function sortTreeByOrder(array &$nodes): void
    {
        usort($nodes, function ($a, $b) {
            $order = ((int) ($a['sort_order'] ?? 0)) <=> ((int) ($b['sort_order'] ?? 0));
            if ($order !== 0) {
                return $order;
            }

            $label = strnatcasecmp(
                $this->labelSortKey((string) ($a['label'] ?? '')),
                $this->labelSortKey((string) ($b['label'] ?? ''))
            );
            if ($label !== 0) {
                return $label;
            }

            return ((int) ($a['id'] ?? 0)) <=> ((int) ($b['id'] ?? 0));
        });

        foreach ($nodes as &$node) {
            if (!empty($node['children']) && is_array($node['children'])) {
                $this->sortTreeByOrder($node['children']);
            }
        }
        unset($node);
    }

    private function labelSortKey(string $label): string
    {
        $label = trim(preg_replace('/\s+/', ' ', $label) ?? '');
        $label = preg_replace('/^[^[:alnum:]]+/u', '', $label) ?? $label;
        $label = preg_replace('/^(the|an|a)\s+/iu', '', $label) ?? $label;

        return function_exists('mb_strtolower')
            ? mb_strtolower($label, 'UTF-8')
            : strtolower($label);
    }

    public function clearCache(): void
    {
        // simplest: flush; or if you have a tagged cache, clear only keys
        cache()->clean();
    }
}