<?php

namespace App\Services;

use Menu;
use Nwidart\Menus\MenuBuilder;
use Nwidart\Menus\MenuItem;
use ReflectionClass;

class AdminMenuGroupingService
{
    public function apply(string $menuName = 'admin-sidebar-menu'): void
    {
        $groups = config('admin_menu_groups', []);

        if (empty($groups)) {
            return;
        }

        Menu::modify($menuName, function (MenuBuilder $menu) use ($groups) {
            $items = collect($menu->getOrderedItems())
                ->filter(function (MenuItem $item) {
                    return ! $item->isHeader() && ! $item->isDivider();
                })
                ->values();

            if ($items->isEmpty()) {
                return;
            }

            $groupBuckets = [];
            foreach (array_keys($groups) as $groupKey) {
                $groupBuckets[$groupKey] = [];
            }

            foreach ($items as $item) {
                $groupKey = $this->resolveGroupKey($item, $groups);
                if (! isset($groupBuckets[$groupKey])) {
                    $groupBuckets[$groupKey] = [];
                }
                $groupBuckets[$groupKey][] = $item;
            }

            $newItems = [];
            $assigned = [];

            foreach ($groups as $groupKey => $groupConfig) {
                $groupItems = $groupBuckets[$groupKey] ?? [];
                if (empty($groupItems)) {
                    continue;
                }

                usort($groupItems, function (MenuItem $a, MenuItem $b) {
                    return ((int) ($a->order ?? 0)) <=> ((int) ($b->order ?? 0));
                });

                $newItems[] = MenuItem::make([
                    'name' => 'header',
                    'title' => $this->resolveLabel($groupConfig),
                    'attributes' => [
                        'data-group' => $groupKey,
                        'class' => 'nav-small-cap--collapsible',
                    ],
                    'order' => (int) ($groupItems[0]->order ?? 0) - 1,
                ]);

                foreach ($groupItems as $groupItem) {
                    $newItems[] = $groupItem;
                    $assigned[spl_object_id($groupItem)] = true;
                }
            }

            foreach ($items as $item) {
                if (! isset($assigned[spl_object_id($item)])) {
                    $newItems[] = $item;
                }
            }

            $this->setMenuItems($menu, $newItems);
        });
    }

    protected function resolveLabel(array $groupConfig): string
    {
        if (! empty($groupConfig['label_key'])) {
            return (string) __($groupConfig['label_key']);
        }

        return (string) ($groupConfig['label'] ?? '');
    }

    protected function resolveGroupKey(MenuItem $item, array $groups): string
    {
        $attrs = $item->attributes ?? [];

        if (! empty($attrs['data-menu-group'])) {
            $key = (string) $attrs['data-menu-group'];
            if (isset($groups[$key])) {
                return $key;
            }
        }

        $module = $attrs['data-module'] ?? null;
        if ($module) {
            foreach ($groups as $key => $config) {
                if (! empty($config['modules']) && in_array($module, $config['modules'], true)) {
                    return $key;
                }
            }
        }

        $order = (int) ($item->order ?? 0);

        foreach ($groups as $key => $config) {
            if (empty($config['orders'])) {
                continue;
            }

            [$min, $max] = $config['orders'];
            if ($order >= $min && $order <= $max) {
                return $key;
            }
        }

        foreach (array_reverse(array_keys($groups)) as $fallbackKey) {
            if (! empty($groups[$fallbackKey]['orders'])) {
                continue;
            }

            if (! empty($groups[$fallbackKey]['modules'])) {
                return $fallbackKey;
            }
        }

        return array_key_first($groups) ?: 'dashboard';
    }

    protected function setMenuItems(MenuBuilder $menu, array $items): void
    {
        $reflection = new ReflectionClass($menu);
        $property = $reflection->getProperty('items');
        $property->setAccessible(true);
        $property->setValue($menu, $items);
    }
}