<?php

declare(strict_types=1);

namespace App\Filament\Resources\Roles\Pages;

use App\Support\Permissions;
use Spatie\Permission\PermissionRegistrar;

/**
 * Bridges the form's per-group checkbox state and the role's single
 * `permissions` relationship.
 *
 * The form splits permissions across one component per resource for
 * readability; the database wants one flat set. This trait converts in both
 * directions and keeps the two in step.
 */
trait HandlesRolePermissions
{
    /**
     * Permission names captured on the way to saving, held here because the
     * relationship can only be synced once the role row exists.
     *
     * @var array<int, string>
     */
    protected array $selectedPermissions = [];

    /**
     * Expand the role's flat permission set into the form's grouped shape.
     *
     * @param  array<string, mixed>  $data
     * @return array<string, mixed>
     */
    protected function mutateFormDataBeforeFill(array $data): array
    {
        $held = $this->getRecord()->permissions->pluck('name')->all();

        foreach (Permissions::grouped() as $group => $permissions) {
            $data['permission_groups'][$group] = array_values(array_intersect($permissions, $held));
        }

        return $data;
    }

    /**
     * @param  array<string, mixed>  $data
     * @return array<string, mixed>
     */
    protected function mutateFormDataBeforeSave(array $data): array
    {
        return $this->extractPermissions($data);
    }

    /**
     * @param  array<string, mixed>  $data
     * @return array<string, mixed>
     */
    protected function mutateFormDataBeforeCreate(array $data): array
    {
        return $this->extractPermissions($data);
    }

    protected function afterSave(): void
    {
        $this->syncSelectedPermissions();
    }

    protected function afterCreate(): void
    {
        $this->syncSelectedPermissions();
    }

    /**
     * @param  array<string, mixed>  $data
     * @return array<string, mixed>
     */
    protected function extractPermissions(array $data): array
    {
        $groups = $data['permission_groups'] ?? [];
        unset($data['permission_groups']);

        // Intersecting with the catalogue means a stale or hand-crafted value
        // in the payload cannot grant a permission the app does not define.
        $this->selectedPermissions = array_values(array_intersect(
            array_merge(...array_values(array_map(fn ($v) => (array) $v, $groups)) ?: [[]]),
            Permissions::all(),
        ));

        return $data;
    }

    protected function syncSelectedPermissions(): void
    {
        $this->getRecord()->syncPermissions($this->selectedPermissions);

        // spatie caches the permission map; without this the change would not
        // take effect until the cache expired.
        app(PermissionRegistrar::class)->forgetCachedPermissions();
    }
}