<?php
namespace App\Actions;
use App\Models\Post;
use App\Models\User;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Gate;
use Illuminate\Support\Facades\Validator;
class SaveDraft
{
    public function handle(User $user, Post $post, string $title, int $expectedVersion): Post
    {
        Gate::forUser($user)->authorize('update', $post);
        $data = Validator::make(['title' => trim($title)], ['title' => ['required', 'string', 'max:200']])->validate();
        $changed = Post::query()->whereKey($post->getKey())
            ->where('status', 'draft')
            ->where('version', $expectedVersion)
            ->update(['title' => $data['title'], 'version' => DB::raw('version + 1')]);
        abort_unless($changed === 1, 409, 'Post changed; reload before saving.');
        return $post->fresh();
    }
}