module Server.Features.Teacher.CreateTopic

open Giraffe
open Domain
open Domain.Contracts
open Server.Store

let private create (store: Store) (ownerId: UserId) (req: CreateTopicRequest) : Result<Topic, string> =
    if System.String.IsNullOrWhiteSpace req.Name then
        Error "Название темы не может быть пустым"
    else
        let topic: Topic = { Id = Id.newTopicId (); OwnerId = ownerId; Name = req.Name }
        store.AddTopic topic
        Ok topic

let handler (store: Store) : HttpHandler =
    bindJson<CreateTopicRequest> (fun req next ctx ->
        task {
            let result =
                Server.Auth.requireRole [ Teacher; Admin ] ctx.User
                |> Result.bind (fun uid -> create store uid req)

            return! json result next ctx
        })