module Server.Features.Teacher.DeleteQuiz

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

let private delete (store: Store) (ownerId: UserId) (req: DeleteQuizRequest) : Result<unit, string> =
    match store.TryGetQuiz req.QuizId with
    | None -> Error "Тест не найден"
    | Some quiz when quiz.OwnerId <> ownerId -> Error "Доступ запрещён"
    | Some _ ->
        if store.AnyAttemptsForQuiz req.QuizId then
            Error "Тест уже проходили, удаление невозможно"
        else
            store.RemoveQuiz req.QuizId
            Ok()

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

            return! json result next ctx
        })