# Pastebin Zui39kYI
{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE DataKinds           #-}
{-# LANGUAGE DeriveGeneric       #-}
{-# LANGUAGE FlexibleContexts    #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications    #-}
{-# LANGUAGE TypeFamilies        #-}
{-# LANGUAGE TypeOperators       #-}

module Servant.ActiveResource where

import Data.Kind (Type)
import Servant.API
import Servant.API.Generic
import Servant.Server.Generic
import Servant.Server.UVerb

class Monad (ResourceMonad id) => Resource id where
  type StoredResourceData id :: Type
  type ResourceMonad id :: Type -> Type

  listResource ::
    ResourceMonad id [StoredResourceData id]

serveResourceT :: forall id. Resource id => ResourceRoutes id (AsServerT (ResourceMonad id))
serveResourceT =
  ResourceRoutes
    { listRoute = listResource @id >>= respond . WithStatus @200
    }

data ResourceRoutes id route = ResourceRoutes
  { listRoute ::
      route
        :- UVerb 'GET '[JSON] '[WithStatus 200 [StoredResourceData id]]
  }
  deriving (Generic)