{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}

{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE DataKinds           #-}
{-# LANGUAGE TypeFamilies        #-}
{-# LANGUAGE TypeOperators       #-}

{- |
Copyright: (c) 2020 Kowainik
SPDX-License-Identifier: MPL-2.0
Maintainer: Kowainik <xrom.xkov@gmail.com>

Safe 'Id' representation.
-}

module Stan.Core.Id
    ( Id (..)
    , AnyId
    , castId
    ) where

import Data.Aeson.Micro (ToJSON)
import Data.Type.Equality (type (==))


{- | A wrapper around the textual value to safely represent IDs for different
structures by using a phantom parameter.
-}
newtype Id a = Id
    { Id a -> Text
unId :: Text
    } deriving stock (Int -> Id a -> ShowS
[Id a] -> ShowS
Id a -> String
(Int -> Id a -> ShowS)
-> (Id a -> String) -> ([Id a] -> ShowS) -> Show (Id a)
forall a. Int -> Id a -> ShowS
forall a. [Id a] -> ShowS
forall a. Id a -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Id a] -> ShowS
$cshowList :: forall a. [Id a] -> ShowS
show :: Id a -> String
$cshow :: forall a. Id a -> String
showsPrec :: Int -> Id a -> ShowS
$cshowsPrec :: forall a. Int -> Id a -> ShowS
Show)
      deriving newtype (Id a -> Id a -> Bool
(Id a -> Id a -> Bool) -> (Id a -> Id a -> Bool) -> Eq (Id a)
forall a. Id a -> Id a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: Id a -> Id a -> Bool
$c/= :: forall a. Id a -> Id a -> Bool
== :: Id a -> Id a -> Bool
$c== :: forall a. Id a -> Id a -> Bool
Eq, Eq (Id a)
Eq (Id a) =>
(Id a -> Id a -> Ordering)
-> (Id a -> Id a -> Bool)
-> (Id a -> Id a -> Bool)
-> (Id a -> Id a -> Bool)
-> (Id a -> Id a -> Bool)
-> (Id a -> Id a -> Id a)
-> (Id a -> Id a -> Id a)
-> Ord (Id a)
Id a -> Id a -> Bool
Id a -> Id a -> Ordering
Id a -> Id a -> Id a
forall a. Eq (Id a)
forall a.
Eq a =>
(a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
forall a. Id a -> Id a -> Bool
forall a. Id a -> Id a -> Ordering
forall a. Id a -> Id a -> Id a
min :: Id a -> Id a -> Id a
$cmin :: forall a. Id a -> Id a -> Id a
max :: Id a -> Id a -> Id a
$cmax :: forall a. Id a -> Id a -> Id a
>= :: Id a -> Id a -> Bool
$c>= :: forall a. Id a -> Id a -> Bool
> :: Id a -> Id a -> Bool
$c> :: forall a. Id a -> Id a -> Bool
<= :: Id a -> Id a -> Bool
$c<= :: forall a. Id a -> Id a -> Bool
< :: Id a -> Id a -> Bool
$c< :: forall a. Id a -> Id a -> Bool
compare :: Id a -> Id a -> Ordering
$ccompare :: forall a. Id a -> Id a -> Ordering
$cp1Ord :: forall a. Eq (Id a)
Ord, Int -> Id a -> Int
Id a -> Int
(Int -> Id a -> Int) -> (Id a -> Int) -> Hashable (Id a)
forall a. Int -> Id a -> Int
forall a. Id a -> Int
forall a. (Int -> a -> Int) -> (a -> Int) -> Hashable a
hash :: Id a -> Int
$chash :: forall a. Id a -> Int
hashWithSalt :: Int -> Id a -> Int
$chashWithSalt :: forall a. Int -> Id a -> Int
Hashable, Id a -> Value
(Id a -> Value) -> ToJSON (Id a)
forall a. Id a -> Value
forall a. (a -> Value) -> ToJSON a
toJSON :: Id a -> Value
$ctoJSON :: forall a. Id a -> Value
ToJSON)

{- | A type alias for the situations when we don't care about the parameter of
'Id' but don't want to deal with type variables.
-}
type AnyId = Id ()

{- | Unsafe cast of 'Id'. Implementation uses smart trick to enforce usage
always with @TypeApplications@.
-}
castId
    :: forall to from to'
    .  ((to == to') ~ 'True)
    => Id from
    -> Id to'
castId :: Id from -> Id to'
castId (Id a :: Text
a) = Text -> Id to'
forall a. Text -> Id a
Id Text
a