module Stackctl.OneOrListOf
  ( OneOrListOf
  , fromList
  ) where

import Stackctl.Prelude

import Data.Aeson

-- | Type representing one @a@ or a list of @a@
--
-- This type is isomorphic both @'NonEmpty' a@ and @'Either' a [a]@. Its primary
-- use-case is to parse Yaml (through its 'FromJSON') where users may specify a
-- list of values, but specifying a single value is worth supporting, typically
-- for backwards-compatibility:
--
-- @
-- something:
--   field:
--     - one
--     - two
--
-- something:
--   field: one # => should be treated like field: [one]
-- @
--
-- The 'Foldable' instance should be used to treat the value like a list, such
-- as extracting it directly via 'toList'.
--
-- Implementation note: this type preserves the form in which it was decoded (in
-- other words, it's not a @newtype@ over one of the isomorphic types mentioned
-- above), so that we can encode it back out in the same format.
data OneOrListOf a = One a | List [a]
  deriving stock (OneOrListOf a -> OneOrListOf a -> Bool
forall a. Eq a => OneOrListOf a -> OneOrListOf a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: OneOrListOf a -> OneOrListOf a -> Bool
$c/= :: forall a. Eq a => OneOrListOf a -> OneOrListOf a -> Bool
== :: OneOrListOf a -> OneOrListOf a -> Bool
$c== :: forall a. Eq a => OneOrListOf a -> OneOrListOf a -> Bool
Eq, Int -> OneOrListOf a -> ShowS
forall a. Show a => Int -> OneOrListOf a -> ShowS
forall a. Show a => [OneOrListOf a] -> ShowS
forall a. Show a => OneOrListOf a -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [OneOrListOf a] -> ShowS
$cshowList :: forall a. Show a => [OneOrListOf a] -> ShowS
show :: OneOrListOf a -> String
$cshow :: forall a. Show a => OneOrListOf a -> String
showsPrec :: Int -> OneOrListOf a -> ShowS
$cshowsPrec :: forall a. Show a => Int -> OneOrListOf a -> ShowS
Show, forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
forall a x. Rep (OneOrListOf a) x -> OneOrListOf a
forall a x. OneOrListOf a -> Rep (OneOrListOf a) x
$cto :: forall a x. Rep (OneOrListOf a) x -> OneOrListOf a
$cfrom :: forall a x. OneOrListOf a -> Rep (OneOrListOf a) x
Generic, forall a. Eq a => a -> OneOrListOf a -> Bool
forall a. Num a => OneOrListOf a -> a
forall a. Ord a => OneOrListOf a -> a
forall m. Monoid m => OneOrListOf m -> m
forall a. OneOrListOf a -> Bool
forall a. OneOrListOf a -> Int
forall a. OneOrListOf a -> [a]
forall a. (a -> a -> a) -> OneOrListOf a -> a
forall m a. Monoid m => (a -> m) -> OneOrListOf a -> m
forall b a. (b -> a -> b) -> b -> OneOrListOf a -> b
forall a b. (a -> b -> b) -> b -> OneOrListOf a -> b
forall (t :: * -> *).
(forall m. Monoid m => t m -> m)
-> (forall m a. Monoid m => (a -> m) -> t a -> m)
-> (forall m a. Monoid m => (a -> m) -> t a -> m)
-> (forall a b. (a -> b -> b) -> b -> t a -> b)
-> (forall a b. (a -> b -> b) -> b -> t a -> b)
-> (forall b a. (b -> a -> b) -> b -> t a -> b)
-> (forall b a. (b -> a -> b) -> b -> t a -> b)
-> (forall a. (a -> a -> a) -> t a -> a)
-> (forall a. (a -> a -> a) -> t a -> a)
-> (forall a. t a -> [a])
-> (forall a. t a -> Bool)
-> (forall a. t a -> Int)
-> (forall a. Eq a => a -> t a -> Bool)
-> (forall a. Ord a => t a -> a)
-> (forall a. Ord a => t a -> a)
-> (forall a. Num a => t a -> a)
-> (forall a. Num a => t a -> a)
-> Foldable t
product :: forall a. Num a => OneOrListOf a -> a
$cproduct :: forall a. Num a => OneOrListOf a -> a
sum :: forall a. Num a => OneOrListOf a -> a
$csum :: forall a. Num a => OneOrListOf a -> a
minimum :: forall a. Ord a => OneOrListOf a -> a
$cminimum :: forall a. Ord a => OneOrListOf a -> a
maximum :: forall a. Ord a => OneOrListOf a -> a
$cmaximum :: forall a. Ord a => OneOrListOf a -> a
elem :: forall a. Eq a => a -> OneOrListOf a -> Bool
$celem :: forall a. Eq a => a -> OneOrListOf a -> Bool
length :: forall a. OneOrListOf a -> Int
$clength :: forall a. OneOrListOf a -> Int
null :: forall a. OneOrListOf a -> Bool
$cnull :: forall a. OneOrListOf a -> Bool
toList :: forall a. OneOrListOf a -> [a]
$ctoList :: forall a. OneOrListOf a -> [a]
foldl1 :: forall a. (a -> a -> a) -> OneOrListOf a -> a
$cfoldl1 :: forall a. (a -> a -> a) -> OneOrListOf a -> a
foldr1 :: forall a. (a -> a -> a) -> OneOrListOf a -> a
$cfoldr1 :: forall a. (a -> a -> a) -> OneOrListOf a -> a
foldl' :: forall b a. (b -> a -> b) -> b -> OneOrListOf a -> b
$cfoldl' :: forall b a. (b -> a -> b) -> b -> OneOrListOf a -> b
foldl :: forall b a. (b -> a -> b) -> b -> OneOrListOf a -> b
$cfoldl :: forall b a. (b -> a -> b) -> b -> OneOrListOf a -> b
foldr' :: forall a b. (a -> b -> b) -> b -> OneOrListOf a -> b
$cfoldr' :: forall a b. (a -> b -> b) -> b -> OneOrListOf a -> b
foldr :: forall a b. (a -> b -> b) -> b -> OneOrListOf a -> b
$cfoldr :: forall a b. (a -> b -> b) -> b -> OneOrListOf a -> b
foldMap' :: forall m a. Monoid m => (a -> m) -> OneOrListOf a -> m
$cfoldMap' :: forall m a. Monoid m => (a -> m) -> OneOrListOf a -> m
foldMap :: forall m a. Monoid m => (a -> m) -> OneOrListOf a -> m
$cfoldMap :: forall m a. Monoid m => (a -> m) -> OneOrListOf a -> m
fold :: forall m. Monoid m => OneOrListOf m -> m
$cfold :: forall m. Monoid m => OneOrListOf m -> m
Foldable)

fromList :: [a] -> OneOrListOf a
fromList :: forall a. [a] -> OneOrListOf a
fromList = forall a. [a] -> OneOrListOf a
List

instance Semigroup (OneOrListOf a) where
  One a
a <> :: OneOrListOf a -> OneOrListOf a -> OneOrListOf a
<> One a
b = forall a. [a] -> OneOrListOf a
List [a
a, a
b]
  One a
a <> List [a]
bs = forall a. [a] -> OneOrListOf a
List forall a b. (a -> b) -> a -> b
$ a
a forall a. a -> [a] -> [a]
: [a]
bs
  List [a]
as <> One a
b = forall a. [a] -> OneOrListOf a
List forall a b. (a -> b) -> a -> b
$ [a]
as forall a. Semigroup a => a -> a -> a
<> [a
b]
  List [a]
as <> List [a]
bs = forall a. [a] -> OneOrListOf a
List forall a b. (a -> b) -> a -> b
$ [a]
as forall a. Semigroup a => a -> a -> a
<> [a]
bs

instance FromJSON a => FromJSON (OneOrListOf a) where
  parseJSON :: Value -> Parser (OneOrListOf a)
parseJSON = \case
    Array Array
xs -> forall a. [a] -> OneOrListOf a
List forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (t :: * -> *) a. Foldable t => t a -> [a]
toList forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
traverse forall a. FromJSON a => Value -> Parser a
parseJSON Array
xs
    Value
v -> forall a. a -> OneOrListOf a
One forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. FromJSON a => Value -> Parser a
parseJSON Value
v

instance ToJSON a => ToJSON (OneOrListOf a) where
  toJSON :: OneOrListOf a -> Value
toJSON = \case
    One a
a -> forall a. ToJSON a => a -> Value
toJSON a
a
    List [a]
as -> forall a. ToJSON a => a -> Value
toJSON [a]
as
  toEncoding :: OneOrListOf a -> Encoding
toEncoding = \case
    One a
a -> forall a. ToJSON a => a -> Encoding
toEncoding a
a
    List [a]
as -> forall a. ToJSON a => a -> Encoding
toEncoding [a]
as