{-# LANGUAGE TupleSections #-}
module Hcompta.Tag where

import qualified Data.List.NonEmpty as NonEmpty
import           Data.List.NonEmpty (NonEmpty(..))
import           Data.Maybe (Maybe(..))
import qualified Data.Text as Text
import           Data.Text (Text)
import           Prelude (Int)

-- * The 'Tag' type

-- | An 'Tag' is a non-empty list of 'Section'.
type Tag     = (Path, Value)
type Section = Text
type Path    = NonEmpty Section
type Value   = Text

-- | Return the 'Tag' formed by the given 'Path' and 'Value'.
tag :: Path -> Value -> Tag
tag = (,)

-- | Return the 'Value' formed by the given 'Section' and 'Section's.
path :: Section -> [Section] -> Path
path = (:|)

-- | Return the 'Value' of a 'Tag', if any.
value :: Tag -> Maybe Value
value (_, v) | Text.null v = Nothing
value (_, v) = Just v

-- | Return the number of 'Section's in the given 'Tag'.
depth :: Path -> Int
depth = NonEmpty.length

-- | Return an 'Tag' from the given list.
from_List :: [Section] -> Path
from_List = NonEmpty.fromList