{-# LANGUAGE TemplateHaskell   #-}

    -- * Lenses
    , volume
    , english
    , alBhed

import           Data.Maybe   (fromJust)

import           Data.Maybe      (fromJust)
import qualified Data.Text       as T

import qualified Data.Text    as T

import           Control.Lens
import           Control.Lens.TH

    { primerVolume  :: Volume
    , primerEnglish :: Char
    , primerAlBhed  :: Char

    { _volume  :: Volume
    , _english :: Char
    , _alBhed  :: Char

makeLenses ''Primer

      -- * Modify
    , addLocation

import           Control.Lens

empty :: Index

empty :: AlBhed.Index.Index

singleton :: Primer -> Location -> Index

singleton :: Primer -> Location -> AlBhed.Index.Index

addLocation :: Primer -> Location -> Index -> Index
addLocation primer location index = undefined

-- | If the primer is not in the index then we add the primer and location to the index
addLocation :: Primer -> Location -> AlBhed.Index.Index -> AlBhed.Index.Index
addLocation primer location [] = [(primer, NonEmptyList.singleton location)]
addLocation primer location (x:xs)
    | x ^. _1 . volume == primer ^. volume = (x & _2 %~ NonEmptyList.push location):xs
    | otherwise = x:addLocation primer location xs