lib/Hcompta/Format/Ledger/Balance.hs

   1 {-# LANGUAGE NamedFieldPuns #-}
   2 module Hcompta.Format.Ledger.Balance where
   3
   4 import           Hcompta.Model (Transaction)
   5 import qualified Hcompta.Calc.Balance as Balance
   6 import qualified Hcompta.Format.Ledger.Journal as Journal
   7 import           Hcompta.Format.Ledger.Journal (Journal(..))
   8 import qualified Hcompta.Lib.Foldable as Lib.Foldable
   9
  10 -- * The 'Balance.Equilibre' type
  11
  12 -- | Return the first 'Transaction' (if any) which does not respect 'Balance.is_equilibrable'
  13 --   with the path of 'Journal's leading to that 'Transaction'.
  14 equilibre :: Journal -> Maybe ((Transaction, Balance.Equilibre), [Journal])
  15 equilibre =
  16         Journal.find
  17          (\Journal{Journal.transactions} ->
  18                 Lib.Foldable.find
  19                  (Lib.Foldable.find
  20                          (\tr -> do
  21                                 let bal = Balance.transaction tr Balance.nil
  22                                 let eq = Balance.equilibre bal
  23                                 if Balance.is_equilibrable eq
  24                                         then Nothing
  25                                         else Just (tr, eq)
  26                          )
  27                  )
  28                  transactions
  29          )