module Anoma.Balance;

import Anoma.Prelude open;
import Data.ByteString open;
import Anoma.Resource open;
import Anoma.Kind open;

import Data.Map as Map;

type Balance := balance : List (Kind × Int) -> Balance;

emptyBalance : Balance := balance nil;

addBalance : Balance -> Balance -> Balance
  | (balance xs) (balance ys) :=
    balance (Map.toList (Map.fromListWith (+) (xs ++ ys)));

negateBalance : Balance -> Balance
  | (balance bs) := balance (map (b in bs) second neg b);

subBalance (b1 : Balance) (b2 : Balance) : Balance :=
  addBalance b1 (negateBalance b2);

sumBalances (bs : List Balance) : Balance :=
  for (acc := emptyBalance) (b in bs)
    addBalance acc b;

balanceIsZero : Balance -> Bool
  | (balance bs) := all (b in bs) snd b == 0;