1 files changed, 29 insertions, 40 deletions
diff --git a/lib/Malodivo/Budget.hs b/lib/Malodivo/Budget.hs
index a707cec..657cf14 100644
--- a/lib/Malodivo/Budget.hs
+++ b/lib/Malodivo/Budget.hs
@@ -3,20 +3,32 @@
 Budget planning in the Kingdom of Malodivo.
 
 -}
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DeriveGeneric #-}
+
 module Malodivo.Budget
-  ( DistrictFunds
-  , normalizeDown
-  , manyToOne
+  ( BillBudget
   , manyToMany
+  , manyToOne
+  , normalizeDown
   ) where
 
+import GHC.Generics (Generic)
+
+import Data.Aeson (ToJSON)
 import qualified Data.HashMap.Strict as HM
 
 import qualified Malodivo.Types.Bill as B
 import qualified Malodivo.Types.District as D
 
--- | Convenient type. Describes available or allocated funds per 'District'.
-type DistrictFunds = HM.HashMap D.District Integer
+-- | This is output type. It describes contribution of each district into a bill.
+data BillBudget = BillBudget
+  { bill :: B.Bill
+  , districts :: [D.DistrictInfo]
+  } deriving (Generic, ToJSON)
+
+zipBills :: [B.Bill] -> [D.DistrictFunds] -> [BillBudget]
+zipBills = zipWith $ \b df -> BillBudget {bill = b, districts = D.df2di df}
 
 {-|
 Normalize list of integers, i. e. proportionally decrease each list element
@@ -125,52 +137,29 @@ True
 
 -}
 manyToOne ::
-     DistrictFunds -- ^ Amounts of available funds per district.
+     D.DistrictFunds -- ^ Amounts of available funds per district.
   -> B.Bill -- ^ A bill requiring funding.
-  -> DistrictFunds -- ^ Contribution of each district.
-manyToOne funds bill = fundRaising (B.amount bill) funds
+  -> D.DistrictFunds -- ^ Contribution of each district.
+manyToOne df b = fundRaising (B.amount b) df
 
 {-|
 Districts funding multiple bills. No constraints.
-
->>> :set -XOverloadedStrings
->>> import Data.Maybe (fromJust)
->>> import qualified Data.HashMap.Strict as HM
->>> import qualified Malodivo.Types.Bill as B
->>> import qualified Malodivo.Types.District as D
->>> import qualified Malodivo.Types.Ministry as M
-
->>> let billA = B.Bill { B.amount = 30, B.name = "Bill A", B.ministry = M.Science }
->>> let billB = B.Bill { B.amount = 10, B.name = "Bill B", B.ministry = M.Welfare }
->>> let equalAmountBills = take 3 (repeat billB)
->>> let nonEqualAmountBills = [billA, billB]
-
-
-If all bills requires the same amount, funds of a single district are
-allocated evenly:
-
->>> let funds = HM.fromList [(D.Palolene, 100)]
->>> let contribution = manyToMany funds equalAmountBills
->>> all (== B.amount (head equalAmountBills)) (fromJust . HM.lookup D.Palolene <$> contribution)
-True
-
 -}
 manyToMany ::
-     DistrictFunds -- ^ Amounts of available funds per district.
+     D.DistrictFunds -- ^ Amounts of available funds per district.
   -> [B.Bill] -- ^ Bills requiring funding.
-  -> [DistrictFunds] -- ^ Contribution of each district to each bill.
-manyToMany funds bills =
-  flip fundRaising funds <$> normalizeDown fundsTotal billAmounts
+  -> [BillBudget] -- ^ Contribution of each district to each bill.
+manyToMany df bills = zipBills bills allocated
   where
     billAmounts = B.amount <$> bills
-    fundsTotal = sum $ HM.elems funds
+    fundsTotal = sum $ HM.elems df
+    allocated = flip fundRaising df <$> normalizeDown fundsTotal billAmounts
 
 -- | Helper function to maintain DRY and backward compatibility.
 fundRaising ::
      Integer -- ^ Amount to be raised.
-  -> DistrictFunds -- ^ Amounts of available funds per district.
-  -> DistrictFunds -- ^ Contribution of each district.
-fundRaising needed df = HM.fromList $ zip districts funds'
+  -> D.DistrictFunds -- ^ Amounts of available funds per district.
+  -> D.DistrictFunds -- ^ Contribution of each district.
+fundRaising needed df = HM.fromList $ zip ds (normalizeDown needed fs)
   where
-    (districts, funds) = unzip $ HM.toList df
-    funds' = normalizeDown needed funds
+    (ds, fs) = unzip $ HM.toList df