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|
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE QuasiQuotes #-}
module Main
( main
) where
import Control.Arrow ((&&&))
import Control.Monad (when)
import Data.Version (showVersion)
import GHC.Generics (Generic)
import System.Environment (getArgs)
import System.Exit (die)
import Data.Aeson (FromJSON, eitherDecode, encode)
import qualified Data.ByteString.Lazy as L
import qualified Data.HashMap.Strict as HM
import qualified System.Console.Docopt.NoTH as O
import Text.InterpolatedString.Perl6 (qc)
import Malodivo.Budget (manyToOne)
import Malodivo.Types.Bill (Bill)
import Malodivo.Types.District (District)
import Paths_malodivo (version) -- from cabal
usage :: String
usage =
"malodivo " ++
showVersion version ++
" - budget planning tool for the Kingdom of Malodivo" ++
[qc|
This utility reads input JSON data from standard input
and writes output JSON data to standard output.
Usage: malodivo [options] < input.json > output.json
Options:
-h, --help Show this message and exit
|]
data DistrictInfo = DistrictInfo
{ name :: District
, availableFunds :: Integer
} deriving (Generic, FromJSON)
data SimpleInput = SimpleInput
{ bills :: [Bill]
, districts :: [DistrictInfo]
} deriving (Generic, FromJSON)
process :: IO ()
process = do
input <- L.getContents
case eitherDecode input of
Left err -> die err
Right si -> do
let nbills = length . bills $ si
funds =
HM.fromListWith (+) . map (name &&& availableFunds) $ districts si
when (nbills /= 1) $ die "We needs exactly one bill in input"
when (HM.null funds) $ die "We needs at least one district"
L.putStr . encode $ manyToOne funds (head . bills $ si)
main :: IO ()
main = do
doco <- O.parseUsageOrExit usage
args <- O.parseArgsOrExit doco =<< getArgs
if args `O.isPresent` O.longOption "help"
then putStrLn $ O.usage doco
else process
|