module MonthlyPaymentJob
  ( monthlyPaymentJobListener
  ) where

import Control.Monad.IO.Class (liftIO)

import Data.Time.Clock
import Data.Time.LocalTime
import Data.Time.Calendar

import Database.Persist (entityVal, insert)

import Job (jobListener)

import Model.Database
import Model.Payment (getMonthlyPayments)
import Model.JobKind
import Model.Frequency

monthlyPaymentJobListener :: IO ()
monthlyPaymentJobListener =
  let lastExecutionTooOld = fmap not . belongToCurrentMonth
      runJob () = monthlyPaymentJob
      msDelay = 1000000 * 60 * 60
  in  jobListener MonthlyPaymentJob lastExecutionTooOld runJob msDelay

belongToCurrentMonth :: UTCTime -> IO Bool
belongToCurrentMonth time = do
  month <- getLocalMonth time
  actualMonth <- getCurrentTime >>= getLocalMonth
  return (month == actualMonth)

getLocalMonth :: UTCTime -> IO Int
getLocalMonth time = do
  timeZone <- getCurrentTimeZone
  let (_, month, _) = toGregorian . localDay $ utcToLocalTime timeZone time
  return month

monthlyPaymentJob :: Persist ()
monthlyPaymentJob = do
  monthlyPayments <- map entityVal <$> getMonthlyPayments
  now <- liftIO $ getCurrentTime
  let punctualPayments = map (\p -> p { paymentFrequency = Punctual, paymentCreation = now }) monthlyPayments
  sequence_ $ map insert punctualPayments