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module Payer
( getExceedingPayers
, useIncomesFrom
, cumulativeIncomesSince
) where
import qualified Data.List as List
import Data.Map (Map)
import qualified Data.Map as M
import qualified Data.Maybe as Maybe
import Data.Time (NominalDiffTime, UTCTime (..))
import qualified Data.Time as Time
import Data.Time.Calendar (Day)
import Common.Model (ExceedingPayer (..), Income (..),
User (..), UserId)
data Payer = Payer
{ _payer_userId :: UserId
, _payer_preIncomePayments :: Int
, _payer_postIncomePayments :: Int
, _payer_incomes :: [Income]
}
data PostPaymentPayer = PostPaymentPayer
{ _postPaymentPayer_userId :: UserId
, _postPaymentPayer_preIncomePayments :: Int
, _postPaymentPayer_cumulativeIncome :: Int
, _postPaymentPayer_ratio :: Float
}
getExceedingPayers :: UTCTime -> [User] -> [Income] -> Map UserId Int -> Map UserId Int -> Maybe Day -> [ExceedingPayer]
getExceedingPayers currentTime users incomes preIncomeRepartition postIncomeRepartition firstPayment =
let userIds = map _user_id users
payers = getPayers userIds incomes preIncomeRepartition postIncomeRepartition
exceedingPayersOnPreIncome =
exceedingPayersFromAmounts . map (\p -> (_payer_userId p, _payer_preIncomePayments p)) $ payers
mbSince = useIncomesFrom userIds incomes firstPayment
in case mbSince of
Just since ->
let postPaymentPayers = map (getPostPaymentPayer currentTime since) payers
mbMaxRatio = safeMaximum . map _postPaymentPayer_ratio $ postPaymentPayers
in case mbMaxRatio of
Just maxRatio ->
exceedingPayersFromAmounts
. map (\p -> (_postPaymentPayer_userId p, getFinalDiff maxRatio p))
$ postPaymentPayers
Nothing ->
exceedingPayersOnPreIncome
_ ->
exceedingPayersOnPreIncome
useIncomesFrom :: [UserId] -> [Income] -> Maybe Day -> Maybe Day
useIncomesFrom userIds incomes firstPayment =
case (firstPayment, incomeDefinedForAll userIds incomes) of
(Just d1, Just d2) -> Just (max d1 d2)
_ -> Nothing
dayUTCTime :: Day -> UTCTime
dayUTCTime = flip UTCTime (Time.secondsToDiffTime 0)
getPayers :: [UserId] -> [Income] -> Map UserId Int -> Map UserId Int -> [Payer]
getPayers userIds incomes preIncomeRepartition postIncomeRepartition =
flip map userIds (\userId -> Payer
{ _payer_userId = userId
, _payer_preIncomePayments = M.findWithDefault 0 userId preIncomeRepartition
, _payer_postIncomePayments = M.findWithDefault 0 userId postIncomeRepartition
, _payer_incomes = filter ((==) userId . _income_userId) incomes
}
)
exceedingPayersFromAmounts :: [(UserId, Int)] -> [ExceedingPayer]
exceedingPayersFromAmounts userAmounts =
case mbMinAmount of
Nothing ->
[]
Just minAmount ->
filter (\payer -> _exceedingPayer_amount payer > 0)
. map (\userAmount ->
ExceedingPayer
{ _exceedingPayer_userId = fst userAmount
, _exceedingPayer_amount = snd userAmount - minAmount
}
)
$ userAmounts
where mbMinAmount = safeMinimum . map snd $ userAmounts
getPostPaymentPayer :: UTCTime -> Day -> Payer -> PostPaymentPayer
getPostPaymentPayer currentTime since payer =
PostPaymentPayer
{ _postPaymentPayer_userId = _payer_userId payer
, _postPaymentPayer_preIncomePayments = _payer_preIncomePayments payer
, _postPaymentPayer_cumulativeIncome = cumulativeIncome
, _postPaymentPayer_ratio = (fromIntegral . _payer_postIncomePayments $ payer) / (fromIntegral cumulativeIncome)
}
where cumulativeIncome = cumulativeIncomesSince currentTime since (_payer_incomes payer)
getFinalDiff :: Float -> PostPaymentPayer -> Int
getFinalDiff maxRatio payer =
let postIncomeDiff =
truncate $ -1.0 * (maxRatio - _postPaymentPayer_ratio payer) * (fromIntegral . _postPaymentPayer_cumulativeIncome $ payer)
in postIncomeDiff + _postPaymentPayer_preIncomePayments payer
incomeDefinedForAll :: [UserId] -> [Income] -> Maybe Day
incomeDefinedForAll userIds incomes =
let userIncomes = map (\userId -> filter ((==) userId . _income_userId) $ incomes) userIds
firstIncomes = map (Maybe.listToMaybe . List.sortOn _income_date) userIncomes
in if all Maybe.isJust firstIncomes
then Maybe.listToMaybe . reverse . List.sort . map _income_date . Maybe.catMaybes $ firstIncomes
else Nothing
cumulativeIncomesSince :: UTCTime -> Day -> [Income] -> Int
cumulativeIncomesSince currentTime since incomes =
getCumulativeIncome currentTime (getOrderedIncomesSince since incomes)
getOrderedIncomesSince :: Day -> [Income] -> [Income]
getOrderedIncomesSince since incomes =
let mbStarterIncome = getIncomeAt since incomes
orderedIncomesSince = filter (\income -> _income_date income >= since) incomes
in (Maybe.maybeToList mbStarterIncome) ++ orderedIncomesSince
getIncomeAt :: Day -> [Income] -> Maybe Income
getIncomeAt day incomes =
case incomes of
[x] ->
if _income_date x < day
then Just $ x { _income_date = day }
else Nothing
x1 : x2 : xs ->
if _income_date x1 < day && _income_date x2 >= day
then Just $ x1 { _income_date = day }
else getIncomeAt day (x2 : xs)
[] ->
Nothing
getCumulativeIncome :: UTCTime -> [Income] -> Int
getCumulativeIncome currentTime incomes =
sum
. map durationIncome
. getIncomesWithDuration currentTime
. List.sortOn incomeTime
$ incomes
getIncomesWithDuration :: UTCTime -> [Income] -> [(NominalDiffTime, Int)]
getIncomesWithDuration currentTime incomes =
case incomes of
[] ->
[]
[income] ->
[(Time.diffUTCTime currentTime (incomeTime income), _income_amount income)]
(income1 : income2 : xs) ->
(Time.diffUTCTime (incomeTime income2) (incomeTime income1), _income_amount income1) : (getIncomesWithDuration currentTime (income2 : xs))
incomeTime :: Income -> UTCTime
incomeTime = dayUTCTime . _income_date
durationIncome :: (NominalDiffTime, Int) -> Int
durationIncome (duration, income) =
truncate $ duration * fromIntegral income / (nominalDay * 365 / 12)
nominalDay :: NominalDiffTime
nominalDay = 86400
safeMinimum :: (Ord a) => [a] -> Maybe a
safeMinimum [] = Nothing
safeMinimum xs = Just . minimum $ xs
safeMaximum :: (Ord a) => [a] -> Maybe a
safeMaximum [] = Nothing
safeMaximum xs = Just . maximum $ xs
|
