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module Model.Payer
( getOrderedExceedingPayers
) where
import qualified Data.List as List
import Data.Map (Map)
import qualified Data.Map as Map
import qualified Data.Maybe as Maybe
import Data.Time (NominalDiffTime, UTCTime (..))
import qualified Data.Time as Time
import Common.Model (Income (..), IncomeId, Payment (..), User (..),
UserId)
type Users = Map UserId User
type Payers = Map UserId Payer
type Incomes = Map IncomeId Income
type Payments = [Payment]
data Payer = Payer
{ preIncomePaymentSum :: Int
, postIncomePaymentSum :: Int
, _incomes :: [Income]
}
data PostPaymentPayer = PostPaymentPayer
{ _preIncomePaymentSum :: Int
, _cumulativeIncome :: Int
, ratio :: Float
}
data ExceedingPayer = ExceedingPayer
{ _userId :: UserId
, amount :: Int
} deriving (Show)
getOrderedExceedingPayers :: UTCTime -> [User] -> [Income] -> Payments -> [ExceedingPayer]
getOrderedExceedingPayers currentTime users incomes payments =
let usersMap = Map.fromList . map (\user -> (_user_id user, user)) $ users
incomesMap = Map.fromList . map (\income -> (_income_id income, income)) $ incomes
payers = getPayers currentTime usersMap incomesMap payments
exceedingPayersOnPreIncome =
exceedingPayersFromAmounts
. Map.toList
. Map.map preIncomePaymentSum
$ payers
mbSince = useIncomesFrom usersMap incomesMap payments
in case mbSince of
Just since ->
let postPaymentPayers = Map.map (getPostPaymentPayer currentTime since) payers
mbMaxRatio =
safeMaximum
. map (ratio . snd)
. Map.toList
$ postPaymentPayers
in case mbMaxRatio of
Just maxRatio ->
exceedingPayersFromAmounts
. Map.toList
. Map.map (getFinalDiff maxRatio)
$ postPaymentPayers
Nothing ->
exceedingPayersOnPreIncome
_ ->
exceedingPayersOnPreIncome
useIncomesFrom :: Users -> Incomes -> Payments -> Maybe UTCTime
useIncomesFrom users incomes payments =
let firstPaymentTime = safeHead . List.sort . map paymentTime $ payments
mbIncomeTime = incomeDefinedForAll (Map.keys users) incomes
in case (firstPaymentTime, mbIncomeTime) of
(Just t1, Just t2) -> Just (max t1 t2)
_ -> Nothing
paymentTime :: Payment -> UTCTime
paymentTime = flip UTCTime (Time.secondsToDiffTime 0) . _payment_date
getPayers :: UTCTime -> Users -> Incomes -> Payments -> Payers
getPayers currentTime users incomes payments =
let userIds = Map.keys users
incomesDefined = incomeDefinedForAll userIds incomes
in Map.fromList
. map (\userId ->
( userId
, Payer
{ preIncomePaymentSum =
totalPayments
(\p -> paymentTime p < (Maybe.fromMaybe currentTime incomesDefined))
userId
payments
, postIncomePaymentSum =
totalPayments
(\p ->
case incomesDefined of
Nothing -> False
Just t -> paymentTime p >= t
)
userId
payments
, _incomes = filter ((==) userId . _income_userId) (Map.elems incomes)
}
)
)
$ userIds
exceedingPayersFromAmounts :: [(UserId, Int)] -> [ExceedingPayer]
exceedingPayersFromAmounts userAmounts =
case mbMinAmount of
Nothing ->
[]
Just minAmount ->
filter (\payer -> amount payer > 0)
. map (\userAmount ->
ExceedingPayer
{ _userId = fst userAmount
, amount = snd userAmount - minAmount
}
)
$ userAmounts
where mbMinAmount = safeMinimum . map snd $ userAmounts
getPostPaymentPayer :: UTCTime -> UTCTime -> Payer -> PostPaymentPayer
getPostPaymentPayer currentTime since payer =
PostPaymentPayer
{ _preIncomePaymentSum = preIncomePaymentSum payer
, _cumulativeIncome = cumulativeIncome
, ratio = (fromIntegral . postIncomePaymentSum $ payer) / (fromIntegral cumulativeIncome)
}
where cumulativeIncome = cumulativeIncomesSince currentTime since (_incomes payer)
getFinalDiff :: Float -> PostPaymentPayer -> Int
getFinalDiff maxRatio payer =
let postIncomeDiff =
truncate $ -1.0 * (maxRatio - ratio payer) * (fromIntegral . _cumulativeIncome $ payer)
in postIncomeDiff + _preIncomePaymentSum payer
incomeDefinedForAll :: [UserId] -> Incomes -> Maybe UTCTime
incomeDefinedForAll userIds incomes =
let userIncomes = map (\userId -> filter ((==) userId . _income_userId) . Map.elems $ incomes) userIds
firstIncomes = map (safeHead . List.sortOn incomeTime) userIncomes
in if all Maybe.isJust firstIncomes
then safeHead . reverse . List.sort . map incomeTime . Maybe.catMaybes $ firstIncomes
else Nothing
cumulativeIncomesSince :: UTCTime -> UTCTime -> [Income] -> Int
cumulativeIncomesSince currentTime since incomes =
getCumulativeIncome currentTime (getOrderedIncomesSince since incomes)
getOrderedIncomesSince :: UTCTime -> [Income] -> [Income]
getOrderedIncomesSince time incomes =
let mbStarterIncome = getIncomeAt time incomes
orderedIncomesSince = filter (\income -> incomeTime income >= time) incomes
in (Maybe.maybeToList mbStarterIncome) ++ orderedIncomesSince
getIncomeAt :: UTCTime -> [Income] -> Maybe Income
getIncomeAt time incomes =
case incomes of
[x] ->
if incomeTime x < time
then Just $ x { _income_date = utctDay time }
else Nothing
x1 : x2 : xs ->
if incomeTime x1 < time && incomeTime x2 >= time
then Just $ x1 { _income_date = utctDay time }
else getIncomeAt time (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 = flip UTCTime (Time.secondsToDiffTime 0) . _income_date
durationIncome :: (NominalDiffTime, Int) -> Int
durationIncome (duration, income) =
truncate $ duration * fromIntegral income / (nominalDay * 365 / 12)
nominalDay :: NominalDiffTime
nominalDay = 86400
safeHead :: [a] -> Maybe a
safeHead [] = Nothing
safeHead (x : _) = Just x
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
totalPayments :: (Payment -> Bool) -> UserId -> Payments -> Int
totalPayments paymentFilter userId payments =
sum
. map _payment_cost
. filter (\payment -> paymentFilter payment && _payment_user payment == userId)
$ payments
|
