{-# LANGUAGE MultiWayIf #-}
{-# LANGUAGE TemplateHaskell #-}
module PayPal.Adaptive.Core where
import Prelude hiding (mapM)
import Control.Applicative
import Control.Exception
import Control.Lens hiding ((.=))
import Data.Aeson
import Data.Aeson.TH hiding (Options)
import Data.Aeson.Types hiding (Options)
import Data.ByteString.Lazy (ByteString)
import Data.Char
import Data.Maybe
import Data.Monoid
import Data.Text (Text)
import qualified Data.Text as T
import Data.Text.Encoding
import Data.Text.Read
import Data.Traversable
import qualified Data.Vector as V
import Network.Wreq
--------------------------------------------------
-- Client
--------------------------------------------------
data Client = Client
{ _clAppId :: Text
, _clUserId :: Text
, _clEnv :: Env
, _clPassword :: Text
, _clSig :: Text
-- | Not needed for authentication, but deposits are sent
-- to here and withdrawals are sent from here. Must be the
-- email associated with your PayPal app.
, _clAccountEmail :: Text
} deriving (Eq, Show)
data Env = Sandbox | Production deriving (Eq, Show, Read)
--------------------------------------------------
-- Errors
--------------------------------------------------
-- | Text is an error message in all the below types.
--
-- AeShouldNotHappen is meant to cover PayPal responses to API requests
-- that this library doesn't support sending in the first place.
-- TODO: is this actually how we're using it?
data AdaptiveErr
= AeConnectionErr Text
| AeDecodeFailed ByteString Text
| AeInvalidCredentials
-- ^ Just a wrapper around an AeErrCodes Int.
| AeNoSuchEmail
-- ^ Just a wrapper around an AeErrCodes Int. Raised when the Deposit
-- sender email or the Withdrawal account email doesn't exist.
| AeErrCodes [Int]
| AePending PayResp
| AeRefused PayResp
| AeShouldNotHappen PayResp Text
deriving (Eq, Show)
-- Error responses are what's returned if, e.g., your password is incorrect.
--
-- Here's an example error response. Only the parts we parse are included.
--
-- {
-- "error": [
-- {
-- "errorId": "111111",
-- }
-- ]
-- }
instance FromJSON AdaptiveErr where
parseJSON = withObject "error response" $ \o ->
AeErrCodes . V.toList <$> (mapM parseErrId =<< o .: "error")
-- | Exported by PayPal.Adaptive.Internal
parseErrId :: Value -> Parser Int
parseErrId = withObject "error array item" $ \o -> do
a <- o .: "errorId"
case decimal a of
Left _ -> fail "Could not parse error response code to Int"
Right (b,_) -> return b
--------------------------------------------------
-- * Payment Responses
--------------------------------------------------
-- | Used for forgiving attempts to parse PayPal responses. For instance,
-- this library never expects more than one PayInfo. We still try to
-- parse them as a list here so we can still sucessfully parse a PayResp
-- to use in an 'AdaptiveError' if for some reason more than one 'PayInfo'
-- is returned
data PayResp = PayResp
{ _prPayError :: Maybe Text
, _prPayExecStatus :: PayExecStatus
, _prPayKey :: PayKey
, _prPayInfos :: [PayInfo]
} deriving (Eq, Show)
-- | A version of 'PayResp' for completed transactions.
--
-- Status fields are omitted since they should be complete.
--
-- Has no separate field for a 'PayInfo' list since successful transactions
-- will always have exactly one. Instead the pay info fields have been
-- flattened into the top level of this structure.
data CompletePayResp = CompletePayResp
{ _crPayKey :: PayKey
, _crReceiver :: Receiver
, _crSenderTransactionId :: TransactionId
, _crTransactionId :: TransactionId
} deriving (Eq, Show)
checkComplete :: PayResp -> Either AdaptiveErr CompletePayResp
checkComplete pr = do
errorFieldNothing pr
payExecStatusCompleted pr
checkPayKey pr
info <- getPayInfo pr
sid <- transactionIdJust pr (_piSenderTransactionId info)
transactionStatusCompleted pr info
tid <- transactionIdJust pr (_piTransactionId info)
return $ CompletePayResp (_prPayKey pr) (_piReceiver info) sid tid
instance FromJSON PayResp where
parseJSON = withObject "PayResp" $ \o -> do
e <- o .:? "payErrorList"
k <- o .: "payKey"
s <- o .:? "paymentExecStatus"
s' <- o .:? "status"
status <- maybe (fail "no paymentExecStatus or status") return (if isJust s then s else s')
a <- o .:? "paymentInfoList"
case a of
Nothing -> return $ PayResp e status k mempty
Just v -> do
infos <- v .:? "paymentInfo" .!= mempty
return $ PayResp e status k infos
-- | This refers to the processing of this request. To make sure a payment
-- has actually gone through, check 'TransactionStatus' instead.
--
-- PayPal returns this using the JSON object key "paymentExecStatus"
-- in responses to Withdrawal and Deposit and "status" in responses to
-- LookupPayment.
data PayExecStatus
= PeCreated
| PeCompleted
| PeIncomplete
| PeError
| PeReversalError
| PeProcessing
| PePending
deriving (Eq, Show, Read)
-- | Expires after three hours.
--
-- <https://developer.paypal.com/docs/classic/api/adaptive-payments/Pay_API_Operation/>
newtype PayKey = PayKey { _unPayKey :: Text } deriving (Eq, Show)
instance FromJSON PayKey where
parseJSON = withText "PayKey" $ return . PayKey
instance ToJSON PayKey where
toJSON (PayKey a) = toJSON a
-- | Right toPayPal responses return a PayInfo along with a
-- _piTransactionStatus Just, with some exceptions.
--
-- 1. Withdrawals to nonexistent accounts return no PayInfos.
--
-- 2. Lookups on such transactions return one PayInfo with a
-- _piTransactionStatus of Nothing.
--
-- 3. Deposits don't return PayInfos.
--
-- 4. Lookups on such transactions return one PayInfo with a
-- _piTransactionStatus of Nothing.
--
-- NOTE: We use the same newtype for both _piSenderTransactionId and
-- _piTransactionStatus. They will have different values, but either
-- can be used to look up a payment.
data PayInfo = PayInfo
{ _piReceiver :: Receiver
, _piSenderTransactionId :: Maybe TransactionId
, _piTransactionStatus :: Maybe TransactionStatus
, _piTransactionId :: Maybe TransactionId
} deriving (Eq, Show)
data Receiver = Receiver
{ _reAmount :: Text
-- ^ Haven't converted this to Money yet because I'm not sure how
-- to determine its currency.
, _reEmail :: Text
, _reAccountId :: Text
} deriving (Eq, Show)
newtype TransactionId = TransactionId { _unTransactionId :: Text } deriving (Eq, Show)
instance FromJSON TransactionId where
parseJSON = withText "TransactionId" $ return . TransactionId
instance ToJSON TransactionId where
toJSON (TransactionId a) = toJSON a
data TransactionStatus
= TsCompleted
| TsPending
| TsCreated
| TsPartiallyRefunded
| TsDenied
| TsProcessing
| TsReversed
| TsRefunded
| TsFailed
deriving (Eq, Show, Read)
--------------------------------------------------
-- Money
--------------------------------------------------
data Money = USD { _usdCents :: Int } deriving (Eq, Show)
-- NOTE: Once we add more currencies this instance will violate the
-- Monoid laws.
instance Monoid Money where
mempty = USD 0
mappend (USD c1) (USD c2) = USD $ c1 + c2
m2Currency :: Money -> Text
m2Currency (USD _) = "USD"
m2PayPal :: Money -> String
m2PayPal (USD c) =
let s = show (abs c)
a = case length s of
0 -> "0.00"
1 -> "0.0" <> s
2 -> "0." <> s
_ -> tailInsert 2 '.' s
in if c < 0 then '-':a else a
where
tailInsert :: Int -> a -> [a] -> [a]
tailInsert i x xs =
let (ys, zs) = splitAt i (reverse xs)
in reverse (ys <> pure x <> zs)
--------------------------------------------------
-- Internal Helpers
--------------------------------------------------
-- | "en_US" is hardcoded because it's the only supported error language.
requestEnvelope :: Value
requestEnvelope = object ["errorLanguage" .= ("en_US" :: Text)]
ppPost :: (ToJSON a) => Client -> Text -> a -> IO (Either AdaptiveErr (Response ByteString))
ppPost c endpoint p = catch (return . Right =<< runPost) handler
where
runPost :: IO (Response ByteString)
runPost = postWith opts (clBaseUrl <> T.unpack endpoint) (toJSON p)
clBaseUrl :: String
clBaseUrl =
case _clEnv c of
Sandbox -> "https://svcs.sandbox.paypal.com/AdaptivePayments/"
Production -> "https://svcs.paypal.com/AdaptivePayments/"
handler :: SomeException -> IO (Either AdaptiveErr (Response ByteString))
handler e = return . Left . AeConnectionErr . T.pack . show $ e
opts :: Options
opts = defaults
& header "X-PAYPAL-SECURITY-USERID" .~ [ encodeUtf8 (_clUserId c) ]
& header "X-PAYPAL-SECURITY-PASSWORD" .~ [ encodeUtf8 (_clPassword c) ]
& header "X-PAYPAL-SECURITY-SIGNATURE" .~ [ encodeUtf8 (_clSig c) ]
& header "X-PAYPAL-APPLICATION-ID" .~ [ encodeUtf8 (_clAppId c) ]
& header "X-PAYPAL-REQUEST-DATA-FORMAT" .~ [ "JSON" ]
& header "X-PAYPAL-RESPONSE-DATA-FORMAT" .~ [ "JSON" ]
ppDecode :: Response ByteString -> Either AdaptiveErr PayResp
ppDecode r =
let b = r ^. responseBody
in case eitherDecode b of
Right d -> Right d
Left e -> -- If the response isn't a PayResp, it might be a PayPal error message.
case decode b of
Just (AeErrCodes codes) -> Left $ codeErr codes
_ -> Left $ AeDecodeFailed b (T.pack e)
where
codeErr :: [Int] -> AdaptiveErr
codeErr cs =
if | elem 520003 cs -> AeInvalidCredentials
| elem 589039 cs -> AeNoSuchEmail
| otherwise -> AeErrCodes cs
payExecStatusCompleted :: PayResp -> Either AdaptiveErr ()
payExecStatusCompleted a =
case _prPayExecStatus a of
PeCompleted -> Right ()
PeProcessing -> Left $ AePending a
PePending -> Left $ AePending a
PeError -> Left $ AeRefused a
_ -> Left $ AeShouldNotHappen a "unsupported PayExecStatus"
-- | TODO: this makes the assumption that an empty PayInfo list means
-- the transaction is pending. Is this always right?
getPayInfo :: PayResp -> Either AdaptiveErr PayInfo
getPayInfo a =
case _prPayInfos a of
[] -> Left $ AePending a
[info] -> Right info
_ -> Left $ AeShouldNotHappen a "more than one PayInfo in reponse"
transactionStatusCompleted :: PayResp -> PayInfo -> Either AdaptiveErr ()
transactionStatusCompleted a info =
case _piTransactionStatus info of
Just TsCompleted -> Right ()
Just TsPending -> Left $ AePending a
Just TsProcessing -> Left $ AePending a
Just TsDenied -> Left $ AeRefused a
Just TsFailed -> Left $ AeRefused a
_ -> Left $ AeShouldNotHappen a "unsupported TransactionStatus"
errorFieldNothing :: PayResp -> Either AdaptiveErr ()
errorFieldNothing a
| _prPayError a == Nothing = Right ()
| otherwise = Left $ AeShouldNotHappen a
"PayResp error field is Just in otherwise correct payment"
checkPayKey :: PayResp -> Either AdaptiveErr ()
checkPayKey a
| T.null . _unPayKey . _prPayKey $ a =
Left $ AeShouldNotHappen a "got a PayKey with length zero"
| otherwise = Right ()
payExecStatusCreated :: PayResp -> Either AdaptiveErr ()
payExecStatusCreated a =
case _prPayExecStatus a of
PeCreated -> Right ()
PeProcessing -> Left $ AePending a
PePending -> Left $ AePending a
PeError -> Left $ AeRefused a
_ -> Left $ AeShouldNotHappen a "unsupported PayExecStatus"
noPayInfo :: PayResp -> Either AdaptiveErr ()
noPayInfo a =
case _prPayInfos a of
[] -> Right ()
_ -> Left $ AeShouldNotHappen a
"At least one PayInfo present in otherwise successful deposit resp"
transactionIdJust :: PayResp -> Maybe TransactionId -> Either AdaptiveErr TransactionId
transactionIdJust a Nothing = Left $ AeShouldNotHappen a "expected a Just for Maybe TransactionId"
transactionIdJust _ (Just tid) = Right tid
$(deriveFromJSON defaultOptions { constructorTagModifier = map toUpper . drop 2 } ''PayExecStatus)
$(deriveFromJSON defaultOptions { fieldLabelModifier = (\(x:xs) -> toLower x:xs) . drop 3 } ''PayInfo)
$(deriveFromJSON defaultOptions { fieldLabelModifier = (\(x:xs) -> toLower x:xs) . drop 3 } ''Receiver)
$(deriveFromJSON defaultOptions { constructorTagModifier = map toUpper . camelTo '_' . drop 2 } ''TransactionStatus)