fradrive/src/Utils.hs
2018-10-17 22:30:47 +02:00

455 lines
13 KiB
Haskell

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TypeSynonymInstances, FlexibleInstances #-}
{-# LANGUAGE TypeFamilies, FlexibleContexts, ConstraintKinds #-}
{-# LANGUAGE QuasiQuotes, TemplateHaskell #-}
{-# LANGUAGE ViewPatterns #-}
{-# OPTIONS_GHC -fno-warn-orphans #-} -- Monad FormResult
module Utils
( module Utils
) where
import ClassyPrelude.Yesod
-- import Data.Double.Conversion.Text -- faster implementation for textPercent?
import Data.Foldable as Fold hiding (length)
import Data.CaseInsensitive (CI)
import qualified Data.CaseInsensitive as CI
import qualified Data.ByteString.Lazy as LBS
import Utils.DB as Utils
import Utils.TH as Utils
import Utils.DateTime as Utils
import Utils.PathPiece as Utils
import Utils.Message as Utils
import Utils.Lang as Utils
import Text.Blaze (Markup, ToMarkup)
import Data.Char (isDigit)
import Data.Text (dropWhileEnd, takeWhileEnd, justifyRight)
import Numeric (showFFloat)
import Control.Lens
import Data.Set (Set)
import qualified Data.Set as Set
import Data.Map (Map)
import qualified Data.Map as Map
-- import qualified Data.List as List
import Control.Monad.Trans.Except (ExceptT(..), throwE, runExceptT)
import Control.Monad.Trans.Maybe (MaybeT(..))
import Control.Monad.Catch
import qualified Database.Esqueleto as E (Value, unValue)
import Language.Haskell.TH
import Instances.TH.Lift ()
import Text.Shakespeare.Text (st)
import qualified Data.Aeson as Aeson
-----------
-- Yesod --
-----------
newtype MsgRendererS site = MsgRenderer { render :: (forall msg. RenderMessage site msg => msg -> Text) }
getMsgRenderer :: forall m site. (MonadHandler m, HandlerSite m ~ site) => m (MsgRendererS site)
getMsgRenderer = do
mr <- getMessageRender
return $ MsgRenderer (mr . SomeMessage :: forall msg. RenderMessage site msg => msg -> Text)
instance Monad FormResult where
FormMissing >>= _ = FormMissing
(FormFailure errs) >>= _ = FormFailure errs
(FormSuccess a) >>= f = f a
guardAuthResult :: MonadHandler m => AuthResult -> m ()
guardAuthResult AuthenticationRequired = notAuthenticated
guardAuthResult (Unauthorized t) = permissionDenied t
guardAuthResult Authorized = return ()
data UnsupportedAuthPredicate route = UnsupportedAuthPredicate String route
deriving (Eq, Ord, Typeable, Show)
instance (Show route, Typeable route) => Exception (UnsupportedAuthPredicate route)
unsupportedAuthPredicate :: ExpQ
unsupportedAuthPredicate = do
logFunc <- logErrorS
[e| \tag route -> do
$(return logFunc) "AccessControl" [st|"!#{tag}" used on route that doesn't support it: #{tshow route}|]
unauthorizedI (UnsupportedAuthPredicate tag route)
|]
---------------------
-- Text and String --
---------------------
tickmark :: IsString a => a
tickmark = fromString ""
-- Avoid annoying warnings:
tickmarkS :: String
tickmarkS = tickmark
tickmarkT :: Text
tickmarkT = tickmark
text2Html :: Text -> Html
text2Html = toHtml -- prevents ambiguous types
toWgt :: (ToMarkup a, MonadBaseControl IO m, MonadThrow m, MonadIO m) =>
a -> WidgetT site m ()
toWgt = toWidget . toHtml
-- Convenience Functions to avoid type signatures:
text2widget :: (MonadBaseControl IO m, MonadThrow m, MonadIO m) =>
Text -> WidgetT site m ()
text2widget t = [whamlet|#{t}|]
citext2widget :: (MonadBaseControl IO m, MonadThrow m, MonadIO m) =>
(CI Text) -> WidgetT site m ()
citext2widget t = [whamlet|#{CI.original t}|]
str2widget :: (MonadBaseControl IO m, MonadThrow m, MonadIO m) =>
String -> WidgetT site m ()
str2widget s = [whamlet|#{s}|]
display2widget :: (MonadBaseControl IO m, MonadThrow m, MonadIO m, DisplayAble a) =>
a -> WidgetT site m ()
display2widget = text2widget . display
withFragment :: Monad m => MForm m (a, WidgetT site IO ()) -> Markup -> MForm m (a, WidgetT site IO ())
withFragment form html = (flip fmap) form $ \(x, widget) -> (x, toWidget html >> widget)
-- Types that can be converted to Text for direct displayed to User! (Show for debugging, Display for Production)
{- (not so sure we really want to get rid of display?!) DEPRECATED display "Create RenderMessage Instances instead!" -}
class DisplayAble a where
display :: a -> Text
-- Default definitions for types belonging to Show (allows empty instance declarations)
default display :: Show a => a -> Text
display = pack . show
instance DisplayAble Text where
display = id
instance DisplayAble String where
display = pack
instance DisplayAble Int
instance DisplayAble Int64
instance DisplayAble Integer
instance DisplayAble Rational where
display r = showFFloat (Just 2) (rat2float r) ""
& pack
& dropWhileEnd ('0'==)
& dropWhileEnd ('.'==)
where
rat2float :: Rational -> Double
rat2float = fromRational
instance DisplayAble a => DisplayAble (Maybe a) where
display Nothing = ""
display (Just x) = display x
instance DisplayAble a => DisplayAble (E.Value a) where
display = display . E.unValue
instance DisplayAble a => DisplayAble (CI a) where
display = display . CI.original
{- We do not want DisplayAble for every Show-Class:
We want to explicitly verify that the resulting text can be displayed to the User!
For example: UTCTime values were shown without proper format rendering!
instance {-# OVERLAPPABLE #-} Show a => DisplayAble a where -- The easy way out of UndecidableInstances (TypeFamilies would have been proper, but are much more complicated)
display = pack . show
-}
textPercent :: Double -> Text -- slow, maybe use Data.Double.Conversion.Text.toFixed instead?
textPercent x = lz <> (pack $ show rx) <> "%"
where
round' :: Double -> Int -- avoids annoying warning
round' = round
rx :: Double
rx = fromIntegral (round' $ 1000.0*x) / 10.0
lz = if rx < 10.0 then "0" else ""
stepTextCounterCI :: CI Text -> CI Text -- find and increment rightmost-number, preserving leading zeroes
stepTextCounterCI = CI.map stepTextCounter
stepTextCounter :: Text -> Text -- find and increment rightmost-number, preserving leading zeroes
stepTextCounter text
| (Just i) <- readMay number =
let iplus1 = tshow (succ i :: Int)
zeroip = justifyRight (length number) '0' iplus1
in prefix <> zeroip <> suffix
| otherwise = text
where -- no splitWhile nor findEnd in Data.Text
suffix = takeWhileEnd (not . isDigit) text
number = takeWhileEnd isDigit $ dropWhileEnd (not . isDigit) text
prefix = dropWhileEnd isDigit $ dropWhileEnd (not . isDigit) text
-- Data.Text.groupBy ((==) `on` isDigit) $ Data.Text.pack "12.ProMo Ue3bung00322 34 (H)"
-- ["12",".ProMo Ue","3","bung","00322"," ","34"," (H)"]
------------
-- Tuples --
------------
fst3 :: (a,b,c) -> a
fst3 (x,_,_) = x
snd3 :: (a,b,c) -> b
snd3 (_,y,_) = y
trd3 :: (a,b,c) -> c
trd3 (_,_,z) = z
-- Further projections are available via TemplateHaskell, defined in Utils.Common:
-- $(projN n m) :: (t1,..,tn) -> tm (for m<=n)
-- snd3 = $(projNI 3 2)
-----------
-- Lists --
-----------
-- notNull = not . null
lastMaybe :: [a] -> Maybe a
lastMaybe [] = Nothing
lastMaybe [h] = Just h
lastMaybe (_:t) = lastMaybe t
lastMaybe' :: [a] -> Maybe a
lastMaybe' l = fmap snd $ l ^? _Snoc
mergeAttrs :: [(Text, Text)] -> [(Text, Text)] -> [(Text, Text)]
mergeAttrs = mergeAttrs' `on` sort
where
special = [ ("class", \v1 v2 -> v1 <> " " <> v2)
]
mergeAttrs' (x1@(n1, v1):xs1) (x2@(n2, v2):xs2)
| Just merge <- lookup n1 special
, n2 == n1
= mergeAttrs' ((n1, merge v1 v2) : xs1) xs2
| Just _ <- lookup n1 special
, n1 < n2
= x2 : mergeAttrs' (x1:xs1) xs2
| otherwise = x1 : mergeAttrs' xs1 (x2:xs2)
mergeAttrs' [] xs2 = xs2
mergeAttrs' xs1 [] = xs1
----------
-- Maps --
----------
infixl 5 !!!
(!!!) :: (Ord k, Monoid v) => Map k v -> k -> v
(!!!) m k = (fromMaybe mempty) $ Map.lookup k m
groupMap :: (Ord k, Ord v) => [(k,v)] -> Map k (Set v)
groupMap l = Map.fromListWith mappend $ [(k, Set.singleton v) | (k,v) <- l]
partMap :: (Ord k, Monoid v) => [(k,v)] -> Map k v
partMap = Map.fromListWith mappend
invertMap :: (Ord k, Ord v) => Map k v -> Map v (Set k)
invertMap = groupMap . map swap . Map.toList
-----------
-- Maybe --
-----------
toMaybe :: Bool -> a -> Maybe a
toMaybe True = Just
toMaybe False = const Nothing
toNothing :: a -> Maybe b
toNothing = const Nothing
toNothingS :: String -> Maybe b
toNothingS = const Nothing
maybeAdd :: Num a => Maybe a -> Maybe a -> Maybe a -- treats Nothing as neutral/zero, unlike fmap
maybeAdd (Just x) (Just y) = Just (x + y)
maybeAdd Nothing y = y
maybeAdd x Nothing = x
maybeEmpty :: Monoid m => Maybe a -> (a -> m) -> m
maybeEmpty (Just x) f = f x
maybeEmpty Nothing _ = mempty
whenIsJust :: Monad m => Maybe a -> (a -> m ()) -> m ()
whenIsJust (Just x) f = f x
whenIsJust Nothing _ = return ()
ifMaybeM :: Monad m => Maybe a -> b -> (a -> m b) -> m b -- more convenient argument order as compared to maybeM
ifMaybeM Nothing dft _ = return dft
ifMaybeM (Just x) _ act = act x
maybeM :: Monad m => m b -> (a -> m b) -> m (Maybe a) -> m b
maybeM dft act mb = mb >>= maybe dft act
maybeT :: Monad m => m a -> MaybeT m a -> m a
maybeT x m = runMaybeT m >>= maybe x return
maybeT_ :: Monad m => MaybeT m () -> m ()
maybeT_ = void . runMaybeT
catchIfMaybeT :: (MonadCatch m, Exception e) => (e -> Bool) -> m a -> MaybeT m a
catchIfMaybeT p act = catchIf p (lift act) (const mzero)
mcons :: Maybe a -> [a] -> [a]
mcons Nothing xs = xs
mcons (Just x) xs = x:xs
newtype NTop a = NTop a -- treat Nothing as Top for Ord (Maybe a); default implementation treats Nothing as bottom
instance Eq a => Eq (NTop (Maybe a)) where
(NTop x) == (NTop y) = x == y
instance Ord a => Ord (NTop (Maybe a)) where
compare (NTop Nothing) (NTop Nothing) = EQ
compare (NTop Nothing) _ = GT
compare _ (NTop Nothing) = LT
compare (NTop (Just x)) (NTop (Just y)) = compare x y
------------
-- Either --
------------
maybeLeft :: Either a b -> Maybe a
maybeLeft (Left a) = Just a
maybeLeft _ = Nothing
maybeRight :: Either a b -> Maybe b
maybeRight (Right b) = Just b
maybeRight _ = Nothing
whenIsLeft :: Monad m => Either a b -> (a -> m ()) -> m ()
whenIsLeft (Left x) f = f x
whenIsLeft (Right _) _ = return ()
whenIsRight :: Monad m => Either a b -> (b -> m ()) -> m ()
whenIsRight (Right x) f = f x
whenIsRight (Left _) _ = return ()
---------------
-- Exception --
---------------
maybeExceptT :: Monad m => e -> m (Maybe b) -> ExceptT e m b
maybeExceptT err act = lift act >>= maybe (throwE err) return
maybeMExceptT :: Monad m => (m e) -> m (Maybe b) -> ExceptT e m b
maybeMExceptT err act = lift act >>= maybe (lift err >>= throwE) return
whenExceptT :: Monad m => Bool -> e -> ExceptT e m ()
whenExceptT b err = when b $ throwE err
whenMExceptT :: Monad m => Bool -> (m e) -> ExceptT e m ()
whenMExceptT b err = when b $ lift err >>= throwE
guardExceptT :: Monad m => Bool -> e -> ExceptT e m ()
guardExceptT b err = unless b $ throwE err
guardMExceptT :: Monad m => Bool -> (m e) -> ExceptT e m ()
guardMExceptT b err = unless b $ lift err >>= throwE
exceptT :: Monad m => (e -> m b) -> (a -> m b) -> ExceptT e m a -> m b
exceptT f g = either f g <=< runExceptT
catchIfMExceptT :: (MonadCatch m, Exception e) => (e -> m e') -> (e -> Bool) -> m a -> ExceptT e' m a
catchIfMExceptT err p act = catchIf p (lift act) (throwE <=< lift . err)
------------
-- Monads --
------------
shortCircuitM :: Monad m => (a -> Bool) -> m a -> m a -> (a -> a -> a) -> m a
shortCircuitM sc mx my bop = do
x <- mx
case sc x of
True -> return x
False -> bop <$> pure x <*> my
guardM :: MonadPlus m => m Bool -> m ()
guardM f = guard =<< f
assertM :: MonadPlus m => (a -> Bool) -> m a -> m a
assertM f x = x >>= assertM' f
assertM' :: MonadPlus m => (a -> Bool) -> a -> m a
assertM' f x = x <$ guard (f x)
-- Some Utility Functions from Agda.Utils.Monad
-- | Monadic if-then-else.
ifM :: Monad m => m Bool -> m a -> m a -> m a
ifM c m m' =
do b <- c
if b then m else m'
-- | @ifNotM mc = ifM (not <$> mc)@
ifNotM :: Monad m => m Bool -> m a -> m a -> m a
ifNotM c = flip $ ifM c
-- | Lazy monadic conjunction.
and2M :: Monad m => m Bool -> m Bool -> m Bool
and2M ma mb = ifM ma mb (return False)
andM :: (Foldable f, Monad m) => f (m Bool) -> m Bool
andM = Fold.foldr and2M (return True)
allM :: (Functor f, Foldable f, Monad m) => f a -> (a -> m Bool) -> m Bool
allM xs f = andM $ fmap f xs
-- | Lazy monadic disjunction.
or2M :: Monad m => m Bool -> m Bool -> m Bool
or2M ma mb = ifM ma (return True) mb
orM :: (Foldable f, Monad m) => f (m Bool) -> m Bool
orM = Fold.foldr or2M (return False)
anyM :: (Functor f, Foldable f, Monad m) => f a -> (a -> m Bool) -> m Bool
anyM xs f = orM $ fmap f xs
--------------
-- Sessions --
--------------
setSessionJson :: (PathPiece k, ToJSON v, MonadHandler m) => k -> v -> m ()
setSessionJson (toPathPiece -> key) (LBS.toStrict . Aeson.encode -> val) = setSessionBS key val
lookupSessionJson :: (PathPiece k, FromJSON v, MonadHandler m) => k -> m (Maybe v)
lookupSessionJson (toPathPiece -> key) = (Aeson.decode' . LBS.fromStrict =<<) <$> lookupSessionBS key