{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE ConstraintKinds #-}
module Data.Wrapper.PSQ
#if 0
     ( module Data.Wrapper.PSQ , module Data.PSQueue ) where

import Data.PSQueue hiding (foldr, foldl)
import qualified Data.PSQueue as PSQueue

type PSQKey k = (Ord k)

-- | Wrapper over PSQueue-style foldr to implement a psqueues-style interface.
fold' :: (Ord k, Ord p) => (k -> p -> () -> a -> a) -> a -> PSQ k p -> a
fold' f a q = PSQueue.foldr f' a q
 where
    f' (k :-> prio) x = f k prio () x

#else
    ( module Data.Wrapper.PSQ , module HashPSQ ) where

import Data.OrdPSQ as OrdPSQ hiding (insert, map, singleton, minView)
import qualified Data.OrdPSQ as OrdPSQ

import Data.HashPSQ as HashPSQ hiding (insert, map, singleton, minView)
import qualified Data.HashPSQ as Q
import Data.Hashable

type PSQ' k p v = HashPSQ k p v
type PSQ k p    = PSQ' k p ()

type Binding' k p v = (k,p,v)
type Binding k p    = Binding' k p ()

type PSQKey k = (Hashable k, Ord k)

pattern (:->) :: k -> p -> Binding k p
pattern k :-> p <- (k,p,_) where k :-> p = (k,p,())

-- I tried defining (::->) :: (k,v) -> p -> Binding' k p v
-- but no luck...
pattern Binding :: k -> v -> p -> Binding' k p v
pattern Binding k v p <- (k,p,v) where Binding k v p = (k,p,v)

key :: (k,p,v) -> k
key (k,p,v) = k
{-# INLINE key #-}

prio :: (k,p,v) -> p
prio (k,p,v) = p
{-# INLINE prio #-}

insert :: (PSQKey k, Ord p) => k -> p -> PSQ k p -> PSQ k p
insert k p q = Q.insert k p () q
{-# INLINE insert #-}

insert' :: (PSQKey k, Ord p) => k -> v -> p -> PSQ' k p v -> PSQ' k p v
insert' k v p q = Q.insert k p v q
{-# INLINE insert' #-}

insertWith :: (PSQKey k, Ord p) => (p -> p -> p) -> k -> p -> PSQ k p -> PSQ k p
insertWith f k p0 q = snd $ Q.alter f' k q
 where
    f' (Just (p,())) = ((),Just (f p0 p, ()))
    f' Nothing      = ((),Nothing)
{-# INLINE insertWith #-}

singleton :: (PSQKey k, Ord p) => k -> p -> PSQ k p
singleton k p = Q.singleton k p ()
{-# INLINE singleton #-}

minView :: (PSQKey k, Ord p) => PSQ' k p v -> Maybe (Binding' k p v, PSQ' k p v)
minView q = fmap (\(k,p,v,q') -> (Binding k v p, q')) $ Q.minView q
{-# INLINE minView #-}

#endif