import "JavaBuiltin" as Java

importJava "org.simantics.scl.runtime.unification.UTag" where
    data UTag a t
    
    @JavaName "<init>"
    uTag :: Integer -> (t -> <Proc> a) -> (a -> t) -> UTag a t

importJava "java.lang.Object" where
    data Unifiable a

uId :: a -> Unifiable a
uId = Java.unsafeCoerce 

importJava "org.simantics.scl.runtime.unification.UCons" where
    @JavaName "<init>"
    uCons :: UTag a t -> t -> Unifiable a

importJava "org.simantics.scl.runtime.unification.UPending" where
    @JavaName "<init>"
    uPending :: (<Proc> a) -> Unifiable a

importJava "org.simantics.scl.runtime.unification.UVar" where
    @JavaName "<init>"
    uVar :: <Proc> Unifiable a

importJava "org.simantics.scl.runtime.unification.Unification" where
    unify :: Unifiable a -> Unifiable a -> <Proc> ()
    extractWithDefault :: (<Proc> a) -> Unifiable a -> <Proc> a

class Default a where
    createDefault :: <Proc> a

instance Default () where
    createDefault = ()
    
instance (Default a, Default b) => Default (a, b) where
    createDefault = (createDefault, createDefault)

instance (Default a, Default b, Default c) => Default (a, b, c) where
    createDefault = (createDefault, createDefault, createDefault)
    
instance Default Double where
    createDefault = fail "Double type has no default value."

instance Default Integer where
    createDefault = fail "Integer type has no default value."

@inline
extract :: Default a => Unifiable a -> <Proc> a
extract u = extractWithDefault createDefault u

importJava "gnu.trove.map.hash.THashMap" where
    data UMap a b
    
    @JavaName "<init>"
    createUMap :: <Proc> UMap a b

importJava "org.simantics.scl.runtime.unification.UMapUtils" where
    @JavaName put
    putUMap :: UMap a b -> a -> Unifiable b -> <Proc> ()
    @JavaName put
    putUMapC :: UMap a b -> a -> b -> <Proc> ()
    @JavaName get
    getUMapWithDefault :: (<Proc> b) -> UMap a b -> a -> <Proc> b

getUMap :: Default b => UMap a b -> a -> <Proc> b
getUMap = getUMapWithDefault createDefault