{- |
Copyright  : Will Thompson, Iñaki García Etxebarria and Jonas Platte
License    : LGPL-2.1
Maintainer : Iñaki García Etxebarria (garetxe@gmail.com)

The GParameter struct is an auxiliary structure used
to hand parameter name\/value pairs to 'GI.GObject.Objects.Object.objectNew'.
-}

module GI.GObject.Structs.Parameter
    ( 

-- * Exported types
    Parameter(..)                           ,
    newZeroParameter                        ,
    noParameter                             ,


 -- * Properties
-- ** name #attr:name#
    clearParameterName                      ,
    getParameterName                        ,
    parameter_name                          ,
    setParameterName                        ,


-- ** value #attr:value#
    getParameterValue                       ,
    parameter_value                         ,




    ) where

import Data.GI.Base.ShortPrelude
import qualified Data.GI.Base.ShortPrelude as SP
import qualified Data.GI.Base.Overloading as O
import qualified Prelude as P

import qualified Data.GI.Base.Attributes as GI.Attributes
import qualified Data.GI.Base.ManagedPtr as B.ManagedPtr
import qualified Data.GI.Base.GError as B.GError
import qualified Data.GI.Base.GVariant as B.GVariant
import qualified Data.GI.Base.GParamSpec as B.GParamSpec
import qualified Data.GI.Base.CallStack as B.CallStack
import qualified Data.Text as T
import qualified Data.ByteString.Char8 as B
import qualified Data.Map as Map
import qualified Foreign.Ptr as FP


newtype Parameter = Parameter (ManagedPtr Parameter)
instance WrappedPtr Parameter where
    wrappedPtrCalloc = callocBytes 32
    wrappedPtrCopy = \p -> withManagedPtr p (copyBytes 32 >=> wrapPtr Parameter)
    wrappedPtrFree = Just ptr_to_g_free

-- | Construct a `Parameter` struct initialized to zero.
newZeroParameter :: MonadIO m => m Parameter
newZeroParameter = liftIO $ wrappedPtrCalloc >>= wrapPtr Parameter

instance tag ~ 'AttrSet => Constructible Parameter tag where
    new _ attrs = do
        o <- newZeroParameter
        GI.Attributes.set o attrs
        return o


noParameter :: Maybe Parameter
noParameter = Nothing

getParameterName :: MonadIO m => Parameter -> m (Maybe T.Text)
getParameterName s = liftIO $ withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 0) :: IO CString
    result <- SP.convertIfNonNull val $ \val' -> do
        val'' <- cstringToText val'
        return val''
    return result

setParameterName :: MonadIO m => Parameter -> CString -> m ()
setParameterName s val = liftIO $ withManagedPtr s $ \ptr -> do
    poke (ptr `plusPtr` 0) (val :: CString)

clearParameterName :: MonadIO m => Parameter -> m ()
clearParameterName s = liftIO $ withManagedPtr s $ \ptr -> do
    poke (ptr `plusPtr` 0) (FP.nullPtr :: CString)

data ParameterNameFieldInfo
instance AttrInfo ParameterNameFieldInfo where
    type AttrAllowedOps ParameterNameFieldInfo = '[ 'AttrSet, 'AttrGet, 'AttrClear]
    type AttrSetTypeConstraint ParameterNameFieldInfo = (~) CString
    type AttrBaseTypeConstraint ParameterNameFieldInfo = (~) Parameter
    type AttrGetType ParameterNameFieldInfo = Maybe T.Text
    type AttrLabel ParameterNameFieldInfo = "name"
    type AttrOrigin ParameterNameFieldInfo = Parameter
    attrGet _ = getParameterName
    attrSet _ = setParameterName
    attrConstruct = undefined
    attrClear _ = clearParameterName

parameter_name :: AttrLabelProxy "name"
parameter_name = AttrLabelProxy


getParameterValue :: MonadIO m => Parameter -> m GValue
getParameterValue s = liftIO $ withManagedPtr s $ \ptr -> do
    let val = ptr `plusPtr` 8 :: (Ptr GValue)
    val' <- (newBoxed GValue) val
    return val'

data ParameterValueFieldInfo
instance AttrInfo ParameterValueFieldInfo where
    type AttrAllowedOps ParameterValueFieldInfo = '[ 'AttrGet]
    type AttrSetTypeConstraint ParameterValueFieldInfo = (~) (Ptr GValue)
    type AttrBaseTypeConstraint ParameterValueFieldInfo = (~) Parameter
    type AttrGetType ParameterValueFieldInfo = GValue
    type AttrLabel ParameterValueFieldInfo = "value"
    type AttrOrigin ParameterValueFieldInfo = Parameter
    attrGet _ = getParameterValue
    attrSet _ = undefined
    attrConstruct = undefined
    attrClear _ = undefined

parameter_value :: AttrLabelProxy "value"
parameter_value = AttrLabelProxy



instance O.HasAttributeList Parameter
type instance O.AttributeList Parameter = ParameterAttributeList
type ParameterAttributeList = ('[ '("name", ParameterNameFieldInfo), '("value", ParameterValueFieldInfo)] :: [(Symbol, *)])

type family ResolveParameterMethod (t :: Symbol) (o :: *) :: * where
    ResolveParameterMethod l o = O.MethodResolutionFailed l o

instance (info ~ ResolveParameterMethod t Parameter, O.MethodInfo info Parameter p) => O.IsLabelProxy t (Parameter -> p) where
    fromLabelProxy _ = O.overloadedMethod (O.MethodProxy :: O.MethodProxy info)

#if MIN_VERSION_base(4,9,0)
instance (info ~ ResolveParameterMethod t Parameter, O.MethodInfo info Parameter p) => O.IsLabel t (Parameter -> p) where
    fromLabel _ = O.overloadedMethod (O.MethodProxy :: O.MethodProxy info)
#endif