{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE Rank2Types #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# OPTIONS_GHC -fconstraint-solver-iterations=6 #-}
-- | Symantic for 'Int'.
module Language.Symantic.Compiling.Int where

import qualified Data.Function as Fun
import Data.Proxy
import Data.String (IsString)
import Data.Text (Text)
import qualified Data.Text as Text
import Data.Type.Equality ((:~:)(Refl))

import Language.Symantic.Typing
import Language.Symantic.Compiling.Term
import Language.Symantic.Interpreting
import Language.Symantic.Transforming.Trans

-- * Class 'Sym_Int'
class Sym_Int term where
	int :: Int -> term Int
	default int :: Trans t term => Int -> t term Int
	int = trans_lift . int

type instance Sym_of_Iface (Proxy Int) = Sym_Int
type instance Consts_of_Iface (Proxy Int) = Proxy Int ': Consts_imported_by Int
type instance Consts_imported_by Int =
 [ Proxy Bounded
 , Proxy Enum
 , Proxy Eq
 , Proxy Integral
 , Proxy Num
 , Proxy Ord
 , Proxy Real
 ]

instance Sym_Int HostI where
	int = HostI
instance Sym_Int TextI where
	int a = TextI $ \_p _v ->
		Text.pack (show a)
instance (Sym_Int r1, Sym_Int r2) => Sym_Int (DupI r1 r2) where
	int x = int x `DupI` int x

instance Const_from Text cs => Const_from Text (Proxy Int ': cs) where
	const_from "Int" k = k (ConstZ kind)
	const_from s k = const_from s $ k . ConstS
instance Show_Const cs => Show_Const (Proxy Int ': cs) where
	show_const ConstZ{} = "Int"
	show_const (ConstS c) = show_const c

instance -- Proj_ConC
 ( Proj_Const cs Int
 , Proj_Consts cs (Consts_imported_by Int)
 ) => Proj_ConC cs (Proxy Int) where
	proj_conC _ (TyConst q :$ TyConst c)
	 | Just Refl <- eq_skind (kind_of_const c) SKiType
	 , Just Refl <- proj_const c (Proxy::Proxy Int)
	 = Just $ case () of
		 _ | Just Refl <- proj_const q (Proxy::Proxy Bounded)  -> Just Con
		   | Just Refl <- proj_const q (Proxy::Proxy Enum)     -> Just Con
		   | Just Refl <- proj_const q (Proxy::Proxy Eq)       -> Just Con
		   | Just Refl <- proj_const q (Proxy::Proxy Integral) -> Just Con
		   | Just Refl <- proj_const q (Proxy::Proxy Num)      -> Just Con
		   | Just Refl <- proj_const q (Proxy::Proxy Ord)      -> Just Con
		   | Just Refl <- proj_const q (Proxy::Proxy Real)     -> Just Con
		 _ -> Nothing
	proj_conC _c _q = Nothing
instance -- Term_fromI
 ( AST ast
 , Lexem ast ~ LamVarName
 , Inj_Const (Consts_of_Ifaces is) Int
 , Show_Const (Consts_of_Ifaces is)
 ) => Term_fromI is (Proxy Int) ast where
	term_fromI ast _ctx k =
		case ast_lexem ast of
		 "int" -> int_from
		 _ -> Left $ Error_Term_unsupported
		where
		int_from =
			let ty = tyInt in
			from_lex (Text.pack $ show_type ty) ast $ \(i::Int) as ->
			k as ty $ TermLC $ Fun.const $ int i

-- | The 'Int' 'Type'
tyInt :: Inj_Const cs Int => Type cs Int
tyInt = TyConst inj_const

sym_Int :: Proxy Sym_Int
sym_Int = Proxy

syInt :: IsString a => Syntax a
syInt = Syntax "Int" []