{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE NoMonomorphismRestriction #-}
{-# LANGUAGE Rank2Types #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -fno-warn-missing-signatures #-}
module Expr.Int.Test where

import Test.Tasty
import Test.Tasty.HUnit

import Control.Arrow (left)
-- import Data.Functor.Identity (Identity)
-- import Control.Monad.IO.Class (MonadIO(..))
import Data.Proxy (Proxy(..))
import Data.Text (Text)
import Data.Type.Equality ((:~:)(Refl))
import Prelude hiding (and, not, or)

import Language.LOL.Symantic.Repr
import Language.LOL.Symantic.Expr
import Language.LOL.Symantic.Type
-- import Language.LOL.Symantic.Trans

import AST.Test

-- * Class 'Sym_Int_Vars'

-- | A few boolean variables.
class Sym_Int_Vars repr where
	x :: repr Int
	y :: repr Int
	z :: repr Int
instance Sym_Int_Vars (Repr_Text fun) where
	x = Repr_Text $ \_p _v -> "x"
	y = Repr_Text $ \_p _v -> "y"
	z = Repr_Text $ \_p _v -> "z"

-- * Expressions
e1 = int 1 `add` int 0
e2 = (int 1 `add` int 0) `add` neg (int 1 `add` int 1)
e3 = (int 1 `add` neg (int 0)) `add` (int 1 `add` neg (int 1))
e4 = int 0 `add` neg (int 1)
e5 = int 1 `add` neg x
e6 = x `add` y
e7 = (x `add` y) `add` z
e8 = x `add` (y `add` int 1)

-- * Tests
(==>) ast expected =
	testCase (show ast) $
	case expr_lambda_int_from (Proxy::Proxy IO) ast of
	 Left err -> Left err @?= snd `left` expected
	 Right (Exists_Type_and_Repr ty (Forall_Repr r)) ->
		case expected of
		 Left (_, err) -> Right ("…"::String) @?= Left err
		 Right (ty_expected::Type_Root_of_Expr (Expr_Lambda_Int IO) h, _::h, _::Text) ->
			(>>= (@?= (\(_::Proxy h, err) -> err) `left` expected)) $
			case ty `type_eq` ty_expected of
			 Nothing -> return $ Left $
				error_expr (Proxy::Proxy (Expr_Lambda_Int IO)) $
				Error_Expr_Type_mismatch ast
				 (Exists_Type ty)
				 (Exists_Type ty_expected)
			 Just Refl -> do
				h <- host_from_expr r
				return $
					Right
					 ( ty
					 , h
					 , text_from_expr r
					 -- , (text_from_expr :: Repr_Text IO h -> String) r
					 )

tests :: TestTree
tests = testGroup "Int" $
 [ AST "int" [AST "1" []] ==> Right
	 ( type_int
	 , 1
	 , "1" )
 , AST "bool" [AST "True" []] ==> Left (Proxy::Proxy Bool,
	Error_Expr_Alt_Curr $
	Error_Expr_Unsupported $ AST "bool" [AST "True" []])
 , AST "add"
	 [ AST "int" [AST "1" []]
	 , AST "int" [AST "1" []]
	 ] ==> Right
	 ( type_int
	 , 2
	 , "1 + 1" )
 , let ast = AST "app"
	 [ AST "int" [AST "1" []]
	 , AST "int" [AST "1" []]
	 ] in ast ==> Left (Proxy::Proxy Int,
	Error_Expr_Alt_Curr $
	Error_Expr_Type_mismatch ast
	 (Exists_Type (type_var SZero `type_fun` type_var (SSucc SZero)
	 ::Type_Fun_Int IO (IO Zero -> IO (Succ Zero))))
	 (Exists_Type type_int))
 , AST "app"
	 [ AST "val"
		 [ AST "x" []
		 , AST "Int" []
		 , AST "var" [AST "x" []]
		 ]
	 , AST "int" [AST "1" []]
	 ] ==> Right
	 ( type_int
	 , 1
	 , "(\\x0 -> x0) 1" )
 , AST "app"
	 [ AST "val"
		 [ AST "x" []
		 , AST "Int" []
		 , AST "add"
			 [ AST "var" [AST "x" []]
			 , AST "int" [AST "1" []]
			 ]
		 ]
	 , AST "int" [AST "1" []]
	 ] ==> Right
	 ( type_int
	 , 2
	 , "(\\x0 -> x0 + 1) 1" )
 , AST "let_val"
	 [ AST "x" []
	 , AST "int" [AST "1" []]
	 , AST "add"
		 [ AST "var" [AST "x" []]
		 , AST "int" [AST "1" []]
		 ]
	 ] ==> Right
	 ( type_int
	 , 2
	 , "let x0 = 1 in x0 + 1" )
 ]