{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE NoMonomorphismRestriction #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeOperators #-}
{-# OPTIONS_GHC -fno-warn-missing-signatures #-}

module Expr.Functor.Test where

import Test.Tasty
import Test.Tasty.HUnit

import Control.Arrow (left)
import Data.Proxy (Proxy(..))
import Data.Text (Text)
import Data.Type.Equality ((:~:)(Refl))
import Prelude hiding ((&&), not, (||), (==), fmap, (+))

import Language.Symantic.Type
import Language.Symantic.Expr as Expr
import Language.Symantic.Repr

import AST.Test

-- * Expressions
t = bool True
f = bool False
e1 = fmap (val $ \x -> x + int 1) (list $ int Prelude.<$> [1..3])

-- * Tests
type Ex lam = Expr_Root
 (   Expr_Lambda_App lam
 .|. Expr_Lambda_Val lam
 .|. Expr_Maybe lam
 .|. Expr_List lam
 .|. Expr_Functor lam
 .|. Expr_Int
 .|. Expr_Bool
 )
ex_from = root_expr_from (Proxy::Proxy (Ex lam)) (Proxy::Proxy lam)

(==>) ast expected =
	testCase (show ast) $
	case ex_from 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 (Ex IO) h, _::h, _::Text) ->
			(>>= (@?= (\(_::Proxy h, err) -> err) `left` expected)) $
			case ty `eq_type` ty_expected of
			 Nothing -> return $ Left $
				error_expr (Proxy::Proxy (Ex 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_String IO h -> Text) r
					 )

tests :: TestTree
tests = testGroup "Functor"
 [ AST "fmap"
	 [ AST "val"
		 [ AST "x" []
		 , AST "Int" []
		 , AST "+" [ AST "var" [AST "x" []]
		           , AST "int" [AST "1" []] ]
		 ]
	 , AST "list"
		 [ AST "Int" []
		 , AST "int" [AST "1" []]
		 , AST "int" [AST "2" []]
		 , AST "int" [AST "3" []]
		 ]
	 ] ==> Right
	 ( type_list type_int
	 , [2,3,4]
	 , "fmap (\\x0 -> x0 + 1) [1, 2, 3]" )
 ]