open TypeInference

let tests_typeof =
  let x = Identifier.fresh () in
  let y = Identifier.fresh () in
  [ (* Int Const *)
    "0", Term.IntConst 0, Some Type.Int
  ; (* Correct function *)
    ( "fun x -> fun y -> x + y"
    , Term.(Fun (x, Fun (y, Binop (Var x, Plus, Var y))))
    , Some Type.(Arrow (Int, Arrow (Int, Int))) )
  ; (* Not typed variable *)
    "x", Var "x", None
  ; (* Operation *)
    "1 + 2", Binop (IntConst 1, Plus, IntConst 2), Some Int
  ; (* Pair *)
    "(1, 2)", Pair (IntConst 1, IntConst 2), Some (Product (Int, Int))
  ; (* Projection with first *)
    "fst (1, 2)", Proj (First, Pair (IntConst 1, IntConst 2)), Some Int
  ; (* Projection with second *)
    "snd (1, 2)", Proj (Second, Pair (IntConst 1, IntConst 2)), Some Int
  ; (* Apply (int) into (fun : int -> int) *)
    ( "(fun x -> x + 1) 5"
    , App (Fun (x, Binop (Var x, Plus, IntConst 1)), IntConst 5)
    , Some Type.Int )
  ; (* Apply product (int * int) into a not compatible function (fun : int -> int) *)
    ( "(fun x -> x + 1) (1, 2)"
    , App (Fun (x, Binop (Var x, Plus, IntConst 1)), Pair (IntConst 1, IntConst 2))
    , None )
  ]
;;

let typeModule = (module Type : Alcotest.TESTABLE with type t = Type.t)

let check_typeof term_text term expected_type =
  let open Alcotest in
  test_case term_text `Quick (fun () ->
    check (option typeModule) "Same type" expected_type (Inference.typeof term))
;;

let () =
  let open Alcotest in
  run
    "Inference"
    [ ( "typeof"
      , List.map
          (fun (term_text, term, expected_type) ->
            check_typeof term_text term expected_type)
          tests_typeof )
    ]
;;