open Nock_lib
open Noun
open Nock

let atom = atom_of_int

let check_noun name expect actual =
  let rec to_string noun =
    match noun with
    | Atom z -> Z.to_string z
    | Cell (h, t) -> Printf.sprintf "[%s %s]" (to_string h) (to_string t)
  in
  Printf.printf "[%s] expect=%s actual=%s\n%!"
    name (to_string expect) (to_string actual);
  Alcotest.(check bool) name true (equal expect actual)

let check_eval name subject formula expect =
  let result = nock subject formula in
  check_noun name expect result

let check_exit name f =
  Alcotest.check_raises name Exit f

let test_slots () =
  let tree =
    cell
      (cell (atom 1) (atom 2))
      (cell (atom 3) (atom 4))
  in
  check_noun "slot 1" tree (slot Z.one tree);
  check_noun "slot 2" (cell (atom 1) (atom 2)) (slot (Z.of_int 2) tree);
  check_noun "slot 3" (cell (atom 3) (atom 4)) (slot (Z.of_int 3) tree);
  check_noun "slot 4" (atom 1) (slot (Z.of_int 4) tree);
  check_noun "slot 5" (atom 2) (slot (Z.of_int 5) tree);
  check_noun "slot 6" (atom 3) (slot (Z.of_int 6) tree);
  check_noun "slot 7" (atom 4) (slot (Z.of_int 7) tree);
  check_exit "slot invalid axis" (fun () -> ignore (slot Z.zero tree))

let test_opcode_0 () =
  let subject = cell (atom 4) (atom 5) in
  check_eval "axis 1" subject (cell (atom 0) (atom 1)) subject;
  check_eval "axis 2" subject (cell (atom 0) (atom 2)) (atom 4);
  check_eval "axis 3" subject (cell (atom 0) (atom 3)) (atom 5)

let test_opcode_1 () =
  let subject = atom 99 in
  check_eval "const atom" subject (cell (atom 1) (atom 42)) (atom 42);
  check_eval "const cell" subject (cell (atom 1) (cell (atom 1) (atom 2)))
    (cell (atom 1) (atom 2))

let test_opcode_2 () =
  let subject = atom 42 in
  let formula =
    cell (atom 2)
      (cell (cell (atom 1) (atom 99))
        (cell (atom 1) (cell (atom 0) (atom 1))))
  in
  check_eval "recursive eval" subject formula (atom 99)

let test_opcode_3 () =
  check_eval "cell test atom" (atom 42)
    (cell (atom 3) (cell (atom 1) (atom 42)))
    (atom 1);
  check_eval "cell test cell" (atom 42)
    (cell (atom 3) (cell (atom 1) (cell (atom 1) (atom 2))))
    (atom 0)

let test_opcode_4 () =
  check_eval "increment constant" (atom 0)
    (cell (atom 4) (cell (atom 1) (atom 41)))
    (atom 42);
  check_eval "increment subject" (atom 0)
    (cell (atom 4) (cell (atom 0) (atom 1)))
    (atom 1)

let test_opcode_5 () =
  check_eval "not equal" (atom 0)
    (cell (atom 5)
      (cell (cell (atom 1) (atom 4)) (cell (atom 1) (atom 5))))
    (atom 1);
  check_eval "equal" (atom 0)
    (cell (atom 5)
      (cell (cell (atom 1) (atom 4)) (cell (atom 1) (atom 4))))
    (atom 0)

let test_opcode_6 () =
  check_eval "if zero" (atom 42)
    (cell (atom 6)
      (cell (cell (atom 1) (atom 0))
        (cell (cell (atom 1) (atom 11)) (cell (atom 1) (atom 22)))))
    (atom 11);
  check_eval "if one" (atom 42)
    (cell (atom 6)
      (cell (cell (atom 1) (atom 1))
        (cell (cell (atom 1) (atom 11)) (cell (atom 1) (atom 22)))))
    (atom 22)

let test_opcode_7 () =
  check_eval "compose" (atom 42)
    (cell (atom 7)
      (cell (cell (atom 1) (atom 99)) (cell (atom 0) (atom 1))))
    (atom 99)

let test_opcode_8 () =
  check_eval "push" (atom 42)
    (cell (atom 8)
      (cell (cell (atom 1) (atom 99)) (cell (atom 0) (atom 1))))
    (cell (atom 99) (atom 42))

let test_opcode_9 () =
  let subject =
    cell
      (atom 99)
      (cell (atom 4) (cell (atom 0) (atom 2)))
  in
  let formula =
    cell (atom 9)
      (cell (atom 3)
        (cell (atom 0) (atom 1)))
  in
  check_eval "call formula at axis 3" subject formula (atom 100)

let test_opcode_10 () =
  check_eval "hint" (atom 42)
    (cell (atom 10)
      (cell (atom 99) (cell (atom 1) (atom 11))))
    (atom 11)

let test_opcode_11 () =
  check_eval "hint dyn" (atom 42)
    (cell (atom 11)
      (cell (atom 99) (cell (atom 1) (atom 11))))
    (atom 11)

let tests =
  [
    "slots", `Quick, test_slots;
    "opcode 0", `Quick, test_opcode_0;
    "opcode 1", `Quick, test_opcode_1;
    "opcode 2", `Quick, test_opcode_2;
    "opcode 3", `Quick, test_opcode_3;
    "opcode 4", `Quick, test_opcode_4;
    "opcode 5", `Quick, test_opcode_5;
    "opcode 6", `Quick, test_opcode_6;
    "opcode 7", `Quick, test_opcode_7;
    "opcode 8", `Quick, test_opcode_8;
    "opcode 9", `Quick, test_opcode_9;
    "opcode 10", `Quick, test_opcode_10;
    "opcode 11", `Quick, test_opcode_11;
  ]

let () = Alcotest.run "nock" [ "core", tests ]