open MiniFun.Semantics
open MiniFun.Types

(* -------------------------------------------------------------------------- *)
(* Identity program *)
let program =
  Function
    ("a",
     FunctionType (IntegerType, IntegerType),
     (Variable "a")
    )
;;

match reduce program 1 with
  Ok o ->  Printf.printf "Identity program: %d\n" o
| Error _ -> Printf.printf "Identity program: error\n"

(* -------------------------------------------------------------------------- *)
(* Constant program *)
let program =
  Function
    ("a",
     FunctionType (IntegerType, IntegerType),
     (Integer 1)
    )
;;

match reduce program 10 with
  Ok o -> Printf.printf "Constant program: %d\n" o
| Error _ -> Printf.printf "Constant program: error\n"

(* -------------------------------------------------------------------------- *)
(* Partial application of function program *)
let program =
  LetIn
    ("f",
     (Function ("x",
                FunctionType (IntegerType, FunctionType (IntegerType, IntegerType)),
                (Function ("y", FunctionType (IntegerType, IntegerType),
                           Plus (Variable "x", Variable "y"))
                )
               )),
     (Application (Variable "f", Integer 3))
    )
;;

match reduce program 2 with
  Ok o -> Printf.printf "Partial application of function program: %d\n" o
| Error _ -> Printf.printf "Partial application of function program: error\n"

(* -------------------------------------------------------------------------- *)
(* Partial application of function program *)
let program =
  LetFun
    ("f",
     "x",
     FunctionType (IntegerType, IntegerType),
     (Function ("y",
                FunctionType (IntegerType, IntegerType),
                Plus (Variable "x", Variable "y"))),
     (Application (Variable "f", Integer 3))
    )
;;

match reduce program 3 with
  Ok o -> Printf.printf "Partial application of function program: %d\n" o
| Error _ -> Printf.printf "Partial application of function program: error\n"

(* -------------------------------------------------------------------------- *)
(* Passing functions to functions program *)
let program =
  LetIn
    ("f",
     (Function (
         "z",
         FunctionType (FunctionType (IntegerType, IntegerType), IntegerType),
         (Function (
             "y",
             FunctionType (FunctionType (IntegerType, IntegerType), IntegerType),
             Function (
               "x",
               FunctionType (IntegerType, IntegerType),
               (IfThenElse (
                   CmpLess (Variable "x", Integer 0),
                   (Application (Variable "y", Variable "x")),
                   (Application (Variable "z", Variable "x"))
                 )))
           ))
       )),
     (Application
        (
          (Application
             (Variable "f",
              Function ("x", FunctionType (IntegerType, IntegerType), Plus (Variable "x", Integer 1))
             )
          ),
          Function ("x", FunctionType (IntegerType, IntegerType), Minus (Variable "x", Integer 1))
        )
     )
    )
;;

match reduce program (3) with
  Ok o -> Printf.printf "Passing functions to functions program 1: %d\n" o
| Error _ -> Printf.printf "Passing functions to functions program 1: error\n";;

match reduce program (-3) with
  Ok o -> Printf.printf "Passing functions to functions program 2: %d\n" o
| Error _ -> Printf.printf "Passing functions to functions program 2: error\n"

(* -------------------------------------------------------------------------- *)
(* Recursive function program *)
let program =
  LetFun
    ("f",
     "x",
     FunctionType (IntegerType, IntegerType),
     (IfThenElse (CmpLess (Variable "x", Integer 2),Integer 1, Plus (Variable "x", Application (Variable "f", Minus (Variable "x", Integer 1))))),
     (Variable "f")
    )
;;

match reduce program 10 with
  Ok o -> Printf.printf "Recursive function program: %d\n" o
| Error _ -> Printf.printf "Recursive function program: error\n"

(* -------------------------------------------------------------------------- *)
(* Scope program *)
let program =
  LetIn
    ("f",
     (LetIn ("a", Integer 1, (Function ("y", FunctionType (IntegerType, IntegerType), Plus (Variable "y", Variable "a"))))),
     (LetIn ("a", Integer 2, Variable "f"))
    )
;;

match reduce program 4 with
  Ok o -> Printf.printf "Scope program: %d\n" o
| Error _ -> Printf.printf "Scope program: error\n"

(* -------------------------------------------------------------------------- *)
(* Factorial program *)
let program =
  LetFun (
    "f",
    "x",
    FunctionType (IntegerType, IntegerType),
    (IfThenElse (CmpLessEq (Variable "x", Integer 0), Integer 1, Times (Variable "x", Application (Variable "f", Minus (Variable "x", Integer 1))))),
    (Variable "f")
  )
;;

match reduce program 10 with
  Ok o -> Printf.printf "Factorial program: %d\n" o
| Error _ -> Printf.printf "Factorial program: error\n"

(* -------------------------------------------------------------------------- *)
(* Hailstone sequence's lenght program *)

let program =

  LetFun (
    "collatz",
    "input",
    FunctionType (TupleType (IntegerType, IntegerType), IntegerType),
    (
      IfThenElse (BNot (Cmp (First (Variable "input"), Integer 1)),
                  (IfThenElse (Cmp (Modulo (First (Variable "input"), Integer 2), Integer 0),
                               Application (Variable "collatz",
                                            Tuple (
                                              Division (First (Variable "input"), Integer 2),
                                              Plus (Integer 1, Second (Variable "input")))),
                               Application (Variable "collatz",
                                            Tuple (
                                              Plus (Integer 1, Times (Integer 3, First (Variable "input"))),
                                              Plus (Integer 1, Second (Variable "input")))))),
                 (Second (Variable "input")))
    ),
    (Function ("x",
               FunctionType (IntegerType, IntegerType),
               Application (Variable "collatz", Tuple (Variable "x", Integer 1))))
  )
;;

match reduce program 77031 with
  Ok o -> Printf.printf "Hailstone sequence's lenght program: %d\n" o
| Error _ -> Printf.printf "Hailstone sequence's lenght program: error\n"

(* -------------------------------------------------------------------------- *)
(* Sum multiples of 3 and 5 program *)

let program =
  LetFun (
    "sum",
    "n",
    FunctionType (IntegerType, IntegerType),
    (IfThenElse ((BOr (Cmp (Modulo (Variable "n", Integer 3), Integer 0), Cmp (Modulo (Variable "n", Integer 5), Integer 0))),
                 Plus (Variable "n", Application (Variable "sum", Minus (Variable "n", Integer 1))),
                 (IfThenElse ((CmpLessEq (Variable "n", Integer 1)),
                              (Integer 0),
                              (Application (Variable "sum", Minus (Variable "n", Integer 1))))
                 ))
    ),
    (Variable "sum")
  )
;;

match reduce program 12345 with
  Ok o -> Printf.printf "Sum multiples of 3 and 5 program: %d\n" o
| Error _ -> Printf.printf "Sum multiples of 3 and 5 program: error\n"

(* -------------------------------------------------------------------------- *)
(* Rand program *)
let program =
  Function (
    "x",
    FunctionType (IntegerType, IntegerType),
    Rand (Variable "x")
  )

;;

match reduce program 10 with
  Ok o -> if o < 10 then Printf.printf "Rand program: %b\n" true
  else Printf.printf "Rand program: %b\n" false
| Error _ -> Printf.printf "Rand program: error\n"

(* -------------------------------------------------------------------------- *)
(* Fibonacci program *)
let program =
  LetFun (
    "fib",
    "i",
    FunctionType (IntegerType, FunctionType (IntegerType, FunctionType (IntegerType, IntegerType))),
    Function (
      "a",
      FunctionType (IntegerType, FunctionType (IntegerType, IntegerType)),
      Function (
        "b",
        FunctionType (IntegerType, IntegerType),
        (IfThenElse (Cmp (Variable "i", Integer 0),
                     Variable "a",
                     Application (
                       Application (
                         Application (
                           Variable "fib",
                           Minus (Variable "i", Integer 1)),
                         Variable "b"),
                       Plus (Variable "a", Variable "b")
                     )
                    ))
      )
    ),
    Function ("x",
              FunctionType (IntegerType, IntegerType),
              Application (
                Application (
                  Application (
                    Variable "fib",
                    Variable "x"
                  ),
                  Integer 0
                ),
                Integer 1
              )
             )
  )
;;

match reduce program 48 with
  Ok o -> Printf.printf "Fibonacci program: %d\n" o
| Error _ -> Printf.printf "Fibonacci program: error\n"