open MiniImp
open Lexing

(* -------------------------------------------------------------------------- *)
(*                             Command Arguments                              *)

let () =
  Clap.description "Interpreter for MiniImp language.";

  let files = Clap.section ~description: "Files to consider." "FILES" in
  let values = Clap.section ~description: "Input values." "VALUES" in

  let input = Clap.mandatory_string
      ~description: "Input file."
      ~placeholder: "FILENAME"
      ~section: files
      ~long: "input"
      ~short: 'i'
      ()
  in

  let registers = Clap.default_int
      ~description: "Optional number of registers available."
      ~placeholder: "INT"
      ~section: values
      ~long: "registers"
      ~short: 'r'
      4
  in

  let evalb = Clap.flag
      ~description: "Optional flag for evaluating the generated risc code."
      ~section: values
      ~set_long: "eval"
      ~set_short: 'e'
      false
  in

  let inputval = Clap.default_int
      ~description: "Optional input value to feed to the program. \
                     If not specified it is read from stdin."
      ~placeholder: "INT"
      ~section: values
      ~long: "value"
      ~short: 'v'
      0
  in

  let output = Clap.optional_string
      ~description: "Output file. If not specified output is printed on stdout."
      ~placeholder: "FILENAME"
      ~section: files
      ~long: "output"
      ~long_synonyms: ["out"; "result"]
      ~short: 'o'
      ()
  in

  Clap.close ();

(* -------------------------------------------------------------------------- *)
(*                                Interpreter                                 *)

  let print_position outx lexbuf =
    let pos = lexbuf.lex_curr_p in
    Printf.fprintf outx "Encountered \"%s\" at %s:%d:%d"
      (Lexing.lexeme lexbuf) pos.pos_fname
      pos.pos_lnum (pos.pos_cnum - pos.pos_bol + 1)
  in

  let interpret_file inch (registers: int) outch =
    let lexbuf = Lexing.from_channel inch in
    let program =
      try Parser.prg Lexer.read lexbuf with
      | Lexer.LexingError msg ->
        Printf.fprintf stderr "%a: %s\n" print_position lexbuf msg;
        exit (-1)
      | Parser.Error ->
        Printf.fprintf stderr "%a: syntax error\n" print_position lexbuf;
        exit (-1)
    in
    let return_value =
      program |>
      CfgImp.convert_io inputval |>
      CfgRISC.convert
    in

    let () = (
      match DefinedVariables.compute_defined_variables return_value |>
            DefinedVariables.check_undefined_variables
      with
      | None -> ()
      | Some l ->
        Printf.printf "Error: undefined variables: %a\n"
          DefinedVariables.Variable.pplist l;
        exit (-1)
    ) in

    let return_value =
      return_value |>
      LiveVariables.compute_live_variables |>
      LiveVariables.optimize_cfg |>
      LiveVariables.compute_cfg |>
      ReduceRegisters.reduceregisters registers |>
      RISC.convert
    in

    if not evalb
    then Printf.fprintf outch "%a\n" RISC.RISCAssembly.pp return_value
    else Printf.fprintf outch "%d\n" (RISCSemantics.reduce return_value)
  in

  let inx = In_channel.open_text input in
  let outx = match output with
      None -> stdout
    | Some f -> Out_channel.open_text f
  in

  interpret_file inx registers outx;