open Uxn
open Effect.Deep

let trace = Option.is_some (Sys.getenv_opt "UXNEMU_DEBUG")

module System = Varvara.System.Make ()
module Console = Varvara.Console.Make ()
module Devices = Uxn.Device.Compose (System) (Console)

let print_stack ~name (Machine.Stack { data; sp }) =
  Fmt.epr "%s: @[%a@]@." name
    (Fmt.on_bytes (Fmt.octets ()))
    (Bytes.sub data 0 sp)

let run m pc =
  let dev = Machine.dev m in
  let ram = Machine.ram m in
  try Machine.dispatch ~trace m pc with
  | effect Machine.Trace (pc, instr, args), k ->
      if trace then begin
        Fmt.epr "PC = %04x | %6s %a@." pc (Instr.to_string instr)
          (Fmt.list ~sep:(Fmt.any " ") (Fmt.fmt "%02x"))
          args;
        Out_channel.flush stderr
      end;
      continue k ()
  | effect Machine.BRK, _ -> ()
  | effect Machine.DEI (`Byte, port), k -> (
      match Devices.dei m port with
      | Some v -> continue k v
      | None -> continue k (Bytes.get_uint8 dev port))
  | effect Machine.DEI (`Short, port), k -> (
      match Devices.dei2 m port with
      | Some v -> continue k v
      | None -> continue k (Util.get_uint16_wrap dev port))
  | effect Machine.DEO (port, value), k ->
      (match port with
      | _ when Devices.can_handle port -> Devices.deo m port value
      | 0xaa -> Varvara.File.file_lengths.(0) <- Bytes.get_uint16_be dev 0xaa
      | 0xa4 ->
          let addr = Bytes.get_uint16_be dev 0xa4 in
          let len = Varvara.File.file_lengths.(0) in
          let result = Varvara.File.file_stat ram 0 addr len in
          Varvara.File.file_success dev 0xa2 result
      | 0xa6 ->
          let result = Varvara.File.file_delete 0 in
          Varvara.File.file_success dev 0xa2 (if result = 0 then 1 else 0)
      | 0xa8 ->
          let addr = Bytes.get_uint16_be dev 0xa8 in
          let result = Varvara.File.file_init ram 0 addr in
          Varvara.File.file_success dev 0xa2 result
      | 0xac ->
          let addr = Bytes.get_uint16_be dev 0xac in
          let len = Varvara.File.file_lengths.(0) in
          let result = Varvara.File.file_read ram 0 addr len in
          Varvara.File.file_success dev 0xa2 result
      | 0xae ->
          let addr = Bytes.get_uint16_be dev 0xae in
          let len = Varvara.File.file_lengths.(0) in
          let append = Bytes.get_uint8 dev 0xa7 in
          let result = Varvara.File.file_write ram 0 addr len append in
          Varvara.File.file_success dev 0xa2 result
      | 0xba -> Varvara.File.file_lengths.(1) <- Bytes.get_uint16_be dev 0xba
      | 0xb4 ->
          let addr = Bytes.get_uint16_be dev 0xb4 in
          let len = Varvara.File.file_lengths.(1) in
          let result = Varvara.File.file_stat ram 1 addr len in
          Varvara.File.file_success dev 0xb2 result
      | 0xb6 ->
          let result = Varvara.File.file_delete 1 in
          Varvara.File.file_success dev 0xb2 (if result = 0 then 1 else 0)
      | 0xb8 ->
          let addr = Bytes.get_uint16_be dev 0xb8 in
          let result = Varvara.File.file_init ram 1 addr in
          Varvara.File.file_success dev 0xb2 result
      | 0xbc ->
          let addr = Bytes.get_uint16_be dev 0xbc in
          let len = Varvara.File.file_lengths.(1) in
          let result = Varvara.File.file_read ram 1 addr len in
          Varvara.File.file_success dev 0xb2 result
      | 0xbe ->
          let addr = Bytes.get_uint16_be dev 0xbe in
          let len = Varvara.File.file_lengths.(1) in
          let append = Bytes.get_uint8 dev 0xb7 in
          let result = Varvara.File.file_write ram 1 addr len append in
          Varvara.File.file_success dev 0xb2 result
      | _ -> ());
      continue k ()

let main () =
  if Array.length Sys.argv < 2 then (
    Fmt.epr "usage: uxnemu file.rom\n";
    exit 1);

  let code =
    In_channel.with_open_bin Sys.argv.(1) (fun i -> In_channel.input_all i)
  in

  In_channel.set_binary_mode stdin true;
  Out_channel.set_binary_mode stdout true;

  let mach = Machine.create code in
  let dev = Machine.dev mach in

  let has_args = Array.length Sys.argv > 2 in
  Bytes.set_uint8 dev 0x17 (if has_args then 1 else 0);

  run mach 0x100;

  if Console.state.console_vector <> 0 then begin
    let console_input ch ty =
      Bytes.set_uint8 dev 0x12 ch;
      Bytes.set_uint8 dev 0x17 ty;
      if Bytes.get_uint8 dev 0x0f = 0 then run mach Console.state.console_vector
    in
    if has_args then begin
      for i = 2 to Array.length Sys.argv - 1 do
        let arg = Sys.argv.(i) in
        String.iter
          (fun c ->
            if Bytes.get_uint8 dev 0x0f = 0 then console_input (Char.code c) 2)
          arg;
        if Bytes.get_uint8 dev 0x0f = 0 then
          console_input 0 (if i = Array.length Sys.argv - 1 then 4 else 3)
      done
    end;
    try
      while Bytes.get_uint8 dev 0x0f = 0 do
        match In_channel.input_byte stdin with
        | None -> raise Exit
        | Some c -> console_input c 1
      done
    with Exit -> console_input 0 4
  end;

  if trace then begin
    print_stack ~name:"wst" (Machine.wst mach);
    print_stack ~name:"rst" (Machine.rst mach)
  end;
  exit (Bytes.get_uint8 dev 0x0f land 0x7f)

let _ = main ()