/* -*-comment-start: "//";comment-end:""-*-
 * GNU Mes --- Maxwell Equations of Software
 * Copyright © 2016,2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 *
 * This file is part of GNU Mes.
 *
 * GNU Mes is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or (at
 * your option) any later version.
 *
 * GNU Mes is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
 */

// CONSTANT STRUCT_TYPE 0
#define STRUCT_TYPE 0
// CONSTANT STRUCT_PRINTER 1
#define STRUCT_PRINTER 1

int g_depth;
SCM fdisplay_ (SCM, int, int);

SCM
display_helper (SCM x, int cont, char* sep, int fd, int write_p)
{
  fdputs (sep, fd);
  if (g_depth == 0)
    return cell_unspecified;
  g_depth = g_depth - 1;

  int t = TYPE (x);
  if (t == TCHAR)
    {
      if (!write_p)
        fdputc (VALUE (x), fd);
      else
        {
          fdputs ("#", fd);
          long v = VALUE (x);
          if (v == '\0') fdputs ("\\nul", fd);
          else if (v == '\a') fdputs ("\\alarm", fd);
          else if (v == '\b') fdputs ("\\backspace", fd);
          else if (v == '\t') fdputs ("\\tab", fd);
          else if (v == '\n') fdputs ("\\newline", fd);
          else if (v == '\v') fdputs ("\\vtab", fd);
          else if (v == '\f') fdputs ("\\page", fd);
          //Nyacc bug
          // else if (v == '\r') fdputs ("return", fd);
          else if (v == 13) fdputs ("\\return", fd);
          else if (v == ' ') fdputs ("\\space", fd);
          else
            {
              if (v >= 32 && v <= 127)
                fdputc ('\\', fd);
              fdputc (VALUE (x), fd);
            }
        }
    }
  else if (t == TCLOSURE)
    {
      fdputs ("#<closure ", fd);
      SCM circ = CADR (x);
      SCM name = CADR (circ);
      SCM args = CAR (CDDR (x));
      display_helper (CAR (name), 0, "", fd, 0);
      fdputc (' ', fd);
      display_helper (args, 0, "", fd, 0);
      fdputs (">", fd);
    }
  else if (t == TMACRO)
    {
      fdputs ("#<macro ", fd);
      display_helper (CDR (x), cont, "", fd, 0);
      fdputs (">", fd);
    }
  else if (t == TVARIABLE)
    {
      fdputs ("#<variable ", fd);
      display_helper (CAR (VARIABLE (x)), cont, "", fd, 0);
      fdputs (">", fd);
    }
  else if (t == TNUMBER)
    {
      fdputs (itoa (VALUE (x)), fd);
    }
  else if (t == TPAIR)
    {
      if (!cont)
        fdputs ("(", fd);
      if (CAR (x) == cell_circular
          && CADR (x) != cell_closure)
        {
          fdputs ("(*circ* . ", fd);
          int i = 0;
          x = CDR (x);
          while (x != cell_nil && i++ < 10)
            {
              fdisplay_ (CAAR (x), fd, write_p); fdputs (" ", fd);
              x = CDR (x);
            }
          fdputs (" ...)", fd);
        }
      else
        {
          if (x && x != cell_nil)
            fdisplay_ (CAR (x), fd, write_p);
          if (CDR (x) && TYPE (CDR (x)) == TPAIR)
            display_helper (CDR (x), 1, " ", fd, write_p);
          else if (CDR (x) && CDR (x) != cell_nil)
            {
              if (TYPE (CDR (x)) != TPAIR)
                fdputs (" . ", fd);
              fdisplay_ (CDR (x), fd, write_p);
            }
        }
      if (!cont)
        fdputs (")", fd);
    }
  else if (t == TKEYWORD
           || t == TPORT
           || t == TSPECIAL
           || t == TSTRING
           || t == TSYMBOL)
    {
      if (t == TPORT)
        {
          fdputs ("#<port ", fd);
          fdputs (itoa (PORT (x)), fd);
          fdputs (" " ,fd);
          x = STRING (x);
        }
      if (t == TKEYWORD)
        fdputs ("#:", fd);
      if ((write_p && t == TSTRING) || t == TPORT)
        fdputc ('"', fd);
      char const *s = CSTRING (x);
#if 0
      s += START (x);
      size_t length = LEN (x);
#else
      size_t length = LENGTH (x);
#endif
      for (size_t i=0; i < length; i++)
        {
          long v = write_p ? s[i] : -1;
          if (v == '\0') fdputs ("\\0", fd);
          else if (v == '\a') fdputs ("\\a", fd);
          else if (v == '\b') fdputs ("\\b", fd);
          else if (v == '\t') fdputs ("\\t", fd);
          else if (v == '\v') fdputs ("\\v", fd);
          else if (v == '\n') fdputs ("\\n", fd);
          else if (v == '\f') fdputs ("\\f", fd);
#if 1 //__MESC__
      //Nyacc bug
          else if (v == 13) fdputs ("\\r", fd);
          else if (v == 27) fdputs ("\\e", fd);
#else
          //else if (v == '\r') fdputs ("\\r", fd);
          //Nyacc crash
          //else if (v == '\e') fdputs ("\\e", fd);
#endif
          else if (v == '\\') fdputs ("\\\\", fd);
          else if (v == '"') fdputs ("\\\"", fd);
          else fdputc (s[i], fd);
        }
      if ((write_p && t == TSTRING) || t == TPORT)
        fdputc ('"', fd);
      if (t == TPORT)
        fdputs (">", fd);
    }
  else if (t == TREF)
    fdisplay_ (REF (x), fd, write_p);
  else if (t == TSTRUCT)
    {
      //SCM printer = STRUCT (x) + 1;
      SCM printer = struct_ref_ (x, STRUCT_PRINTER);
      if (TYPE (printer) == TREF)
        printer = REF (printer);
      if (TYPE (printer) == TCLOSURE
          || builtin_p (printer) == cell_t)
        apply (printer, cons (x, cell_nil), r0);
      else
        {
          fdputs ("#<", fd);
          fdisplay_ (STRUCT (x), fd, write_p);
          SCM t = CAR (x);
          long size = LENGTH (x);
          for (long i=2; i<size; i++)
            {
              fdputc (' ', fd);
              fdisplay_ (STRUCT (x) + i, fd, write_p);
            }
          fdputc ('>', fd);
        }
    }
  else if (t == TVECTOR)
    {
      fdputs ("#(", fd);
      SCM t = CAR (x);
      for (long i = 0; i<LENGTH (x); i++)
        {
          if (i)
            fdputc (' ', fd);
          fdisplay_ (VECTOR (x) + i, fd, write_p);
        }
      fdputc (')', fd);
    }
  else
    {
      fdputs ("<", fd);
      fdputs (itoa (t), fd);
      fdputs (":", fd);
      fdputs (itoa (x), fd);
      fdputs (">", fd);
    }
  return 0;
}

SCM
display_ (SCM x)
{
  g_depth = 5;
  return display_helper (x, 0, "", __stdout, 0);
}

SCM
display_error_ (SCM x)
{
  g_depth = 5;
  return display_helper (x, 0, "", __stderr, 0);
}

SCM
display_port_ (SCM x, SCM p)
{
  assert (TYPE (p) == TNUMBER);
  return fdisplay_ (x, VALUE (p), 0);
}

SCM
write_ (SCM x)
{
  g_depth = 5;
  return display_helper (x, 0, "", __stdout, 1);
}

SCM
write_error_ (SCM x)
{
  g_depth = 5;
  return display_helper (x, 0, "", __stderr, 1);
}

SCM
write_port_ (SCM x, SCM p)
{
  assert (TYPE (p) == TNUMBER);
  return fdisplay_ (x, VALUE (p), 1);
}

SCM
fdisplay_ (SCM x, int fd, int write_p) ///((internal))
{
  g_depth = 5;
  return display_helper (x, 0, "", fd, write_p);
}

SCM
exit_ (SCM x) ///((name . "exit"))
{
  assert (TYPE (x) == TNUMBER);
  exit (VALUE (x));
}

SCM
frame_printer (SCM frame)
{
  fdputs ("#<", __stdout); display_ (struct_ref_ (frame, 2));
  fdputc (' ', __stdout);
  fdputs ("procedure: ", __stdout); display_ (struct_ref_ (frame, 3));
  fdputc ('>', __stdout);
}

SCM
make_frame_type () ///((internal))
{
  SCM record_type = cell_symbol_record_type; // FIXME
  SCM fields = cell_nil;
  fields = cons (cell_symbol_procedure, fields);
  fields = cons (fields, cell_nil);
  fields = cons (cell_symbol_frame, fields);
  return make_struct (record_type, fields, cell_unspecified);
}

SCM
make_frame (SCM stack, long index)
{
  SCM frame_type = make_frame_type ();
  long array_index = (STACK_SIZE-(index*FRAME_SIZE));
  SCM procedure = g_stack_array[array_index+FRAME_PROCEDURE];
  if (!procedure)
    procedure = cell_f;
  SCM values = cell_nil;
  values = cons (procedure, values);
  values = cons (cell_symbol_frame, values);
  return make_struct (frame_type, values, cstring_to_symbol ("frame-printer"));
}

SCM
make_stack_type () ///((internal))
{
  SCM record_type = cell_symbol_record_type; // FIXME
  SCM fields = cell_nil;
  fields = cons (cstring_to_symbol ("frames"), fields);
  fields = cons (fields, cell_nil);
  fields = cons (cell_symbol_stack, fields);
  return make_struct (record_type, fields, cell_unspecified);
}

SCM
make_stack (SCM stack) ///((arity . n))
{
  SCM stack_type = make_stack_type ();
  long size = (STACK_SIZE-g_stack) / FRAME_SIZE;
  SCM frames = make_vector__ (size);
  for (long i=0; i<size; i++)
    {
      SCM frame = make_frame (stack, i);
      vector_set_x_ (frames, i, frame);
    }
  SCM values = cell_nil;
  values = cons (frames, values);
  values = cons (cell_symbol_stack, values);
  return make_struct (stack_type, values, cell_unspecified);
}

SCM
stack_length (SCM stack)
{
  SCM frames = struct_ref_ (stack, 3);
  return vector_length (frames);
}

SCM
stack_ref (SCM stack, SCM index)
{
  SCM frames = struct_ref_ (stack, 3);
  return vector_ref (frames, index);
}

SCM
xassq (SCM x, SCM a) ///for speed in core only
{
  while (a != cell_nil && x != CDAR (a))
    a = CDR (a);
  return a != cell_nil ? CAR (a) : cell_f;
}

SCM
memq (SCM x, SCM a)
{
  int t = TYPE (x);
  if (t == TCHAR
      || t == TNUMBER)
      {
        SCM v = VALUE (x);
        while (a != cell_nil && v != VALUE (CAR (a)))
          a = CDR (a);
      }
    else if (t == TKEYWORD)
      {
        while (a != cell_nil
               && (TYPE (CAR (a)) != TKEYWORD
                   || string_equal_p (x, CAR (a)) == cell_f))
          a = CDR (a);
      }
    else
      while (a != cell_nil && x != CAR (a))
        a = CDR (a);
  return a != cell_nil ? a : cell_f;
}

SCM
equal2_p (SCM a, SCM b)
{
 equal2:
  if (a == b)
    return cell_t;
  if (TYPE (a) == TPAIR && TYPE (b) == TPAIR)
    {
      if (equal2_p (CAR (a), CAR (b)) == cell_t)
        {
          a = CDR (a);
          b = CDR (b);
          goto equal2;
        }
      return cell_f;
    }
  if (TYPE (a) == TSTRING && TYPE (b) == TSTRING)
    return string_equal_p (a, b);
  if (TYPE (a) == TVECTOR && TYPE (b) == TVECTOR)
    {
      if (LENGTH (a) != LENGTH (b))
        return cell_f;
      for (long i=0; i < LENGTH (a); i++)
        {
          SCM ai = VECTOR (a) + i;
          SCM bi = VECTOR (b) + i;
          if (TYPE (ai) == TREF)
            ai = REF (ai);
          if (TYPE (bi) == TREF)
            bi = REF (bi);
          if (equal2_p (ai, bi) == cell_f)
            return cell_f;
        }
      return cell_t;
    }
  return eq_p (a, b);
}

SCM
last_pair (SCM x)
{
  while (x != cell_nil && CDR (x) != cell_nil)
    x = CDR (x);
  return x;
}

SCM
pair_p (SCM x)
{
  return TYPE (x) == TPAIR ? cell_t : cell_f;
}