/*************************************************************************
*									 *
*	 YAP Prolog 							 *
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
*									 *
**************************************************************************
*									 *
* File:		charcodes.c						 *
* Last rev:	5/2/88							 *
* mods:									 *
* comments:	Character codes and character conversion		 *
*									 *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif

/*
 * This file includes the definition of a pipe related IO.
 *
 */

#include "Yap.h"
#include "Yatom.h"
#include "YapHeap.h"
#include "yapio.h"
#include <stdlib.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDARG_H
#include <stdarg.h>
#endif
#ifdef _WIN32
#if HAVE_IO_H
/* Windows */
#include <io.h>
#endif
#if HAVE_SOCKET
#include <winsock2.h>
#endif
#include <windows.h>
#ifndef S_ISDIR
#define S_ISDIR(x) (((x)&_S_IFDIR) == _S_IFDIR)
#endif
#endif
#include "iopreds.h"
#include "eval.h"

static Int p_change_type_of_char(USES_REGS1);
static Int p_type_of_char(USES_REGS1);

Term Yap_StringToNumberTerm(char *s, encoding_t *encp) {
  CACHE_REGS
  int sno;
  Term t;

  sno = Yap_open_buf_read_stream(s, strlen(s), encp, MEM_BUF_USER);
  if (sno < 0)
    return FALSE;
  if (encp)
    GLOBAL_Stream[sno].encoding = *encp;
  else
    GLOBAL_Stream[sno].encoding = LOCAL_encoding;
  while (*s && isblank(*s++))
    ;
  t = Yap_scan_num(GLOBAL_Stream + sno);
  if (t == TermNil) {
    CACHE_REGS
    int sign = 1;
    if (s[0] == '+') {
      s++;
    }
    if (s[0] == '-') {
      s++;
      sign = -1;
    }
    if (strcmp(s, "inf") == 0) {
      if (sign > 0) {
        return MkFloatTerm(INFINITY);
      } else {
        return MkFloatTerm(-INFINITY);
      }
    } 
    if (strcmp(s, "nan") == 0) {
      if (sign > 0) {
        return MkFloatTerm(NAN);
      } else {
        return MkFloatTerm(-NAN);
      }
    }
  }
  Yap_CloseStream(sno);
  UNLOCK(GLOBAL_Stream[sno].streamlock);
  return t;
}

const char *encvs[] = {"LANG", "LC_ALL", "LC_CTYPE", NULL};

// wher we can fins an encoding
typedef struct enc_map {
  const char *s;
  encoding_t e;
} enc_map_t;

static enc_map_t ematches[] = {
    {"UTF-8", ENC_ISO_UTF8},
    {"UTF-16", ENC_UTF16_LE}, // ok, this is a very bad name
    {"UCS-2", ENC_UTF16_LE},  // ok, this is probably gone by now
    {"ISO-LATIN1", ENC_ISO_LATIN1},
    {"ISO-8859-1", ENC_ISO_LATIN1},
    {"Windows-1252", ENC_ISO_LATIN1}, // almost, but not quite
    {"CP-1252", ENC_ISO_LATIN1},
    {"C", ENC_ISO_ASCII},
    {NULL, ENC_OCTET}};

static encoding_t DefaultEncoding(void) {
  encoding_t rc;
  int i = 0, j;
  char *enc;
  while (encvs[i]) {
    char *v = getenv(encvs[i]);
    if (v) {
      enc = strrchr(v, '.');
      /* that's how it is supposed to be, except in OSX */
      if (!enc)
        enc = v;
      else
        enc++;
      // now that we have one name, try to match it
      j = 0;
      while (ematches[j].s) {
        if (!strcmp(ematches[j].s, enc))
          return ematches[j].e;
      }
    }
    i++;
  }
// by default, return UTF-8
// except in _WIN32
#ifdef _WIN32
  rc = ENC_UTF16_BE;
#else
  rc = ENC_ISO_UTF8;
#endif
  {
    int j = 0;
    while (rc != ematches[j].e)
      j++;
    Yap_Warning("YAP will use default encoding %s", ematches[j].s);
  }
  return rc;
}

encoding_t Yap_DefaultEncoding(void) {
  CACHE_REGS
  return LOCAL_encoding;
}

void Yap_SetDefaultEncoding(encoding_t new_encoding) {
  CACHE_REGS
  LOCAL_encoding = new_encoding;
}

static Int get_default_encoding(USES_REGS1) {
  Term out = MkIntegerTerm(Yap_DefaultEncoding());
  return Yap_unify(ARG1, out);
}

static Int p_encoding(USES_REGS1) { /* '$encoding'(Stream,N) */
  int sno =
      Yap_CheckStream(ARG1, Input_Stream_f | Output_Stream_f, "encoding/2");
  Term t = Deref(ARG2);
  if (sno < 0)
    return FALSE;
  if (IsVarTerm(t)) {
    UNLOCK(GLOBAL_Stream[sno].streamlock);
    return Yap_unify(ARG2, MkIntegerTerm(GLOBAL_Stream[sno].encoding));
  }
  GLOBAL_Stream[sno].encoding = IntegerOfTerm(Deref(ARG2));
  UNLOCK(GLOBAL_Stream[sno].streamlock);
  return TRUE;
}

static Int toupper2(USES_REGS1) {
  Int out = IntegerOfTerm(Deref(ARG1)), uout;
  if (out < 0) {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER_CODE, ARG1, "toupper");
    return FALSE;
  }
  if (out < 128)
    uout = toupper(out);
  else
    uout = towupper(out);
  return Yap_unify(ARG2, MkIntegerTerm(uout));
}

static Int tolower2(USES_REGS1) {
  Int out = IntegerOfTerm(Deref(ARG1)), uout;
  if (out < 0) {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER_CODE, ARG1, "tolower");
    return FALSE;
  }
  if (out < 128)
    uout = tolower(out);
  else
    uout = towlower(out);
  return Yap_unify(ARG2, MkIntegerTerm(uout));
}

static Int
    p_change_type_of_char(USES_REGS1) { /* change_type_of_char(+char,+type) */
  Term t1 = Deref(ARG1);
  Term t2 = Deref(ARG2);
  if (!IsVarTerm(t1) && !IsIntegerTerm(t1))
    return FALSE;
  if (!IsVarTerm(t2) && !IsIntegerTerm(t2))
    return FALSE;
  Yap_chtype[IntegerOfTerm(t1)] = IntegerOfTerm(t2);
  return TRUE;
}

static Int p_type_of_char(USES_REGS1) { /* type_of_char(+char,-type)      */
  Term t;

  Term t1 = Deref(ARG1);
  if (!IsVarTerm(t1) && !IsIntegerTerm(t1))
    return FALSE;
  t = MkIntTerm(Yap_chtype[IntegerOfTerm(t1)]);
  return Yap_unify(t, ARG2);
}

int ISOWGetc(int sno) {
  int ch = GLOBAL_Stream[sno].stream_wgetc(sno);
  if (ch != EOF && GLOBAL_CharConversionTable != NULL) {

    if (ch < NUMBER_OF_CHARS) {
      /* only do this in ASCII */
      return GLOBAL_CharConversionTable[ch];
    }
  }
  return ch;
}

static Int p_force_char_conversion(USES_REGS1) {
  int i;

  /* don't actually enable it until someone tries to add a conversion */
  if (GLOBAL_CharConversionTable2 == NULL)
    return (TRUE);
  for (i = 0; i < MaxStreams; i++) {
    if (!(GLOBAL_Stream[i].status & Free_Stream_f))
      GLOBAL_Stream[i].stream_wgetc_for_read = ISOWGetc;
  }
  GLOBAL_CharConversionTable = GLOBAL_CharConversionTable2;
  return (TRUE);
}

static Int p_disable_char_conversion(USES_REGS1) {
  int i;

  for (i = 0; i < MaxStreams; i++) {
    if (!(GLOBAL_Stream[i].status & Free_Stream_f))
      GLOBAL_Stream[i].stream_wgetc_for_read = GLOBAL_Stream[i].stream_wgetc;
  }
  GLOBAL_CharConversionTable = NULL;
  return (TRUE);
}

static Int char_conversion(USES_REGS1) {
  Term t0 = Deref(ARG1), t1 = Deref(ARG2);
  unsigned char *s0, *s1;

  if (IsVarTerm(t0)) {
    Yap_Error(INSTANTIATION_ERROR, t0, "char_conversion/2");
    return (FALSE);
  }
  if (!IsAtomTerm(t0)) {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t0, "char_conversion/2");
    return (FALSE);
  }
  s0 = RepAtom(AtomOfTerm(t0))->UStrOfAE;
  if (s0[1] != '\0') {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t0, "char_conversion/2");
    return (FALSE);
  }
  if (IsVarTerm(t1)) {
    Yap_Error(INSTANTIATION_ERROR, t1, "char_conversion/2");
    return (FALSE);
  }
  if (!IsAtomTerm(t1)) {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t1, "char_conversion/2");
    return (FALSE);
  }
  s1 = RepAtom(AtomOfTerm(t1))->UStrOfAE;
  if (s1[1] != '\0') {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t1, "char_conversion/2");
    return (FALSE);
  }
  /* check if we do have a table for converting characters */
  if (GLOBAL_CharConversionTable2 == NULL) {
    int i;

    /* don't create a table if we don't need to */
    if (s0[0] == s1[0])
      return (TRUE);
    GLOBAL_CharConversionTable2 =
        Yap_AllocCodeSpace(NUMBER_OF_CHARS * sizeof(char));
    while (GLOBAL_CharConversionTable2 == NULL) {
      if (!Yap_growheap(FALSE, NUMBER_OF_CHARS * sizeof(char), NULL)) {
        Yap_Error(RESOURCE_ERROR_HEAP, TermNil, LOCAL_ErrorMessage);
        return (FALSE);
      }
    }
    if (trueGlobalPrologFlag(CHAR_CONVERSION_FLAG)) {
      CACHE_REGS
      if (p_force_char_conversion(PASS_REGS1) == FALSE)
        return (FALSE);
    }
    for (i = 0; i < NUMBER_OF_CHARS; i++)
      GLOBAL_CharConversionTable2[i] = i;
  }
  /* just add the new entry */
  GLOBAL_CharConversionTable2[(int)s0[0]] = s1[0];
  /* done */
  return (TRUE);
}

static Int p_current_char_conversion(USES_REGS1) {
  Term t0, t1;
  unsigned char *s0, *s1;

  if (GLOBAL_CharConversionTable == NULL) {
    return (FALSE);
  }
  t0 = Deref(ARG1);
  if (IsVarTerm(t0)) {
    Yap_Error(INSTANTIATION_ERROR, t0, "current_char_conversion/2");
    return (FALSE);
  }
  if (!IsAtomTerm(t0)) {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t0, "current_char_conversion/2");
    return (FALSE);
  }
  s0 = RepAtom(AtomOfTerm(t0))->UStrOfAE;
  if (s0[1] != '\0') {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t0, "current_char_conversion/2");
    return (FALSE);
  }
  t1 = Deref(ARG2);
  if (IsVarTerm(t1)) {
    char out[2];
    if (GLOBAL_CharConversionTable[(int)s0[0]] == '\0')
      return (FALSE);
    out[0] = GLOBAL_CharConversionTable[(int)s0[0]];
    out[1] = '\0';
    return (Yap_unify(ARG2, MkAtomTerm(Yap_LookupAtom(out))));
  }
  if (!IsAtomTerm(t1)) {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t1, "current_char_conversion/2");
    return (FALSE);
  }
  s1 = RepAtom(AtomOfTerm(t1))->UStrOfAE;
  if (s1[1] != '\0') {
    Yap_Error(REPRESENTATION_ERROR_CHARACTER, t1, "current_char_conversion/2");
    return (FALSE);
  } else {
    return (GLOBAL_CharConversionTable[(int)s0[0]] == '\0' &&
            GLOBAL_CharConversionTable[(int)s0[0]] == s1[0]);
  }
}

static Int p_all_char_conversions(USES_REGS1) {
  Term out = TermNil;
  int i;

  if (GLOBAL_CharConversionTable == NULL) {
    return (FALSE);
  }
  for (i = NUMBER_OF_CHARS; i > 0;) {
    i--;
    if (GLOBAL_CharConversionTable[i] != '\0') {
      Term t1, t2;
      char s[2];
      s[1] = '\0';
      s[0] = GLOBAL_CharConversionTable[i];
      t1 = MkAtomTerm(Yap_LookupAtom(s));
      out = MkPairTerm(t1, out);
      s[0] = i;
      t2 = MkAtomTerm(Yap_LookupAtom(s));
      out = MkPairTerm(t2, out);
    }
  }
  return (Yap_unify(ARG1, out));
}

void Yap_InitChtypes(void) {
  DefaultEncoding();
  Yap_InitCPred("$change_type_of_char", 2, p_change_type_of_char,
                SafePredFlag | SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("$type_of_char", 2, p_type_of_char,
                SafePredFlag | SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("toupper", 2, toupper2, SafePredFlag);
  Yap_InitCPred("tolower", 2, tolower2, SafePredFlag);
  Yap_InitCPred("char_conversion", 2, char_conversion, SyncPredFlag);

  Yap_InitCPred("$get_default_encoding", 1, get_default_encoding,
                SafePredFlag | HiddenPredFlag);

  Yap_InitCPred("$encoding", 2, p_encoding, SafePredFlag | SyncPredFlag),

      Yap_InitCPred("$current_char_conversion", 2, p_current_char_conversion,
                    SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("$all_char_conversions", 1, p_all_char_conversions,
                SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("$force_char_conversion", 0, p_force_char_conversion,
                SyncPredFlag | HiddenPredFlag);
  Yap_InitCPred("$disable_char_conversion", 0, p_disable_char_conversion,
                SyncPredFlag | HiddenPredFlag);
}