/*
 * Copyright notice from original mutt:
 * Copyright (C) 1999-2000 Thomas Roessler <roessler@does-not-exist.org>
 *
 * This file is part of mutt-ng, see http://www.muttng.org/.
 * It's licensed under the GNU General Public License,
 * please see the file GPL in the top level source directory.
 */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#include <ctype.h>

#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <errno.h>

#include "mutt.h"
#include "charset.h"
#include "ascii.h"

#include "lib/mem.h"
#include "lib/intl.h"
#include "lib/str.h"

#ifndef EILSEQ
# define EILSEQ EINVAL
#endif

/* 
 * The following list has been created manually from the data under:
 * http://www.isi.edu/in-notes/iana/assignments/character-sets
 * Last update: 2000-09-07
 *
 * Note that it includes only the subset of character sets for which
 * a preferred MIME name is given.
 */

static struct {
  char *key;
  char *pref;
} PreferredMIMENames[] = {
  {
  "ansi_x3.4-1968", "us-ascii"}, {
  "iso-ir-6", "us-ascii"}, {
  "iso_646.irv:1991", "us-ascii"}, {
  "ascii", "us-ascii"}, {
  "iso646-us", "us-ascii"}, {
  "us", "us-ascii"}, {
  "ibm367", "us-ascii"}, {
  "cp367", "us-ascii"}, {
  "csASCII", "us-ascii"}, {
  "csISO2022KR", "iso-2022-kr"}, {
  "csEUCKR", "euc-kr"}, {
  "csISO2022JP", "iso-2022-jp"}, {
  "csISO2022JP2", "iso-2022-jp-2"}, {
  "ISO_8859-1:1987", "iso-8859-1"}, {
  "iso-ir-100", "iso-8859-1"}, {
  "iso_8859-1", "iso-8859-1"}, {
  "latin1", "iso-8859-1"}, {
  "l1", "iso-8859-1"}, {
  "IBM819", "iso-8859-1"}, {
  "CP819", "iso-8859-1"}, {
  "csISOLatin1", "iso-8859-1"}, {
  "ISO_8859-2:1987", "iso-8859-2"}, {
  "iso-ir-101", "iso-8859-2"}, {
  "iso_8859-2", "iso-8859-2"}, {
  "latin2", "iso-8859-2"}, {
  "l2", "iso-8859-2"}, {
  "csISOLatin2", "iso-8859-2"}, {
  "ISO_8859-3:1988", "iso-8859-3"}, {
  "iso-ir-109", "iso-8859-3"}, {
  "ISO_8859-3", "iso-8859-3"}, {
  "latin3", "iso-8859-3"}, {
  "l3", "iso-8859-3"}, {
  "csISOLatin3", "iso-8859-3"}, {
  "ISO_8859-4:1988", "iso-8859-4"}, {
  "iso-ir-110", "iso-8859-4"}, {
  "ISO_8859-4", "iso-8859-4"}, {
  "latin4", "iso-8859-4"}, {
  "l4", "iso-8859-4"}, {
  "csISOLatin4", "iso-8859-4"}, {
  "ISO_8859-6:1987", "iso-8859-6"}, {
  "iso-ir-127", "iso-8859-6"}, {
  "iso_8859-6", "iso-8859-6"}, {
  "ECMA-114", "iso-8859-6"}, {
  "ASMO-708", "iso-8859-6"}, {
  "arabic", "iso-8859-6"}, {
  "csISOLatinArabic", "iso-8859-6"}, {
  "ISO_8859-7:1987", "iso-8859-7"}, {
  "iso-ir-126", "iso-8859-7"}, {
  "ISO_8859-7", "iso-8859-7"}, {
  "ELOT_928", "iso-8859-7"}, {
  "ECMA-118", "iso-8859-7"}, {
  "greek", "iso-8859-7"}, {
  "greek8", "iso-8859-7"}, {
  "csISOLatinGreek", "iso-8859-7"}, {
  "ISO_8859-8:1988", "iso-8859-8"}, {
  "iso-ir-138", "iso-8859-8"}, {
  "ISO_8859-8", "iso-8859-8"}, {
  "hebrew", "iso-8859-8"}, {
  "csISOLatinHebrew", "iso-8859-8"}, {
  "ISO_8859-5:1988", "iso-8859-5"}, {
  "iso-ir-144", "iso-8859-5"}, {
  "ISO_8859-5", "iso-8859-5"}, {
  "cyrillic", "iso-8859-5"}, {
  "csISOLatinCyrillic", "iso8859-5"}, {
  "ISO_8859-9:1989", "iso-8859-9"}, {
  "iso-ir-148", "iso-8859-9"}, {
  "ISO_8859-9", "iso-8859-9"}, {
  "latin5", "iso-8859-9"},      /* this is not a bug */
  {
  "l5", "iso-8859-9"}, {
  "csISOLatin5", "iso-8859-9"}, {
  "ISO_8859-10:1992", "iso-8859-10"}, {
  "iso-ir-157", "iso-8859-10"}, {
  "latin6", "iso-8859-10"},     /* this is not a bug */
  {
  "l6", "iso-8859-10"}, {
  "csISOLatin6" "iso-8859-10"}, {
  "csKOI8r", "koi8-r"}, {
  "MS_Kanji", "Shift_JIS"},     /* Note the underscore! */
  {
  "csShiftJis", "Shift_JIS"}, {
  "Extended_UNIX_Code_Packed_Format_for_Japanese", "EUC-JP"}, {
  "csEUCPkdFmtJapanese", "EUC-JP"}, {
  "csGB2312", "gb2312"}, {
  "csbig5", "big5"},
    /* 
     * End of official brain damage.  What follows has been taken
     * from glibc's localedata files. 
     */
  {
  "iso_8859-13", "iso-8859-13"}, {
  "iso-ir-179", "iso-8859-13"}, {
  "latin7", "iso-8859-13"},     /* this is not a bug */
  {
  "l7", "iso-8859-13"}, {
  "iso_8859-14", "iso-8859-14"}, {
  "latin8", "iso-8859-14"},     /* this is not a bug */
  {
  "l8", "iso-8859-14"}, {
  "iso_8859-15", "iso-8859-15"}, {
  "latin9", "iso-8859-15"},     /* this is not a bug */
    /* Suggested by Ionel Mugurel Ciobica <tgakic@sg10.chem.tue.nl> */
  {
  "latin0", "iso-8859-15"},     /* this is not a bug */
  {
  "iso_8859-16", "iso-8859-16"}, {
  "latin10", "iso-8859-16"},    /* this is not a bug */
    /* 
     * David Champion <dgc@uchicago.edu> has observed this with
     * nl_langinfo under SunOS 5.8. 
     */
  {
  "646", "us-ascii"},
    /* 
     * http://www.sun.com/software/white-papers/wp-unicode/
     */
  {
  "eucJP", "euc-jp"}, {
  "PCK", "Shift_JIS"}, {
  "ko_KR-euc", "euc-kr"}, {
  "zh_TW-big5", "big5"},
    /* seems to be common on some systems */
  {
  "sjis", "Shift_JIS"}, {
  "euc-jp-ms", "eucJP-ms"},
    /*
     * If you happen to encounter system-specific brain-damage with
     * respect to character set naming, please add it above this
     * comment, and submit a patch to <mutt-dev@mutt.org>. 
     */
    /* End of aliases.  Please keep this line last. */
  {
  NULL, NULL}
};

#ifdef HAVE_LANGINFO_CODESET
# include <langinfo.h>


void mutt_set_langinfo_charset (void)
{
  char buff[LONG_STRING];
  char buff2[LONG_STRING];

  strfcpy (buff, nl_langinfo (CODESET), sizeof (buff));
  mutt_canonical_charset (buff2, sizeof (buff2), buff);

  /* finally, set $charset */
  if (!(Charset = str_dup (buff2)))
    Charset = str_dup ("iso-8859-1");
}

#else

void mutt_set_langinfo_charset (void)
{
  Charset = str_dup ("iso-8859-1");
}

#endif

void mutt_canonical_charset (char *dest, size_t dlen, const char *name)
{
  size_t i;
  char *p;
  char scratch[LONG_STRING];

  /* catch some common iso-8859-something misspellings */
  if (!ascii_strncasecmp (name, "8859", 4) && name[4] != '-')
    snprintf (scratch, sizeof (scratch), "iso-8859-%s", name + 4);
  else if (!ascii_strncasecmp (name, "8859-", 5))
    snprintf (scratch, sizeof (scratch), "iso-8859-%s", name + 5);
  else if (!ascii_strncasecmp (name, "iso8859", 7) && name[7] != '-')
    snprintf (scratch, sizeof (scratch), "iso_8859-%s", name + 7);
  else if (!ascii_strncasecmp (name, "iso8859-", 8))
    snprintf (scratch, sizeof (scratch), "iso_8859-%s", name + 8);
  else
    strfcpy (scratch, NONULL (name), sizeof (scratch));

  for (i = 0; PreferredMIMENames[i].key; i++)
    if (!ascii_strcasecmp (scratch, PreferredMIMENames[i].key) ||
        !str_casecmp (scratch, PreferredMIMENames[i].key)) {
      strfcpy (dest, PreferredMIMENames[i].pref, dlen);
      return;
    }

  strfcpy (dest, scratch, dlen);

  /* for cosmetics' sake, transform to lowercase. */
  for (p = dest; *p; p++)
    *p = ascii_tolower (*p);
}

int mutt_chscmp (const char *s, const char *chs)
{
  char buffer[STRING];

  if (!s)
    return 0;

  mutt_canonical_charset (buffer, sizeof (buffer), s);
  return !ascii_strcasecmp (buffer, chs);
}


#ifndef HAVE_ICONV

iconv_t iconv_open (const char *tocode, const char *fromcode)
{
  return (iconv_t) (-1);
}

size_t iconv (iconv_t cd, ICONV_CONST char **inbuf, size_t * inbytesleft,
              char **outbuf, size_t * outbytesleft)
{
  return 0;
}

int iconv_close (iconv_t cd)
{
  return 0;
}

#endif /* !HAVE_ICONV */


/*
 * Like iconv_open, but canonicalises the charsets
 */

iconv_t mutt_iconv_open (const char *tocode, const char *fromcode, int flags)
{
  char tocode1[SHORT_STRING];
  char fromcode1[SHORT_STRING];
  char *tocode2, *fromcode2;
  char *tmp;

  iconv_t cd;

  mutt_canonical_charset (tocode1, sizeof (tocode1), tocode);

#ifdef M_ICONV_HOOK_TO
  /* Not used. */
  if ((flags & M_ICONV_HOOK_TO) && (tmp = mutt_charset_hook (tocode1)))
    mutt_canonical_charset (tocode1, sizeof (tocode1), tmp);
#endif

  mutt_canonical_charset (fromcode1, sizeof (fromcode1), fromcode);
  if ((flags & M_ICONV_HOOK_FROM) && (tmp = mutt_charset_hook (fromcode1)))
    mutt_canonical_charset (fromcode1, sizeof (fromcode1), tmp);

  if ((cd = iconv_open (tocode1, fromcode1)) != (iconv_t) - 1)
    return cd;
  if ((tocode2 = mutt_iconv_hook (tocode1))
      && (fromcode2 = mutt_iconv_hook (fromcode1)))
    return iconv_open (tocode2, fromcode2);

  return (iconv_t) - 1;
}


/*
 * Like iconv, but keeps going even when the input is invalid
 * If you're supplying inrepls, the source charset should be stateless;
 * if you're supplying an outrepl, the target charset should be.
 */

size_t mutt_iconv (iconv_t cd, ICONV_CONST char **inbuf, size_t * inbytesleft,
                   char **outbuf, size_t * outbytesleft,
                   ICONV_CONST char **inrepls, const char *outrepl)
{
  size_t ret = 0, ret1;
  ICONV_CONST char *ib = *inbuf;
  size_t ibl = *inbytesleft;
  char *ob = *outbuf;
  size_t obl = *outbytesleft;

  for (;;) {
    ret1 = iconv (cd, &ib, &ibl, &ob, &obl);
    if (ret1 != (size_t) - 1)
      ret += ret1;
    if (ibl && obl && errno == EILSEQ) {
      if (inrepls) {
        /* Try replacing the input */
        ICONV_CONST char **t;

        for (t = inrepls; *t; t++) {
          ICONV_CONST char *ib1 = *t;
          size_t ibl1 = str_len (*t);
          char *ob1 = ob;
          size_t obl1 = obl;

          iconv (cd, &ib1, &ibl1, &ob1, &obl1);
          if (!ibl1) {
            ++ib, --ibl;
            ob = ob1, obl = obl1;
            ++ret;
            break;
          }
        }
        if (*t)
          continue;
      }
      /* Replace the output */
      if (!outrepl)
        outrepl = "?";
      iconv (cd, 0, 0, &ob, &obl);
      if (obl) {
        int n = str_len (outrepl);

        if (n > obl) {
          outrepl = "?";
          n = 1;
        }
        memcpy (ob, outrepl, n);
        ++ib, --ibl;
        ob += n, obl -= n;
        ++ret;
        iconv (cd, 0, 0, 0, 0); /* for good measure */
        continue;
      }
    }
    *inbuf = ib, *inbytesleft = ibl;
    *outbuf = ob, *outbytesleft = obl;
    return ret;
  }
}


/*
 * Convert a string
 * Used in rfc2047.c and rfc2231.c
 */

int mutt_convert_string (char **ps, const char *from, const char *to,
                         int flags)
{
  iconv_t cd;
  ICONV_CONST char *repls[] = { "\357\277\275", "?", 0 };
  char *s = *ps;

  if (!s || !*s)
    return 0;

  if (to && from && (cd = mutt_iconv_open (to, from, flags)) != (iconv_t) - 1) {
    int len;
    ICONV_CONST char *ib;
    char *buf, *ob;
    size_t ibl, obl;
    ICONV_CONST char **inrepls = 0;
    char *outrepl = 0;

    if (mutt_is_utf8 (to))
      outrepl = "\357\277\275";
    else if (mutt_is_utf8 (from))
      inrepls = repls;
    else
      outrepl = "?";

    len = str_len (s);
    ib = s, ibl = len + 1;
    obl = MB_LEN_MAX * ibl;
    ob = buf = mem_malloc (obl + 1);

    mutt_iconv (cd, &ib, &ibl, &ob, &obl, inrepls, outrepl);
    iconv_close (cd);

    *ob = '\0';

    mem_free (ps);
    *ps = buf;

    str_adjust (ps);
    return 0;
  }
  else
    return -1;
}


/*
 * FGETCONV stuff for converting a file while reading it
 * Used in sendlib.c for converting from mutt's Charset
 */

struct fgetconv_s {
  FILE *file;
  iconv_t cd;
  char bufi[512];
  char bufo[512];
  char *p;
  char *ob;
  char *ib;
  size_t ibl;
  ICONV_CONST char **inrepls;
};

struct fgetconv_not {
  FILE *file;
  iconv_t cd;
};

FGETCONV *fgetconv_open (FILE * file, const char *from, const char *to,
                         int flags)
{
  struct fgetconv_s *fc;
  iconv_t cd = (iconv_t) - 1;
  static ICONV_CONST char *repls[] = { "\357\277\275", "?", 0 };

  if (from && to)
    cd = mutt_iconv_open (to, from, flags);

  if (cd != (iconv_t) - 1) {
    fc = mem_malloc (sizeof (struct fgetconv_s));
    fc->p = fc->ob = fc->bufo;
    fc->ib = fc->bufi;
    fc->ibl = 0;
    fc->inrepls = mutt_is_utf8 (to) ? repls : repls + 1;
  }
  else
    fc = mem_malloc (sizeof (struct fgetconv_not));
  fc->file = file;
  fc->cd = cd;
  return (FGETCONV *) fc;
}

char *fgetconvs (char *buf, size_t l, FGETCONV * _fc)
{
  int c;
  size_t r;

  for (r = 0; r + 1 < l;) {
    if ((c = fgetconv (_fc)) == EOF)
      break;
    buf[r++] = (char) c;
    if (c == '\n')
      break;
  }
  buf[r] = '\0';

  if (r)
    return buf;
  else
    return NULL;
}

int fgetconv (FGETCONV * _fc)
{
  struct fgetconv_s *fc = (struct fgetconv_s *) _fc;

  if (!fc)
    return EOF;
  if (fc->cd == (iconv_t) - 1)
    return fgetc (fc->file);
  if (!fc->p)
    return EOF;
  if (fc->p < fc->ob)
    return (unsigned char) *(fc->p)++;

  /* Try to convert some more */
  fc->p = fc->ob = fc->bufo;
  if (fc->ibl) {
    size_t obl = sizeof (fc->bufo);

    iconv (fc->cd, (ICONV_CONST char **) &fc->ib, &fc->ibl, &fc->ob, &obl);
    if (fc->p < fc->ob)
      return (unsigned char) *(fc->p)++;
  }

  /* If we trusted iconv a bit more, we would at this point
   * ask why it had stopped converting ... */

  /* Try to read some more */
  if (fc->ibl == sizeof (fc->bufi) ||
      (fc->ibl && fc->ib + fc->ibl < fc->bufi + sizeof (fc->bufi))) {
    fc->p = 0;
    return EOF;
  }
  if (fc->ibl)
    memcpy (fc->bufi, fc->ib, fc->ibl);
  fc->ib = fc->bufi;
  fc->ibl +=
    fread (fc->ib + fc->ibl, 1, sizeof (fc->bufi) - fc->ibl, fc->file);

  /* Try harder this time to convert some */
  if (fc->ibl) {
    size_t obl = sizeof (fc->bufo);

    mutt_iconv (fc->cd, (ICONV_CONST char **) &fc->ib, &fc->ibl, &fc->ob,
                &obl, fc->inrepls, 0);
    if (fc->p < fc->ob)
      return (unsigned char) *(fc->p)++;
  }

  /* Either the file has finished or one of the buffers is too small */
  fc->p = 0;
  return EOF;
}

void fgetconv_close (FGETCONV ** _fc)
{
  struct fgetconv_s *fc = (struct fgetconv_s *) *_fc;

  if (fc->cd != (iconv_t) - 1)
    iconv_close (fc->cd);
  mem_free (_fc);
}

char *mutt_get_first_charset (const char *charset)
{
  static char fcharset[SHORT_STRING];
  const char *c, *c1;

  c = charset;
  if (!str_len (c))
    return "us-ascii";
  if (!(c1 = strchr (c, ':')))
    return ((char*) charset);
  strfcpy (fcharset, c, c1 - c + 1);
  return fcharset;
}

static size_t convert_string (ICONV_CONST char *f, size_t flen,
                              const char *from, const char *to,
                              char **t, size_t * tlen)
{
  iconv_t cd;
  char *buf, *ob;
  size_t obl, n;
  int e;

  cd = mutt_iconv_open (to, from, 0);
  if (cd == (iconv_t) (-1))
    return (size_t) (-1);
  obl = 4 * flen + 1;
  ob = buf = mem_malloc (obl);
  n = iconv (cd, &f, &flen, &ob, &obl);
  if (n == (size_t) (-1) || iconv (cd, 0, 0, &ob, &obl) == (size_t) (-1)) {
    e = errno;
    mem_free (&buf);
    iconv_close (cd);
    errno = e;
    return (size_t) (-1);
  }
  *ob = '\0';

  *tlen = ob - buf;

  mem_realloc (&buf, ob - buf + 1);
  *t = buf;
  iconv_close (cd);

  return n;
}

int mutt_convert_nonmime_string (char **ps)
{
  const char *c, *c1;

  for (c = AssumedCharset; c; c = c1 ? c1 + 1 : 0) {
    char *u = *ps;
    char *s = NULL;
    char *fromcode;
    size_t m, n;
    size_t ulen = str_len (*ps);
    size_t slen;

    if (!u || !*u)
      return 0;

    c1 = strchr (c, ':');
    n = c1 ? c1 - c : str_len (c);
    if (!n)
      continue;
    fromcode = mem_malloc (n + 1);
    strfcpy (fromcode, c, n + 1);
    m = convert_string (u, ulen, fromcode, Charset, &s, &slen);
    mem_free (&fromcode);
    if (m != (size_t) (-1)) {
      mem_free (ps);
      *ps = s;
      return 0;
    }
  }
  return -1;
}