/*   Cataract - Static web photo gallery generator
 *   Copyright (C) 2008 Tomas Bzatek <tbzatek@users.sourceforge.net>
 *
 *   This program 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 2
 *   of the License, or any later version.
 *
 *   This program 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 this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>

#include "gallery-utils.h"



static char *
strstr_exclude (const char *haystack, const char *needle, const char *exclude_when)
{
  const char *src;
  char *found;

  src = haystack;

  while (src && strstr (src, needle)) {
    found = strstr (src, needle);

    /*  skip if found 'exclude_when' at the same place as 'search'  */
    if (exclude_when && (found == strstr (haystack, exclude_when))) {
      src += strlen (exclude_when);
      continue;
    }
    else
      return found;
  }

  return NULL;
}

/*
 *   str_replace: replace substring 'search' with a 'replace' string
 *                - multiple occurrences of the string are replaced
 *                - specify 'exclude_when' if you want to skip replace when a string found at the place of 'search'
 *                - reallocates the original string
 */
void
str_replace (char **dst, const char *search, const char *replace, const char *exclude_when)
{
  #define REPLACE_MAX_LENGTH 32768
  static char d[REPLACE_MAX_LENGTH];
  char *src;
  char *found;
  int i;

  /* TODO: add range checking */

  if (strstr (*dst, search) == NULL || strlen (*dst) == 0 ||
      strlen (search) == 0 || strlen (replace) == 0)
    return;

  i = 0;
  src = *dst;
  while (strstr_exclude (src, search, exclude_when)) {
    found = strstr_exclude (src, search, exclude_when);

    /*  copy the data between search string  */
    if (found > src) {
      memcpy (&d[i], src, found - src);
      i += found - src;
    }

    /*  copy replace string instead  */
    memcpy (&d[i], replace, strlen (replace));
    i += strlen (replace);
    src = found + strlen (search);
  }

  /*  copy the rest  */
  if (src) {
    memcpy (&d[i], src, strlen (src));
    i += strlen (src);
  }
  d[i] = 0x0;


#ifdef __DEBUG_ALL__
  printf ("str_replace('%s', '%s') = '%s' --> '%s'\n", search, replace, *dst, &d[0]);
#endif

  /*  return fixed string  */
  free (*dst);
  *dst = g_strdup (&d[0]);
}


/*
 *   copy_file: copy file from src to dst
 */
gboolean
copy_file (const char *src, const char *dst)
{
  #define BUFFER_SIZE 65536

  FILE *fin;
  FILE *fout;
  void *buffer;
  int size_r;

  fin = fopen (src, "r");
  if (fin == NULL) {
    fprintf (stderr, "copy_file: error reading file \"%s\": %s\n", src, strerror (errno));
    return FALSE;
  }

  fout = fopen (dst, "w");
  if (fout == NULL) {
    fprintf (stderr, "copy_file: error writing to file \"%s\": %s\n", dst, strerror (errno));
    fclose (fin);
    return FALSE;
  }

  buffer = malloc (BUFFER_SIZE);
  memset (buffer, 0, BUFFER_SIZE);
  size_r = BUFFER_SIZE;

  while ((! feof (fin)) && (size_r == BUFFER_SIZE)) {
    size_r = fread (buffer, 1, BUFFER_SIZE, fin);
    fwrite (buffer, 1, size_r, fout);
  }

  fclose (fout);
  fclose (fin);
  free (buffer);

  return TRUE;
}


/*
 *   make_string: make string of 'substr' substrings
 *                - returns newly allocated string
 */
char *
make_string (const char* substr, const int count)
{
  int i;
  char *s;

  s = malloc (strlen (substr) * count + 1);
  for (i = 0; i < count; i++)
	  memcpy (s + (strlen (substr) * i), substr, strlen (substr));
  s[strlen (substr) * count] = 0;
  return s;
}


/*
 *   fix_entities: replace all invalid & entities with &amp;
 *                 - returns newly allocated string
 */
void
fix_entities (char **str)
{
  static char d[REPLACE_MAX_LENGTH];
  char *src;
  char *found;
  char *scan;
  int i;

  /* TODO: add range checking */

  if (! *str || strstr (*str, "&") == NULL)
    return;

  i = 0;
  src = *str;
  while (strstr (src, "&")) {
    found = strstr (src, "&");

    /*  copy the data between search string  */
    memcpy (&d[i], src, found - src + 1);
    i += found - src + 1;

    /*  scroll to next whitespace  */
    scan = found + 1;
    while (scan && (
          (*scan >= 0x41 && *scan <= 0x5a) || (*scan >= 0x61 && *scan <= 0x7a) ||  /* A-Z, a-z */
          (*scan >= 0x30 && *scan <= 0x39) || (*scan == 0x23)                      /* 0-9, #   */
          ))
      scan++;

    if (scan && (*scan == 0x3b)) {
      /*  this is semicolon, correctly closed entity  */
      /*   -- ignore  */
    }
    else {
      /*  replace with &amp;  */
      memcpy (&d[i], "amp;", 4);
      i += 4;
    }
    src = found + 1;
  }

  /*  copy the rest  */
  if (src) {
    memcpy (&d[i], src, strlen (src));
    i += strlen (src);
  }
  d[i] = 0x0;


#ifdef __DEBUG_ALL__
  printf ("fix_entities: '%s' --> '%s'\n", *str, &d[0]);
#endif

  /*  return fixed string  */
  free (*str);
  *str = g_strdup (&d[0]);
}