/*
 * libcsync -- a library to sync a directory with another
 *
 * Copyright (c) 2008-2013 by Andreas Schneider <asn@cryptomilk.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "config_csync.h"

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include "c_lib.h"
#include "c_private.h"

#include "csync_private.h"
#include "csync_exclude.h"
#include "csync_misc.h"

#define CSYNC_LOG_CATEGORY_NAME "csync.exclude"
#include "csync_log.h"

#ifndef NDEBUG
static
#endif
int _csync_exclude_add(c_strlist_t **inList, const char *string) {
    c_strlist_t *list;

    if (*inList == NULL) {
        *inList = c_strlist_new(32);
        if (*inList == NULL) {
            return -1;
        }
    }

    if ((*inList)->count == (*inList)->size) {
        list = c_strlist_expand(*inList, 2 * (*inList)->size);
        if (list == NULL) {
            return -1;
        }
        *inList = list;
    }

    return c_strlist_add(*inList, string);
}

int csync_exclude_load(const char *fname, c_strlist_t **list) {
  int fd = -1;
  int i = 0;
  int rc = -1;
  int64_t size;
  char *buf = NULL;
  char *entry = NULL;
  mbchar_t *w_fname;

  if (fname == NULL) {
      return -1;
  }

#ifdef _WIN32
  _fmode = _O_BINARY;
#endif

  w_fname = c_utf8_to_locale(fname);
  if (w_fname == NULL) {
      return -1;
  }

  fd = _topen(w_fname, O_RDONLY);
  c_free_locale_string(w_fname);
  if (fd < 0) {
    return -1;
  }

  size = lseek(fd, 0, SEEK_END);
  if (size < 0) {
    rc = -1;
    goto out;
  }
  lseek(fd, 0, SEEK_SET);
  if (size == 0) {
    rc = 0;
    goto out;
  }
  buf = c_malloc(size + 1);
  if (read(fd, buf, size) != size) {
    rc = -1;
    goto out;
  }
  buf[size] = '\0';

  /* FIXME: Use fgets and don't add duplicates */
  entry = buf;
  for (i = 0; i < size; i++) {
    if (buf[i] == '\n' || buf[i] == '\r') {
      if (entry != buf + i) {
        buf[i] = '\0';
        if (*entry != '#') {
          CSYNC_LOG(CSYNC_LOG_PRIORITY_TRACE, "Adding entry: %s", entry);
          rc = _csync_exclude_add(list, entry);
          if (rc < 0) {
              goto out;
          }
        }
      }
      entry = buf + i + 1;
    }
  }

  rc = 0;
out:
  SAFE_FREE(buf);
  close(fd);
  return rc;
}

void csync_exclude_clear(CSYNC *ctx) {
  c_strlist_clear(ctx->excludes);
}

void csync_exclude_destroy(CSYNC *ctx) {
  c_strlist_destroy(ctx->excludes);
}

CSYNC_EXCLUDE_TYPE csync_excluded(CSYNC *ctx, const char *path, int filetype) {

    CSYNC_EXCLUDE_TYPE match = CSYNC_NOT_EXCLUDED;

    match = csync_excluded_no_ctx( ctx->excludes, path, filetype );

    return match;
}

// See http://support.microsoft.com/kb/74496 and
// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
// Additionally, we ignore '$Recycle.Bin', see https://github.com/owncloud/client/issues/2955
static const char* win_reserved_words[] = {"CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5",
                                           "COM6", "COM7", "COM8", "COM9", "LPT1", "LPT2", "LPT3", "LPT4",
                                           "LPT5", "LPT6", "LPT7", "LPT8", "LPT9", "CLOCK$", "$Recycle.Bin" };

bool csync_is_windows_reserved_word(const char* filename) {

  size_t win_reserve_words_len = sizeof(win_reserved_words) / sizeof(char*);
  size_t j;

  for (j = 0; j < win_reserve_words_len; j++) {
    int len_reserved_word = strlen(win_reserved_words[j]);
    int len_filename = strlen(filename);
    if (len_filename == 2 && filename[1] == ':') {
        if (filename[0] >= 'a' && filename[0] <= 'z') {
            return true;
        }
        if (filename[0] >= 'A' && filename[0] <= 'Z') {
            return true;
        }
    }
    if (c_strncasecmp(filename, win_reserved_words[j], len_reserved_word) == 0) {
        if (len_filename == len_reserved_word) {
            return true;
        }
        if ((len_filename > len_reserved_word) && (filename[len_reserved_word] == '.')) {
            return true;
        }
    }
  }
  return false;
}

CSYNC_EXCLUDE_TYPE csync_excluded_no_ctx(c_strlist_t *excludes, const char *path, int filetype) {
  size_t i = 0;
  const char *p = NULL;
  char *bname = NULL;
  char *dname = NULL;
  char *prev_dname = NULL;
  char *conflict = NULL;
  int rc = -1;
  CSYNC_EXCLUDE_TYPE match = CSYNC_NOT_EXCLUDED;
  CSYNC_EXCLUDE_TYPE type  = CSYNC_NOT_EXCLUDED;

    for (p = path; *p; p++) {
      switch (*p) {
        case '\\':
        case ':':
        case '?':
        case '*':
        case '"':
        case '>':
        case '<':
        case '|':
          return CSYNC_FILE_EXCLUDE_INVALID_CHAR;
        default:
          break;
      }
    }

  /* split up the path */
  dname = c_dirname(path);
  bname = c_basename(path);

  if (bname == NULL || dname == NULL) {
      match = CSYNC_NOT_EXCLUDED;
      SAFE_FREE(bname);
      SAFE_FREE(dname);
      goto out;
  }

  rc = csync_fnmatch(".csync_journal.db*", bname, 0);
  if (rc == 0) {
      match = CSYNC_FILE_SILENTLY_EXCLUDED;
      SAFE_FREE(bname);
      SAFE_FREE(dname);
      goto out;
  }

  // check the strlen and ignore the file if its name is longer than 254 chars.
  // whenever changing this also check createDownloadTmpFileName
  if (strlen(bname) > 254) {
      match = CSYNC_FILE_EXCLUDE_LONG_FILENAME;
      SAFE_FREE(bname);
      SAFE_FREE(dname);
      goto out;
  }

#ifdef _WIN32
  // Windows cannot sync files ending in spaces (#2176). It also cannot
  // distinguish files ending in '.' from files without an ending,
  // as '.' is a separator that is not stored internally, so let's
  // not allow to sync those to avoid file loss/ambiguities (#416)
  size_t blen = strlen(bname);
  if (blen > 1 && (bname[blen-1]== ' ' || bname[blen-1]== '.' )) {
      match = CSYNC_FILE_EXCLUDE_INVALID_CHAR;
      SAFE_FREE(bname);
      SAFE_FREE(dname);
      goto out;
  }

  if (csync_is_windows_reserved_word(bname)) {
    match = CSYNC_FILE_EXCLUDE_INVALID_CHAR;
    SAFE_FREE(bname);
    SAFE_FREE(dname);
    goto out;
  }
#endif

  rc = csync_fnmatch(".owncloudsync.log*", bname, 0);
  if (rc == 0) {
      match = CSYNC_FILE_SILENTLY_EXCLUDED;
      SAFE_FREE(bname);
      SAFE_FREE(dname);
      goto out;
  }

  /* Always ignore conflict files, not only via the exclude list */
  rc = csync_fnmatch("*_conflict-*", bname, 0);
  if (rc == 0) {
      match = CSYNC_FILE_SILENTLY_EXCLUDED;
      SAFE_FREE(bname);
      SAFE_FREE(dname);
      goto out;
  }

  if (getenv("CSYNC_CONFLICT_FILE_USERNAME")) {
      rc = asprintf(&conflict, "*_conflict_%s-*", getenv("CSYNC_CONFLICT_FILE_USERNAME"));
      if (rc < 0) {
          goto out;
      }
      rc = csync_fnmatch(conflict, path, 0);
      if (rc == 0) {
          match = CSYNC_FILE_SILENTLY_EXCLUDED;
          SAFE_FREE(conflict);
          SAFE_FREE(bname);
          SAFE_FREE(dname);
          goto out;
      }
      SAFE_FREE(conflict);
  }

  SAFE_FREE(bname);
  SAFE_FREE(dname);

  if( ! excludes ) {
      goto out;
  }

  /* Loop over all exclude patterns and evaluate the given path */
  for (i = 0; match == CSYNC_NOT_EXCLUDED && i < excludes->count; i++) {
      bool match_dirs_only = false;
      char *pattern_stored = c_strdup(excludes->vector[i]);
      char* pattern = pattern_stored;

      type = CSYNC_FILE_EXCLUDE_LIST;
      if (strlen(pattern) < 1) {
	  SAFE_FREE(pattern_stored);
          continue;
      }
      /* Ecludes starting with ']' means it can be cleanup */
      if (pattern[0] == ']') {
          ++pattern;
          if (filetype == CSYNC_FTW_TYPE_FILE) {
              type = CSYNC_FILE_EXCLUDE_AND_REMOVE;
          }
      }
      /* Check if the pattern applies to pathes only. */
      if (pattern[strlen(pattern)-1] == '/') {
          match_dirs_only = true;
          pattern[strlen(pattern)-1] = '\0'; /* Cut off the slash */
      }

      /* check if the pattern contains a / and if, compare to the whole path */
      if (strchr(pattern, '/')) {
          rc = csync_fnmatch(pattern, path, FNM_PATHNAME);
          if( rc == 0 ) {
              match = type;
          }
          /* if the pattern requires a dir, but path is not, its still not excluded. */
          if (match_dirs_only && filetype != CSYNC_FTW_TYPE_DIR) {
              match = CSYNC_NOT_EXCLUDED;
          }
      }

      /* if still not excluded, check each component of the path */
      if (match == CSYNC_NOT_EXCLUDED) {
          int trailing_component = 1;
          dname = c_dirname(path);
          bname = c_basename(path);

          if (bname == NULL || dname == NULL) {
              match = CSYNC_NOT_EXCLUDED;
	      SAFE_FREE(bname);
	      SAFE_FREE(dname);
              SAFE_FREE(pattern_stored);
              goto out;
          }

          /* Check each component of the path */
          do {
              /* Do not check the bname if its a file and the pattern matches dirs only. */
              if ( !(trailing_component == 1 /* it is the trailing component */
                     && match_dirs_only      /* but only directories are matched by the pattern */
                     && filetype == CSYNC_FTW_TYPE_FILE) ) {
                  /* Check the name component against the pattern */
                  rc = csync_fnmatch(pattern, bname, 0);
                  if (rc == 0) {
                      match = type;
                  }
              }
              if (!(c_streq(dname, ".") || c_streq(dname, "/"))) {
                  rc = csync_fnmatch(pattern, dname, 0);
                  if (rc == 0) {
                      match = type;
                  }
              }
              trailing_component = 0;
              prev_dname = dname;
              SAFE_FREE(bname);
              bname = c_basename(prev_dname);
              dname = c_dirname(prev_dname);
              SAFE_FREE(prev_dname);

          } while( match == CSYNC_NOT_EXCLUDED && !c_streq(dname, ".")
                     && !c_streq(dname, "/") );
      }
      SAFE_FREE(pattern_stored);
      SAFE_FREE(bname);
      SAFE_FREE(dname);
  }


out:

  return match;
}