/****************************************************************************
 * tools/cfgdefine.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <string.h>
#include <ctype.h>
#include "cfgdefine.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Public Data
 ****************************************************************************/

char line[LINESIZE + 1];

/****************************************************************************
 * Private Data
 ****************************************************************************/

/* These are configuration variable name that are quoted by configuration
 * tool but which must be unquoted when used in C code.
 */

static const char *dequote_list[] =
{
  /* NuttX */

  "CONFIG_DEBUG_OPTLEVEL",                /* Custom debug level */
  "CONFIG_EXECFUNCS_NSYMBOLS_VAR",        /* Variable holding number of symbols in the table */
  "CONFIG_EXECFUNCS_SYMTAB_ARRAY",        /* Symbol table array used by exec[l|v] */
  "CONFIG_INIT_ARGS",                     /* Argument list of entry point */
  "CONFIG_INIT_SYMTAB",                   /* Global symbol table */
  "CONFIG_INIT_NEXPORTS",                 /* Global symbol table size */
  "CONFIG_INIT_ENTRYPOINT",               /* Name of entry point function */
  "CONFIG_MODLIB_SYMTAB_ARRAY",           /* Symbol table array used by modlib functions */
  "CONFIG_MODLIB_NSYMBOLS_VAR",           /* Variable holding number of symbols in the table */
  "CONFIG_PASS1_BUILDIR",                 /* Pass1 build directory */
  "CONFIG_PASS1_TARGET",                  /* Pass1 build target */
  "CONFIG_PASS1_OBJECT",                  /* Pass1 build object */
  "CONFIG_TTY_LAUNCH_ENTRYPOINT",         /* Name of entry point from tty launch */
  "CONFIG_TTY_LAUNCH_ARGS",               /* Argument list of entry point from tty launch */

  /* NxWidgets/NxWM */

  "CONFIG_NXWM_BACKGROUND_IMAGE",         /* Name of bitmap image class */
  "CONFIG_NXWM_CALIBRATION_ICON",         /* Name of bitmap image class */
  "CONFIG_NXWM_HEXCALCULATOR_ICON",       /* Name of bitmap image class */
  "CONFIG_NXWM_MINIMIZE_BITMAP",          /* Name of bitmap image class */
  "CONFIG_NXWM_NXTERM_ICON",              /* Name of bitmap image class */
  "CONFIG_NXWM_STARTWINDOW_ICON",         /* Name of bitmap image class */
  "CONFIG_NXWM_STOP_BITMAP",              /* Name of bitmap image class */

  /* apps/ definitions */

  "CONFIG_NSH_SYMTAB_ARRAYNAME",          /* Symbol table array name */
  "CONFIG_NSH_SYMTAB_COUNTNAME",          /* Name of the variable holding the number of symbols */
  NULL                                    /* Marks the end of the list */
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/* Skip over any spaces */

static char *skip_space(char *ptr)
{
  while (*ptr && isspace((int)*ptr)) ptr++;
  return ptr;
}

/* Find the end of a variable string */

static char *find_name_end(char *ptr)
{
  while (*ptr && (isalnum((int)*ptr) || *ptr == '_')) ptr++;
  return ptr;
}

/* Find the end of a value string */

static char *find_value_end(char *ptr)
{
  while (*ptr && !isspace((int)*ptr))
    {
      if (*ptr == '"')
        {
          do ptr++; while (*ptr && (*ptr != '"' || *(ptr - 1) == '\\'));
          if (*ptr) ptr++;
        }
      else
        {
          do ptr++; while (*ptr && !isspace((int)*ptr) && *ptr != '"');
        }
    }

  return ptr;
}

/* Read the next line from the configuration file */

static char *read_line(FILE *stream)
{
  char *ptr;

  for (; ; )
    {
      line[LINESIZE] = '\0';
      if (!fgets(line, LINESIZE, stream))
        {
          return NULL;
        }
      else
        {
          ptr = skip_space(line);
          if (*ptr && *ptr != '#' && *ptr != '\n')
            {
              return ptr;
            }
        }
    }
}

/* Parse the line from the configuration file into a variable name
 * string and a value string.
 */

static void parse_line(char *ptr, char **varname, char **varval)
{
  *varname = ptr;
  *varval = NULL;

  /* Parse to the end of the variable name */

  ptr = find_name_end(ptr);

  /* An equal sign is expected next, perhaps after some white space */

  if (*ptr && *ptr != '=')
    {
      /* Some else follows the variable name.  Terminate the variable
       * name and skip over any spaces.
       */

      *ptr = '\0';
       ptr = skip_space(ptr + 1);
    }

  /* Verify that the equal sign is present */

  if (*ptr == '=')
    {
      /* Make sure that the variable name is terminated (this was already
       * done if the name was followed by white space.
       */

      *ptr = '\0';

      /* The variable value should follow =, perhaps separated by some
       * white space.
       */

      ptr = skip_space(ptr + 1);
      if (*ptr)
        {
          /* Yes.. a variable follows.  Save the pointer to the start
           * of the variable string.
           */

          *varval = ptr;

          /* Find the end of the variable string and make sure that it
           * is terminated.
           */

          ptr = find_value_end(ptr);
          *ptr = '\0';
        }
    }
}

static char *dequote_value(const char *varname, char *varval)
{
  const char **dqnam;
  char *dqval = varval;
  char *ptr;
  int len;
  int i;

  if (dqval)
    {
      /* Check if the variable name is in the dequoted list of strings */

      for (dqnam = dequote_list; *dqnam; dqnam++)
        {
          if (strcmp(*dqnam, varname) == 0)
            {
              break;
            }
        }

      /* Did we find the variable name in the list of configuration variables
       * to be dequoted?
       */

      if (*dqnam)
        {
          /* Yes... Check if there is a trailing quote */

          len = strlen(dqval);
          if (dqval[len - 1] == '"')
            {
              /* Yes... replace it with a terminator */

              dqval[len - 1] = '\0';
              len--;
            }

          /* Is there a leading quote? */

          if (dqval[0] == '"')
            {
              /* Yes.. skip over the leading quote */

              dqval++;
              len--;
            }

          /* A special case is a quoted list of quoted strings.  In that case
           * we will need to remove the backspaces from the internally quoted
           * strings.  NOTE: this will not handle nested quoted quotes.
           */

          for (ptr = dqval; *ptr; ptr++)
            {
              /* Check for a quoted quote */

              if (ptr[0] == '\\' && ptr[1] == '"')
                {
                  /* Delete the backslash by moving the rest of the string */

                  for (i = 0; ptr[i]; i++)
                    {
                      ptr[i] = ptr[i + 1];
                    }

                  len--;
                }
            }

          /* Handle the case where nothing is left after dequoting */

          if (len <= 0)
            {
              dqval = NULL;
            }
        }
    }

  return dqval;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

void generate_definitions(FILE *stream)
{
  char *varname;
  char *varval;
  char *ptr;

  /* Loop until the entire file has been parsed. */

  do
    {
      /* Read the next line from the file */

      ptr = read_line(stream);
      if (ptr)
        {
          /* Parse the line into a variable and a value field */

          parse_line(ptr, &varname, &varval);

          /* Was a variable name found? */

          if (varname)
            {
              /* Yes.. dequote the value if necessary */

              varval = dequote_value(varname, varval);

              /* If no value was provided or if the special value 'n' was
               * provided, then undefine the configuration variable.
               */

              if (!varval || strcmp(varval, "n") == 0)
                {
                  printf("#undef %s\n", varname);
                }

              /* Simply define the configuration variable to '1' if it has
               * the special value "y"
               */

              else if (strcmp(varval, "y") == 0)
                {
                  printf("#define %s 1\n", varname);
                }

              /* Or to '2' if it has the special value 'm' */

              else if (strcmp(varval, "m") == 0)
                {
                  printf("#define %s 2\n", varname);
                }

              /* Otherwise, use the value as provided */

              else
                {
                  printf("#define %s %s\n", varname, varval);
                }
            }
        }
    }
  while (ptr);
}