/* parser config.in
 *
 * Version 1.0
 * Eric Youngdale
 * 10/95
 *
 * The general idea here is that we want to parse a config.in file and 
 * from this, we generate a wish script which gives us effectively the
 * same functionality that the original config.in script provided.
 *
 * This task is split roughly into 3 parts.  The first parse is the parse
 * of the input file itself.  The second part is where we analyze the 
 * #ifdef clauses, and attach a linked list of tokens to each of the
 * menu items.  In this way, each menu item has a complete list of
 * dependencies that are used to enable/disable the options.
 * The third part is to take the configuration database we have build,
 * and build the actual wish script.
 *
 * This file contains the code to do the first parse of config.in.
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "tkparse.h"

struct kconfig * config = NULL;
struct kconfig * clast = NULL;
struct kconfig * koption = NULL;
static int lineno = 0;
static int menus_seen = 0;
static char * current_file = NULL;
static int do_source(char * filename);
static char * get_string(char *pnt, char ** labl);
static int choose_number = 0;


/*
 * Simple function just to skip over spaces and tabs in config.in.
 */
static char * skip_whitespace(char * pnt)
{
  while( *pnt && (*pnt == ' ' || *pnt == '\t')) pnt++;
  return pnt;
}

/*
 * This function parses a conditional from a config.in (i.e. from an ifdef)
 * and generates a linked list of tokens that describes the conditional.
 */
static struct condition * parse_if(char * pnt)
{
  char * opnt;
  struct condition *list;
  struct condition *last;
  struct condition *cpnt;
  char varname[64];
  char * pnt1;

  opnt = pnt;

  /*
   * We need to find the various tokens, and build the linked list.
   */
  pnt = skip_whitespace(pnt);
  if( *pnt != '[' ) return NULL;
  pnt++;
  pnt = skip_whitespace(pnt);

  list = last = NULL;
  while(*pnt && *pnt != ']') {

    pnt = skip_whitespace(pnt);
    if(*pnt== '\0' || *pnt == ']') break;

    /*
     * Allocate memory for the token we are about to parse, and insert
     * it in the linked list.
     */
    cpnt = (struct condition *) malloc(sizeof(struct condition));
    memset(cpnt, 0, sizeof(struct condition));
    if( last == NULL )
      {
        list = last = cpnt;
      }
    else
      {
        last->next = cpnt;
        last = cpnt;
      }

    /*
     * Determine what type of operation this token represents.
     */
    if( *pnt == '-' && pnt[1] == 'a' )
      {
        cpnt->op = op_and;
        pnt += 2;
        continue;
      }

    if( *pnt == '-' && pnt[1] == 'o' )
      {
        cpnt->op = op_or;
        pnt += 2;
        continue;
      }

    if( *pnt == '!' && pnt[1] == '=' )
      {
        cpnt->op = op_neq;
        pnt += 2;
        continue;
      }

    if( *pnt == '=')
      {
        cpnt->op = op_eq;
        pnt += 1;
        continue;
      }

    if( *pnt == '!')
      {
        cpnt->op = op_bang;
        pnt += 1;
        continue;
      }

    if( *pnt != '"' ) goto error;  /* This cannot be right. */
    pnt++;
    if( *pnt == '`' )
      {
        cpnt->op = op_shellcmd;
        pnt1 = varname;
        pnt++;
        while(*pnt && *pnt != '`') *pnt1++ = *pnt++;
        *pnt1++ = '\0';
        cpnt->variable.str = strdup(varname);
        if( *pnt == '`' ) pnt++;
        if( *pnt == '"' ) pnt++;
        continue;
      }
    if( *pnt == '$' )
      {
        cpnt->op = op_variable;
        pnt1 = varname;
        pnt++;
        while(*pnt && *pnt != '"') *pnt1++ = *pnt++;
        *pnt1++ = '\0';
        cpnt->variable.str = strdup(varname);
        if( *pnt == '"' ) pnt++;
        continue;
      }

    cpnt->op = op_constant;
    pnt1 = varname;
    while(*pnt && *pnt != '"') *pnt1++ = *pnt++;
    *pnt1++ = '\0';
    cpnt->variable.str = strdup(varname);
    if( *pnt == '"' ) pnt++;
    continue;
  }

  return list;

 error:
  if(current_file != NULL) 
    fprintf(stderr, 
            "Bad if clause at line %d(%s):%s\n", lineno, current_file, opnt);
  else
    fprintf(stderr,
            "Bad if clause at line %d:%s\n", lineno, opnt);
  return NULL;
}

/*
 * This function looks for a quoted string, from the input buffer, and
 * returns a pointer to a copy of this string.  Any characters in
 * the string that need to be "quoted" have a '\' character inserted
 * in front - this way we can directly write these strings into
 * wish scripts.
 */
static char * get_qstring(char *pnt, char ** labl)
{
  char quotechar;
  char newlabel[1024];
  char * pnt1;
  char * pnt2;

  while( *pnt && *pnt != '"' && *pnt != '\'') pnt++;
  if (*pnt == '\0') return pnt;

  quotechar = *pnt++;
  pnt1 = newlabel;
  while(*pnt && *pnt != quotechar && pnt[-1] != '\\')
    {
      /*
       * Quote the character if we need to.
       */
      if( *pnt == '"' || *pnt == '\'' || *pnt == '[' || *pnt == ']')
        *pnt1++ = '\\';

      *pnt1++ = *pnt++;
    }
  *pnt1++ = '\0';

  pnt2 = (char *) malloc(strlen(newlabel) + 1);
  strcpy(pnt2, newlabel);
  *labl = pnt2;

  /*
   * Skip over last quote, and whitespace.
   */
  pnt++;
  pnt = skip_whitespace(pnt);
  return pnt;
}

static char * parse_choices(struct kconfig * choice_kcfg, char * pnt)
{
  struct kconfig * kcfg;
  int index = 1;

  /*
   * Choices appear in pairs of strings.  The parse is fairly trivial.
   */
  while(1)
    {
      pnt = skip_whitespace(pnt);
      if(*pnt == '\0') break;

      kcfg = (struct kconfig *) malloc(sizeof(struct kconfig));
      memset(kcfg, 0, sizeof(struct kconfig));
      kcfg->tok = tok_choice;
      if( clast != NULL )
        {
          clast->next = kcfg;
          clast = kcfg;
        }
      else
        {
          clast = config = kcfg;
        }

      pnt = get_string(pnt, &kcfg->label);
      pnt = skip_whitespace(pnt);
      pnt = get_string(pnt, &kcfg->optionname);
      kcfg->choice_label = choice_kcfg;
      kcfg->choice_value = index++;
      if( strcmp(kcfg->label, choice_kcfg->value) == 0 )
        choice_kcfg->choice_value = kcfg->choice_value;
    }
    
    return pnt;
}


/*
 * This function grabs one text token from the input buffer
 * and returns a pointer to a copy of just the identifier.
 * This can be either a variable name (i.e. CONFIG_NET),
 * or it could be the default value for the option.
 */
static char * get_string(char *pnt, char ** labl)
{
  char newlabel[1024];
  char * pnt1;
  char * pnt2;

  if (*pnt == '\0') return pnt;

  pnt1 = newlabel;
  while(*pnt && *pnt != ' ' && *pnt != '\t')
    {
      *pnt1++ = *pnt++;
    }
  *pnt1++ = '\0';

  pnt2 = (char *) malloc(strlen(newlabel) + 1);
  strcpy(pnt2, newlabel);
  *labl = pnt2;

  if( *pnt ) pnt++;
  return pnt;
}


/*
 * Top level parse function.  Input pointer is one complete line from config.in
 * and the result is that we create a token that describes this line
 * and insert it into our linked list.
 */
void parse(char * pnt) {
  enum token tok;
  struct kconfig * kcfg;
  char tmpbuf[24],fake_if[1024];

  /*
   * Ignore comments and leading whitespace.
   */

  pnt = skip_whitespace(pnt);
  while( *pnt && (*pnt == ' ' || *pnt == '\t')) pnt++;
  if(! *pnt ) return;
  if( *pnt == '#' ) return;

  /*
   * Now categorize the next token.
   */
  tok = tok_unknown;
  if      (strncmp(pnt, "mainmenu_name", 13) == 0) 
    {
      tok = tok_menuname;
      pnt += 13;
    }
  else if      (strncmp(pnt, "source", 6) == 0) 
    {
      pnt += 7;
      pnt = skip_whitespace(pnt);
      do_source(pnt);
      return;
    }
  else if (strncmp(pnt, "mainmenu_option", 15) == 0) 
    {
      menus_seen++;
      tok = tok_menuoption;
      pnt += 15;
    }
  else if (strncmp(pnt, "$MAKE ", 6) == 0) 
    {
      tok = tok_make;
    }
  else if (strncmp(pnt, "comment", 7) == 0) 
    {
      tok = tok_comment;
      pnt += 7;
    }
  else if (strncmp(pnt, "choice", 6) == 0) 
    {
      tok = tok_choose;
      pnt += 6;
    }
  else if (strncmp(pnt, "define_bool", 11) == 0) 
    {
      tok = tok_define;
      pnt += 11;
    }
  else if (strncmp(pnt, "bool", 4) == 0) 
    {
      tok = tok_bool;
      pnt += 4;
    }
  else if (strncmp(pnt, "tristate", 8) == 0) 
    {
      tok = tok_tristate;
      pnt += 8;
    }
  else if (strncmp(pnt, "dep_tristate", 12) == 0) 
    {
      tok = tok_dep_tristate;
      pnt += 12;
    }
  else if (strncmp(pnt, "int", 3) == 0) 
    {
      tok = tok_int;
      pnt += 3;
    }
  else if (strncmp(pnt, "hex", 3) == 0) 
    {
      tok = tok_hex;
      pnt += 3;
    }
  else if (strncmp(pnt, "string", 6) == 0) 
    {
      tok = tok_string;
      pnt += 6;
    }
  else if (strncmp(pnt, "if", 2) == 0) 
    {
      tok = tok_if;
      pnt += 2;
    }
  else if (strncmp(pnt, "else", 4) == 0) 
    {
      tok = tok_else;
      pnt += 4;
    }
  else if (strncmp(pnt, "fi", 2) == 0) 
    {
      tok = tok_fi;
      pnt += 2;
    }
  else if (strncmp(pnt, "endmenu", 7) == 0) 
    {
      tok = tok_endmenu;
      pnt += 7;
    }

  if( tok == tok_unknown)
    {
      if( clast != NULL && clast->tok == tok_if 
          && strcmp(pnt,"then") == 0) return;
      if( current_file != NULL )
        fprintf(stderr, "unknown command=%s(%s %d)\n", pnt,
                current_file, lineno);
      else
        fprintf(stderr, "unknown command=%s(%d)\n", pnt,lineno);
      return;
    }

  /*
   * Allocate memory for this item, and attach it to the end of the linked
   * list.
   */
  kcfg = (struct kconfig *) malloc(sizeof(struct kconfig));
  memset(kcfg, 0, sizeof(struct kconfig));
  kcfg->tok = tok;
  if( clast != NULL )
    {
      clast->next = kcfg;
      clast = kcfg;
    }
  else
    {
      clast = config = kcfg;
    }

  pnt = skip_whitespace(pnt);

  /*
   * Now parse the remaining parts of the option, and attach the results
   * to the structure.
   */
  switch (tok)
    {
    case tok_choose:
      pnt = get_qstring(pnt, &kcfg->label);
      pnt = get_qstring(pnt, &kcfg->optionname);
      pnt = get_string(pnt, &kcfg->value);
      /*
       * Now we need to break apart the individual options into their
       * own configuration structures.
       */
      parse_choices(kcfg, kcfg->optionname);
      free(kcfg->optionname);
      sprintf(tmpbuf, "tmpvar_%d", choose_number++);
      kcfg->optionname = strdup(tmpbuf);
      break;
    case tok_define:
      pnt = get_string(pnt, &kcfg->optionname);
      if(*pnt == 'y' || *pnt == 'Y' ) kcfg->value = "1";
      if(*pnt == 'n' || *pnt == 'N' ) kcfg->value = "0";
      if(*pnt == 'm' || *pnt == 'M' ) kcfg->value = "2";
      break;
    case tok_menuname:
      pnt = get_qstring(pnt, &kcfg->label);
      break;
    case tok_bool:
    case tok_tristate:
      pnt = get_qstring(pnt, &kcfg->label);
      pnt = get_string(pnt, &kcfg->optionname);
      break;
    case tok_int:
    case tok_hex:
    case tok_string:
      pnt = get_qstring(pnt, &kcfg->label);
      pnt = get_string(pnt, &kcfg->optionname);
      pnt = get_string(pnt, &kcfg->value);
      break;
    case tok_dep_tristate:
      pnt = get_qstring(pnt, &kcfg->label);
      pnt = get_string(pnt, &kcfg->optionname);
      pnt = skip_whitespace(pnt);
      if( *pnt == '$') pnt++;
      pnt = get_string(pnt, &kcfg->depend.str);

      /*
       * Create a conditional for this object's dependency.
       *
       * We can't use "!= n" because this is internally converted to "!= 0"
       * and if UMSDOS depends on MSDOS which depends on FAT, then when FAT
       * is disabled MSDOS has 16 added to its value, making UMSDOS fully
       * available.  Whew.
       *
       * This is more of a hack than a fix.  Nested "if" conditionals are
       * probably affected too - that +/- 16 affects things in too many
       * places.  But this should do for now.
       */
      sprintf(fake_if,"[ \"$%s\" = \"y\" -o \"$%s\" = \"m\" ]; then",
                kcfg->depend.str,kcfg->depend.str);
      kcfg->cond = parse_if(fake_if);
      if(kcfg->cond == NULL )
        {
          exit(1);
        }
      break;
    case tok_comment:
      pnt = get_qstring(pnt, &kcfg->label);
      if( koption != NULL )
        {
          pnt = get_qstring(pnt, &kcfg->label);
          koption->label = kcfg->label;
          koption = NULL;
        }
      break;
    case tok_menuoption:
      if( strncmp(pnt, "next_comment", 12) == 0)
        {
          koption = kcfg;
        }
      else
        {
          pnt = get_qstring(pnt, &kcfg->label);
        }
      break;
    case tok_make:
      kcfg->value=strdup(pnt);
      break;
    case tok_else:
    case tok_fi:
    case tok_endmenu:
      break;
    case tok_if:
      /*
       * Conditionals are different.  For the first level parse, only
       * tok_if and tok_dep_tristate items have a ->cond chain attached.
       */
      kcfg->cond = parse_if(pnt);
      if(kcfg->cond == NULL )
        {
          exit(1);
        }
      break;
    default:
      exit(0);
    }
    
    return;
}

/*
 * Simple function to dump to the screen what the condition chain looks like.
 */
void dump_if(struct condition * cond)
{
  printf(" ");
  while(cond != NULL )
    {
      switch(cond->op){
      case op_eq:
        printf(" = ");
        break;
      case op_bang:
        printf(" ! ");
        break;
      case op_neq:
        printf(" != ");
        break;
      case op_and:
        printf(" -a ");
        break;
      case op_lparen:
        printf("(");
        break;
      case op_rparen:
        printf(")");
        break;
      case op_variable:
        printf("$%s", cond->variable.str);
        break;
      case op_constant:
        printf("'%s'", cond->variable.str);
        break;
      default:
        break;
      }
      cond = cond->next;
    }

  printf("\n");
}

static int do_source(char * filename)
{
  char buffer[1024];
  int  offset;
  int old_lineno;
  char * old_file;
  char * pnt;
  FILE * infile;

  if( strcmp(filename, "-") == 0 )
    infile = stdin;
  else
    infile = fopen(filename,"r");

  /*
   * If our cwd was in the scripts directory, we might have to go up one
   * to find the sourced file.
   */
  if(!infile) {
    strcpy (buffer, "../");
    strcat (buffer, filename);
    infile = fopen(buffer,"r");
  }

  if(!infile) {
    fprintf(stderr,"Unable to open file %s\n", filename);
    return 1;
  }
  old_lineno = lineno;
  lineno = 0;
  if( infile != stdin ) {
    old_file = current_file;
    current_file = filename;
  }
  offset = 0;
  while(1)
    {
      fgets(&buffer[offset], sizeof(buffer) - offset, infile);
      if(feof(infile)) break;

      /*
       * Strip the trailing return character.
       */
      pnt = buffer + strlen(buffer) - 1;
      if( *pnt == '\n') *pnt-- = 0;
      lineno++;
      if( *pnt == '\\' )
        {
          offset = pnt - buffer;
        }
      else
        {
          parse(buffer);
          offset = 0;
        }
    }
  fclose(infile);
  if( infile != stdin ) {
    current_file = old_file;
  }
  lineno = old_lineno;
  return 0;
}

int main(int argc, char * argv[])
{
#if 0
  char buffer[1024];
  char * pnt;
  struct kconfig * cfg;
  int    i;
#endif

  /*
   * Read stdin to get the top level script.
   */
  do_source("-");

  if( menus_seen == 0 )
    {
      fprintf(stderr,"The config.in file for this platform does not support\n");
      fprintf(stderr,"menus.\n");
      exit(1);
    }
  /*
   * Input file is now parsed.  Next we need to go through and attach
   * the correct conditions to each of the actual menu items and kill
   * the if/else/endif tokens from the list.  We also flag the menu items
   * that have other things that depend upon its setting.
   */
  fix_conditionals(config);

  /*
   * Finally, we generate the wish script.
   */
  dump_tk_script(config);

#if 0
  /*
   * Now dump what we have so far.  This is only for debugging so that
   * we can display what we think we have in the list.
   */
  for(cfg = config; cfg; cfg = cfg->next)
    {

      if(cfg->cond != NULL && cfg->tok != tok_if)
        dump_if(cfg->cond);

      switch(cfg->tok)
        {
        case tok_menuname:
          printf("main_menuname ");
          break;
        case tok_bool:
          printf("bool ");
          break;
        case tok_tristate:
          printf("tristate ");
          break;
        case tok_dep_tristate:
          printf("dep_tristate ");
          break;
        case tok_int:
          printf("int ");
          break;
        case tok_hex:
          printf("hex ");
          break;
        case tok_string:
          printf("istring ");
          break;
        case tok_comment:
          printf("comment ");
          break;
        case tok_menuoption:
          printf("menuoption ");
          break;
        case tok_else:
          printf("else");
          break;
        case tok_fi:
          printf("fi");
          break;
        case tok_if:
          printf("if");
          break;
        default:
        }

      switch(cfg->tok)
        {
        case tok_menuoption:
        case tok_comment:
        case tok_menuname:
          printf("%s\n", cfg->label);
          break;
        case tok_bool:
        case tok_tristate:
        case tok_dep_tristate:
        case tok_int:
        case tok_hex:
        case tok_string:
          printf("%s %s\n", cfg->label, cfg->optionname);
          break;
        case tok_if:
          dump_if(cfg->cond);
          break;
        case tok_nop:
        case tok_endmenu:
          break;
        default:
          printf("\n");
        }
    }
#endif

  return 0;

}