#include "lemon-conf.h"

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

static char *where = NULL;
static int first_time = 1;

void lexer_init(char *starts)
{
  where = starts;
}

int lexer_token(char **token, int *token_type)
{
  char *next;
  if(first_time)
    {
      next = where;
      first_time = 0;
    }
  else
    {
      next = NULL;
    }
  next = strtok(next," \t\n");

  if(next == NULL)
    return 0;

  char *newtoken = strdup(next);

  if(strcmp(newtoken,"stanza") == 0)
    {
      *token_type = STANZA;
    }
  else if(strcmp(newtoken,"{") == 0)
    {
      *token_type = LBRACE;
    }
  else if(strcmp(newtoken,"}") == 0)
    {
      *token_type = RBRACE;
    }
  else if(strcmp(newtoken,";") == 0)
    {
      *token_type = SEMICOLON;
    }
  else if(strcmp(newtoken,"=") == 0)
    {
      *token_type = EQUAL;
    }
  else // must be IDENTIFIER, NUMBER, OR STRING
    {
      if( (*newtoken == '"') && (*(newtoken+strlen(newtoken)-1) == '"') )
	{
	  *token_type = STRING;
	}
      else if(isdigit(*newtoken))
	{
	  int i;
	  for(i=0;i<strlen(newtoken);i++)
	    {
	      if(!isdigit(*(newtoken+i)))
		{
		  fprintf(stderr,"Lexer error: token '%s' begins with digit, but has non-digit embedded.\n",newtoken);
		  exit(2);
		}
	    }
	  *token_type = NUMBER;
	}
	else // only possibility is an identifier
	  {
	    int i;
	    for(i=0;i<strlen(newtoken);i++)
	      {
		if(!isalnum(*(newtoken+i)) && *(newtoken+i) != '_')
		  {
		    fprintf(stderr,"Lexer error: token '%s' must be an identifier, but has alphabetical/numeric/underscore embedded.\n",newtoken);
		    exit(2);
		  }
	      }
	    *token_type = IDENTIFIER;
	  }
    }
  *token = newtoken;
  return 1;
}