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

#include "eo_tokenizer.h"

%%{
   machine common;

   action inc_line {
      toknz->current_line += 1;
   }

   action save_start_line {
      toknz->token_start_line = toknz->current_line;
   }

   cr                = '\n';
   cr_neg            = "[^\n]";
   ws                = "[ \t\r]";
   newline           = cr @inc_line;
   ignore            = (0x00..0x20 - cr)* newline?;

   c_comment         = "/*" ( any | '\n' @inc_line )* :>> "*/";
   cpp_comment       = "//" (any - cr)* newline;
   comment           = ( c_comment | cpp_comment ) > save_start_line;

}%%

%%{
   machine eo_tokenizer;
   include common;

   access toknz->;
   variable p toknz->p;
   variable pe toknz->pe;
   variable eof toknz->eof;

   action show_comment {
      DBG("comment %03d:%03d", toknz->token_start_line, toknz->current_line);
   }

   action show_ignore {
      DBG("ignore %d (%d)", toknz->current_line, (toknz->te - toknz->ts));
   }

   action error {
      /* TODO find a more elegant way,
       *  -> cant't use $err() or $!error on scanner
       *  -> fgoto another machine to eat the line, ts is set to NULL
       */
      char buf[BUFSIZE];
      char *s, *d;
      for (s = fpc, d = buf; (s <= toknz->pe); s++)
        {
           if ( (int)*s == 13 || (int)*s == 10)
             break;
           *d++ = *s;
        }
      *d = '\0';
      ERR("error line %d : %s...", toknz->current_line, buf);
      toknz->cs = eo_tokenizer_error;
      fbreak;
   }

   main := |*
      ignore => show_ignore;
      comment => show_comment;
      any => error;
   *|;

}%%

%% write data;

Eina_Bool
eo_tokenizer_walk(Eo_Tokenizer *toknz, const char *source)
{
   INF("tokenize %s...", source);
   toknz->source = eina_stringshare_add(source);

   FILE *stream;

   int done = 0;
   int have = 0;

   stream = fopen(toknz->source, "r");
   if (!stream)
     {
        ERR("unable to read in %s", toknz->source);
        return EINA_FALSE;
     }

   %% write init;

   while (!done)
     {
        int len;
        int space;

        toknz->p = toknz->buf + have;
        space = BUFSIZE - have;

        if (space == 0)
          {
             ERR("out of buffer space");
             fclose(stream);
             exit(EXIT_FAILURE);
          }

        len = fread(toknz->p, 1, space, stream);
        if (len == 0) break;
        toknz->pe = toknz->p + len;

        if (len < space)
          {
             toknz->eof = toknz->pe;
             done = 1;
          }

        %% write exec;

        if ( toknz->cs == %%{ write error; }%% )
            break;

        if ( toknz->ts == 0 )
          have = 0;
        else
          {
             /* There is a prefix to preserve, shift it over. */
             have = toknz->pe - toknz->ts;
             memmove( toknz->buf, toknz->ts, have);
             toknz->te = toknz->buf + (toknz->te - toknz->ts);
             toknz->ts = toknz->buf;
          }
     }

   fclose(stream);

   return EINA_TRUE;
}

Eo_Tokenizer*
eo_tokenizer_get()
{
   Eo_Tokenizer *toknz = calloc(1, sizeof(Eo_Tokenizer));
   if (!toknz) return NULL;

   toknz->ts = NULL;
   toknz->te = NULL;
   /* toknz->top = 0; */
   toknz->source = NULL;
   toknz->max_nesting = 10;
   toknz->current_line = 1;
   toknz->current_nesting = 0;
   toknz->token_start_line = 0;

   return toknz;
}

void
eo_tokenizer_free(Eo_Tokenizer *toknz)
{
   if (toknz->source)
       eina_stringshare_del(toknz->source);

   free(toknz);
}