/*
 * parser.c, SJ
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <piler.h>


struct _state parse_message(struct session_data *sdata, struct __config *cfg){
   FILE *f;
   char buf[MAXBUFSIZE];
   struct _state state;
   int i, len;

   init_state(&state);

   f = fopen(sdata->ttmpfile, "r");
   if(!f){
      syslog(LOG_PRIORITY, "%s: cannot open", sdata->ttmpfile);
      return state;
   }


   state.mfd = open(sdata->tmpframe, O_CREAT|O_RDWR, S_IRUSR|S_IWUSR);
   if(state.mfd == -1){
      syslog(LOG_PRIORITY, "%s: cannot open frame file: %s", sdata->ttmpfile, sdata->tmpframe);
      return state;
   }


   while(fgets(buf, sizeof(buf)-1, f)){
      parse_line(buf, &state, sdata, cfg);
   }

   close(state.mfd); state.mfd = 0;
   fclose(f);


   free_list(state.boundaries);
   free_list(state.rcpt);

   trimBuffer(state.b_subject);
   fixupEncodedHeaderLine(state.b_subject);


   for(i=1; i<=state.n_attachments; i++){
      digest_file(state.attachments[i].internalname, &(state.attachments[i].digest[0]));
      fixupEncodedHeaderLine(state.attachments[i].filename);

      if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: attachment list: i:%d, name=*%s*, type: *%s*, size: %d, int.name: %s, digest: %s", sdata->ttmpfile, i, state.attachments[i].filename, state.attachments[i].type, state.attachments[i].size, state.attachments[i].internalname, state.attachments[i].digest);
   }


   if(state.message_id[0] == 0) snprintf(state.message_id, SMALLBUFSIZE-1, "null");

   len = strlen(state.b_from);
   if(state.b_from[len-1] == ' ') state.b_from[len-1] = '\0';

   len = strlen(state.b_to);
   if(state.b_to[len-1] == ' ') state.b_to[len-1] = '\0';

   syslog(LOG_PRIORITY, "%s: from=%s, to=%s, subj=%s, message-id=%s", sdata->ttmpfile, state.b_from, state.b_to, state.b_subject, state.message_id);

   return state;
}


int parse_line(char *buf, struct _state *state, struct session_data *sdata, struct __config *cfg){
   char *p, puf[SMALLBUFSIZE];
   int x, len, b64_len, boundary_line=0;

   state->line_num++;
   len = strlen(buf);

   //printf("buf: %s", buf);

   if(state->message_rfc822 == 0 && (buf[0] == '\r' || buf[0] == '\n') ){
      state->message_state = MSG_BODY;

      if(state->is_header == 1) state->is_header = 0;
      state->is_1st_header = 0;
   }


   if(state->message_state == MSG_BODY && state->fd != -1 && is_item_on_string(state->boundaries, buf) == 0){
      //printf("dumping: %s", buf);
      write(state->fd, buf, len);
      state->attachments[state->n_attachments].size += len;
   }
   else {
      state->saved_size += len;
      //printf("%s", buf);
      write(state->mfd, buf, len);
   }


   if(state->message_state == MSG_BODY && state->has_to_dump == 1 &&  state->pushed_pointer == 0){
      //printf("####name: %s, type: %s, base64: %d\n", state->filename, state->type, state->base64);

      state->pushed_pointer = 1;


      // this is a real attachment to dump
      if(state->base64 == 1 && strlen(state->filename) > 5 && strlen(state->type) > 3 && state->n_attachments < MAX_ATTACHMENTS-1){
         state->n_attachments++;

         snprintf(state->attachments[state->n_attachments].filename, TINYBUFSIZE-1, "%s", state->filename);
         snprintf(state->attachments[state->n_attachments].type, TINYBUFSIZE-1, "%s", state->type);
         snprintf(state->attachments[state->n_attachments].internalname, TINYBUFSIZE-1, "%s.a%d", sdata->ttmpfile, state->n_attachments);

         //printf("DUMP FILE: %s\n", state->attachments[state->n_attachments].internalname);
         state->fd = open(state->attachments[state->n_attachments].internalname, O_CREAT|O_RDWR, S_IRUSR|S_IWUSR);
         if(state->fd == -1){

            state->attachments[state->n_attachments].size = 0;
            memset(state->attachments[state->n_attachments].type, 0, TINYBUFSIZE);
            memset(state->attachments[state->n_attachments].filename, 0, TINYBUFSIZE);
            memset(state->attachments[state->n_attachments].internalname, 0, TINYBUFSIZE);
            memset(state->attachments[state->n_attachments].digest, 0, 2*DIGEST_LENGTH+1);

            syslog(LOG_PRIORITY, "%s: error opening %s", sdata->ttmpfile, state->attachments[state->n_attachments].internalname);

            state->n_attachments--;
            state->has_to_dump = 0;

         }
         else {
            snprintf(puf, sizeof(puf)-1, "ATTACHMENT_POINTER_%s.a%d_XXX_PILER", sdata->ttmpfile, state->n_attachments);
            write(state->mfd, puf, strlen(puf));
            //printf("%s", puf);
         }
      }
      else {
         state->has_to_dump = 0;
      }

   }



   if(*buf == '.' && *(buf+1) == '.') buf++;

   /* undefined message state */
   if(state->is_header == 1 && buf[0] != ' ' && buf[0] != '\t' && strchr(buf, ':')) state->message_state = MSG_UNDEF;

   /* skip empty lines */

   if(state->message_rfc822 == 0 && (buf[0] == '\r' || buf[0] == '\n') ){
      return 0;
   }

   trimBuffer(buf);


   /* skip the first line, if it's a "From <email address> date" format */
   if(state->line_num == 1 && strncmp(buf, "From ", 5) == 0) return 0;

   if(state->is_header == 0 && buf[0] != ' ' && buf[0] != '\t') state->message_state = MSG_BODY;

   if((state->content_type_is_set == 0 || state->is_header == 1) && strncasecmp(buf, "Content-Type:", strlen("Content-Type:")) == 0) state->message_state = MSG_CONTENT_TYPE;
   else if(strncasecmp(buf, "Content-Transfer-Encoding:", strlen("Content-Transfer-Encoding:")) == 0) state->message_state = MSG_CONTENT_TRANSFER_ENCODING;
   else if(strncasecmp(buf, "Content-Disposition:", strlen("Content-Disposition:")) == 0) state->message_state = MSG_CONTENT_DISPOSITION;


   if(state->message_state == MSG_CONTENT_TYPE || state->message_state == MSG_CONTENT_TRANSFER_ENCODING) state->is_header = 1;


   /* header checks */

   if(state->is_header == 1){

      if(strncasecmp(buf, "From:", strlen("From:")) == 0) state->message_state = MSG_FROM;
      else if(strncasecmp(buf, "To:", 3) == 0) state->message_state = MSG_TO;
      else if(strncasecmp(buf, "Cc:", 3) == 0) state->message_state = MSG_CC;
      else if(strncasecmp(buf, "Message-Id:", 11) == 0) state->message_state = MSG_MESSAGE_ID;
      else if(strncasecmp(buf, "Subject:", strlen("Subject:")) == 0) state->message_state = MSG_SUBJECT;
      else if(strncasecmp(buf, "Date:", strlen("Date:")) == 0 && sdata->sent == 0) sdata->sent = parse_date_header(buf);

      if(state->message_state == MSG_MESSAGE_ID && state->message_id[0] == 0){
         p = strchr(buf+11, ' ');
         if(p) p = buf + 12;
         else p = buf + 11;

         snprintf(state->message_id, SMALLBUFSIZE-1, "%s", p);
      }

      /* we are interested in only From:, To:, Subject:, Received:, Content-*: header lines */
      if(state->message_state <= 0) return 0;
   }


   if((p = strcasestr(buf, "boundary"))){
      x = extract_boundary(p, state);
   }


   if(state->is_1st_header == 1 && state->message_state == MSG_SUBJECT && strlen(state->b_subject) + strlen(buf) < MAXBUFSIZE-1){

      if(state->b_subject[0] == '\0'){
         strncat(state->b_subject, buf+strlen("Subject:"), MAXBUFSIZE-1);
      }
      else {

         p = strrchr(state->b_subject, ' ');
         if(p && ( strcasestr(p+1, "?Q?") || strcasestr(p+1, "?B?") ) ){
            strncat(state->b_subject, buf+1, MAXBUFSIZE-1);
         }
         else strncat(state->b_subject, buf, MAXBUFSIZE-1);

      }

   }


   /* Content-type: checking */

   if(state->message_state == MSG_CONTENT_TYPE){
      state->message_rfc822 = 0;

      /* extract Content type */

      p = strchr(buf, ':');
      if(p){
         p++;
         if(*p == ' ' || *p == '\t') p++;
         snprintf(state->type, TINYBUFSIZE-1, "%s", p);
         state->content_type_is_set = 1;
         p = strchr(state->type, ';');
         if(p) *p = '\0';
      }


      if(strcasestr(buf, "text/plain") ||
         strcasestr(buf, "multipart/mixed") ||
         strcasestr(buf, "multipart/alternative") ||
         strcasestr(buf, "multipart/report") ||
         strcasestr(buf, "message/delivery-status") ||
         strcasestr(buf, "text/rfc822-headers") ||
         strcasestr(buf, "message/rfc822") ||
         strcasestr(buf, "application/ms-tnef")
      ){
         state->textplain = 1;
      }
      else if(strcasestr(buf, "text/html")){
         state->texthtml = 1;
      }

      /* switch (back) to header mode if we encounterd an attachment with "message/rfc822" content-type */

      if(strcasestr(buf, "message/rfc822")){
         state->message_rfc822 = 1;
         state->is_header = 1;
      }


      if(strcasestr(buf, "charset") && strcasestr(buf, "UTF-8")) state->utf8 = 1;
   }


   if((state->message_state == MSG_CONTENT_TYPE || state->message_state == MSG_CONTENT_DISPOSITION) && strlen(state->filename) < 5){
      extractNameFromHeaderLine(buf, "name", state->filename);
   }


   if(state->message_state == MSG_CONTENT_TRANSFER_ENCODING){
      if(strcasestr(buf, "base64")) state->base64 = 1;
      if(strcasestr(buf, "quoted-printable")) state->qp = 1;
   }



   /* boundary check, and reset variables */

   boundary_line = is_item_on_string(state->boundaries, buf);

   if(!strstr(buf, "boundary=") && !strstr(buf, "boundary =") && boundary_line == 1){
      state->content_type_is_set = 0;

      if(state->has_to_dump == 1){
         if(state->fd != -1) close(state->fd);
         state->fd = -1;
      }


      state->has_to_dump = 1;

      state->base64 = 0; state->textplain = 0; state->texthtml = state->octetstream = 0;
      state->skip_html = 0;
      state->utf8 = 0;
      state->qp = 0;

      state->realbinary = 0;

      state->pushed_pointer = 0;

      memset(state->filename, 0, TINYBUFSIZE);
      memset(state->type, 0, TINYBUFSIZE);

      state->message_state = MSG_UNDEF;

      return 0;      
   }

   if(boundary_line == 1){ return 0; }


   /* end of boundary check */


   /* skip irrelevant headers */
   if(state->is_header == 1 && state->message_state != MSG_FROM && state->message_state != MSG_TO && state->message_state != MSG_CC) return 0;


   /* don't process body if it's not a text or html part */
   if(state->message_state == MSG_BODY && state->textplain == 0 && state->texthtml == 0) return 0;


   if(state->base64 == 1 && state->message_state == MSG_BODY){
      b64_len = decodeBase64(buf);
      fixupBase64EncodedLine(buf, state);
   }


   if(state->texthtml == 1 && state->message_state == MSG_BODY) markHTML(buf, state);

   if(state->message_state == MSG_BODY){
      if(state->qp == 1)   decodeQP(buf);
      if(state->utf8 == 1) decodeUTF8(buf);
   }

   decodeURL(buf);

   if(state->texthtml == 1) decodeHTML(buf);


   translateLine((unsigned char*)buf, state);

   reassembleToken(buf);


   if(state->is_header == 1) p = strchr(buf, ' ');
   else p = buf;

   //printf("a: *%s*\n", buf);

   do {
      memset(puf, 0, sizeof(puf));
      p = split(p, ' ', puf, sizeof(puf)-1);

      if(puf[0] == '\0') continue;

      degenerateToken((unsigned char*)puf);

      if(puf[0] == '\0') continue;

      strncat(puf, " ", sizeof(puf)-1);

      if(strncasecmp(puf, "http://", 7) == 0 || strncasecmp(puf, "https://", 8) == 0) fixURL(puf);

      if(state->is_header == 0 && strncmp(puf, "URL*", 4) && (puf[0] == ' ' || strlen(puf) > MAX_WORD_LEN || isHexNumber(puf)) ) continue;


      len = strlen(puf);

      if(state->message_state == MSG_FROM && strchr(puf, '@') && state->is_1st_header == 1 && state->b_from[0] == '\0' && strlen(state->b_from) < SMALLBUFSIZE-len-1)
         memcpy(&(state->b_from[strlen(state->b_from)]), puf, len);

      else if((state->message_state == MSG_TO || state->message_state == MSG_CC) && state->is_1st_header == 1 && strchr(puf, '@') && strlen(state->b_to) < SMALLBUFSIZE-len-1){

         if(is_string_on_list(state->rcpt, puf) == 0){
            append_list(&(state->rcpt), puf);
            memcpy(&(state->b_to[strlen(state->b_to)]), puf, len);
         }
      }
      else if(state->message_state == MSG_BODY && strlen(state->b_body) < BIGBUFSIZE-len-1)
         memcpy(&(state->b_body[strlen(state->b_body)]), puf, len);

   } while(p);

   return 0;
}