/**---------------------------------------------------------------------------*/
// File: hudmail\mime.c
// A component of the Workflow system of subsidized contract administration.
// Copyright (c) 2001, Richard Heurtley. All rights reserved.
/**---------------------------------------------------------------------------*/
#include "common.h"
#include "mime.h"
/**---------------------------------------------------------------------------*/
#define DISPOSITION_NONE	(1)
#define DISPOSITION_INLINE	(2)
#define DISPOSITION_ATTACHMENT	(3)

#define ENCODING_7BIT		(1)
#define ENCODING_QUOTED		(2)
#define ENCODING_BASE64		(3)

#define TYPE_TEXTPLAIN		(1)
#define TYPE_MESSAGERFC822	(2)
/**---------------------------------------------------------------------------*/
typedef struct
{
 int type;
 int disposition;
 int encoding;
 char *fromp;
} LOCAL;
/**---------------------------------------------------------------------------*/
static LOCAL l;
/**---------------------------------------------------------------------------*/
// reset message coding attributes

static void Defaults(void)
{
 l.type = TYPE_TEXTPLAIN;
 l.encoding = ENCODING_7BIT;
 l.disposition = DISPOSITION_NONE;
 RETURNVOID;
}
/**---------------------------------------------------------------------------*/
static int MessageParse
(
 LIST *linelistp,
 char *begboundp,
 char *endboundp,
 char *inboxpathp,
 char *recvpathp,
 int *ascnump
)
{
 int rv = 0;
 int nlines;
 unsigned char c0;
 unsigned char c1;
 unsigned char c2;
 unsigned char c3;
 unsigned char b0;
 unsigned char b1;
 unsigned char b2;
 unsigned char b3;
 unsigned char ch;
 unsigned char bytes[3];
 int byte;
 int nbytes;
 int i;
 unsigned char *p;
 FILE *filep;
 char *linep;
 char *line0p;
 char *line1p;
 char *line2p;
 char *line3p;
 LIST linelist;
 LISTLOOP lineloop;
 char filename[8+1+3+1];

 static char inboxpathfile[256];

 static unsigned char back[256];
 static unsigned char forward[] =
  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"		// 26
  "abcdefghijklmnopqrstuvwxyz"		// 52
  "0123456789"				// 62
  "+/";					// 64

 if (!back[0])
 {
  memset(back, 0xff, sizeof(back));
  for (i = 0; i < 64; i++)
   back[forward[i]] = i;
  back['='] = 0;		// '=' maps to zero
 }

 ListZero(&linelist, 8);
 filep = 0;
/**---------------------------------------------------------------------------*/
// get attachment

 for (;;)
 {
  linep = ListCurObjGet(linelistp);
  if (!linep)
   break;
  if (begboundp && streq(linep, begboundp))
   break;
  if (endboundp && streq(linep, endboundp))
   break;
  ListObjAppend(&linelist, linep);
  ListNextObjGet(linelistp);
 }

 if
 (
  l.disposition != DISPOSITION_ATTACHMENT
  &&
  l.disposition != DISPOSITION_INLINE
 )
  goto EGRESS;

// nuke trailing blank lines

 for (;;)
 {
  linep = ListLastObjGet(&linelist);
  if (!linep)
   break;
  if (linep[0])
   break;
  ListObjDelete(&linelist, linep);
 }

// delete trailing "..Y" lines

 line0p = ListLastObjGet(&linelist);
 if (line0p && streq(line0p, "Y "))
 {
  line1p = ListPrevObjGet(&linelist);
  if (line1p && streq(line1p, ". "))
  {
   line2p = ListPrevObjGet(&linelist);
   if (line2p && streq(line2p, ". "))
   {
    ListObjDelete(&linelist, line0p);
    ListObjDelete(&linelist, line1p);
    ListObjDelete(&linelist, line2p);
   }
  }
 }

// nuke trailing blank lines again

 for (;;)
 {
  linep = ListLastObjGet(&linelist);
  if (!linep)
   break;
  if (linep[0])
   break;
  ListObjDelete(&linelist, linep);
 }
/**---------------------------------------------------------------------------*/
// delete destination and subject lines

// Posted: Mon, 12 Nov 2001 11:00:01 -0500 (EST)
// From:   TRACMTEST
// To:     TRACM08941
// Subj:   HUD CFS TRACS DATA 011112 124373
// 
// TRACM08941 
//  
// HUD CFS TRACS DATA 011112 124373 
//  
// PROCESSING MAILBOX ID: @*@ TRACM08941TRACM00105MATTV2.0.1.A000011004200108040211122001101227COLNYSQ11KATHY RICHARDS P O BOX 467         IRONWOOD       MI49938000000 

 ListFirstObj(&linelist);

 linep = ListNextObjGet(&linelist);
 if (!linep || !strieqz(linep, "posted:"))
  goto NODELETE;
 linep = ListNextObjGet(&linelist);
 if (!linep || !strieqz(linep, "from:"))
  goto NODELETE;
 linep = ListNextObjGet(&linelist);
 if (!linep || !strieqz(linep, "to:"))
  goto NODELETE;
 linep = ListNextObjGet(&linelist);
 if (!linep || !strieqz(linep, "subj:"))
  goto NODELETE;
 linep = ListNextObjGet(&linelist);
 if (!linep || !streq(linep, ""))
  goto NODELETE;

 line0p = ListNextObjGet(&linelist);
 if (!line0p || !streqz(line0p, "TRACM"))	// destination
  goto NODELETE;
 line1p = ListNextObjGet(&linelist);
 if (!line1p || !streq(line1p, " "))
  goto NODELETE;
 line2p = ListNextObjGet(&linelist);
 if (!line2p || !streqz(line2p, "HUD"))		// subject
  goto NODELETE;
 line3p = ListNextObjGet(&linelist);
 if (!line3p || !streq(line3p, " "))
  goto NODELETE;

 ListObjDelete(&linelist, line0p);
 ListObjDelete(&linelist, line1p);
 ListObjDelete(&linelist, line2p);
 ListObjDelete(&linelist, line3p);

NODELETE:
/**---------------------------------------------------------------------------*/
// ignore HUD attached message

 if (linelist.nnodes == 2)
 {
  line0p = ListFirstObjGet(&linelist);
  line1p = ListNextObjGet(&linelist);
  if
  (
   stristr(line0p, "mailbox")
   &&
   stristr(line0p, "tracmhelp")
   &&
   stristr(line1p, "right-click")
   &&
   stristr(line1p, "attachment")
  )
  goto EGRESS;
 }

 if (!linelist.nnodes)			// if no data
  goto EGRESS;				// skip attachment
/**---------------------------------------------------------------------------*/
// save the attachment

 for (;;)				// get the next filename
 {
  sprintf(filename, "%5.5d.asc", *ascnump);
  strbuild(inboxpathfile, inboxpathp, SEP, filename, 0);
  (*ascnump)++;
  if (*ascnump >= 100000)
   *ascnump = 0;
  if (!FileExist(inboxpathfile))
   break;
 }

 filep = fopen(inboxpathfile, "wb");
 IF(!filep,Unable to create file.);

 nlines = 0;

 if (l.encoding == ENCODING_7BIT)
 {
  LISTLOOPL(line)
   fprintf(filep, "%s\r\n", linep);
  nlines = linelist.nnodes;
 }
 else
 if (l.encoding == ENCODING_QUOTED)
 {
  p = ListFirstObjGet(&linelist);
  for (;;)				// infinite loop
  {
   if (!*p)				// hard break
   {
    fprintf(filep, "%s", "\r\n");
    nlines++;
    goto LINENEXT;
   }
   else
   if (*p != '=')			// regular character
   {
    fprintf(filep, "%c", *p);
    p++;
    continue;
   }
   else
   {
    p++;				// skip '='
    if (*(p+0) && *(p+1))		// if two digits
    {
     c0 = *p++;
     c0 = toupper(c0);
     if (c0 >= 'A')
      c0 -= 'A' - ('9' + 1);
     c0 &= 0x0f;

     c1 = *p++;
     c1 = toupper(c1);
     if (c1 >= 'A')
      c1 -= 'A' - ('9' + 1);
     c1 &= 0x0f;

     ch = (c0 << 4) | c1;

     if (ch == '\n')
     {
      fprintf(filep, "%c", '\r');
      nlines++;
     }

     fprintf(filep, "%c", ch);

     continue;
    }
   }

// soft breaks fall through

LINENEXT:

   p = ListNextObjGet(&linelist);	// get next line
   if (!p)				// if no more data
    break;				// break out of infinite loop

  }					// for (;;)
 }
 else
 if (l.encoding == ENCODING_BASE64)
 {
  p = ListFirstObjGet(&linelist);
  for (;;)				// infinite loop
  {
   if (*(p+0) && *(p+1) && *(p+2) && *(p+3))	// if there's a quad
   {
    c0 = *p++;
    c1 = *p++;
    c2 = *p++;
    c3 = *p++;
    b0 = back[c0];
    b1 = back[c1];
    b2 = back[c2];
    b3 = back[c3];
    bytes[0] = (b0 << 2) | (b1 >> 4);
    bytes[1] = (b1 << 4) | (b2 >> 2);
    bytes[2] = (b2 << 6) | (b3 >> 0);

    nbytes = 3;
    if (c2 == '=')
     nbytes--;
    if (c3 == '=')
     nbytes--;

    fwrite(bytes, 1, nbytes, filep);

    for (byte = 0; byte < nbytes; byte++)
    {
     if (bytes[byte] == '\n')
      nlines++;
    }
   }
   else					// no quad, get next line
   {
    p = ListNextObjGet(&linelist);	// get next line
    if (!p)				// if no more data
     break;				// break out of infinite loop
   }
  }					// for (;;)
 }

 fclose(filep);
 filep = 0;

 LOGF("Saved %d lines from %s as %s", nlines, l.fromp, filename);

 rv = FileCopy(inboxpathp, filename, recvpathp);
 IF(rv,Unable to copy file to receive directory.);

EGRESS:

 if (filep)
  fclose(filep);

 ListFree(&linelist);

 Defaults();		// reset message coding attributes

 RETURN(rv);
}
/**---------------------------------------------------------------------------*/
int MIMEParse
(
 LIST *linelistp,
 char *begboundp,
 char *endboundp,
 char *inboxpathp,
 char *recvpathp,
 int *ascnump
)
{
 int rv = 0;
 char *linep;
 char *p;
 char *fromp;
 char *boundp;

 static int nest;

 Defaults();

 nest++;
 if (nest == 1)
  l.fromp = "<unknown>";

 fromp = l.fromp;

 for (;;)
 {
  linep = ListCurObjGet(linelistp);
  if (!linep)
   goto EGRESS;

// this must be first because a null line matches strieqz()
// start parsing message on a blank line

  if (!linep[0])	
  {
   ListNextObjGet(linelistp);
   rv = MessageParse
   (
    linelistp,
    begboundp,
    endboundp,
    inboxpathp,
    recvpathp,
    ascnump
   );
   continue;
  }

// if end boundary then exit

  if (endboundp && streq(linep, endboundp))
  {
   ListNextObjGet(linelistp);			// get next line
   goto EGRESS;
  }

// get parameters

  if (strieqz(linep, "content-type: text/plain"))
  {
   l.type = TYPE_TEXTPLAIN;
   goto LINENEXT;
  }
  if (strieqz(linep, "content-type: message/rfc822"))
  {
   l.type = TYPE_MESSAGERFC822;
   goto LINENEXT;
  }
  if (strieqz(linep, "content-transfer-encoding: 7bit"))
  {
   l.encoding = ENCODING_7BIT;
   goto LINENEXT;
  }
  if (strieqz(linep, "content-transfer-encoding: base64"))
  {
   l.encoding = ENCODING_BASE64;
   goto LINENEXT;
  }
  if (strieqz(linep, "content-transfer-encoding: quoted-printable"))
  {
   l.encoding = ENCODING_QUOTED;
   goto LINENEXT;
  }
  if (strieqz(linep, "content-disposition: inline"))
  {
   l.disposition = DISPOSITION_INLINE;
   goto LINENEXT;
  }
  if (strieqz(linep, "content-disposition: attachment"))
  {
   l.disposition = DISPOSITION_ATTACHMENT;
   goto LINENEXT;
  }
  if (strieqz(linep, "from"))
  {
   l.fromp = "<unknown>";
   p = strchr(linep, ':');
   if (!p) goto LINENEXT;
   for (p++; *p && isspace(*p); p++);		// find beginning of string
   if (!*p) goto LINENEXT;
   l.fromp = p;
   goto LINENEXT;
  }
/**---------------------------------------------------------------------------*/
// nest on boundary strings

  if (stristr(linep, "boundary=\""))	
  {
   char *begboundp;
   char *endboundp;

   p = stristr(linep, "boundary=\"");
   p = strchr(p, '\"');
   if (!p) goto LINENEXT;
   boundp = ++p;
   p = strchr(boundp, '\"');
   if (!p) goto LINENEXT;
   *p = 0;

   begboundp = MemGet(2 + strlen(boundp)     + 1);
   endboundp = MemGet(2 + strlen(boundp) + 2 + 1);
   strcpy(begboundp, "--");
   strcat(begboundp, boundp);
   strcpy(endboundp, begboundp);
   strcat(endboundp, "--");

   ListNextObjGet(linelistp);				// get next line

   rv = MIMEParse				// returns at EOF or endboundp
   (
    linelistp,
    begboundp,
    endboundp,
    inboxpathp,
    recvpathp,
    ascnump
   );

   MemFree(begboundp);
   MemFree(endboundp);

   goto LINENEXT;
  }
/**---------------------------------------------------------------------------*/
LINENEXT:

  ListNextObjGet(linelistp);
 }				// for (;;)

EGRESS:

 l.fromp = fromp;

 nest--;

 RETURN(rv);
}