/* Copyright 1996 by Eric S. Raymond
 * All rights reserved.
 * For license terms, see the file COPYING in this directory.
 */

/***********************************************************************
  module:       driver.c
  project:      popclient
  programmer:   Eric S. Raymond
  description:  Generic driver for mail fetch method protocols

 ***********************************************************************/

#include  <config.h>
#include  <varargs.h>

#include  <stdio.h>
#if defined(STDC_HEADERS)
#include  <string.h>
#endif
#if defined(HAVE_UNISTD_H)
#include  <unistd.h>
#endif

#include  <sys/time.h>
#include  <ctype.h>
#include  <errno.h>

#include  "socket.h"
#include  "popclient.h"

static struct method *protocol;

char tag[TAGLEN];
static int tagnum;
#define GENSYM	(sprintf(tag, "a%04d", ++tagnum), tag)

/*********************************************************************
  function:      do_protocol
  description:   retrieve messages from the specified mail server
                 using a given set of methods

  arguments:     
    queryctl     fully-specified options (i.e. parsed, defaults invoked,
                 etc).
    proto        protocol method pointer

  return value:  exit code from the set of PS_.* constants defined in 
                 popclient.h
  calls:
  globals:       reads outlevel.
 *********************************************************************/

int do_protocol(queryctl, proto)
struct hostrec *queryctl;
struct method *proto;
{
    int ok, len;
    int mboxfd;
    char buf [POPBUFSIZE];
    int socket;
    int first,number,count;

    tagnum = 0;
    protocol = proto;

    /* open stdout or the mailbox, locking it if it is a folder */
    if (queryctl->output == TO_FOLDER || queryctl->output == TO_STDOUT) 
	if ((mboxfd = openuserfolder(queryctl)) < 0) 
	    return(PS_IOERR);
    
    /* open the socket */
    if ((socket = Socket(queryctl->servername,protocol->port)) < 0) {
	perror("do_protocol: socket");
	ok = PS_SOCKET;
	goto closeUp;
    }

    /* accept greeting message from server */
    ok = (protocol->parse_response)(buf, socket);
    if (ok != 0) {
	if (ok != PS_SOCKET)
	    gen_transact(socket, protocol->exit_cmd);
	close(socket);
	goto closeUp;
    }

    /* print the greeting */
    if (outlevel > O_SILENT && outlevel < O_VERBOSE) 
	fprintf(stderr,"%s greeting: %s\n", protocol->name, buf);

    /* try to get authorized to fetch mail */
    ok = (protocol->getauth)(socket, queryctl, buf);
    if (ok == PS_ERROR)
	ok = PS_AUTHFAIL;
    if (ok != 0)
	goto cleanUp;

    /* compute count and first */
    if ((*protocol->getrange)(socket, queryctl, &count, &first) != 0)
	goto cleanUp;

    /* show them how many messages we'll be downloading */
    if (outlevel > O_SILENT && outlevel < O_VERBOSE)
	if (first > 1) 
	    fprintf(stderr,"%d messages in folder, %d new messages.\n", 
		    count, count - first + 1);
	else
	    fprintf(stderr,"%d %smessages in folder.\n", count, ok ? "" : "new ");

    if (count > 0) { 
	for (number = queryctl->flush ? 1 : first;  number<=count; number++) {

	    char *cp;

	    /* open the mail pipe if we're using an MDA */
	    if (queryctl->output == TO_MDA
		&& (queryctl->fetchall || number >= first)) {
		ok = (mboxfd = openmailpipe(queryctl)) < 0 ? -1 : 0;
		if (ok != 0)
		    goto cleanUp;
	    }
           
	    if (queryctl->flush && number < first && !queryctl->fetchall) 
		ok = 0;  /* no command to send here, will delete message below */
	    else
	    {
		(*protocol->fetch)(socket, number, linelimit, &len);
		if (outlevel == O_VERBOSE)
		    if (protocol->delimited)
		    fprintf(stderr,"fetching message %d (delimited)\n",number);
		else
		    fprintf(stderr,"fetching message %d (%d bytes)\n",number,len);
		ok = gen_readmsg(socket,mboxfd,len,protocol->delimited,
				  queryctl->servername,
				  queryctl->output == TO_MDA, 
				  queryctl->rewrite);
		if (protocol->trail)
		    (*protocol->trail)(socket, queryctl, number);
		if (ok != 0)
		    goto cleanUp;
	    }

	    /* maybe we delete this message now? */
	    if ((number < first && queryctl->flush) || !queryctl->keep) {
		if (outlevel > O_SILENT && outlevel < O_VERBOSE) 
		    fprintf(stderr,"flushing message %d\n", number);
		else
		    ;
		ok = gen_transact(socket, protocol->delete_cmd, number);
		if (ok != 0)
		    goto cleanUp;
	    }

	    /* close the mail pipe, we'll reopen before next message */
	    if (queryctl->output == TO_MDA
		&& (queryctl->fetchall || number >= first)) {
		ok = closemailpipe(mboxfd);
		if (ok != 0)
		    goto cleanUp;
	    }
	}

	/* remove all messages flagged for deletion */
        if (!queryctl->keep && protocol->expunge_cmd)
	{
	    ok = gen_transact(socket, protocol->expunge_cmd);
	    if (ok != 0)
		goto cleanUp;
        }

	ok = gen_transact(socket, protocol->exit_cmd);
	if (ok == 0)
	    ok = PS_SUCCESS;
	close(socket);
	goto closeUp;
    }
    else {
	ok = gen_transact(socket, protocol->exit_cmd);
	if (ok == 0)
	    ok = PS_NOMAIL;
	close(socket);
	goto closeUp;
    }

cleanUp:
    if (ok != 0 && ok != PS_SOCKET)
	gen_transact(socket, protocol->exit_cmd);

closeUp:
    if (queryctl->output == TO_FOLDER)
	if (closeuserfolder(mboxfd) < 0 && ok == 0)
	    ok = PS_IOERR;
    
    if (ok == PS_IOERR || ok == PS_SOCKET) 
	perror("do_protocol: cleanUp");

    return(ok);
}

/*********************************************************************
  function:      gen_send
  description:   Assemble command in print style and send to the server

  arguments:     
    socket       socket to which the server is connected.
    fmt          printf-style format

  return value:  none.
  calls:         SockPuts.
  globals:       reads outlevel.
 *********************************************************************/

void gen_send(socket, fmt, va_alist)
int socket;
const char *fmt;
va_dcl {

  char buf [POPBUFSIZE];
  va_list ap;

  if (protocol->tagged)
      (void) sprintf(buf, "%s ", GENSYM);
  else
      buf[0] = '\0';

  va_start(ap);
  vsprintf(buf + strlen(buf), fmt, ap);
  va_end(ap);

  SockPuts(socket, buf);

  if (outlevel == O_VERBOSE)
    fprintf(stderr,"> %s\n", buf);
}

/*********************************************************************
  function:      gen_transact
  description:   Assemble command in print style and send to the server.
                 then accept a protocol-dependent response.

  arguments:     
    socket       socket to which the server is connected.
    fmt          printf-style format

  return value:  none.
  calls:         SockPuts, imap_ok.
  globals:       reads outlevel.
 *********************************************************************/

int gen_transact(socket, fmt, va_alist)
int socket;
const char *fmt;
va_dcl {

  int ok;
  char buf [POPBUFSIZE];
  va_list ap;

  if (protocol->tagged)
      (void) sprintf(buf, "%s ", GENSYM);
  else
      buf[0] = '\0';

  va_start(ap);
  vsprintf(buf + strlen(buf), fmt, ap);
  va_end(ap);

  SockPuts(socket, buf);

  if (outlevel == O_VERBOSE)
    fprintf(stderr,"> %s\n", buf);

  ok = (protocol->parse_response)(buf,socket);
  if (ok != 0 && outlevel > O_SILENT && outlevel < O_VERBOSE)
    fprintf(stderr,"%s\n",buf);

  return(ok);
}

/*********************************************************************
  function:      gen_readmsg
  description:   Read the message content 

 as described in RFC 1225.
  arguments:     
    socket       ... to which the server is connected.
    mboxfd       open file descriptor to which the retrieved message will
                 be written.
    len          length of text 
    pophost      name of the POP host 
    topipe       true if we're writing to the system mailbox pipe.

  return value:  zero if success else PS_* return code.
  calls:         SockGets.
  globals:       reads outlevel. 
 *********************************************************************/

int gen_readmsg (socket,mboxfd,len,delimited,pophost,topipe,rewrite)
int socket;
int mboxfd;
long len;
int delimited;
char *pophost;
int topipe;
int rewrite;
{ 
  char buf [MSGBUFSIZE]; 
  char *bufp;
  char savec;
  char fromBuf[MSGBUFSIZE];
  int n;
  int needFrom;
  int inheaders;
  int lines,sizeticker;
  time_t now;
  /* This keeps the retrieved message count for display purposes */
  static int msgnum = 0;  

  /* set up for status message if outlevel allows it */
  if (outlevel > O_SILENT && outlevel < O_VERBOSE) {
    fprintf(stderr,"reading message %d",++msgnum);
    /* won't do the '...' if retrieved messages are being sent to stdout */
    if (mboxfd == 1)
      fputs(".\n",stderr);
    else
      ;
  }
  else
    ;

  /* read the message content from the server */
  inheaders = 1;
  lines = 0;
  sizeticker = MSGBUFSIZE;
  while (delimited || len > 0) {
    if ((n = SockGets(socket,buf,sizeof(buf))) < 0)
      return(PS_SOCKET);
    len -= n;
    bufp = buf;
    if (buf[0] == '\r' || buf[0] == '\n')
      inheaders = 0;
    if (*bufp == '.') {
      bufp++;
      if (delimited && *bufp == 0)
        break;  /* end of message */
    }
    strcat(bufp,"\n");
     
    /* Check for Unix 'From' header, and add a bogus one if it's not
       present -- only if not using an MDA.
       XXX -- should probably parse real From: header and use its 
              address field instead of bogus 'POPmail' string. 
    */
    if (!topipe && lines == 0) {
      if (strlen(bufp) >= strlen("From ")) {
        savec = *(bufp + 5);
        *(bufp + 5) = 0;
        needFrom = strcmp(bufp,"From ") != 0;
        *(bufp + 5) = savec;
      }
      else
        needFrom = 1;
      if (needFrom) {
        now = time(NULL);
        sprintf(fromBuf,"From POPmail %s",ctime(&now));
        if (write(mboxfd,fromBuf,strlen(fromBuf)) < 0) {
          perror("gen_readmsg: write");
          return(PS_IOERR);
        }
      }
    }

    /*
     * Edit some headers so that replies will work properly.
     */
    if (inheaders && rewrite)
      reply_hack(bufp, pophost);

    /* write this line to the file */
    if (write(mboxfd,bufp,strlen(bufp)) < 0) {
      perror("gen_readmsg: write");
      return(PS_IOERR);
    }

    sizeticker -= strlen(bufp);
    if (sizeticker <= 0) {
      if (outlevel > O_SILENT && outlevel < O_VERBOSE && mboxfd != 1)
        fputc('.',stderr);
      sizeticker = MSGBUFSIZE;
    }
    lines++;
  }

  if (!topipe) {
    /* The server may not write the extra newline required by the Unix
       mail folder format, so we write one here just in case */
    if (write(mboxfd,"\n",1) < 0) {
      perror("gen_readmsg: write");
      return(PS_IOERR);
    }
  }
  else {
    /* The mail delivery agent may require a terminator.  Write it if
       it has been defined */
#ifdef BINMAIL_TERM
    if (write(mboxfd,BINMAIL_TERM,strlen(BINMAIL_TERM)) < 0) {
      perror("gen_readmsg: write");
      return(PS_IOERR);
    }
#endif
    }

  /* finish up display output */
  if (outlevel == O_VERBOSE)
    fprintf(stderr,"(%d lines of message content)\n",lines);
  else if (outlevel > O_SILENT && mboxfd != 1) 
    fputs(".\n",stderr);
  else
    ;
  return(0);
}