#include <unistd.h>
#include <sys/stat.h>
#include "env.h"
#include "genalloc.h"
#include "stralloc.h"
#include "buffer.h"
#include "getln.h"
#include "logmsg.h"
#include "open.h"
#include "lock.h"
#include "gfrom.h"
#include "str.h"
#include "exit.h"
#include "myctime.h"
#include "maildir.h"
#include "prioq.h"

char *mbox;
char *mboxtmp;

int rename(const char *,const char *); // stdio.h

stralloc filenames = {0};
prioq pq = {0};
prioq pq2 = {0};

stralloc line = {0};

stralloc ufline = {0};

char inbuf[BUFFER_INSIZE];
char outbuf[BUFFER_OUTSIZE];

#define WHO "maildir2mbox"

void die_nomem() { logmsg(WHO,111,FATAL,"out of memory"); }

int main()
{
 buffer bi;
 buffer bo;
 struct prioq_elt pe;
 int fdoldmbox;
 int fdnewmbox;
 int fd;
 int match;
 int fdlock;

 umask(077);

 mbox = env_get("MAIL");
 if (!mbox) logmsg(WHO,111,FATAL,"MAIL not set");
 mboxtmp = env_get("MAILTMP");
 if (!mboxtmp) logmsg(WHO,111,FATAL,"MAILTMP not set");

 if (maildir_chdir() == -1)
   logmsg(WHO,110,FATAL,"Can't changet maildir");
 maildir_clean(&filenames);
 if (maildir_scan(&pq,&filenames,1,1) == -1)
   logmsg(WHO,112,FATAL,"Can't read maidir");

 if (!prioq_min(&pq,&pe)) _exit(0); /* nothing new */

 fdlock = open_append(mbox);
 if (fdlock == -1)
   logmsg(WHO,111,FATAL,B("unable to lock: ",mbox));
 if (lock_ex(fdlock) == -1)
   logmsg(WHO,111,FATAL,B("unable to lock: ",mbox));

 fdoldmbox = open_read(mbox);
 if (fdoldmbox == -1)
   logmsg(WHO,112,FATAL,B("unable to read: ",mbox));

 fdnewmbox = open_trunc(mboxtmp);
 if (fdnewmbox == -1)
   logmsg(WHO,112,FATAL,B("unable to create: ",mboxtmp));

 buffer_init(&bi,read,fdoldmbox,inbuf,sizeof(inbuf));
 buffer_init(&bo,write,fdnewmbox,outbuf,sizeof(outbuf));

 switch (buffer_copy(&bo,&bi)) {
   case -2: logmsg(WHO,112,FATAL,B("unable to read: ",mbox));
   case -3: logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
 }

 while (prioq_min(&pq,&pe)) {
   prioq_delmin(&pq);
   if (!prioq_insert(&pq2,&pe)) die_nomem();

   fd = open_read(filenames.s + pe.id);
   if (fd == -1)
     logmsg(WHO,112,FATAL,B("unable to read: $MAILDIR/",filenames.s + pe.id));
   buffer_init(&bi,read,fd,inbuf,sizeof(inbuf));

   if (getln(&bi,&line,&match,'\n') != 0)
     logmsg(WHO,112,FATAL,B("unable to read: $MAILDIR/",filenames.s + pe.id));
   
   if (!stralloc_copys(&ufline,"From XXX ")) die_nomem();
   if (match)
     if (stralloc_starts(&line,"Return-Path: <")) {
       if (line.s[14] == '>') {
         if (!stralloc_copys(&ufline,"From MAILER-DAEMON ")) die_nomem();
       } else {
	       int i;
         if (!stralloc_ready(&ufline,line.len)) die_nomem();
         if (!stralloc_copys(&ufline,"From ")) die_nomem();

	 for (i = 14;i < line.len - 2;++i)
	   if ((line.s[i] == ' ') || (line.s[i] == '\t'))
	     ufline.s[ufline.len++] = '-';
	   else
	     ufline.s[ufline.len++] = line.s[i];
         if (!stralloc_cats(&ufline," ")) die_nomem();
	}
      }
   if (!stralloc_cats(&ufline,myctime(pe.dt))) die_nomem();
   if (buffer_put(&bo,ufline.s,ufline.len) == -1)
     logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));

   while (match && line.len) {
     if (gfrom(line.s,line.len))
       if (buffer_puts(&bo,">") == -1)
         logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
     if (buffer_put(&bo,line.s,line.len) == -1)
       logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
     if (!match) {
       if (buffer_puts(&bo,"\n") == -1)
         logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
       break;
     }
     if (getln(&bi,&line,&match,'\n') != 0)
       logmsg(WHO,112,FATAL,B("unable to read: $MAILDIR/",filenames.s + pe.id));
   }
   if (buffer_puts(&bo,"\n"))
     logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));

   close(fd);
 }

 if (buffer_flush(&bo) == -1)
   logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
 if (fsync(fdnewmbox) == -1)
   logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
 if (close(fdnewmbox) == -1) /* NFS dorks */
   logmsg(WHO,112,FATAL,B("unable to write to: ",mboxtmp));
 if (rename(mboxtmp,mbox) == -1)
   logmsg(WHO,112,FATAL,B("unable to move ",mboxtmp," to: ",mbox));
 
 while (prioq_min(&pq2,&pe)) {
   prioq_delmin(&pq2);
   if (unlink(filenames.s + pe.id) == -1)
     logmsg(WHO,0,WARN,B("$MAILDIR/",filenames.s + pe.id," will be delivered twice; unable to unlink"));
 }

 _exit(0);
}