#include <sys/types.h>

#include <time.h>

#include "datetime.h"

#include "fork.h"

#include "wait.h"

#include "fd.h"

#include "fmt.h"

#include "strerr.h"

#include "substdio.h"

#include "subfd.h"

#include "readwrite.h"

#include "exit.h"

#define FATAL "predate: fatal: "

static char *montab[12] = {

"Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"

};

char num[FMT_ULONG];

char outbuf[1024];

void main(argc,argv)

int argc;

char **argv;

{

  time_t now;

  struct tm *tm;

  struct datetime dt;

  datetime_sec utc;

  datetime_sec local;

  int minutes;

  int pi[2];

  substdio ss;

  int wstat;

  int pid;

  sig_pipeignore();

  if (!argv[1])

    strerr_die1x(100,"predate: usage: predate child");

  if (pipe(pi) == -1)

    strerr_die2sys(111,FATAL,"unable to create pipe: ");

  switch(pid = fork()) {

    case -1:

      strerr_die2sys(111,FATAL,"unable to fork: ");

    case 0:

      close(pi[1]);

      if (fd_move(0,pi[0]) == -1)

	strerr_die2sys(111,FATAL,"unable to set up fds: ");

      sig_pipedefault();

      execvp(argv[1],argv + 1);

      strerr_die4sys(111,FATAL,"unable to run ",argv[1],": ");

  }

  close(pi[0]);

  substdio_fdbuf(&ss,write,pi[1],outbuf,sizeof(outbuf));

  time(&now);

  tm = gmtime(&now);

  dt.year = tm->tm_year;

  dt.mon = tm->tm_mon;

  dt.mday = tm->tm_mday;

  dt.hour = tm->tm_hour;

  dt.min = tm->tm_min;

  dt.sec = tm->tm_sec;

  utc = datetime_untai(&dt); /* utc == now, if gmtime ignores leap seconds */

  tm = localtime(&now);

  dt.year = tm->tm_year;

  dt.mon = tm->tm_mon;

  dt.mday = tm->tm_mday;

  dt.hour = tm->tm_hour;

  dt.min = tm->tm_min;

  dt.sec = tm->tm_sec;

  local = datetime_untai(&dt);

  substdio_puts(&ss,"Date: ");

  substdio_put(&ss,num,fmt_uint(num,dt.mday));

  substdio_puts(&ss," ");

  substdio_puts(&ss,montab[dt.mon]);

  substdio_puts(&ss," ");

  substdio_put(&ss,num,fmt_uint(num,dt.year + 1900));

  substdio_puts(&ss," ");

  substdio_put(&ss,num,fmt_uint0(num,dt.hour,2));

  substdio_puts(&ss,":");

  substdio_put(&ss,num,fmt_uint0(num,dt.min,2));

  substdio_puts(&ss,":");

  substdio_put(&ss,num,fmt_uint0(num,dt.sec,2));

  if (local < utc) {

    minutes = (utc - local + 30) / 60;

    substdio_puts(&ss," -");

    substdio_put(&ss,num,fmt_uint0(num,minutes / 60,2));

    substdio_put(&ss,num,fmt_uint0(num,minutes % 60,2));

  }

  else {

    minutes = (local - utc + 30) / 60;

    substdio_puts(&ss," +");

    substdio_put(&ss,num,fmt_uint0(num,minutes / 60,2));

    substdio_put(&ss,num,fmt_uint0(num,minutes % 60,2));

  }

  substdio_puts(&ss,"\n");

  substdio_copy(&ss,subfdin);

  substdio_flush(&ss);

  close(pi[1]);

  if (wait_pid(&wstat,pid) == -1)

    strerr_die2sys(111,FATAL,"wait failed: ");

  if (wait_crashed(wstat))

    strerr_die2x(111,FATAL,"child crashed");

  _exit(wait_exitcode(wstat));

}