#!/usr/bin/perl -w

################################
# This script creates .forward #
# and .vacation.msg files      #
# for e-mail autoreplying      #
# used by Exim                 #
#                              #
###############################

use strict;
use diagnostics;

my %users = ( #username                 leaves on                 is back on
		user		=>	{van	=>	[17,7,5], tm	=>	[13,8,5], },
	    );
my $vacstd = '/home/user/scripts/.vacation.msg';    #standard away message
my $fwdstd = '/home/user/scripts/.forward';         #standard Exim filter file

-e $vacstd or die("Needed file \"$vacstd\" not found; Quitting.");
-e $fwdstd or die("Needed file \"$fwdstd\" not found; Quitting.");

foreach(keys %users) {
		my $crntuser = $_;        #current user
		my @d = localtime(time);  #date info it needs for comparing
		my $sdate = join('-',@{$users{$crntuser}{van}});  #leaving date
		my $edate = join('-',@{$users{$crntuser}{tm}});   #returning date
		my $cdate = join('-',$d[3],$d[4]+1,$d[5]-100);    #current date
		my @udata = getpwnam($crntuser);                  #user login pass uid gid for chown later
		my $fwdnew = "/home/$_/.forward";                 #filename for fresh Exim filter file

    if($edate eq $cdate) {   #Is the returning date today?
	if(-e $fwdnew) {        #Does the fresh Exim filter file exist?
   	      unlink $fwdnew;   #then delete it
              print "User Scrntuser : File $fwdnew removed due to reached target end date $edate ($cdate); Quitting.";
	      exit 0;           #and we're done for today.
	}
    }

    if($sdate ne $cdate) {
        print "User $crntuser : Target start date $sdate ($cdate) not yet reached.";  #next user if we're not ready yet
        next;
    }
	my $vacnew = "/home/$_/.vacation.msg";     #fresh vacation message file
	print "Creating .vacation file for user $_\n";

	if(-e $vacnew)      #Does it already exist? then go on.
	      { print "File \"$vacnew\" already exists? Wut??\n" ; }
	else {
	     open VACSTD,$vacstd   #open standard vacation file for reading
                  or die("Unable to access standard vacation file \"$vacstd\"; Quitting.");
	     open VACNEW,">$vacnew"  #open fresh vacation file for writing
             or die("Unable to access fresh vacation file \"$vacnew\"; Quitting.");
	     while(<VACSTD>) {
	          s/_DATE_FROM_/$sdate/g;    #replace start date
		  s/_DATE_UNTIL_/$edate/g;   #replace return date
		  print VACNEW $_;           #save to fresh vacation file
	     }
             close VACSTD;
	     close VACNEW;
             print "File \"$vacnew\" successfully written.\n";
	}

    die("Unable to create \"$fwdnew\"; Quitting.")
        if system('cp',$fwdstd,$fwdnew) == -1;  #kill off if we can't copy the exim filter file to the fresh copy.

    die('Error changing file permissions; Quitting.') if
	chown $udata[2],$udata[3],[$vacnew,$fwdnew] <2;  #kill off if we can't set user permissions on fresh filter
                                                         # and vacation message file.

print "File \"$fwdnew\" successfully written.\n"; #Otherwise we'd have die()d so this can be displayed ok :)

} #and we're done.