#!/share/bin/perl -w

#This is the more elaborate example of
# a program that invokes system tasks (via system or backticks)

# Supposedly it is a program that helps markers get listing
# of assignments submitted in laboratory classes that they supervise.
# It has a series of steps like unpacking files, copying files
# running compilations etc.

# The main program gets given a directory containing subdirectories
# with the submissions for each student.  It iterates through that
# directory, invoking "processsubmission" on the contents of
# each individual subdirectory.

# The process submission code invokes tasks such as unpacking files
# copying files, running compilations etc.

sub processsubmission {
	system("gunzip A1.tar.gz");
	$errcode = $? >> 8;
	if($errcode) {
		print "Corrupted gzip file?\n";
		print STDERR "$_ has corrupt gzip file\n";
		return;
	}
	system("tar -xf A1.tar");
	if($errcode) {
		print "Corrupted tar file?\n";
		print STDERR "$_ has corrupt tar file\n";
		return;
	}
	#Remove any .class files
	system("rm -f *.class");
	system("ls -l");


 
	#has student submitted an A.java
	if(-r "A.java") { 
		# if same as that supplied, remove it
		system("diff A.java ../A.java 1>/dev/null 2>/dev/null");
		$code = $? >> 8;
		if($code == 0) { 
print "Removing unneeded A.java\n";
			system("rm A.java"); 
			}
	}
	system("cp ../A.class .");
	
	@files = <*.{java,txt}>;
	foreach $file (@files) {
		print "\f$file:\n";
		system("cat $file");
	}

	system("javac B.java 2>&1 > compile_errs");


	$compile_error = $? >> 8;
	if($compile_error) { 	
		system("tail -100 compile_errs");	
		print "\fAssignment not run because of compilation errors\n";
		}
	else {
		$command = ' 
ulimit -t 5
java B 17 2>&1 < /dev/null > output
tail -100 output
';
		system($command);
	}
	
	system("rm -f *.java *.class *.txt compile_errs output");
	system("gzip A1.tar");
}

#-------------------------------------------------------------------------
#Checks an entry in lab file:
#   Submissions from students in subdirectories (along with a "control" 
#                subdirectory);
#   other entries are for data files used in test script etc
sub valid {
	$name = $_[0];
	if($name =~ /^\.+$/) { return 0; }
	if($name eq "control") { return 0; }
	if(-d $name) { return 1; }
	return 0;
}
#---------------------------------------------------------------------------
# Main program starts here
#
# It wants two command line arguments tutor name, lab (directory) name


$tutor = $ARGV[0];
$dirname = $ARGV[1];
if(!  ((defined $dirname) && (defined $tutor))) {
	print STDERR  <<MSG;
Tutor: 
This  script requires two command line arguments:
1) your name as a banner for printout
2) the directory with the submissions for your lab.
MSG
	exit 1;
}


if(!chdir($dirname)) {
	print STDERR "Couldn't cd to the directory $dirname\n";
	exit 1;
}
$| = 1; 
system("banner $tutor");
print "\f";

#Directory should contain subdirectories, one for each student who
#submitted an assignment
#It also contains other files and a 'control' directory used
#by the submission system.

opendir(CWD, ".");
@entries = readdir(CWD);
closedir(CWD);

@entries = sort @entries;

print "Submissions for your lab received from:\n";
@valid = ();
foreach (@entries) {
	if(valid($_)) { 
		print $_, "\n"; 
		push(@valid, $_); 
		}
}


foreach (@valid) {
	printf "\fStart of record for $_\n";
	print STDERR "$_\n";
	chdir($_) || die "Failed to cd into student's subdirectory\n";
	processsubmission;
	chdir("..");		
}