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use strict;
use threads;
use Thread::Queue;
use threads::shared;


# Create queue
my $oQue = Thread::Queue->new;

my $iThreadMax = 8;
my $iTargetCnt;

my @aTaskList = ();
print "--------------------------------------------\n";
print "Collecting Random Numbers......\n";
my $iMax = 100000;
for (my $i=0; $i<$iMax; $i++) {
	my $iRandNo = int(rand(100)+1);
	push(@aTaskList, $iRandNo);

	if ($i % int($iMax * 0.1) == 0) {
		print "    ".$i."th Number = ".$iRandNo."\n";
	}
}


# Data sharing between threads. Only single level is allowed for hashes.
# Multiple-level hashes are not allowed. So, we use combined keys for multiple levels.
my %hVal_by_ThreadGroup = (); share(%hVal_by_ThreadGroup);        # to share data with other threads.

# Adding Tasks to a Que
print "--------------------------------------------\n";
print "Adding Tasks to a Que......\n";
print "    Target enrolled in a que: ";
foreach my $sCurTask (@aTaskList) {
	$iTargetCnt++;
#	print $sCurTask." ";
	$oQue->enqueue ($sCurTask);
}
print "\n";

if ($iTargetCnt < $iThreadMax ) {
	$iThreadMax = $iTargetCnt;
}
print "    --------------\n";
print "    Total No. of Threads: $iThreadMax\n";
print "    --------------\n";


# Generate Threads and make them do something independently.
for (my $i=0; $i<$iThreadMax; $i++) {
#	print "    New Thread Count: ".$i." --> Generated!!\n";
	$oQue -> enqueue(undef);

	# Main function that you like to handle the tasks after task split
	threads->new(\&funcDoIt, $i);
}

# Join up with the thread for normal finalization
my @aObjTaskNames = threads->list();
foreach my $oCurTask (@aObjTaskNames) {
#	print "Joining Task: ".$oCurTask."\n";
	$oCurTask->join();
}


sub funcDoIt {
#	print "    Function Started...............................\n";
	my $iThreadCnt = shift;               #($i, "a", "b", "c") --> $i
	my $sThread    = sprintf("Thread_%02d", $iThreadCnt);

	my $iCnt = 0;
	while (my $sCurTask = $oQue->dequeue()) {
		$iCnt++;
		my $sCurGroup = "";

		if ($sCurTask % 5 == 1) {
			$sCurGroup = "Group_A";
		} elsif ($sCurTask % 5 == 2) {
			$sCurGroup = "Group_B";
		} elsif ($sCurTask % 5 == 3) {
			$sCurGroup = "Group_C";
		} elsif ($sCurTask % 5 == 4) {
			$sCurGroup = "Group_D";
		} else {
			$sCurGroup = "Group_E";
		}

		my $sCurKey = $sThread."==".$sCurGroup;
		$hVal_by_ThreadGroup{$sCurKey} = $hVal_by_ThreadGroup{$sCurKey}." ".$sCurTask;

	}
	print "    Count of Numbers: ".$iCnt." / ".$sThread."\n";
}









print "--------------------------------------------\n";
print "Rearranging data............................\n";
my %hVal_by_Group = ();
my @aKeys = keys(%hVal_by_ThreadGroup);
foreach my $sCurKey (@aKeys) {
	my @aTemp = split("==", $sCurKey);
	my $sCurGroup = $aTemp[1];

	$hVal_by_Group{$sCurGroup} = $hVal_by_Group{$sCurGroup}." ".$hVal_by_ThreadGroup{$sCurKey};
}







print "--------------------------------------------\n";
my @aGroups = keys(%hVal_by_Group);
foreach my $sCurGroup (sort(@aGroups)) {
	my @aElement = split(" ", $hVal_by_Group{$sCurGroup});
	print $sCurGroup.": Sum = ".funcArraySum(@aElement)." / Mean = ".funcMean(@aElement)." / Cnt = ".($#aElement + 1)."\n";
}









sub funcArraySum {
	my @aData = @_;     # Pre-Existing Array "@_"
	my $fSum = 0;

	foreach my $fCurVal (@aData) {
		$fSum += $fCurVal;
	}

	return $fSum;       # Return a value / Optional
}

sub funcMean {
	my @aData = @_;             # Pre-Existing Array "@_"
	my $fSum = 0;

	foreach my $fCurVal (@aData) {
		$fSum += $fCurVal;
	}

	my $iCnt = $#aData + 1;

	return $fSum/$iCnt;       # Return a value
}

# Refer to the following link for more information.
# https://perldoc.perl.org/Thread/Queue.html
# https://perldoc.perl.org/threads/shared.html
# https://perldoc.perl.org/5.8.8/threads/shared.html