$running = true;
$gameover = false;
@digits = (0,0,0);
$score = 0;
$guess = 0;
$attempt = 0;

sub askQuestion
{
	($prompt) = @_;
	while(true)
	{
		print "$prompt? ";
		$ans = uc <>;
		chomp($ans);
		if($ans ne "")
		{
			return $ans;
		}
		print "PLEASE ANSWER THE QUESTION.\n"
	}
}

sub getIntInput
{
	($prompt) = @_;
	while(true)
	{
		print "$prompt ";
		$ans = <>;
		chomp($ans);
		if(isAnInt($ans) eq true)
		{
			return int($ans);
		}
		print "YOU DID NOT ENTER AN INTEGER.\n"
	}
}

sub isAnInt
{
	($input) = @_;
	if($input =~ /^[-*\d]+$/) { return true; }
}

sub askBinaryQuestion
{
	($prompt) = @_;
	while(true)
	{
		$ans = askQuestion($prompt);
		if($ans eq "YES" or $ans eq "Y") { return true; }
		if($ans eq "NO" or $ans eq "N") { return false; }
		print "PLEASE ANSWER \"YES\" OR \"NO\"\n";
	}
}

sub askToPlayAgain
{
	return askBinaryQuestion("DO YOU WANT TO PLAY AGAIN");
}

sub askToSeeTheRules
{
	return askBinaryQuestion("DO YOU WANT TO SEE THE RULES");
}

sub generateRandomNumber
{
	($minimum) = @_[0];
	($maximum) = @_[1];
	($show) = @_[2];
	$value = int(rand($maximum) + $minimum);
	if($show eq true) { print "$value\n"; }
	return $value;	
}

sub makeIntFromArray
{
	(@arrayIn) = @_;
	return ($arrayIn[0] * 100) + ($arrayIn[1] * 10) + $arrayIn[2];
}

sub makeArrayFromInt
{
	($valIn) = @_;
	@retArray = (0,0,0);
	$retArray[0] = int($valIn / 100);
	$retArray[1] = int(($valIn - ($retArray[0] * 100)) / 10);
	$retArray[2] = $valIn - ($retArray[0] * 100) - ($retArray[1] * 10);
	return @retArray;
}

sub askForGuess
{
	($attempt) = @_;
	while(true)
	{
		$guess = getIntInput("GUESS #$attempt");
		if($guess < 0) { print "PLEASE GUESS A NON-NEGATIVE NUMBER.\n"; }
		elsif($guess < 100 || $guess > 999) { print "PLEASE GUESS A NUMBER BETWEEN 100 AND 999.\n"; }
		else { return $guess; }
	}
}

sub displayRules
{
	print "I WILL THINK OF A THREE-DIGIT NUMBER. YOU WILL TRY TO\n";
	print "GUESS MY NUMBER AND I WILL GIVE YOU CLUES AS FOLLOWS:\n";
	print "  PICO   - ONE DIGIT CORRECT BUT IN THE WRONG POSITION\n";
	print "  FERMI  - ONE DIGIT CORRECT AND IN THE RIGHT POSITION\n";
	print "  BAGELS - NO DIGITS ARE CORRECT\n\n";
	print "YOU GET TWENTY TRIES BEFORE YOU LOSE.\n\n";
}

sub displayGameOver
{
	$number = makeIntFromArray(@digits);
	print "OH WELL, THAT'S TWENTY GUESSES.\n";
	print "MY NUMBER WAS $number.\n";
}

sub createTheNumber
{
	$digits[0] = generateRandomNumber(1, 9, false);
	$gotDigit = false;
	while($gotDigit ne true)
	{
		$digits[1] = generateRandomNumber(0, 9, false);
		if($digits[1] != $digits[0]) { $gotDigit = true; }
	}
	$gotDigit = false;
	while($gotDigit ne true)
	{
		$digits[2] = generateRandomNumber(0, 9, false);
		if($digits[2] != $digits[0] && $digits[2] != $digits[1]) { $gotDigit = true; }
	}
	return @digits;
}

sub checkGuess
{
	($guess) = @_;
	@temp = makeArrayFromInt($guess);
	@vals = (0,0,0);
	if($temp[0] == $digits[0]){ $vals[0] = 1; }
	if($temp[1] == $digits[1]){ $vals[1] = 1; }
	if($temp[2] == $digits[2]){ $vals[2] = 1; }
	if(makeIntFromArray(@vals) == 111) { return true; }
	if($vals[0] == 0)
	{
		if($temp[0] == $digits[1] || $temp[0] == $digits[2]) { $vals[0] = 2; }
	}
	if($vals[1] == 0)
	{
		if($temp[1] == $digits[0] || $temp[1] == $digits[2]) { $vals[1] = 2; }
	}
	if($vals[2] == 0)
	{
		if($temp[2] == $digits[0] || $temp[2] == $digits[1]) { $vals[2] = 2; }
	}
	if(makeIntFromArray(@vals) == 0) { print "BAGELS\n"; }
	else
	{
		if($vals[0] == 1) { print "FERMI "; }
		if($vals[0] == 2) { print "PICO "; }
		if($vals[1] == 1) { print "FERMI "; }
		if($vals[1] == 2) { print "PICO "; }
		if($vals[2] == 1) { print "FERMI"; }
		if($vals[2] == 2) { print "PICO"; }
		print "\n";
	}
	return false;
}

print "*** BAGELS : PERL ***\n";
$running = true;
if(askToSeeTheRules() eq true) { displayRules(); }
$score = 0;
while($running eq true)
{
	$attempt = 1;
	@digits = createTheNumber();
	print "OK, I HAVE A NUMBER IN MIND.\n";
	$gameover = false;
	while($gameover eq false)
	{
		$guess = askForGuess($attempt);
		if(checkGuess($guess) eq true)
		{
			print "YOU GOT IT!!!\n";
			$score++;
			$gameover = true;
		}
		else
		{
			$attempt++;
			if($attempt > 20)
			{
				displayGameOver(@digits);
				$gameover = true;
			}
		}
	}
	print "*** GAME OVER ***\n";
	$running = askToPlayAgain();
}
print "A $score POINT BAGELS BUFF!\n";
print "HOPE YOU HAD FUN. BYE!\n";