use warnings;
use strict;
print "Welcome to Multiplication Challenge\n";
print "What would you like to do?\n";
print "1) FLASHCARD MODE\n";
print "2) TEST MODE\n";
print "3) OPTIONS\n";
print "4) Exit\n";
my $input = undef;
my $max   = undef;
my $min   = 10;

sub menu {
    print "What would you like to do?\n";
    print "1) FLASHCARD MODE\n";
    print "2) TEST MODE\n";
    print "3) OPTIONS\n";
    print "4) Exit\n";
}
while ( $input = (<STDIN>) ) {
    if ( $input =~ /1/ ) {
        print "FLASHCARD MODE\n";
        flashcard();
    }
    elsif ( $input =~ /2/ ) {
        print "TEST MODE\n";
        testmode();
    }
    elsif ( $input =~ /3/ ) {
        print "3\n";
        print "What is the maximum number?\n";
        my $max = (<STDIN>);
        &makeitbig($max);
        &menu();
    }
    elsif ( $input =~ /4/ ) {
        really();
    }

}

sub really {
    print "Are you sure?\n";
    my $input = (<STDIN>);
    if ( $input =~ /y/ ) {
        exit;
    }
    else {
        menu();
    }
}

sub flashcard {
    for ( 1 .. 10 ) {
        my $random1 = int( rand(10) );
        my $random2 = int( rand(10) );
        print "$random1 *  $random2\n";
        my $total = ( $random1 * $random2 );
        &validate($total);
    }
}
my $count = 1;

sub validate {
    my $newdata = shift;
  TRYAGAIN:
    my $input = (<STDIN>);
    if ( $input == $newdata ) {
        print "Correct!\n";
        $count++;
        if ( $count == 10 ) {
            print "Congratulations\n";
            print "You have finished FLASHCARD MODE;\n";
            menu();
        }
    }
    else {
        print "$count: Try again\n";
        goto TRYAGAIN;
    }
}

sub testmode {
    for ( 1 .. 25 ) {
        my $random1 = int( rand(10) );
        my $random2 = int( rand(10) );
        print "Problem  '#'$_\n";
        print "$random1 * $random2\n";
        my $total = ( $random1 * $random2 );
        &validate_low($total);
    }
}
my $meter         = 1;
my @correct       = ();
my $correctanswer = 1;

sub validate_low {
    my $newdata = shift;
    my $input   = (<STDIN>);
    $meter++;
    if ( $input == $newdata ) {
        print "Correct!\n";
        push( @correct, $correctanswer );
    }
    else {
        print "Sorry!\n";
    }
    if ( $meter == 25 ) {
        &calculate();
    }
}

my $sum = 0;

sub calculate {
    foreach (@correct) {
        $sum += $_;
        return $sum;
    }

    my $prcnt = 4 * $sum;
    print "You got $sum answers correctly out of 25. This is $prcnt%\n";
}

sub makeitbig {
    my $other = shift;
    if ( $other == $min ) {
        return $min;
    }
    else {
        return $other;
    }
}