my $dimension = $ARGV[0] || 10;

my ($count, %old, %mines);

my $fill_char = '.';

my @row = map {$fill_char} 1..$dimension;

my @matrix =  map {[@row]} @row;

my @control = ([-1, -1], [-1, 0], [-1, 1],
                    [0, -1], [0, 1],
               [1, -1],  [1, 0],  [1, 1] );

sub print_matrix {
    my $i;
    unshift @_, [map {$_} 1..$dimension];
    for (@_) {
        my @row = @$_;
        unshift @row, $i++ || ' ';
        for (@row) {
            printf("%2s ", $_) ;
        }
        print $/;
    }
}

sub initialize_fields {
    my $i;
    while ($i < $dimension) {
        my ($x, $y) = map {int rand $dimension} 1..2;
        my $mine = join ' ', $x, $y;
        $mines{$mine}++ || $i++;
    }
}

sub check_square {
    die "BOOOOMMMM!!!\n" if is_bomb( @_ );
    cq( @_ );
}

sub cq {
    my ($x, $y) = @_;
    return unless $matrix[$x][$y] eq $fill_char;
    my $value = value( @_ );
    $matrix[$x][$y] = $value;
    unless ( $value ) {
        for ( @control ) {
            @_ = @$_;
            my @nc = ($x + $_[0], $y + $_[1]);
            next if out_of_range( @nc );
            next if $matrix[ $nc[0] ][ $nc[1] ] ne $fill_char;
            cq( @nc );
        }
    }
    $count++;
}

sub value {
    my ($x, $y) = @_;
    my $value;
    for ( @control ) {
        @_ = @$_;
        my @nc = ($x + $_[0], $y + $_[1]);
        next if out_of_range( @nc );
        $value += is_bomb( @nc );
    }
    return $value;
}

sub is_bomb {
    my $mine = join ' ', @_;
    return $mines{$mine} ? 1 : 0;
}

sub out_of_range {
    return grep { $_ < 0 or $_ >= $dimension } @_;
}


initialize_fields;

while (1) {
    print_matrix(@matrix);
    print "YOU WON!!!\n" and exit if $count >= ($dimension ** 2 - $dimension);
    print "Insert (y, x) = ";
    $_ = <STDIN>; print $/;
    my ($command, $x, $y) = /^(x)?\s*(\d+)\D+(\d+)/i;
    $x--; $y--;
    print "x or y out of range!!!\n\n" and next if out_of_range($x, $y);
    if ( $command ) {
        if ( $matrix[$x][$y] eq 'X' ) {
            my $mine = join ' ', $x, $y;
            $matrix[$x][$y] = $old{$mine};
        } else {
            my $mine = join ' ', $x, $y;
            $old{$mine} = $matrix[$x][$y];
            $matrix[$x][$y] = 'X';
        }
    } else {
        check_square($x, $y);
    }
}