package Rocket::LandingGear;

use NASA::System;

sub is_landing_gear_down {
    NASA::System::IsLandingGearDown();
}

sub extend_landing_gear {
    NASA::System::LandingGearDown();
}

sub retract_landing_gear {
    NASA::System::LandingGearUp();
}

my $last_altitude;

sub altitude_change {
    my $altitude = shift;

    if ($altitude > $last_altitude) { # ascending
        if ($altitude > 450 and is_landing_gear_down()) {
            retract_landing_gear();
        }
    }
    else {                            # descending
        if ($altitude < 500 and !is_landing_gear_down()) {
            extend_landing_gear();
        }
    }
    $last_altitude = $altitude;
}

1;