@LAZYGLOBAL off.

run once "lib/node".


function target_ship {
    //
    // Return the target vessel even though a docking port might have been selected as the target.
    //
    if TARGET:istype("Part") {  // e.g. if selected docking port as target
        return TARGET:ship.
    }
    return TARGET.
}


function relative_velocity {
    //
    // Return the relative orbital velocity between the ship and our target in the target's inertial frame of reference.
    //
    if not HASTARGET {
        return V(0,0,0).  // avoids 'has no target' errors upon docking
    }
    return SHIP:velocity:orbit - target_ship():velocity:orbit.
}


function kill_relative_velocity {
    //
    // Kill relative velocity to target if it is above tolerance.
    //
    parameter tolerance is 0.1.

    if relative_velocity():mag < tolerance {
        print "Relative velocity within tolerance of " + tolerance + " m/s".
        return.
    }

    execute_burn(-relative_velocity()).
}