I'm making a RTS in which units can get several cyber-upgrades (individual, not as a global tech-tree upgrade like in most RTS games) before they're created. Now, I'm trying to decide how to do this, logic-wise. The system I have right now is that each unit type (walker, car, etc.) is a class, and when I initiate an instance of the class I add all the modifiers to the constructor, and let the constructor handle all the modifications.
This seems to me like the wrong way to do it - it means copy-pasted code in all the constructors. The other idea I had was to have each modification as a static method that takes a Unit class and modifies it - but the modifications might need access to private memebers (health, speed, etc.), and if I write the methods per-class, again I achieved copy-pasted code. As far as I know there's no way that a external static method can access private fields, and I don't want to create properties for every field, so as not to make the classes too cumbersome to use.
Example, to clarify: let's say I create a new Agent, and I want him to have bionic feet (+5 speed), x-ray vision (change of sight-function) and armored body (change of hit effects). I could use a constructor like Agent(speed, vision, armor), but if I'd later want to create new upgrades, such as fast reactions (+5 initiative), I'd have to change the constructor's signature. I could use a constructor like Agent(List), and then in the constructor create a giant swtich/case for every available upgrade, but then, I'd have to copy it also to the constructor of Vehicle, and make sure I update both of them, exactly the same. What I'd like to do is have a basic constructor and after it have a:
internal delegate void Effect(Unit ent);
void setup(List<Effect> list)
foreach(Effect effect in list) effect(this);
method, and then run every effect in the list on the new Unit, but then the Effect can't access the unit's private members.
Is there an elegant solution to the problem?