Open our Xcode project if it's not already open.

Open the Battlefield.h file.

Define all AI states as enum, as shown in the following code:

typedef NS_ENUM(NSInteger, AIState) {
    StateWanderAround,
    StateMoveToPlayer,
    StateAttack,
    StateRecuperate
};

Inside the Battlefield scene, add a new instance variable called _aiState, which is of the AIState type.

Open the Ship.h file.

Add a callback block type, as shown in the following line of code:

typedef void(^ShipCallback)(void);

Declare three new methods for the Ship class, as shown in the following code:

-(void) moveToX:(float)x andY:(float)y withBlock:(ShipCallback) block;
-(float) checkDistanceToShip:(Ship *)ship;
-(void) moveToShip:(Ship *)ship withBlock:(ShipCallback) block;

Open the Ship.m file.

Move the contents of the -(void) moveToX:(float) x andY:(float) y method into the -(void) moveToX:(float)x...