# We define a new Device type. Think of this as a new "Device" in the editor.
# It will hold our logic for managing the sentry.
struct SentryTestDevice: WorldDevice =
    # This is our "Sentry Entity" variable.
    # We'll assign the actual Sentry Device from the level to this variable later.
    SentryEntity: Entity = Invalid

    # This is the "Main" function. It runs when the game starts.
    OnBegin<override>()<suspends>=
        # 1. Find the Sentry in the level.
        # We use FindEntityByDisplayName to grab the specific Sentry we placed.
        # Make sure your Sentry in the editor is named "TestSentry".
        sentry_device := FindEntityByDisplayName<SentryDevice>("TestSentry")
        
        if sentry_device != Invalid:
            # 2. Get the underlying Entity from the Sentry Device.
            # Devices wrap Entities. We need the Entity to access events.
            SentryEntity := sentry_device.GetEntity()
            
            # 3. SUBSCRIBE to the Elimination Event.
            # This is the magic line. We tell Verse:
            # "When this entity is eliminated, run the 'OnSentryDown' function."
            # The `?` means the Agent might be null (e.g., if the sentry died from storm damage).
            _ := SentryEntity.EliminatedEvent.Subscribe(OnSentryDown)
            
            Print("Sentry is live. Come get some.")
        else:
            Print("Error: Could not find 'TestSentry' in the level!")

    # This function runs ONLY when the sentry dies.
    # It receives the 'Agent' (who killed it) as a parameter.
    OnSentryDown(Agent: ?Agent) =
        # Check if the Agent is valid (i.e., a player or object killed it, not just falling).
        if Agent != Invalid:
            # Get the player's name or ID to print it.
            # For simplicity, we just print a message.
            Print("Sentry eliminated by Agent!")
            
            # REAL-WORLD EXAMPLE:
            # If the Agent is a Player, you would now grant them a weapon.
            # Player := Agent.GetPlayer()
            # Player.GrantItem(ItemGranterDevice.GetGrantedItem())
        else:
            Print("Sentry died mysteriously (no agent).")