using { /Fortnite.com/AI }
using { /Fortnite.com/Characters }
using { /Fortnite.com/Game }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/SpatialMath }
using { /UnrealEngine.com/Temporary/Diagnostics }

# CUSTOM NPC BEHAVIOR — teach a villager to flee when hurt.
#
# An npc_behavior is a Verse class that rides ON TOP of an NPC's built-in brain.
# You attach it to an NPC Character Definition; OnBegin runs the moment the
# character is simulating. Unlike a creative_device, an npc_behavior gets a
# handle to its OWN character through GetAgent[] / GetFortCharacter[], then drives
# it with the navigatable and focus interfaces.
#
# This villager stands still until something damages them — then it sprints away
# from the attacker and keeps its eyes locked on the threat the whole time.
fleeing_villager := class(npc_behavior):

    # How far to run when spooked (centimeters).
    FleeDistance : float = 1200.0

    # OnBegin runs when the NPC enters the simulation. Wire up its damaged event.
    OnBegin<override>()<suspends> : void =
        if:
            Agent := GetAgent[]
            Character := Agent.GetFortCharacter[]
        then:
            Character.DamagedEvent().Subscribe(OnDamaged)
            Print("Villager is on patrol duty... nervously.")

    # When hit, run directly away from the instigator and stare them down.
    OnDamaged(Result : damage_result) : void =
        if:
            Agent := GetAgent[]
            Character := Agent.GetFortCharacter[]
            Navigatable := Character.GetNavigatable[]
            Focus := Character.GetFocusInterface[]
            Attacker := agent[Result.Instigator?]
            AttackerChar := Attacker.GetFortCharacter[]
        then:
            MyPos := Character.GetTransform().Translation
            ThreatPos := AttackerChar.GetTransform().Translation
            # Direction pointing FROM the threat TO us, normalized, then pushed out.
            Away := (MyPos - ThreatPos)
            FleePoint := MyPos + Away * FleeDistance
            Target := MakeNavigationTarget(FleePoint)
            Print("Villager spooked — fleeing!")
            # Keep looking at the attacker while we run (focus never completes
            # on its own, so spawn it as its own fiber).
            spawn{ Focus.MaintainFocus(Attacker) }
            spawn{ RunAway(Navigatable, Target) }

    # Sprint to the flee point; report whether we made it.
    RunAway(Navigatable : navigatable, Target : navigation_target)<suspends> : void =
        Navigatable.SetMovementSpeedMultiplier(2.0)
        Result := Navigatable.NavigateTo(Target, ?MovementType := movement_type.Running)
        if (Result = navigation_result.Reached):
            Print("Villager reached safety.")
        else:
            Print("Villager's escape was blocked!")