From 753a51e6831c1c2128bcaf54b1f6f31223ce80c3 Mon Sep 17 00:00:00 2001
From: "Tormod G. Hellen" <tormod@mbr-targeting.com>
Date: Tue, 14 Jun 2022 23:14:42 +0200
Subject: [PATCH] Make selfish bastards ambush people when they're alone.

---
 CHANGELOG.md               |  1 +
 server/src/rtsim/entity.rs |  4 +++
 server/src/sys/agent.rs    | 52 +++++++++++++++++++++++++++++++++-----
 3 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c24ad07e6b..58e1c16c3c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - Use fluent for translations
 - First tab on Login screen triggers username focus
+- Certain NPCs will now attack when alone with victim
 
 ### Removed
 
diff --git a/server/src/rtsim/entity.rs b/server/src/rtsim/entity.rs
index 077d9c6628..25a25f9785 100644
--- a/server/src/rtsim/entity.rs
+++ b/server/src/rtsim/entity.rs
@@ -706,6 +706,8 @@ impl PersonalityBase {
      * don't want everyone to be completely weird.
      */
     pub fn to_personality(&self) -> Personality {
+        let will_ambush = self.agreeableness < Personality::LOW_THRESHOLD
+            && self.conscientiousness < Personality::LOW_THRESHOLD;
         let mut chat_traits: EnumSet<PersonalityTrait> = EnumSet::new();
         if self.openness > Personality::HIGH_THRESHOLD {
             chat_traits.insert(PersonalityTrait::Open);
@@ -752,12 +754,14 @@ impl PersonalityBase {
         }
         Personality {
             personality_traits: chat_traits,
+            will_ambush,
         }
     }
 }
 
 pub struct Personality {
     pub personality_traits: EnumSet<PersonalityTrait>,
+    pub will_ambush: bool,
 }
 
 #[derive(EnumSetType)]
diff --git a/server/src/sys/agent.rs b/server/src/sys/agent.rs
index 490a03b495..d336a01676 100644
--- a/server/src/sys/agent.rs
+++ b/server/src/sys/agent.rs
@@ -48,6 +48,7 @@ use common::{
 };
 use common_base::prof_span;
 use common_ecs::{Job, Origin, ParMode, Phase, System};
+use itertools::Itertools;
 use rand::{thread_rng, Rng};
 use rayon::iter::ParallelIterator;
 use specs::{Entity as EcsEntity, Join, ParJoin, Read, WriteExpect, WriteStorage};
@@ -748,11 +749,44 @@ impl<'a> AgentData<'a> {
         agent.action_state.timer = 0.0;
         let mut aggro_on = false;
 
+        // Search the area.
+        // TODO: choose target by more than just distance
+        let common::CachedSpatialGrid(grid) = self.cached_spatial_grid;
+
+        let entities_nearby = grid
+            .in_circle_aabr(self.pos.0.xy(), agent.psyche.search_dist())
+            .collect_vec();
+
+        let can_ambush = |entity: EcsEntity, read_data: &ReadData| {
+            let self_different_from_entity = || {
+                read_data
+                    .uids
+                    .get(entity)
+                    .map_or(false, |eu| eu != self.uid)
+            };
+            if self.will_ambush()
+                && self_different_from_entity()
+                && !self.passive_towards(entity, read_data)
+            {
+                let surrounding_humanoids = entities_nearby
+                    .iter()
+                    .filter(|e| read_data.bodies.get(**e).map_or(false, |b| b.is_humanoid()))
+                    .collect_vec();
+                surrounding_humanoids.len() == 2
+                    && surrounding_humanoids.iter().any(|e| **e == entity)
+            } else {
+                false
+            }
+        };
+
         let get_pos = |entity| read_data.positions.get(entity);
         let get_enemy = |(entity, attack_target): (EcsEntity, bool)| {
             if attack_target {
                 if self.is_enemy(entity, read_data) {
                     Some((entity, true))
+                } else if can_ambush(entity, read_data) {
+                    aggro_on = true;
+                    Some((entity, true))
                 } else if self.should_defend(entity, read_data) {
                     if let Some(attacker) = get_attacker(entity, read_data) {
                         if !self.passive_towards(attacker, read_data) {
@@ -822,13 +856,9 @@ impl<'a> AgentData<'a> {
                 || self.can_see_entity(agent, controller, entity, e_pos, read_data)
         };
 
-        // Search the area.
-        // TODO: choose target by more than just distance
-        let common::CachedSpatialGrid(grid) = self.cached_spatial_grid;
-
-        let target = grid
-            .in_circle_aabr(self.pos.0.xy(), agent.psyche.search_dist())
-            .filter_map(is_valid_target)
+        let target = entities_nearby
+            .iter()
+            .filter_map(|e| is_valid_target(*e))
             .filter_map(get_enemy)
             .filter_map(|(entity, attack_target)| {
                 get_pos(entity).map(|pos| (entity, pos, attack_target))
@@ -1632,6 +1662,14 @@ impl<'a> AgentData<'a> {
                 || (is_villager(self.alignment) && is_dressed_as_cultist(entity, read_data)))
     }
 
+    fn will_ambush(&self) -> bool {
+        self.health
+            .map_or(false, |h| h.current() / h.maximum() > 0.7)
+            && self
+                .rtsim_entity
+                .map_or(false, |re| re.brain.personality.will_ambush)
+    }
+
     fn should_defend(&self, entity: EcsEntity, read_data: &ReadData) -> bool {
         let entity_alignment = read_data.alignments.get(entity);