head hunt only when my snake is bigger and into dual mode

snakes/BestBattleSnake.py

@@ -348,6 +348,7 @@ class BestBattleSnake(TemplateSnake):
     enemy_head = (enemy["head"]["x"], enemy["head"]["y"])
     enemy_len = enemy.get("length", len(enemy["body"]))
     encase_target_space = max(8, enemy_len * 2)
+    can_head_hunt = my_len > enemy_len and my_len >= 8
 
     scores:dict[str, float] = {}
     move_safety:dict[str, dict[str, Any]] = {}
@@ -421,10 +422,10 @@ class BestBattleSnake(TemplateSnake):
         score += max(0, 3 - enemy_options) * 95.0
         if reachable_space > enemy_space:
           score += 120.0
-        if direct_head_distance <= 2:
+        if direct_head_distance <= 2 and can_head_hunt:
           score += 40.0
 
-      if my_len > enemy_len:
+      if can_head_hunt:
         if direct_head_distance == 1:
           score += 220.0 * duel_weights["head_pressure"]
         elif direct_head_distance == 2:
@@ -432,6 +433,8 @@ class BestBattleSnake(TemplateSnake):
       else:
         if direct_head_distance <= 2:
           score -= 120.0 * duel_weights["distance_safety"]
+        if direct_head_distance == 1:
+          score -= 180.0 * duel_weights["distance_safety"]
 
       hunger_urgency = max(0.0, (65.0 - my_health) / 65.0)
       if nearest_food_dist is not None:

tests/test_BestBattleSnake.py

@@ -218,6 +218,146 @@ class TestBestBattleSnake(unittest.TestCase):
     move = make_board(game_state).snake_neat_make_a_move()
     self.assertNotEqual(move, "right")
 
+  def test_duel_small_length_lead_does_not_head_hunt(self):
+    game_state = {
+      "game": {
+        "id": "test-duel-small-no-head-hunt",
+        "ruleset": {"name": "standard", "version": "v1.0.0"},
+        "source": "custom",
+        "map": "standard",
+      },
+      "turn": 20,
+      "board": {
+        "height": 11,
+        "width": 11,
+        "food": [{"x": 1, "y": 1}],
+        "hazards": [],
+        "snakes": [
+          {
+            "id": "me",
+            "name": "me",
+            "health": 90,
+            "length": 7,
+            "head": {"x": 5, "y": 5},
+            "body": [
+              {"x": 5, "y": 5},
+              {"x": 5, "y": 4},
+              {"x": 5, "y": 3},
+              {"x": 4, "y": 3},
+              {"x": 4, "y": 4},
+              {"x": 4, "y": 5},
+              {"x": 4, "y": 6},
+            ],
+          },
+          {
+            "id": "enemy",
+            "name": "enemy",
+            "health": 90,
+            "length": 6,
+            "head": {"x": 7, "y": 5},
+            "body": [
+              {"x": 7, "y": 5},
+              {"x": 7, "y": 4},
+              {"x": 7, "y": 3},
+              {"x": 7, "y": 2},
+              {"x": 7, "y": 1},
+              {"x": 6, "y": 1},
+            ],
+          },
+        ],
+      },
+      "you": {
+        "id": "me",
+        "name": "me",
+        "health": 90,
+        "length": 7,
+        "head": {"x": 5, "y": 5},
+        "body": [
+          {"x": 5, "y": 5},
+          {"x": 5, "y": 4},
+          {"x": 5, "y": 3},
+          {"x": 4, "y": 3},
+          {"x": 4, "y": 4},
+          {"x": 4, "y": 5},
+          {"x": 4, "y": 6},
+        ],
+      },
+    }
+
+    move = make_board(game_state).snake_neat_make_a_move()
+    self.assertNotEqual(move, "right")
+
+  def test_duel_big_length_lead_can_head_hunt(self):
+    game_state = {
+      "game": {
+        "id": "test-duel-big-head-hunt",
+        "ruleset": {"name": "standard", "version": "v1.0.0"},
+        "source": "custom",
+        "map": "standard",
+      },
+      "turn": 20,
+      "board": {
+        "height": 11,
+        "width": 11,
+        "food": [{"x": 1, "y": 1}],
+        "hazards": [],
+        "snakes": [
+          {
+            "id": "me",
+            "name": "me",
+            "health": 90,
+            "length": 8,
+            "head": {"x": 5, "y": 5},
+            "body": [
+              {"x": 5, "y": 5},
+              {"x": 5, "y": 4},
+              {"x": 5, "y": 3},
+              {"x": 4, "y": 3},
+              {"x": 4, "y": 4},
+              {"x": 4, "y": 5},
+              {"x": 4, "y": 6},
+              {"x": 5, "y": 6},
+            ],
+          },
+          {
+            "id": "enemy",
+            "name": "enemy",
+            "health": 90,
+            "length": 6,
+            "head": {"x": 7, "y": 5},
+            "body": [
+              {"x": 7, "y": 5},
+              {"x": 7, "y": 4},
+              {"x": 7, "y": 3},
+              {"x": 7, "y": 2},
+              {"x": 7, "y": 1},
+              {"x": 6, "y": 1},
+            ],
+          },
+        ],
+      },
+      "you": {
+        "id": "me",
+        "name": "me",
+        "health": 90,
+        "length": 8,
+        "head": {"x": 5, "y": 5},
+        "body": [
+          {"x": 5, "y": 5},
+          {"x": 5, "y": 4},
+          {"x": 5, "y": 3},
+          {"x": 4, "y": 3},
+          {"x": 4, "y": 4},
+          {"x": 4, "y": 5},
+          {"x": 4, "y": 6},
+          {"x": 5, "y": 6},
+        ],
+      },
+    }
+
+    move = make_board(game_state).snake_neat_make_a_move()
+    self.assertEqual(move, "right")
+
   def test_does_not_step_into_stacked_tail(self):
     game_state = {
       "game": {