enemy btree interface update

src/bullet_heck_gleam.gleam

@@ -333,17 +333,20 @@ fn on_tick(state: WorldState) -> WorldState {
           }
         })
 
-      let #(enemies, player, score) =
-        list.fold(enemies, #([], player, score), fn(acc, e) {
-          let #(enemies, player, score) = acc
+      let #(enemies, bullets, player, score) =
+        list.fold(enemies, #([], bullets, player, score), fn(acc, e) {
+          let #(enemies, bullets, player, score) = acc
           // Apply behavior to enemy
-          let enemy = e.btree(e, dungeon, player, bullets)
+          let enemy.BehaviorResult(_, enemy, new_bullets) =
+            e.btree(enemy.BehaviorInput(e, enemies, dungeon, player))
+
+          let bullets = list.append(new_bullets, bullets)
 
           // Kill enemy if they have fallen into pit
           use <- bool.guard(
             enemy.position.z <=. 0.0
               && dungeon.is_over_pit(dungeon, enemy.position),
-            #(enemies, player, score + enemy.value),
+            #(enemies, bullets, player, score + enemy.value),
           )
 
           // Check player collides with the enemy
@@ -367,11 +370,12 @@ fn on_tick(state: WorldState) -> WorldState {
           // Kill enemy if they have died
           use <- bool.guard(enemy.is_enemy_dead(enemy), #(
             enemies,
+            bullets,
             player,
             score + enemy.value,
           ))
 
-          #([enemy, ..enemies], player, score)
+          #([enemy, ..enemies], bullets, player, score)
         })
 
       let bullets =

src/enemy.gleam

@@ -18,9 +18,37 @@ pub const value = 100
 
 const max_enemy_health = 80
 
+/// Represents the input data needed for an enemy to update.
+pub type BehaviorInput {
+  /// Represents the input data needed for an enemy to update.
+  BehaviorInput(
+    /// The enemy being updated.
+    enemy: Enemy,
+    /// All enemies in the game.
+    enemies: List(Enemy),
+    /// The dungeon the enemy is in.
+    dungeon: Dungeon,
+    /// The player character.
+    player: Player,
+  )
+}
+
+/// Represents the result of an enemy update.
+pub type BehaviorResult {
+  /// Represents the result of an enemy update.
+  BehaviorResult(
+    /// Whether the action can continue
+    success: Bool,
+    /// The updated enemy.
+    enemy: Enemy,
+    /// Any bullets that were fired by the enemy.
+    bullets: List(Bullet),
+  )
+}
+
 /// Represents a function that given world information and an enemy updates the enemy.
 pub type BehaviorTree =
-  fn(Enemy, Dungeon, Player, List(Bullet)) -> Enemy
+  fn(BehaviorInput) -> BehaviorResult
 
 /// Represents an enemy to defeat.
 pub type Enemy {
@@ -50,7 +78,10 @@ pub fn new_enemy(initial_position: Vector) -> Enemy {
     current_health: max_enemy_health,
     max_health: max_enemy_health,
     // TODO: actually make a behavior
-    btree: fn(e, _, _, _) { e },
+    btree: fn(i) {
+      let BehaviorInput(e, _, _, _) = i
+      BehaviorResult(True, e, [])
+    },
   )
 }
 

test/enemy_test.gleam

@@ -3,6 +3,11 @@ import startest.{describe, it}
 import startest/expect
 import vector.{Vector}
 
+fn dummy_btree(i: enemy.BehaviorInput) -> enemy.BehaviorResult {
+  let enemy.BehaviorInput(e, _, _, _) = i
+  enemy.BehaviorResult(True, e, [])
+}
+
 pub fn enemy_tests() {
   describe("enemy", [
     it("new_enemy", fn() {
@@ -20,7 +25,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 100,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         )
         |> enemy.apply_gravity
       expect.to_equal(enemy.velocity, vector.Vector(0.0, 0.0, 0.98))
@@ -32,7 +37,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 100,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         )
         |> enemy.apply_gravity
       expect.to_equal(enemy.position, vector.Vector(0.0, 0.0, 0.0))
@@ -46,7 +51,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 100,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         )
         |> enemy.apply_damage(20)
       expect.to_equal(enemy.current_health, 80)
@@ -59,7 +64,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 100,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         )
         |> enemy.is_enemy_dead,
       )
@@ -70,7 +75,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 0,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         )
         |> enemy.is_enemy_dead,
       )
@@ -83,7 +88,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 100,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         ),
         Vector(10.0, 0.0, 0.0),
         1.0,
@@ -95,7 +100,7 @@ pub fn enemy_tests() {
           rotation: 0.0,
           current_health: 100,
           max_health: 100,
-          btree: fn(e, _, _, _) { e },
+          btree: dummy_btree,
         ),
         Vector(0.0, 0.0, 0.0),
         1.0,