diff --git a/src/main.ts b/src/main.ts
index 432b335..b99177e 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -3,6 +3,7 @@ import { runAsHarvester } from './creep/harvester';
 import { runAsBuilder } from './creep/builder';
 import { runAsUpgrader } from './creep/upgrader';
 import { uniqId } from './utils/Identity';
+import { runTower } from './tower';
 
 function makeName(): string {
   return uniqId();
@@ -125,49 +126,3 @@ export const loop = ErrorMapper.wrapLoop(() => {
     }
   }
 });
-
-function runTower(tower: StructureTower) {
-  const room = tower.room;
-  const hostile = room.find(FIND_HOSTILE_CREEPS);
-  if (hostile.length > 0) {
-    const res = tower.attack(_.first(hostile));
-    console.log('Attack', res);
-    return;
-  }
-
-  const creeps = room.find(FIND_MY_CREEPS, {
-    filter: (c) => c.hits < c.hitsMax
-  });
-  if (creeps.length > 0) {
-    const res = tower.heal(_.first(creeps));
-    console.log('Heal', res);
-    return;
-  }
-
-  // Energy only for attack and heal
-  if (tower.store[RESOURCE_ENERGY] < 500) {
-    return;
-  }
-
-  const roads = room.find(FIND_STRUCTURES, {
-    filter: (s) => s.structureType === STRUCTURE_ROAD && s.hits < s.hitsMax
-  });
-  if (roads.length > 0) {
-    roads.sort((r1, r2) => r1.hits - r2.hits);
-    let road = _.first(roads);
-    const res = tower.repair(road);
-    console.log('Repair', res);
-    return;
-  }
-
-  const structures = room.find(FIND_STRUCTURES, {
-    filter: (s) => s.hits < s.hitsMax
-  });
-  if (structures.length > 0) {
-    structures.sort((r1, r2) => r1.hits - r2.hits);
-    let structure = _.first(structures);
-    const res = tower.repair(structure);
-    console.log('Repair', res);
-    return;
-  }
-}
diff --git a/src/tower.ts b/src/tower.ts
new file mode 100644
index 0000000..4e0cdee
--- /dev/null
+++ b/src/tower.ts
@@ -0,0 +1,47 @@
+const REPAIR_ENERGY_LIMIT = 500;
+
+export function runTower(tower: StructureTower) {
+  const room = tower.room;
+  const hostiles = room.find(FIND_HOSTILE_CREEPS);
+  if (hostiles.length > 0) {
+    const hostile = _.min(hostiles, (h) => h.hits);
+    const res = tower.attack(hostile);
+    console.log('Attack', res);
+    return;
+  }
+
+  const creeps = room.find(FIND_MY_CREEPS, {
+    filter: (c) => c.hits < c.hitsMax
+  });
+  if (creeps.length > 0) {
+    const creep = _.min(creeps, (c) => c.hits);
+    const res = tower.heal(creep);
+    console.log('Heal', res);
+    return;
+  }
+
+  // Energy only for attack and heal
+  if (tower.store[RESOURCE_ENERGY] < REPAIR_ENERGY_LIMIT) {
+    return;
+  }
+
+  const roads = room.find(FIND_STRUCTURES, {
+    filter: (s) => s.structureType === STRUCTURE_ROAD && s.hits < s.hitsMax
+  });
+  if (roads.length > 0) {
+    const road = _.min(roads, (r) => r.hits);
+    const res = tower.repair(road);
+    console.log('Repair', res);
+    return;
+  }
+
+  const structures = room.find(FIND_STRUCTURES, {
+    filter: (s) => s.hits < s.hitsMax
+  });
+  if (structures.length > 0) {
+    const structure = _.min(structures, (s) => s.hits);
+    const res = tower.repair(structure);
+    console.log('Repair', res);
+    return;
+  }
+}