Rework the source so that battle is in its own thing to work on.

battle.cpp

@@ -0,0 +1,39 @@
+#include "rituals.hpp"
+#include "battle.hpp"
+
+namespace combat {
+  void BattleEngine::add_enemy(BattleAction enemy) {
+    combatants.try_emplace(enemy.entity, enemy);
+  }
+
+  bool BattleEngine::plan() {
+    int active = 0;
+
+    for(auto& [entity, enemy] : combatants) {
+      enemy.ai.set_state("enemy_found", true);
+      enemy.ai.set_state("in_combat", true);
+      enemy.ai.update();
+
+      active += enemy.ai.active();
+      // yes, copy it out of the combatants list
+      pending_actions.push_back(enemy);
+    }
+
+    return active > 0;
+  }
+
+  std::optional<BattleAction> BattleEngine::next() {
+    if(pending_actions.size() == 0) return std::nullopt;
+
+    auto ba = pending_actions.back();
+    pending_actions.pop_back();
+    return std::make_optional(ba);
+  }
+
+  void BattleEngine::dump() {
+    for(auto& [entity, enemy] : combatants) {
+      fmt::println("\n\n###### ENTITY #{}", entity);
+      enemy.ai.dump();
+    }
+  }
+}