refactor: add static to functions

- Update functions to be declared as static for improved code clarity
- No functional changes made, only internal refactoring

src/validation.cc

@@ -9,11 +9,9 @@
 #include <algorithm>
 #include <string>
 
-// These functions need to be declared to use the top-down rule and
+static bool player_belongs_to_room(const Player *player, const Room *room);
-// make them as module private functions.
+static bool action_belongs_to_role(const Role *role, const Action *action);
-bool player_belongs_to_room(const Player *player, const Room *room);
+static bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events);
-bool action_belongs_to_role(const Role *role, const Action *action);
-bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events);
 
 /**
  * Validate if an action is valid for a player in a room based on related events.
@@ -68,7 +66,7 @@ ValidationStatus validate_action(
  * @param room Pointer to the room object.
  * @return `true` if the player belongs to the room, otherwise `false`.
  */
-bool player_belongs_to_room(const Player *player, const Room *room) {
+static bool player_belongs_to_room(const Player *player, const Room *room) {
     return std::find(room->players.begin(), room->players.end(), *player) != room->players.end();
 }
 
@@ -79,7 +77,7 @@ bool player_belongs_to_room(const Player *player, const Room *room) {
  * @param action Pointer to the action object.
  * @return `true` if the action belongs to the role, otherwise `false`.
  */
-bool action_belongs_to_role(const Role *role, const Action *action) {
+static bool action_belongs_to_role(const Role *role, const Action *action) {
     return std::find(role->actions.begin(), role->actions.end(), *action) != role->actions.end();
 }
 
@@ -90,7 +88,7 @@ bool action_belongs_to_role(const Role *role, const Action *action) {
  * @param relevantEvents Pointer to the vector of relevant events.
  * @return `true` if the action is allowed, otherwise `false`.
  */
-bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events) {
+static bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events) {
     bool allowed = false;  // Actions are disabled by default
     std::sort(relevant_events->begin(), relevant_events->end());
     for (const auto &event : *relevant_events) {
@@ -104,6 +102,12 @@ bool is_action_allowed(const Action *action, std::vector<Event> *relevant_events
     return allowed;
 }
 
+/**
+ * Convert a ValidationStatus enum value to its corresponding string representation.
+ *
+ * @param status The ValidationStatus enum value to convert.
+ * @return The string representation of the given ValidationStatus.
+ */
 std::string ValidationStatusUtils::to_string(ValidationStatus status) {
     switch (status) {
         case ValidationStatus::PlayerNotInRoom: return "player not in room";

src/validation.hh

@@ -20,8 +20,6 @@ enum class ValidationStatus {
     ActionValid,
 };
 
-std::string validation_status_to_string(ValidationStatus status);
-
 ValidationStatus
   validate_action(Player *actor, const Action *action, Room *room, std::vector<Event> *relatedEvents, Player *target);