Implemented Entity tagged union for highlighted entity (similar to abstract class in some ways)

src/infrastructure/road_manager.zig

@@ -7,13 +7,11 @@ const Node = @import("node.zig").Node;
 pub const RoadManager = struct {
     next_id: usize,
     roads: std.ArrayList(*Road),
-    highlighted_road: ?*Road,
 
     pub fn init() RoadManager {
         return .{
             .next_id = 0,
             .roads = .empty,
-            .highlighted_road = null,
         };
     }
 
@@ -26,9 +24,9 @@ pub const RoadManager = struct {
     }
 
     /// Draws all the roads in the list, sends the information ahead whether the road drawn should be highlighted
-    pub fn draw(self: *const RoadManager, delete_mode: bool) void {
+    pub fn draw(self: *const RoadManager, highlighted_road: ?*Road) void {
         for (self.roads.items) |road| {
-            const is_highlighted = delete_mode and self.highlighted_road != null and self.highlighted_road.? == road;
+            const is_highlighted = if (highlighted_road) |h_road| road == h_road else false;
             road.draw(is_highlighted);
         }
     }
@@ -85,16 +83,13 @@ pub const RoadManager = struct {
         return e.Entity.NotFound;
     }
 
-    /// Sets the pointer to the road that is intersection with pos coordinate
-    pub fn update_highlighted_road(self: *RoadManager, pos: Vector2) void {
+    /// Returns if pos is pointing at a road, or null if it isn't at any
+    pub fn getHighlightedRoad(self: *const RoadManager, pos: Vector2) ?*Road {
         for (self.roads.items) |road| {
-            if (!road.isHighlighted(pos)) continue;
-
-            self.highlighted_road = road;
-            return;
+            if (road.isHighlighted(pos)) return road;
         }
 
-        self.highlighted_road = null;
+        return null;
     }
 };