Fix level generation so entities can't overlap

src/game_state/level.rs

@@ -137,12 +137,26 @@ impl Level {
 
     fn add_entity(entity: Tile, board: Board) -> Board {
         let empty_count = Level::count_empty_tiles(board);
-        let entity_position = thread_rng().gen_range(0, empty_count);
-        let entity_x = entity_position / config::BOARD_HEIGHT;
-        let entity_y = entity_position % config::BOARD_HEIGHT;
+        let mut entity_position = thread_rng().gen_range(0, empty_count);
+
 
         let mut board = board.clone();
-        board[entity_x][entity_y] = entity;
+        for x in 0..board.len() {
+            for y in 0..board[x].len() {
+                if entity_position > 0 {
+                    match board[x][y] {
+                        Tile::Empty => entity_position -= 1,
+                        _ => ()
+                    }
+                }
+                if entity_position == 0 {
+                    board[x][y] = entity;
+                    println!("Add {:?} at {:?}, coords: {}, {}", entity, entity_position, x, y);
+                    return board
+                }
+            }
+        }
+
         board
     }