docs: document grid system and game screen environment (#65)

src/features/grid/components.rs

@@ -1,18 +1,22 @@
 use super::errors::GridError;
 use crate::prelude::*;
 
+/// Component representing a single tile on the grid.
 #[derive(Component)]
 pub struct Tile {
     pub x: u32,
     pub y: u32,
 }
 
+/// Visual marker component for the crop on a tile.
 #[derive(Component)]
 pub struct CropVisual;
 
+/// Visual marker component for the water on a tile.
 #[derive(Component)]
 pub struct WaterVisual;
 
+/// The logical state of a tile.
 #[derive(Component, Default, Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
 pub enum TileState {
     #[default]
@@ -38,6 +42,7 @@ impl TileState {
     }
 }
 
+/// Resource containing grid dimensions and tile entities.
 #[derive(Resource)]
 pub struct Grid {
     pub width: u32,
@@ -46,6 +51,7 @@ pub struct Grid {
 }
 
 impl Grid {
+    /// Returns the entity of the tile at the given position.
     pub fn get_tile(&self, pos: (u32, u32)) -> Result<Entity, GridError> {
         if pos.0 >= self.width || pos.1 >= self.height {
             return Err(GridError::OutOfBounds {
@@ -56,6 +62,7 @@ impl Grid {
         Ok(self.tiles[pos.0 as usize][pos.1 as usize])
     }
 
+    /// Modifies the state of a tile using a mapping function.
     pub fn map_tile_state<F>(
         &self,
         pos: (u32, u32),
@@ -75,6 +82,7 @@ impl Grid {
         Ok(())
     }
 
+    /// Counts the number of tiles that are not unclaimed.
     pub fn count_claimed_tiles(&self, tile_query: &Query<&TileState>) -> u32 {
         self.tiles
             .iter()