a bit more collision detection logic

game_core/src/field/field.rs

@@ -0,0 +1,30 @@
+#[derive(Clone, Copy, PartialEq)]
+pub enum Tile {
+    Empty,
+    Wall,
+    Food,
+}
+
+pub struct Field {
+    pub width: usize,
+    pub height: usize,
+    pub tiles: Vec<Tile>,
+}
+
+impl Field {
+    pub fn new(width: usize, height: usize) -> Self {
+        Self {
+            width,
+            height,
+            tiles: vec![Tile::Empty; width * height],
+        }
+    }
+
+    pub fn get_tile(&self, x: usize, y: usize) -> Tile {
+        self.tiles[y * self.width + x]
+    }
+
+    pub fn set_tile(&mut self, x: usize, y: usize, tile: Tile) {
+        self.tiles[y * self.width + x] = tile;
+    }
+}

game_core/src/field/mod.rs

@@ -0,0 +1 @@
+pub mod field;

game_core/src/game_handler/game_handler.rs

@@ -0,0 +1,15 @@
+use crate::{field::field::Field, snake::snake::SnakeHandler};
+
+pub struct GameData {
+    field: Field,
+    snakes: Vec<SnakeHandler>,
+}
+
+impl GameData {
+    pub fn new(field: Field, snakes: Vec<SnakeHandler>) -> Self {
+        Self {
+            field,
+            snakes,
+        }
+    }
+}

game_core/src/game_handler/mod.rs

@@ -0,0 +1,2 @@
+pub mod game_handler;
+pub mod states;

game_core/src/game_handler/states.rs

@@ -0,0 +1,33 @@
+use std::time::Duration;
+
+use crate::{game_handler::game_handler::GameData, inputs::Inputs};
+
+
+pub trait GameManagerState {
+    fn update(&mut self, delta: Duration, inputs: &Inputs, game_data: &mut GameData) -> Option<Box<dyn GameManagerState>>;
+}
+
+
+pub struct PlayingState {
+    dt_accumulator: Duration,
+}
+
+impl PlayingState {
+    pub fn new() -> Self {
+        Self { dt_accumulator: Duration::ZERO }
+    }
+}
+
+impl GameManagerState for PlayingState {
+    fn update(&mut self, delta: Duration, inputs: &Inputs, game_data: &mut GameData) -> Option<Box<dyn GameManagerState>> {
+        None
+    }
+}
+
+pub struct PausedState;
+
+impl GameManagerState for PausedState {
+    fn update(&mut self, _delta: Duration, _inputs: &Inputs, _game_data: &mut GameData) -> Option<Box<dyn GameManagerState>> {
+        None
+    }
+}

game_core/src/lib.rs

@@ -3,6 +3,8 @@ pub mod inputs;
 pub mod snake;
 pub mod common;
 pub mod traits;
+pub mod field;
+pub mod game_handler;
 
 pub fn add(left: u64, right: u64) -> u64 {
     left + right

game_core/src/snake/snake.rs

@@ -1,6 +1,7 @@
 use std::time::Duration;
 use crate::common::position::Position;
 use crate::inputs::Inputs;
+use crate::field::field::{Field, Tile};
 use crate::snake::states::SnakeState;
 
 pub struct Node {
@@ -43,10 +44,46 @@ impl Snake {
         false
     }
 
-    // TODO: implement this once we have wall data
-    // pub fn is_colliding_against_wall(other_snake: &Snake) {
+    pub fn is_colliding_against_itself(&self) -> bool {
+        let head_pos = self.body.position;
+        let mut current_node = self.body.next.as_deref();
 
-    // }
+        while let Some(node) = current_node {
+            if node.position == head_pos {
+                return true;
+            }
+            current_node = node.next.as_deref();
+        }
+        false
+    }
+
+    pub fn is_reaching_field_boundaries(&self, field: &Field) -> bool {
+        // TODO: implement logic to teleport snake's head to the other side
+        let pos = self.body.position;
+        if pos.x < 0 || pos.x >= field.width as isize || pos.y < 0 || pos.y >= field.height as isize {
+            return true;
+        }
+        false
+
+    }
+
+    pub fn is_colliding_against_wall(&self, field: &Field) -> bool {
+        let pos = self.body.position;
+        if pos.x < 0 || pos.x >= field.width as isize || pos.y < 0 || pos.y >= field.height as isize {
+            return false;
+        }
+        
+        field.get_tile(pos.x as usize, pos.y as usize) == Tile::Wall
+    }
+
+    pub fn is_eating(&self, field: &Field) -> bool {
+        let pos = self.body.position;
+        if pos.x < 0 || pos.x >= field.width as isize || pos.y < 0 || pos.y >= field.height as isize {
+            return false;
+        }
+
+        field.get_tile(pos.x as usize, pos.y as usize) == Tile::Food
+    }
 
     pub fn do_move(&mut self) {
         // probably a more optimal way of approaching this is just
@@ -65,6 +102,16 @@ impl Snake {
         }
     }
 
+    pub fn grow(&mut self) {
+        let mut tail = &mut self.body;
+        while let Some(ref mut next_node) = tail.next {
+            tail = next_node;
+        }
+        tail.next = Some(Box::new(Node {
+            position: tail.position, 
+            next: None,
+        }));
+    }
 }
 
 pub struct SnakeHandler {
@@ -153,4 +200,49 @@ mod tests {
         let first_body = snake.body.next.as_ref().unwrap();
         assert_eq!(first_body.position, Position{x: 10, y: 10});
     }
+
+    #[test]
+    fn test_grow() {
+        // Setup: Snake with just a head at (10, 10)
+        let mut snake = Snake::new(Position { x: 10, y: 10 }, Position { x: 1, y: 0 }, 1.0);
+        assert!(snake.body.next.is_none());
+
+        snake.grow();
+
+        let first_body = snake.body.next.as_ref().unwrap();
+        assert!(first_body.next.is_none());
+        assert_eq!(first_body.position, Position { x: 10, y: 10 });
+
+        snake.grow();
+        
+        let first_body = snake.body.next.as_ref().unwrap();
+        let second_body = first_body.next.as_ref().unwrap();
+        assert_eq!(second_body.position, Position { x: 10, y: 10 });
+    }
+
+    #[test]
+    fn test_is_colliding_against_itself() {
+        // Snake head at (5, 5)
+        let mut snake = Snake::new(Position { x: 5, y: 5 }, Position { x: 1, y: 0 }, 1.0);
+
+        // Body at (5, 5) -> (5, 6) -> (5, 5)
+        snake.body.next = Some(Box::new(Node {
+            position: Position { x: 5, y: 6 },
+            next: Some(Box::new(Node {
+                position: Position { x: 5, y: 5 },
+                next: None,
+            })),
+        }));
+
+        assert!(snake.is_colliding_against_itself());
+
+        // Snake with no self-collision
+        let mut safe_snake = Snake::new(Position { x: 5, y: 5 }, Position { x: 1, y: 0 }, 1.0);
+        safe_snake.body.next = Some(Box::new(Node {
+            position: Position { x: 6, y: 5 },
+            next: None,
+        }));
+
+        assert!(!safe_snake.is_colliding_against_itself());
+    }
 }