monsters move and attack the player

src/level.rs

@@ -9,6 +9,8 @@ use crate::monster::Monster;
 use crate::player::Player;
 use crate::position::HasPosition;
 use crate::position::Position;
+use rand::Rng;
+use rand::rngs::ThreadRng;
 
 pub const LEVEL_WIDTH: usize = 50;
 pub const LEVEL_HEIGHT: usize = 25;
@@ -34,6 +36,7 @@ pub struct Level {
     pub(crate) start: (usize, usize),
     /// the position of the end in the level (either stair down or end point)
     pub(crate) end: (usize, usize),
+    pub(crate) rng: ThreadRng,
 }
 
 impl Level {
@@ -108,7 +111,7 @@ impl Level {
             }
         }
     }
-    pub fn update(&mut self) {
+    pub fn update(&mut self, ticks: u128, player: &mut Player) {
         for (index, a) in &mut self.artifacts.iter().enumerate() {
             if a.was_collected() {
                 self.artifacts.remove(index);
@@ -122,17 +125,43 @@ impl Level {
             }
         }
         for index in 0..self.monsters.len() {
-            if self.can_monster_move(self.monsters[index].as_ref(), 0, 1) {
-                self.monsters[index].get_position().change(0, 1);
-            } else if self.can_monster_move(self.monsters[index].as_ref(), 0, -1) {
-                self.monsters[index].get_position().change(0, -1);
+            if ticks % self.monsters[index].get_ticks_between_steps() != 0 {
+                continue;
+            }
+            loop {
+                // calculate the direction the monster will try to walk
+                let (dx, dy) = match self.rng.gen_range(0..5) {
+                    1 => { (1, 0) }
+                    2 => { (-1, 0) }
+                    3 => { (0, 1) }
+                    4 => { (0, -1) }
+                    _ => { (0, 0) }
+                };
+                if self.can_monster_move(self.monsters[index].as_ref(), dx, dy) {
+                    let (new_x, new_y) = self.monsters[index].get_position().change(dx, dy);
+                    if player.get_immutable_position().get_x() == new_x && player.get_immutable_position().get_y() == new_y {
+                        self.monsters[index].decrease_life(1);
+                        player.change_life(-1);
+                    }
+                    break;
+                }
             }
         }
     }
+
     pub fn can_monster_move(&self, agent: &dyn Monster, dx: i16, dy: i16) -> bool {
         let agent_pos = agent.get_immutable_position();
         let new_x: usize = (agent_pos.get_x() as i16 + dx) as usize;
         let new_y: usize = (agent_pos.get_y() as i16 + dy) as usize;
+
+        if new_x < 0 || new_y < 0 || new_x >= LEVEL_WIDTH || new_y >= LEVEL_HEIGHT {
+            return false;
+        }
+
+        for index in 0..self.monsters.len() {
+            let pos = self.monsters[index].get_immutable_position();
+            if pos.get_x() == new_x && pos.get_y() == new_y { return false; }
+        }
         self.structure[new_x][new_y] != StructureElement::Wall
     }
     pub fn can_player_move(&self, agent: &Player, dx: i16, dy: i16) -> bool {
@@ -157,6 +186,7 @@ impl Level {
             artifacts: Vec::with_capacity(10),
             start: (0, 0),
             end: (0, 0),
+            rng: rand::thread_rng(),
         }
     }
     #[cfg(test)]