try to improve monster handling

src/game.rs

@@ -3,7 +3,8 @@ use crate::level_generator::LevelGenerator;
 use crate::player::Player;
 use crate::position::{HasPosition, Position};
 
-pub const LEVELS: usize = 10;
+/// How many levels does the dungeon have?
+pub const LEVELS: usize = 2;
 
 #[derive(PartialEq)]
 /// represents a state of a game

src/level_generator.rs

@@ -1,4 +1,5 @@
 use std::cmp::{max, min};
+use std::collections::HashMap;
 use std::ops::Range;
 
 use petgraph::algo::min_spanning_tree;
@@ -11,13 +12,13 @@ use rand::Rng;
 
 use crate::artifacts::{Artifact, Chest, Potion};
 use crate::level::{Level, StructureElement};
-use crate::monster::{Monster, Orc, Rat, Snake};
+use crate::monster::{create_monster_by_type, Monster, Orc, Rat, Snake};
 use crate::position::Position;
 
-pub const ROOMS_VERTICAL: usize = 9;
+pub const ROOMS_VERTICAL: usize = 7;
 pub const ROOMS_HORIZONTAL: usize = 7;
 
-pub const ROOM_WIDTH: usize = 7;
+pub const ROOM_WIDTH: usize = 9;
 pub const ROOM_HEIGHT: usize = 6;
 
 #[derive(PartialEq, Copy, Clone)]
@@ -260,6 +261,33 @@ impl LevelGenerator {
         }
         true
     }
+
+    fn select_monster(position: Position, rng: &mut ThreadRng) -> Box<dyn Monster> {
+        let level = position.get_level();
+        let value = rng.gen_range(1..=100);
+
+        let t = [
+            // level 0
+            HashMap::from([("Rat", 1..=100)]),
+            // level 1
+            // HashMap::from([("Rat", 1..=50), ("Snake", 51..=100)]),
+            // // level 2
+            // HashMap::from([("Rat", 1..=40)]),
+        ];
+        if level < t.len() {
+            for (mtype, range) in &t[level] {
+                if range.contains(&value) {
+                    return create_monster_by_type(mtype, position);
+                }
+            }
+        }
+        match rng.gen_range(1..=100) {
+            1..=30 => Box::new(Orc::new_with_position(position)),
+            31..=60 => Box::new(Snake::new_with_position(position)),
+            _ => Box::new(Rat::new_with_position(position)),
+        }
+    }
+
     pub fn render(&self) -> Level {
         let mut rng = rand::thread_rng();
         let mut structure = [[StructureElement::Wall; 1 + ROOMS_HORIZONTAL * ROOM_HEIGHT];
@@ -300,23 +328,10 @@ impl LevelGenerator {
                     let t_x = left + room.offset_x + rng.gen_range(0..room.width);
                     let t_y = top + room.offset_y + rng.gen_range(0..room.height);
                     // TODO randomize enemies here
-                    match rng.gen_range(1..=100) {
-                        1..=30 => {
-                            enemies.push(Box::new(Orc::new_with_position(Position::new(
-                                self.level, t_x, t_y,
-                            ))));
-                        }
-                        31..=60 => {
-                            enemies.push(Box::new(Snake::new_with_position(Position::new(
-                                self.level, t_x, t_y,
-                            ))));
-                        }
-                        _ => {
-                            enemies.push(Box::new(Rat::new_with_position(Position::new(
-                                self.level, t_x, t_y,
-                            ))));
-                        }
-                    };
+                    enemies.push(LevelGenerator::select_monster(
+                        Position::new(self.level, t_x, t_y),
+                        &mut rng,
+                    ));
                 }
 
                 if room.kind == RoomType::End || room.kind == RoomType::StairDown {

src/monster.rs

@@ -103,6 +103,17 @@ impl Snake {
 }
 create_monster!(Snake);
 
+pub fn create_monster_by_type(mtype: &str, position: Position) -> Box<dyn Monster> {
+    match mtype {
+        "Rat" => Box::new(Rat::new_with_position(position)),
+        "Orc" => Box::new(Orc::new_with_position(position)),
+        "Snake" => Box::new(Snake::new_with_position(position)),
+        &_ => {
+            panic!("Unknown species: {}", mtype)
+        }
+    }
+}
+
 #[test]
 fn monsters_can_move() {
     let mut m = Rat::new_with_position(Position::new(0, 0, 0));