Add chapter 2.6

src/damage_system.rs

@@ -0,0 +1,45 @@
+use rltk::console;
+use specs::prelude::*;
+
+use crate::components::{CombatStats, Player, SufferDamage};
+
+pub struct DamageSystem {}
+
+impl<'a> System<'a> for DamageSystem {
+    type SystemData = (
+        WriteStorage<'a, CombatStats>,
+        WriteStorage<'a, SufferDamage>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (mut stats, mut damage) = data;
+
+        for (mut stats, damage) in (&mut stats, &damage).join() {
+            stats.hp -= damage.amount.iter().sum::<i32>();
+        }
+
+        damage.clear();
+    }
+}
+
+pub fn delete_the_dead(ecs: &mut World) {
+    let mut dead: Vec<Entity> = Vec::new();
+    {
+        let combat_stats = ecs.read_storage::<CombatStats>();
+        let players = ecs.read_storage::<Player>();
+        let entities = ecs.entities();
+        for (entity, stats) in (&entities, &combat_stats).join() {
+            if stats.hp < 1 {
+                let player = players.get(entity);
+                match player {
+                    None => dead.push(entity),
+                    Some(_) => console::log("You are dead"),
+                }
+            }
+        }
+    }
+
+    for victim in dead {
+        ecs.delete_entity(victim).expect("Unable to delete");
+    }
+}