Add chapter 2.6

src/melee_combat_system.rs

@@ -0,0 +1,48 @@
+use rltk::console;
+use specs::prelude::*;
+
+use crate::components::{CombatStats, Name, SufferDamage, WantsToMelee};
+
+pub struct MeleeCombatSystem {}
+
+impl<'a> System<'a> for MeleeCombatSystem {
+    type SystemData = (
+        Entities<'a>,
+        WriteStorage<'a, WantsToMelee>,
+        ReadStorage<'a, Name>,
+        ReadStorage<'a, CombatStats>,
+        WriteStorage<'a, SufferDamage>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (entities, mut wants_melee, names, combat_stats, mut inflict_damage) = data;
+
+        for (_entity, wants_melee, name, stats) in
+            (&entities, &wants_melee, &names, &combat_stats).join()
+        {
+            if stats.hp > 0 {
+                let target_stats = combat_stats.get(wants_melee.target).unwrap();
+                if target_stats.hp > 0 {
+                    let target_name = names.get(wants_melee.target).unwrap();
+
+                    let damage = i32::max(0, stats.power - target_stats.defense);
+
+                    if damage == 0 {
+                        console::log(&format!(
+                            "{} is unable to hurt {}",
+                            &name.name, &target_name.name
+                        ));
+                    } else {
+                        console::log(&format!(
+                            "{} hits {}, for {} hp.",
+                            &name.name, &target_name.name, damage
+                        ));
+                        SufferDamage::new_damage(&mut inflict_damage, wants_melee.target, damage)
+                    }
+                }
+            }
+        }
+
+        wants_melee.clear();
+    }
+}