Add chapter 2.9

src/inventory_system.rs

@@ -0,0 +1,116 @@
+use rltk::Rltk;
+use specs::prelude::*;
+
+use crate::{CombatStats, InBackpack, Name, Position, Potion, State, WantsToDrinkPotion, WantsToDropItem, WantsToPickupItem};
+use crate::gamelog::GameLog;
+use crate::gui::ItemMenuResult;
+
+pub struct ItemCollectionSystem {}
+
+impl<'a> System<'a> for ItemCollectionSystem {
+    type SystemData = (
+        ReadExpect<'a, Entity>,
+        WriteExpect<'a, GameLog>,
+        WriteStorage<'a, WantsToPickupItem>,
+        WriteStorage<'a, Position>,
+        ReadStorage<'a, Name>,
+        WriteStorage<'a, InBackpack>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (player_entity, mut gamelog, mut wants_pickup, mut positions, names, mut backpack) =
+            data;
+
+        for pickup in wants_pickup.join() {
+            positions.remove(pickup.item);
+            backpack
+                .insert(
+                    pickup.item,
+                    InBackpack {
+                        owner: pickup.collected_by,
+                    },
+                )
+                .expect("Unable to insert backpack entry");
+
+            if pickup.collected_by == *player_entity {
+                gamelog.entries.push(format!(
+                    "You pick up the {}.",
+                    names.get(pickup.item).unwrap().name
+                ))
+            }
+        }
+
+        wants_pickup.clear();
+    }
+}
+
+pub struct PotionUseSystem {}
+
+impl<'a> System<'a> for PotionUseSystem {
+    type SystemData = (
+        ReadExpect<'a, Entity>,
+        WriteExpect<'a, GameLog>,
+        Entities<'a>,
+        WriteStorage<'a, WantsToDrinkPotion>,
+        ReadStorage<'a, Name>,
+        ReadStorage<'a, Potion>,
+        WriteStorage<'a, CombatStats>
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (player_entity, mut gamelog, entities, mut wants_drink, names, potions, mut combat_stats) = data;
+
+        for (entity, drink, stats) in (&entities, &wants_drink, &mut combat_stats).join() {
+            let potion = potions.get(drink.potion);
+            match potion {
+                None => {}
+                Some(potion) => {
+                    stats.hp = i32::min(stats.max_hp, stats.hp + potion.heal_amount);
+                    if entity == *player_entity {
+                        gamelog.entries.push(format!("You drink the {}, healing {} hp.", names.get(drink.potion).unwrap().name, potion.heal_amount));
+                    }
+                    entities.delete(drink.potion).expect("Delete failed");
+                }
+            }
+        }
+
+        wants_drink.clear();
+    }
+}
+
+pub struct ItemDropSystem {}
+
+impl<'a> System<'a> for ItemDropSystem {
+    type SystemData = (
+        ReadExpect<'a, Entity>,
+        WriteExpect<'a, GameLog>,
+        Entities<'a>,
+        WriteStorage<'a, WantsToDropItem>,
+        ReadStorage<'a, Name>,
+        WriteStorage<'a, Position>,
+        WriteStorage<'a, InBackpack>
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (player_entity, mut gamelog, entities, mut wants_drop, names, mut positions, mut backpack) = data;
+
+        for (entity, to_drop) in (&entities, &wants_drop).join() {
+            let mut dropper_pos: Position = Position { x: 0, y: 0 };
+            {
+                let dropped_pos = positions.get(entity).unwrap();
+                dropper_pos.x = dropped_pos.x;
+                dropper_pos.y = dropped_pos.y;
+            }
+            positions.insert(to_drop.item, Position { x: dropper_pos.x, y: dropper_pos.y }).expect("Unable to insert position");
+            backpack.remove(to_drop.item);
+
+            if entity == *player_entity {
+                gamelog.entries.push(format!("You drop the {}.", names.get(to_drop.item).unwrap().name));
+            }
+        }
+
+        wants_drop.clear();
+    }
+}
+
+