Add a bunch of missing files

src/systems/collisions.rs

@@ -0,0 +1,17 @@
+use crate::prelude::*;
+
+#[system]
+#[read_component(Point)]
+#[read_component(Player)]
+#[read_component(Enemy)]
+pub fn collisions(ecs: &mut SubWorld, commands: &mut CommandBuffer) {
+    let mut player_pos = Point::zero();
+    let mut players = <&Point>::query().filter(component::<Player>());
+    players.iter(ecs).for_each(|pos| player_pos = *pos);
+
+    let mut enemies = <(Entity, &Point)>::query().filter(component::<Enemy>());
+    enemies
+        .iter(ecs)
+        .filter(|(_, pos)| **pos == player_pos)
+        .for_each(|(entity, _)| commands.remove(*entity));
+}

src/systems/end_turn.rs

@@ -0,0 +1,12 @@
+use crate::prelude::*;
+
+#[system]
+pub fn end_turn(#[resource] turn_state: &mut TurnState) {
+    let new_state = match turn_state {
+        TurnState::AwaitingInput => return,
+        TurnState::PlayerTurn => TurnState::MonsterTurn,
+        TurnState::MonsterTurn => TurnState::AwaitingInput,
+    };
+
+    *turn_state = new_state;
+}

src/systems/hud.rs

@@ -0,0 +1,28 @@
+use crate::prelude::*;
+
+#[system]
+#[read_component(Health)]
+#[read_component(Player)]
+pub fn hud(ecs: &SubWorld) {
+    let mut health_query = <&Health>::query().filter(component::<Player>());
+    let player_health = health_query.iter(ecs).next().unwrap();
+    let mut draw_batch = DrawBatch::new();
+    draw_batch.target(2);
+    draw_batch.print_centered(1, "Explore the Dungeon. Cursor keys or ASWD to move.");
+    draw_batch.bar_horizontal(
+        Point::zero(),
+        SCREEN_WIDTH * 2,
+        player_health.current,
+        player_health.max,
+        ColorPair::new(RED, BLACK),
+    );
+    draw_batch.print_color_centered(
+        0,
+        format!(
+            " Health: {} / {} ",
+            player_health.current, player_health.max
+        ),
+        ColorPair::new(WHITE, RED),
+    );
+    draw_batch.submit(10000).expect("Batch error");
+}

src/systems/movement.rs

@@ -0,0 +1,26 @@
+use crate::prelude::*;
+
+#[system(for_each)]
+#[read_component(Player)]
+pub fn movement(
+    entity: &Entity,
+    want_move: &WantsToMove,
+    #[resource] map: &Map,
+    #[resource] camera: &mut Camera,
+    ecs: &mut SubWorld,
+    commands: &mut CommandBuffer,
+) {
+    if map.can_enter_tile(want_move.destination) {
+        commands.add_component(want_move.entity, want_move.destination);
+
+        if ecs
+            .entry_ref(want_move.entity)
+            .unwrap()
+            .get_component::<Player>()
+            .is_ok()
+        {
+            camera.on_player_move(want_move.destination)
+        }
+    }
+    commands.remove(*entity);
+}

src/systems/random_move.rs

@@ -0,0 +1,25 @@
+use crate::prelude::*;
+
+#[system]
+#[read_component(Point)]
+#[read_component(MovingRandomly)]
+pub fn random_move(ecs: &mut SubWorld, commands: &mut CommandBuffer) {
+    let mut movers = <(Entity, &Point, &MovingRandomly)>::query();
+    movers.iter_mut(ecs).for_each(|(entity, pos, _)| {
+        let mut rng = RandomNumberGenerator::new();
+        let destination = match rng.range(0, 4) {
+            0 => Point::new(-1, 0),
+            1 => Point::new(1, 0),
+            2 => Point::new(0, -1),
+            _ => Point::new(0, 1),
+        } + *pos;
+
+        commands.push((
+            (),
+            WantsToMove {
+                entity: *entity,
+                destination,
+            },
+        ));
+    });
+}

src/turn_state.rs

@@ -0,0 +1,6 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum TurnState {
+    AwaitingInput,
+    PlayerTurn,
+    MonsterTurn,
+}