From c454bab2b1447210140c17b3d259c874f7205b02 Mon Sep 17 00:00:00 2001
From: Peter Hart <cinphart@gmail.com>
Date: Wed, 1 Apr 2020 23:28:53 -0400
Subject: [PATCH] initial monster AI system

---
 src/components.rs        |  3 +++
 src/main.rs              | 20 ++++++++++++++------
 src/monster_ai_system.rs | 21 +++++++++++++++++++++
 3 files changed, 38 insertions(+), 6 deletions(-)
 create mode 100644 src/monster_ai_system.rs

diff --git a/src/components.rs b/src/components.rs
index 5f17e23..a3d594e 100644
--- a/src/components.rs
+++ b/src/components.rs
@@ -24,3 +24,6 @@ pub struct Viewshed {
     pub range: i32,
     pub dirty: bool,
 }
+
+#[derive(Component, Debug)]
+pub struct Monster {}
diff --git a/src/main.rs b/src/main.rs
index ed5a245..c93d638 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,6 +9,8 @@ mod components;
 pub use components::*;
 mod visibility_system;
 pub use visibility_system::VisibilitySystem;
+mod monster_ai_system;
+pub use monster_ai_system::MonsterAI;
 
 #[macro_use]
 extern crate specs_derive;
@@ -26,7 +28,7 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     for (_player, pos, viewshed) in (&mut players, &mut positions, &mut viewsheds).join() {
         let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
         if map.tiles[destination_idx] != TileType::Wall {
-            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.x = min(79, max(0, pos.x + delta_x));
             pos.y = min(49, max(0, pos.y + delta_y));
 
             viewshed.dirty = true;
@@ -60,6 +62,8 @@ impl State {
     fn run_systems(&mut self) {
         let mut vis = VisibilitySystem {};
         vis.run_now(&self.ecs);
+        let mut mob = MonsterAI {};
+        mob.run_now(&self.ecs);
         self.ecs.maintain();
     }
 }
@@ -74,8 +78,10 @@ impl GameState for State {
         let renderables = self.ecs.read_storage::<Renderable>();
         let map = self.ecs.fetch::<Map>();
         for (pos, render) in (&positions, &renderables).join() {
-            let idx = map.xy_idx(pos.x,pos.y);
-            if map.visible_tiles[idx] { ctx.set(pos.x, pos.y, render.fg, render.bg, render.glyph); }
+            let idx = map.xy_idx(pos.x, pos.y);
+            if map.visible_tiles[idx] {
+                ctx.set(pos.x, pos.y, render.fg, render.bg, render.glyph);
+            }
         }
     }
 }
@@ -128,6 +134,7 @@ fn main() {
     gs.ecs.register::<Renderable>();
     gs.ecs.register::<Player>();
     gs.ecs.register::<Viewshed>();
+    gs.ecs.register::<Monster>();
 
     gs.ecs
         .create_entity()
@@ -152,9 +159,9 @@ fn main() {
 
     for room in map.rooms.iter().skip(1) {
         let (x, y) = room.center();
-        let glyph = match rng.roll_dice(1,2) {
-            1 =>  { rltk::to_cp437('g') }
-            _ => { rltk::to_cp437('o') }
+        let glyph = match rng.roll_dice(1, 2) {
+            1 => rltk::to_cp437('g'),
+            _ => rltk::to_cp437('o'),
         };
         gs.ecs
             .create_entity()
@@ -169,6 +176,7 @@ fn main() {
                 range: 8,
                 dirty: true,
             })
+            .with(Monster {})
             .build();
     }
 
diff --git a/src/monster_ai_system.rs b/src/monster_ai_system.rs
new file mode 100644
index 0000000..413ea77
--- /dev/null
+++ b/src/monster_ai_system.rs
@@ -0,0 +1,21 @@
+use super::{Map, Monster, Position, Viewshed};
+use rltk::{console, field_of_view, Point};
+use specs::prelude::*;
+
+pub struct MonsterAI {}
+
+impl<'a> System<'a> for MonsterAI {
+    type SystemData = (
+        ReadStorage<'a, Viewshed>,
+        ReadStorage<'a, Position>,
+        ReadStorage<'a, Monster>,
+    );
+
+    fn run(&mut self, data : Self::SystemData) {
+        let (viewshed, pos, monster) = data;
+
+        for (viewshed, pos, monster) in (&viewshed, &pos, &monster).join() {
+            console::log("Monster considers their own existence")
+        }
+    }
+}