From 72ed107d178cbbe3b3b9b39e29117b54bac3a433 Mon Sep 17 00:00:00 2001
From: Alex Bethel <abethel@cs.nmt.edu>
Date: Thu, 6 Jan 2022 14:04:55 -0600
Subject: [PATCH] Disallow player phasing through walls

---
 src/game.rs   |  6 ++++++
 src/player.rs | 23 +++++++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/game.rs b/src/game.rs
index 225ddef..6482dd5 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -98,6 +98,12 @@ impl DungeonLevel {
             DungeonTile::Hallway => '#',
         }
     }
+
+    /// Gets a reference to the tile at the given coordinates. Panics
+    /// of the coordinates are out of bounds.
+    pub fn tile(&self, x: i32, y: i32) -> &DungeonTile {
+        &self.tiles[y as usize][x as usize]
+    }
 }
 
 impl Display for DungeonLevel {
diff --git a/src/player.rs b/src/player.rs
index fd62ad1..8436b07 100644
--- a/src/player.rs
+++ b/src/player.rs
@@ -5,7 +5,7 @@ use specs::prelude::*;
 
 use crate::{
     components::{CharRender, MobAction, Mobile, Player, Position},
-    game::DungeonLevel,
+    game::{DungeonLevel, DungeonTile},
     quit,
 };
 
@@ -53,7 +53,9 @@ pub fn player_turn(ecs: &mut World, screen: &mut Window) {
         };
 
         if let Some(action) = action {
-            break action;
+            if possible(ecs, &action) {
+                break action;
+            }
         }
     };
 
@@ -64,6 +66,23 @@ pub fn player_turn(ecs: &mut World, screen: &mut Window) {
     }
 }
 
+/// Checks whether an action is possible for the player to execute in
+/// the given world.
+fn possible(ecs: &World, action: &MobAction) -> bool {
+    match action {
+        MobAction::Nop => true,
+        MobAction::Move(dx, dy) => {
+            let players = ecs.read_storage::<Player>();
+            let positions = ecs.read_storage::<Position>();
+            let map = ecs.fetch::<DungeonLevel>();
+
+            (&players, &positions)
+                .join()
+                .all(|(_plr, pos)| map.tile(pos.x + dx, pos.y + dy) != &DungeonTile::Wall)
+        }
+    }
+}
+
 /// Renders the state of the world onto the screen.
 fn render_screen(ecs: &mut World, screen: &mut Window) {
     // screen.clear();