From e93573f3a02f6c325c0ee5c0c85e3307b3050173 Mon Sep 17 00:00:00 2001
From: "Timothy J. Warren" <tim@timshomepage.net>
Date: Fri, 24 Dec 2021 14:44:48 -0500
Subject: [PATCH] Complete section 5.5 by swapping locations with non-hostile
 NPCs

---
 src/main.rs   |  3 ++-
 src/player.rs | 49 ++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 40e0003..44bce10 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -402,7 +402,8 @@ impl State {
         }
 
         // Build a new map and place the player
-        let current_depth;
+        #[allow(unused_assignments)]
+        let mut current_depth = 1;
         {
             let worldmap_resource = self.ecs.fetch::<Map>();
             current_depth = worldmap_resource.depth;
diff --git a/src/player.rs b/src/player.rs
index 0bbefd0..02f9e36 100644
--- a/src/player.rs
+++ b/src/player.rs
@@ -8,7 +8,7 @@ use crate::components::{
     Monster, Player, Position, Renderable, Viewshed, WantsToMelee, WantsToPickupItem,
 };
 use crate::game_log::GameLog;
-use crate::{Map, RunState, State, TileType};
+use crate::{Bystander, Map, RunState, State, TileType};
 
 pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut positions = ecs.write_storage::<Position>();
@@ -23,6 +23,9 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut blocks_visibility = ecs.write_storage::<BlocksVisibility>();
     let mut blocks_movement = ecs.write_storage::<BlocksTile>();
     let mut renderables = ecs.write_storage::<Renderable>();
+    let bystanders = ecs.read_storage::<Bystander>();
+
+    let mut swap_entities: Vec<(Entity, i32, i32)> = Vec::new();
 
     for (entity, _player, pos, viewshed) in
         (&entities, &players, &mut positions, &mut viewsheds).join()
@@ -37,16 +40,33 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
         let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
 
         for potential_target in map.tile_content[destination_idx].iter() {
-            if let Some(_target) = combat_stats.get(*potential_target) {
-                wants_to_melee
-                    .insert(
-                        entity,
-                        WantsToMelee {
-                            target: *potential_target,
-                        },
-                    )
-                    .expect("Add target failed");
-                return;
+            if bystanders.get(*potential_target).is_some() {
+                // Note that we want to move the bystander
+                swap_entities.push((*potential_target, pos.x, pos.y));
+
+                // Move the player
+                pos.x = min(map.width - 1, max(0, pos.x + delta_x));
+                pos.y = min(map.height - 1, max(0, pos.y + delta_y));
+                entity_moved
+                    .insert(entity, EntityMoved {})
+                    .expect("Unable to insert moved entity marker");
+
+                viewshed.dirty = true;
+                let mut ppos = ecs.write_resource::<Point>();
+                ppos.x = pos.x;
+                ppos.y = pos.y
+            } else {
+                if combat_stats.get(*potential_target).is_some() {
+                    wants_to_melee
+                        .insert(
+                            entity,
+                            WantsToMelee {
+                                target: *potential_target,
+                            },
+                        )
+                        .expect("Add target failed");
+                    return;
+                }
             }
 
             if let Some(door) = doors.get_mut(*potential_target) {
@@ -73,6 +93,13 @@ pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
             ppos.y = pos.y;
         }
     }
+
+    for m in swap_entities.iter() {
+        if let Some(their_pos) = positions.get_mut(m.0) {
+            their_pos.x = m.1;
+            their_pos.y = m.2;
+        }
+    }
 }
 
 pub fn try_next_level(ecs: &mut World) -> bool {