From e59a89eb2aaf16766320c25da19f3243c198d2d2 Mon Sep 17 00:00:00 2001
From: teknomunk <teknomunk@protonmail.com>
Date: Mon, 8 Apr 2024 21:37:54 +0000
Subject: [PATCH] Implement train reversing

---
 mods/ENTITIES/mcl_minecarts/functions.lua | 12 ++++++++++++
 mods/ENTITIES/mcl_minecarts/movement.lua  | 13 ++++++-------
 mods/ENTITIES/mcl_minecarts/train.lua     |  9 +++++++++
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/mods/ENTITIES/mcl_minecarts/functions.lua b/mods/ENTITIES/mcl_minecarts/functions.lua
index fad6121c0..a3b256022 100644
--- a/mods/ENTITIES/mcl_minecarts/functions.lua
+++ b/mods/ENTITIES/mcl_minecarts/functions.lua
@@ -364,3 +364,15 @@ function mod.get_cart_position(cart_staticdata)
 	return vector.add(data.connected_at, vector.multiply(data.dir or vector.zero(), data.distance or 0))
 end
 
+function mod.reverse_cart_direction(staticdata)
+
+	-- Complete moving thru this block into the next, reverse direction, and put us back at the same position we were at
+	local next_dir = -staticdata.dir
+	staticdata.connected_at = staticdata.connected_at + staticdata.dir
+	staticdata.distance = 1 - (staticdata.distance or 0)
+
+	-- recalculate direction
+	local next_dir,_ = mod:get_rail_direction(staticdata.connected_at, next_dir, nil, nil, staticdata.railtype)
+	staticdata.dir = next_dir
+end
+
diff --git a/mods/ENTITIES/mcl_minecarts/movement.lua b/mods/ENTITIES/mcl_minecarts/movement.lua
index b316d0742..1b84504f1 100644
--- a/mods/ENTITIES/mcl_minecarts/movement.lua
+++ b/mods/ENTITIES/mcl_minecarts/movement.lua
@@ -11,6 +11,7 @@ local MAX_TRAIN_LENGTH = mod.MAX_TRAIN_LENGTH
 -- Imports
 local train_length = mod.train_length
 local update_train = mod.update_train
+local reverse_train = mod.reverse_train
 local link_cart_ahead = mod.link_cart_ahead
 local update_cart_orientation = mod.update_cart_orientation
 local get_cart_data = mod.get_cart_data
@@ -248,14 +249,12 @@ local function calculate_acceleration(self, staticdata)
 end
 
 local function reverse_direction(self, staticdata)
-	-- Complete moving thru this block into the next, reverse direction, and put us back at the same position we were at
-	local next_dir = -staticdata.dir
-	staticdata.connected_at = staticdata.connected_at + staticdata.dir
-	staticdata.distance = 1 - (staticdata.distance or 0)
+	if staticdata.behind or staticdata.ahead then
+		reverse_train(self)
+		return
+	end
 
-	-- recalculate direction
-	local next_dir,_ = mcl_minecarts:get_rail_direction(staticdata.connected_at, next_dir, nil, nil, staticdata.railtype)
-	staticdata.dir = next_dir
+	mod.reverse_cart_direction(staticdata)
 end
 
 local function do_movement_step(self, dtime)
diff --git a/mods/ENTITIES/mcl_minecarts/train.lua b/mods/ENTITIES/mcl_minecarts/train.lua
index 88adb7f87..cac57fa7d 100644
--- a/mods/ENTITIES/mcl_minecarts/train.lua
+++ b/mods/ENTITIES/mcl_minecarts/train.lua
@@ -114,3 +114,12 @@ function mod.link_cart_ahead(cart, cart_ahead)
 	staticdata.ahead = ca_staticdata.uuid
 	ca_staticdata.behind = staticdata.uuid
 end
+
+
+function mod.reverse_train(cart)
+	for c in train_cars(cart) do
+		mod.reverse_cart_direction(c)
+		c.behind,c.ahead = c.ahead,c.behind
+	end
+end
+