From ef65e86547867f02fc2de6bd930e69c8d97209b3 Mon Sep 17 00:00:00 2001
From: Wuzzy <Wuzzy@disroot.org>
Date: Sun, 16 Jul 2023 09:35:09 +0200
Subject: [PATCH] Chess: Fix AI pawn doublestep safe from en passant

---
 src/chess.lua | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/chess.lua b/src/chess.lua
index 9105316..bc96457 100644
--- a/src/chess.lua
+++ b/src/chess.lua
@@ -2036,6 +2036,15 @@ local function ai_move(inv, meta)
 						inv:set_stack("board", choice_to, pieceFrom)
 					end
 
+					-- Note the pawn double step
+					local c_from_x, c_from_y = index_to_xy(choice_from)
+					local c_to_x, c_to_y = index_to_xy(choice_to)
+					if pieceFrom:find("pawn") and math.abs(c_from_y - c_to_y) == 2 then
+						meta:set_int("prevDoublePawnStepTo", choice_to)
+					else
+						meta:set_int("prevDoublePawnStepTo", 0)
+					end
+
 					inv:set_stack("board", choice_from, "")
 				end