From 4c8fdfa3b48200e48f33962137287c01f369346c Mon Sep 17 00:00:00 2001
From: Karma Riuk <riukkarma@gmail.com>
Date: Sun, 2 Feb 2025 23:13:37 +0100
Subject: [PATCH] implemented en passant in legal moves

---
 cpp/src/pieces/pawn.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/cpp/src/pieces/pawn.cpp b/cpp/src/pieces/pawn.cpp
index 91b182f..8fae3f6 100644
--- a/cpp/src/pieces/pawn.cpp
+++ b/cpp/src/pieces/pawn.cpp
@@ -29,6 +29,19 @@ std::vector<Move> pawn_moves(const Board& b, const Coords xy) {
         }
     }
 
+    // -- Capture en passant
+    if (b.en_passant_target != -1) {
+        Coords c = Coords::from_index(b.en_passant_target);
+        int dy = my_colour == Colour::White ? -1 : 1;
+        if (c.y == xy.y + dy && (c.x == xy.x - 1 || c.x == xy.x + 1))
+            ret.push_back(Move{
+                xy.to_index(),
+                c.to_index(),
+                .is_capturing = true,
+                .en_passant = true
+            });
+    }
+
     // -- Promotion
     bool is_on_starting_rank =
         my_colour == Colour::White ? xy.y == 1 : xy.y == 6;