From 0c40eba66fe49e2de4fd0c33cf31385ff1c3b646 Mon Sep 17 00:00:00 2001
From: ElnuDev <elnu@elnu.com>
Date: Wed, 15 Mar 2023 23:40:45 -0700
Subject: [PATCH] Add queen promotion, fix pawn taking two squares ahead

---
 src/Board.java |  7 +++++--
 src/Move.java  |  1 +
 src/Pawn.java  | 12 ++++++++----
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/Board.java b/src/Board.java
index 2bf3dba..e04fd3b 100644
--- a/src/Board.java
+++ b/src/Board.java
@@ -131,9 +131,11 @@ public class Board {
         // White pieces disappear if new move isn't created, don't know why
         Move copiedMove = new Move(new BoardCoordinate(move.from.x, move.from.y), new BoardCoordinate(move.to.x, move.to.y), get(move.to.x, move.to.y));
         copiedMove.submove = move.submove;
+        copiedMove.isPromotion = move.isPromotion;
         moveHistory.add(copiedMove);
         // moveHistory.add(move);
-        set(move.to, get(move.from));
+        Piece movedPiece = get(move.from);
+        set(move.to, move.isPromotion ? new Queen(movedPiece.black, panel) : movedPiece);
         set(move.from, null);
         move(move.submove);
         if (move.submove != null) moveHistory.pop();
@@ -148,7 +150,8 @@ public class Board {
 
     void undoMove(Move move) {
         if (move == null) return;
-        set(move.from, get(move.to));
+        Piece movedPiece = get(move.to);
+        set(move.from, move.isPromotion ? new Pawn(movedPiece.black, panel) : movedPiece);
         set(move.to, move.captured);
     }
 
diff --git a/src/Move.java b/src/Move.java
index 13bbd1f..e45d013 100644
--- a/src/Move.java
+++ b/src/Move.java
@@ -6,6 +6,7 @@ public class Move {
     public Piece captured;
     // e.g. castling, castle move. Done after.
     public Move submove;
+    public boolean isPromotion;
 
     public Move(BoardCoordinate from, BoardCoordinate to) {
         this.from = from;
diff --git a/src/Pawn.java b/src/Pawn.java
index 44e2068..5058adc 100644
--- a/src/Pawn.java
+++ b/src/Pawn.java
@@ -13,8 +13,10 @@ public class Pawn extends Piece {
         ArrayList<Move> possibleMoves = new ArrayList<>();
         if (this.black) {
             if (board.get(position.x, position.y + 1) == null) {
-                possibleMoves.add(new Move(position, new BoardCoordinate(position.x, position.y + 1)));
-                if (!moved) {
+                Move oneForward = new Move(position, new BoardCoordinate(position.x, position.y + 1));
+                oneForward.isPromotion = position.y + 1 == Board.BOARD_SIZE - 1;
+                possibleMoves.add(oneForward);
+                if (!moved && board.get(position.x, position.y + 2) == null) {
                     possibleMoves.add(new Move(position, new BoardCoordinate(position.x, position.y + 2)));
                 }
             }
@@ -27,8 +29,10 @@ public class Pawn extends Piece {
 
         } else {
             if (board.get(position.x, position.y - 1) == null) {
-                possibleMoves.add(new Move(position, new BoardCoordinate(position.x, position.y - 1)));
-                if (!moved) {
+                Move oneForward = new Move(position, new BoardCoordinate(position.x, position.y - 1));
+                oneForward.isPromotion = position.y - 1 == 0;
+                possibleMoves.add(oneForward);
+                if (!moved && board.get(position.x, position.y - 2) == null) {
                     possibleMoves.add(new Move(position, new BoardCoordinate(position.x, position.y - 2)));
                 }
             }