From 6178e7c96395748162601e7b17ae18c6e5ccd74f Mon Sep 17 00:00:00 2001
From: MrGeorgen <moinl6162@gmail.com>
Date: Wed, 4 Sep 2024 08:24:54 +0200
Subject: [PATCH] fixed promotion for the white user

---
 src/chess/evaluate.c |  5 ++---
 src/chess/main.c     | 19 ++++++++++++-------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/chess/evaluate.c b/src/chess/evaluate.c
index 41cc3f0..817d253 100644
--- a/src/chess/evaluate.c
+++ b/src/chess/evaluate.c
@@ -3,7 +3,6 @@
 #include <stdint.h>
 #include <chess/bitboard.h>
 #include <chess/print.h>
-#include <stdio.h>
 
 // These min and max values will not overflow, when negated
 #define INT_16_SAFE_MIN (INT_LEAST16_MIN + 1)
@@ -56,9 +55,9 @@ static int_least16_t alphaBeta(const struct gameState_t gameState, int_fast16_t
 	uint_least8_t movesLength = validMoves(gameState, moves);
 	if(movesLength == 0) {
 		if(kingInCheck(gameState.board, gameState.color)) {
-			return INT_16_SAFE_MIN + 1;
+			return INT_16_SAFE_MIN + 1; // checkmate
 		}
-		return 0;
+		return 0; // stalemate
 	}
 	for(uint_least8_t i = 0; i < movesLength; ++i) {
 		const struct move_t move = moves[i];
diff --git a/src/chess/main.c b/src/chess/main.c
index e8e4973..2c35086 100644
--- a/src/chess/main.c
+++ b/src/chess/main.c
@@ -11,6 +11,9 @@
 #include <chess/bitboard.h>
 #include "evaluate.h"
 
+//#define START_FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+#define START_FEN "rnbqkbnr/PPppppPP/8/8/8/8/ppPPPPpp/RNBQKBNR w KQkq - 0 1"
+
 #define drawPiece(file, rank, piece) do { \
 				const RsvgRectangle rect = {xOffset +  (file) * fieldSize, yOffset + (rank) * fieldSize, fieldSize, fieldSize};\
 				rsvg_handle_render_document(piecesSvg[pieceToSvgI(piece)], cr, &rect, NULL); \
@@ -118,10 +121,11 @@ static void on_click(GtkGestureClick *gesture, int n_press, double x, double y,
 	const uint_least8_t file = adjustedX / fieldSize;
 	const uint_least8_t rank = adjustedY / fieldSize;
 	const uint_least8_t field = file + rank * BOARD_SIZE;
+	const bool promotion_field = rank == (gameState->color == WHITE ? 0 : BOARD_SIZE - 1);
 	if(drawData->selectDst == NOT_SELECTED) {
 		const struct piece_t allPiece = {ALL_PIECES, turn};
 		if(bitboardGet(board, allPiece, field)) {
-			// deaktivated piece by clicking on it again
+			// deactivated piece by clicking on it again
 			if(field == drawData->clickedPiece) {
 				drawData->clickedPiece = NOT_SELECTED;
 				drawData->movesLength = 0;
@@ -141,8 +145,8 @@ static void on_click(GtkGestureClick *gesture, int n_press, double x, double y,
 				}
 			}
 			if(isValidDst) {
-				const struct piece_t piece = pieceAtField(board, field);
-				if(piece.type == PAWN && field < BOARD_SIZE) { // promotion
+				const struct piece_t piece = pieceAtField(board, drawData->clickedPiece);
+				if(piece.type == PAWN && promotion_field) { // promotion
 					drawData->selectDst = field;
 				}
 				else {
@@ -162,12 +166,13 @@ static void on_click(GtkGestureClick *gesture, int n_press, double x, double y,
 			drawData->movesLength = 0;
 		}
 	}
-	else {
-		if(rank != 0) return;
+	else if(promotion_field) {
 		const uint_least8_t uiPos = promotionUiPos(drawData->selectDst);
+		const uint_least8_t i = file - uiPos;
+		if(i >= LENGTH(PROMOTION_PIECES)) return;
 		const uint_least8_t dstPiece = PROMOTION_PIECES[file - uiPos];
 		const uint_least8_t capturedPiece = pieceAtField(board, drawData->selectDst).type;
-		const struct move_t move = {drawData->clickedPiece, drawData->selectDst, 0, PAWN, dstPiece};
+		const struct move_t move = {drawData->clickedPiece, drawData->selectDst, 0, PAWN, dstPiece, capturedPiece};
 		*gameState = userMove(*gameState, move);
 		drawData->selectDst = NOT_SELECTED;
 		drawData->clickedPiece = NOT_SELECTED;
@@ -180,7 +185,7 @@ static void app_activate(GApplication *app, gpointer data) {
 	static RsvgHandle *piecesSvg[16];
 	static uint_least64_t board[BITBOARD_LENGTH];
 	static struct gameState_t gameState;
-	gameState = newGameState(board, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");
+	gameState = newGameState(board, START_FEN);
 	{
 		static struct move_t moves[TOTAL_BOARD_SIZE];
 		static struct drawData_t drawData = {piecesSvg, &gameState, NOT_SELECTED, moves, 0, NOT_SELECTED};