From 31499ed6e1abf8cb39ac3c63859b149d31ad4e5b Mon Sep 17 00:00:00 2001
From: "A.M. Rowsell" <amrowsell@frozenelectronics.ca>
Date: Tue, 26 Aug 2025 20:34:04 -0400
Subject: [PATCH] dev: working on check detection algorithm

---
 Piece.cpp | 57 ++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 7 deletions(-)

diff --git a/Piece.cpp b/Piece.cpp
index 40555f7..bab48ec 100644
--- a/Piece.cpp
+++ b/Piece.cpp
@@ -25,7 +25,7 @@ std::vector<Move> Piece::getLegalMoves(const Square &from, const Board &board) c
 
 std::vector<Move> King::getLegalMoves(const Square &from, const Board &board) const {
     std::vector<Move> moveList;
-    const int directions[8][2] = {
+    std::vector<std::vector<int>> directions = {
         {-1, 0}, // Up
         {-1, -1}, // up-left
         {-1, 1}, // up-right
@@ -39,11 +39,12 @@ std::vector<Move> King::getLegalMoves(const Square &from, const Board &board) co
         // establish r/f for square to check
         int r = from.rank + dir[0];
         int f = from.file + dir[1];
-        if(r >= 0 && r < 8 && f >= 0 && f < 8) {
+        auto ra = static_cast<Rank>(r);
+        auto fi = static_cast<File>(f);
+        Square targetSquare = {ra, fi};
+        if(targetSquare.isValid()) {
             const auto &target = board.boardGrid[r][f]; // examine the target square
-            auto ra = static_cast<Rank>(r);
-            auto fi = static_cast<File>(f);
-            Square targetSquare = {ra, fi};
+            
             if(!target) { // if square is empty (NULL)
                 moveList.push_back({from, targetSquare}); // then it's potentially a legal move
             } else if(target && target->getColour() != this->getColour()) { // if it's occupied with a piece of opposite colour
@@ -61,19 +62,61 @@ std::vector<Move> King::getLegalMoves(const Square &from, const Board &board) co
     // - Determine the piece type
     // - Determine the direction we are looking at (diagonal or not)
     // - If that piece can attack in that direction, it would be check, so remove this move from moveList
+    // We need to add knight attack to the directions to check
+    /*
+     * __3_4___
+     * _1___2__
+     * ___K____
+     * _5___6__
+     * __7_8___ 
+     * 
+     */
+    std::vector<std::vector<int>> knightAttacks = {
+        {-1, -2}, // 1
+        {-1, 2},  // 2
+        {-2, -1}, // 3
+        {-2, 1},  // 4
+        {1, -2},  // 5
+        {1, 2},   // 6
+        {2, -1},  // 7
+        {2, 1}    // 8
+    };
+    directions.insert(directions.end(), knightAttacks.begin(), knightAttacks.end()); // concatenate the knight attacks
     for(auto &moves : moveList) {
-        Square startSquare = moves.to; // get the potential move to square
+        Square startSquare = moves.to; // get the potential moveto square
         for(auto &dir : directions) { // now go through all directions
             int r = startSquare.rank + dir[0];
             int f = startSquare.file + dir[1];
             bool diagonal = (abs(dir[0]) + abs(dir[1]) == 2) ? 1 : 0; // check if diagonal
+            bool knight = (abs(dir[0]) + abs(dir[1]) == 3) ? 1 : 0; // check if knight attack
             while(r >= 0 && r < 8 && f >= 0 && f < 8) {
                 auto &target = board.boardGrid[r][f]; // check what's at the square we're examining
-                if(target && target->getColour() != this->getColour()) { // is it occupied & an enemy?
+                if(!target) {
+                    // empty square, continue
+                    continue;
+                }
+                if(target && (target->getColour() != this->getColour())) { // is it occupied & an enemy?
                     if((target->getPieceType() == QUEEN || target->getPieceType() == BISHOP) && diagonal) {
                         // we are being attacked diagonally on this square, so remove it
                         //moves.to.rank = 255; moves.to.file = 255; // mark as invalid???
                     }
+                    if(target->getPieceType() == KNIGHT && knight) {
+                        // we are being attacked by a knight, so remove it
+                        //moves.to.rank = 255; moves.to.file = 255;
+                    }
+                    if(target->getPieceType() == ROOK && (!diagonal && !knight)) {
+                        // again, being attacked, remove it
+                    }
+                }
+                if(target && (target->getColour() == this->getColour())) {
+                    // we've hit a friendly, stop
+                    break;
+                }
+                if(!knight) {
+                    r += dir[0];
+                    f += dir[1];
+                } else {
+                    break;
                 }
             }
         }