void get_king_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player, Pos piece){
Move* res = NULL;
Move* res_head = res;
Pos pos[4] = { { piece.col - 1, piece.row - 1 }, { piece.col + 1, piece.row - 1 }, { piece.col - 1, piece.row + 1 }, { piece.col + 1, piece.row + 1 } };
Pos curr;
int found_ahead;
for (int p = 0; p < 4; p++){
curr = pos[p];
while (is_valid_pos(curr) && board[curr.col][curr.row] == EMPTY){
add_move(piece, &curr, 1);
curr = get_next_diag(piece, curr);
// BUG - once dests_num == 1 and |dest-start| != 1 add_moves thinks its 1 capture and not a simple move..
}
if (is_valid_pos(curr) && is_opposite(player, board[curr.col][curr.row])){
char tmp = board[curr.row][curr.col];
board[curr.row][curr.col] = EMPTY;
Pos new_piece = get_next_diag(piece, curr);
if (is_valid_pos(new_piece) && board[new_piece.row][new_piece.col] == EMPTY){
found_ahead = get_capture_moves(piece, new_piece, board, player, 1, &new_piece);
if (found_ahead == 0) add_move(piece, &new_piece, 1);
}
board[curr.row][curr.col] = tmp;
}
}
}
int get_capture_moves(Pos start, Pos piece, char board[BOARD_SIZE][BOARD_SIZE], COLOR player, int count, Pos* dests){
Pos pos[4] = { { piece.col - 1, piece.row - 1 }, { piece.col + 1, piece.row - 1 }, { piece.col - 1, piece.row + 1 }, { piece.col + 1, piece.row + 1 } };
int found_now = 0, found_ahead;
for (int p = 0; p < 4; p++)
if (is_valid_pos(pos[p]) && is_opposite(player, board[pos[p].col][pos[p].row])){
Pos new_piece = get_next_diag(piece, pos[p]);
if (is_valid_pos(new_piece) && board[new_piece.col][new_piece.row] == EMPTY){
found_now++;
char tmp = board[pos[p].col][pos[p].row];
board[pos[p].col][pos[p].row] = EMPTY;
Pos* new_dests = malloc(sizeof(Pos) * (count + 1));
for (int i = 0; i < count; i++){
new_dests[i].row = dests[i].row;
new_dests[i].col = dests[i].col;
}
new_dests[count].row = new_piece.row;
new_dests[count].col = new_piece.col;
found_ahead = get_capture_moves(start, new_piece, board, player, count + 1, new_dests);
if (found_ahead == 0){
add_move(start, new_dests, count + 1);
free(new_dests);
}
board[pos[p].row][pos[p].col] = tmp;
}
}
return found_now;
}
// finds all moves of a single king piece
void get_king_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player, Pos piece){
Pos pos[4] = { { piece.col - 1, piece.row - 1 }, { piece.col + 1, piece.row - 1 }, { piece.col - 1, piece.row + 1 }, { piece.col + 1, piece.row + 1 } };
Pos curr, new_piece;
int found_ahead = -1;
for (int p = 0; p < 4; p++){
curr = pos[p];
while (is_valid_pos(curr) && board[curr.col][curr.row] == EMPTY){
add_move(piece, &curr, 0);
curr = get_next_diag(piece, curr);
}
if (is_valid_pos(curr) && is_opposite(player, board[curr.col][curr.row])){
char tmp = board[curr.col][curr.row];
board[curr.col][curr.row] = EMPTY;
board[piece.col][piece.row] = EMPTY;
new_piece = get_next_diag(piece, curr);
if (is_valid_pos(new_piece) && board[new_piece.col][new_piece.row] == EMPTY){
found_ahead = get_capture_moves(piece, new_piece, board, player, 1, &new_piece);
if (found_ahead == 0) add_move(piece, &new_piece, 1);
}
board[curr.col][curr.row] = tmp;
board[piece.col][piece.row] = curr_piece;
}
}
}
// calculates the score of the board from a player's prospective
int calc_score(char board[BOARD_SIZE][BOARD_SIZE], COLOR player){
int score = 0, opposites = 0;
for (int i = 0; i < BOARD_SIZE; i++)
for (int j = 0; j < BOARD_SIZE; j++){
if (is_opposite(player, board[i][j])) opposites++;
score += get_piece_score(board[i][j], player);
}
if (opposites == 0) return 100;
return score;
}
Move * get_all_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player){
moves_head = NULL;
moves = NULL;
Pos p;
for (int i = 0; i < BOARD_SIZE; i++)
for (int j = 0; j < BOARD_SIZE; j++)
if (!is_opposite(player, board[i][j]) && board[i][j] != EMPTY){
p.row = j;
p.col = i;
get_moves_by_piece(board, player, p);
}
clear_illegal_moves(board, player);
return moves_head;
}
Move * get_all_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player){
clear_old_moves(moves_head);
Pos p;
for (int i = 0; i < BOARD_SIZE; i++)
for (int j = 0; j < BOARD_SIZE; j++)
if (!is_opposite(player, board[i][j]) && board[i][j] != EMPTY){
p.row = j;
p.col = i;
if (is_king(board[i][j])) get_king_moves(board, player, p);
else get_man_moves(board, player, p);
}
return moves_head;
// need to handle man becoming kings
}
void get_pawn_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player, Pos piece){
int direction = board[piece.col][piece.row] == BLACK_P ? -1 : 1;
int pawn_row = board[piece.col][piece.row] == BLACK_P ? 6 : 1;
Pos dest;
dest.col = piece.col;
dest.row = piece.row + direction;
if (is_valid_pos(dest)){
if (board[dest.col][dest.row] == EMPTY){
add_move(piece, dest, 0);
if (is_EOB(dest, player)) for (int i = 1; i < 5; i++) add_move(piece, dest, get_piece_by_type(i, player));
}
}
if (piece.row == pawn_row){
dest.row = piece.row + (2 * direction);
if (is_valid_pos(dest)){
if (board[dest.col][dest.row] == EMPTY && board[piece.col][piece.row + direction] == EMPTY) add_move(piece, dest, 0);
}
}
dest.col = piece.col + 1;
dest.row = piece.row + direction;
if (is_valid_pos(dest)){
if (is_opposite(player, board[dest.col][dest.row])){
add_move(piece, dest, 0);
if (is_EOB(dest, player)) for (int i = 1; i < 5; i++) add_move(piece, dest, get_piece_by_type(i, player));
}
}
dest.col = piece.col - 1;
if (is_valid_pos(dest)){
if (is_opposite(player, board[dest.col][dest.row])){
add_move(piece, dest, 0);
if (is_EOB(dest, player)) for (int i = 1; i < 5; i++) add_move(piece, dest, get_piece_by_type(i, player));
}
}
}
Move * get_all_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player){
moves_head = NULL;
moves = NULL;
Pos p;
for (int i = 0; i < BOARD_SIZE; i++)
for (int j = 0; j < BOARD_SIZE; j++)
if (!is_opposite(player, board[i][j]) && board[i][j] != EMPTY){
p.row = j;
p.col = i;
curr_piece = board[i][j];
if (is_king(curr_piece)) get_king_moves(board, player, p);
else get_man_moves(board, player, p);
}
return moves_head;
}
void get_man_moves(char board[BOARD_SIZE][BOARD_SIZE], COLOR player, Pos piece){
Move* res = NULL;
Move* res_head = res;
Pos pos[4] = { { piece.col - 1, piece.row - 1 }, { piece.col + 1, piece.row - 1 }, { piece.col - 1, piece.row + 1 }, { piece.col + 1, piece.row + 1 } };
int direction = 1, found_ahead;
if (player == BLACK) direction = -1;
for (int p = 0; p < 4; p++){
if (is_valid_pos(pos[p]) && pos[p].row == piece.row + direction && board[pos[p].col][pos[p].row] == EMPTY) add_move(piece, &pos[p], 1);
else if (is_valid_pos(pos[p]) && is_opposite(player, board[pos[p].col][pos[p].row])){
char tmp = board[pos[p].row][pos[p].col];
board[pos[p].row][pos[p].col] = EMPTY;
Pos new_piece = get_next_diag(piece, pos[p]);
if (is_valid_pos(new_piece) && board[new_piece.row][new_piece.col] == EMPTY){
found_ahead = get_capture_moves(piece, new_piece, board, player, 1, &new_piece);
if (found_ahead == 0) add_move(piece, &new_piece, 1);
}
board[pos[p].row][pos[p].col] = tmp;
}
}
}
void get_moves_by_piece(char board[BOARD_SIZE][BOARD_SIZE], COLOR player, Pos piece){
Pos* tmp_dests;
switch (board[piece.col][piece.row]){
case WHITE_B: case BLACK_B:
get_bishop_moves(board, player, piece);
return;
case WHITE_R: case BLACK_R:
get_rook_moves(board, player, piece);
return;
case WHITE_Q: case BLACK_Q:
get_bishop_moves(board, player, piece);
get_rook_moves(board, player, piece);
return;
case BLACK_P: case WHITE_P:
get_pawn_moves(board, player, piece);
return;
case WHITE_K: case BLACK_K:
tmp_dests = (Pos[8]) { { piece.col - 1, piece.row - 1 }, { piece.col - 1, piece.row }, { piece.col - 1, piece.row + 1 },
{ piece.col + 1, piece.row - 1 }, { piece.col + 1, piece.row }, { piece.col + 1, piece.row + 1 },
{ piece.col, piece.row - 1 }, { piece.col, piece.row + 1 }
};
break;
case WHITE_N: case BLACK_N:
tmp_dests = (Pos[8]) { { piece.col - 2, piece.row - 1 }, { piece.col - 2, piece.row + 1 },
{ piece.col + 2, piece.row - 1 }, { piece.col + 2, piece.row + 1 },
{ piece.col - 1, piece.row - 2 }, { piece.col + 1, piece.row - 2 },
{ piece.col - 1, piece.row + 2 }, { piece.col + 1, piece.row + 2 }};
break;
default: return;
}
for (int i = 0; i < 8; i++){
if (is_valid_pos(tmp_dests[i])){
if (board[tmp_dests[i].col][tmp_dests[i].row] == EMPTY || is_opposite(player, board[tmp_dests[i].col][tmp_dests[i].row])){
add_move(piece, tmp_dests[i], 0);
}
}
}
return;
}
int is_valid_dest(char board[BOARD_SIZE][BOARD_SIZE], COLOR player, Pos dest){
if (board[dest.col][dest.row] == EMPTY) return 1;
if (is_opposite(player, board[dest.col][dest.row])) return 2;
return 0;
}
// Helper func - checks if a piece belongs to the player
int is_valid_piece(char board[BOARD_SIZE][BOARD_SIZE], Move * move, COLOR color){
if (is_valid_pos(move->piece) && board[move->piece.col][move->piece.row] != EMPTY)
return !is_opposite(color, board[move->piece.col][move->piece.row]);
return 0;
}