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#include <stdbool.h>
#include "othello.h"
bool is_valid_move(const enum player_color board[8][8],
const enum player_color current_player,
const struct move move) {
// The move must be a positive position
if (move.row < 0 || move.col < 0) {
return false;
}
// The move must be an empty spot to be valid
if (board[move.row][move.col] != EMPTY) {
return false;
}
const enum player_color other_color = current_player == WHITE ? BLACK : WHITE;
bool is_valid_up = false;
bool is_valid_down = false;
bool is_valid_left = false;
bool is_valid_right = false;
#define check_valid_direction(direction_bool, start, end_cond, step, cur_pos) \
if (!is_valid_up && !is_valid_down && !is_valid_left && !is_valid_right) { \
bool would_flip_oppenent = false; \
bool has_other_end = false; \
for (int i = start; end_cond && !has_other_end; step) { \
if (cur_pos == current_player) { \
has_other_end = true; \
} else if (cur_pos == other_color) { \
would_flip_oppenent = true; \
} else { \
/* We have reached an empty tile*/ \
break; \
} \
} \
direction_bool = has_other_end && would_flip_oppenent; \
}
check_valid_direction(is_valid_up, move.row - 1, i > 0, i--,
board[i][move.col]);
check_valid_direction(is_valid_down, move.row + 1, i < 8, i++,
board[i][move.col]);
check_valid_direction(is_valid_left, move.col - 1, i > 0, i--,
board[move.row][i]);
check_valid_direction(is_valid_right, move.col + 1, i < 8, i++,
board[move.row][i]);
#undef check_valid_direction
return is_valid_up || is_valid_down || is_valid_left || is_valid_right;
}
bool has_valid_moves(const enum player_color board[8][8],
const enum player_color current_player) {
bool result = false;
struct move move;
for (move.row = 0; move.row < 8 && !result; move.row++) {
for (move.col = 0; move.col < 8 && !result; move.col++) {
result = is_valid_move(board, current_player, move);
}
}
return result;
}
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