+
+static void direction_to_coordinates(unsigned int direction, int* start_y, int* start_x) {
+
+ if (direction == north) {
+ *start_y = *start_y - 1;
+ } else if (direction == north_east) {
+ *start_y = *start_y - 1;
+ *start_x = *start_x + 1;
+ } else if (direction == east) {
+ *start_x = *start_x + 1;
+ } else if (direction == south_east) {
+ *start_y = *start_y + 1;
+ *start_x = *start_x + 1;
+ } else if (direction == south) {
+ *start_y = *start_y + 1;
+ } else if (direction == south_west) {
+ *start_y = *start_y + 1;
+ *start_x = *start_x - 1;
+ } else if (direction == west) {
+ *start_x = *start_x - 1;
+ } else if (direction == north_west) {
+ *start_y = *start_y - 1;
+ *start_x = *start_x - 1;
+ }
+}
+
+bool is_board_full(unsigned int pawn_array[board_size][board_size]) {
+
+ /* an alternate method is to test the round count vs. 60 */
+ for (int i = 1; i <= board_size; i++) {
+ for (int j = 1; j <= board_size; j++) {
+ if (is_box_type(i, j, pawn_array , empty)) {
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
+unsigned int eval_winner(unsigned int nb_white, unsigned int nb_black) {
+
+ if (nb_white > nb_black) {
+ return player_two;
+ } else if (nb_white < nb_black) {
+ return player_one;
+ } else {
+ return 0;
+ }
+}
+
+static unsigned int count_pawn_to_reverse_one_direction(int y, int x, int direction, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) {
+ unsigned int nb_pawns_reversed = 0;
+ int moving_y = y, moving_x = x;
+
+ /* count the pawns to reverse in the chosen direction */
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ while (true) {
+ if (!is_valid_coordinates(moving_y, moving_x) || is_box_type(moving_y, moving_x, pawn_array, empty)) {
+ return 0;
+ }
+ if (is_box_type(moving_y, moving_x, pawn_array, current_player)) {
+ break;
+ }
+ nb_pawns_reversed++;
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ }
+ return nb_pawns_reversed;
+}
+
+/* revert the pawns if needed in one direction */
+static unsigned int reverse_one_direction(int y, int x, int direction, unsigned int current_player, unsigned int pawn_array[board_size][board_size], bool dry_run) {
+ unsigned int nb_pawns_reversed = 0;
+ int moving_y = y, moving_x = x;
+
+ nb_pawns_reversed = count_pawn_to_reverse_one_direction(moving_y, moving_x, direction, current_player, pawn_array);
+
+ /* now reverse the needed pawns */
+ if (nb_pawns_reversed > 0 && !dry_run) {
+ moving_y = y, moving_x = x;
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ while (!is_box_type(moving_y, moving_x, pawn_array, current_player)) {
+ reverse_pawn(moving_y, moving_x, pawn_array);
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ }
+ }
+ return nb_pawns_reversed;
+}
+
+/* loop optimized version of valid_shot function changing nothing to the pawns 2D array */
+bool is_legal_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) {
+ unsigned int nb_pawns_reversed = 0;
+
+ if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) {
+ return false;
+ }
+
+ for (unsigned int direction = north; direction <= north_west; direction++) {
+ nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, true);
+ if (nb_pawns_reversed > 0) {
+ return true;
+ }
+ }
+ return false;
+}
+
+/* play the shot if legal and flip or reverse the necessary pawns */
+unsigned int valid_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) {
+ unsigned int nb_pawns_reversed = 0;
+
+ if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) {
+ return 0;
+ }
+
+ for (unsigned int direction = north; direction <= north_west; direction++) {
+ nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, false);
+ }
+
+ if (nb_pawns_reversed == 0) {
+ return nb_pawns_reversed;
+ }
+
+ set_pawn(y, x, current_player, pawn_array);
+ return nb_pawns_reversed;
+}
+
+static void add_shots_list_cell(int y, int x, unsigned int type, struct shots_list_s* shots_list) {
+ struct shots_list_s* list_cell = (struct shots_list_s*)malloc(sizeof(struct shots_list_s));
+ if (!list_cell) {
+ exit(EXIT_FAILURE);
+ }
+
+ if (type > 0 && type < 5 && is_valid_coordinates(y, x)) {
+ list_cell->y = y;
+ list_cell->x = x;
+ list_cell->type = type;
+ list_add_tail(&(list_cell->list), &(shots_list->list));
+ }
+}
+
+void free_shots_list(struct shots_list_s* shots_list) {
+ struct shots_list_s* list_counter;
+
+ while (!list_empty(&shots_list->list)) {
+ list_counter = list_entry(shots_list->list.next, struct shots_list_s, list);
+ list_del(&(list_counter->list));
+ free(list_counter);
+ }
+
+}
+
+void build_playable_shots_list(unsigned int current_player, struct shots_list_s* shots_list, unsigned int pawn_array[board_size][board_size]) {
+
+ for (unsigned int i = 0; i <= board_size; i++) {
+ for (unsigned int j = 0; j <= board_size; j++) {
+ if (is_legal_shot(i, j, current_player, pawn_array)) {
+ add_shots_list_cell(i, j, hint_allowed, shots_list);
+ /* FIXME: a neighbourhood detection is needed
+ } else if (is_box_type(i, j, pawn_array, empty)){
+ add_shots_list_cell(i, j, hint_forbidden, shots_list);
+ */
+ }
+ }
+ }
+}