+ 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(unsigned int y, unsigned 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);
+ */
+ }
+ }
+ }