#include "snake.h"
#include <stdlib.h>

struct snake* add_snake(struct snake* snake, int x, int y) {
    struct snake* head = calloc(1, sizeof(struct snake));
    if (head == NULL) {
        return NULL; // Handle memory allocation failure
    }
    head->x = x;
    head->y = y;
    head->next = snake;
    return head;
}

struct snake* remove_snake(struct snake* snake) {
    if (snake == NULL) {
        return NULL;
    }
    if (snake->next == NULL) {
        free(snake);
        return NULL;
    }

    struct snake* this = snake;
    struct snake* prev = NULL;
    while (this->next != NULL) {
        prev = this;
        this = this->next;
    }

    free(this);
    prev->next = NULL;
    return snake;
}

void free_snake(struct snake* sn) {
    if (sn == NULL) {
        return;
    }
    free_snake(sn->next);
    free(sn);
}

int is_snake(struct snake* snake, int x, int y) {
    for (struct snake* this = snake; this != NULL; this = this->next) {
        if (this->x == x && this->y == y) {
            return 1;
        }
    }
    return 0;
}

int step_state(struct state* st) {
    int nx = (st->snake->x + st->sx);
    int ny = (st->snake->y + st->sy);
    return END_CONTINUE;
}