#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));
    head->x = x;
    head->y = y;
    head->next = snake;

    return head;
}

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

    previous_element->next=NULL;
    
    return snake;
}

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

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