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

struct snake* add_snake(struct snake* snake,int x,int y) {
    // Allocate memory for the new snake part
    struct snake* new_snake_part = calloc(1, sizeof(struct snake));
    if (new_snake_part == NULL) {
        return NULL; // Memory allocation failed
    }
    // Set coordinates of the new snake part
    new_snake_part->x = x;
    new_snake_part->y = y;
    // The new snake part becomes the head of the snake
    new_snake_part->next = snake;
    return new_snake_part;
}

struct snake* remove_snake(struct snake* snake) {
    if (snake == NULL) {
        return NULL;
    }
    struct snake* current = snake;
    struct snake* prev = NULL;
    while (current->next != NULL) {
        prev = current;
        current = current->next;
    }
    if (prev != NULL) {
        prev->next = NULL;
    } else {
        // If prev is NULL, it means we are removing the head of the list
        // and the new head will be the next node
        snake = NULL;
    }
    free(current);
    return snake;
}

int is_snake(struct snake* snake,int x, int y) {
    // Traverse the snake linked list
    struct snake* current = snake;
    while (current != NULL) {
        // Check if current snake part has the given coordinates
        if (current->x == x && current->y == y) {
            return 1; // Coordinates found in the snake
        }
        current = current->next;
    }
    return 0; // Coordinates not found in the snake
}

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

int step_state(struct state* state) {
    // Implementation of this function is left to you
    return END_CONTINUE;
}