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

Snake *new_snake(void)
{
    Snake *snake = (Snake *)malloc(sizeof(Snake));
    if (snake == NULL)
    {
        fprintf(stderr, "Memory allocation failed\n");
        exit(EXIT_FAILURE);
    }

    snake->size = 0;
    snake->segments_list = NULL;

    return snake;
}

void add_segment(Snake *snake, int x, int y)
{
    Position *new_segment = (Position *)malloc(sizeof(Position));
    if (new_segment == NULL)
    {
        fprintf(stderr, "Memory allocation failed\n");
        exit(EXIT_FAILURE);
    }

    new_segment->x = x;
    new_segment->y = y;
    new_segment->next = NULL;

    if (snake->segments_list == NULL)
    {
        snake->segments_list = new_segment;
    }
    else
    {
        Position *current = snake->segments_list;
        while (current->next != NULL)
        {
            current = current->next;
        }
        current->next = new_segment;
    }

    snake->size++;
}

void free_snake(Snake *snake)
{
    Position *current = snake->segments_list;
    while (current != NULL)
    {
        Position *next = current->next;
        free(current);
        current = next;
    }
    free(snake);
}

void crawl(Snake *snake, struct GridStruct *g)
{
    Position *new_head = (Position *)malloc(sizeof(Position));
    Position *current;
    if (new_head == NULL)
    {
        fprintf(stderr, "Memory allocation failed\n");
        exit(EXIT_FAILURE);
    }

    new_head->x = snake->segments_list->x;
    new_head->y = snake->segments_list->y;

    switch (snake->dir)
    {
    case LEFT:
        new_head->x = (new_head->x - 1 + g->nbc) % g->nbc;
        break;
    case RIGHT:
        new_head->x = (new_head->x + 1) % g->nbc;
        break;
    case TOP:
        new_head->y = (new_head->y - 1 + g->nbl) % g->nbl;
        break;
    case BOTTOM:
        new_head->y = (new_head->y + 1) % g->nbl;
        break;
    }

    new_head->next = snake->segments_list;
    snake->segments_list = new_head;

    current = snake->segments_list;
    while (current->next != NULL && current->next->next != NULL)
    {
        current = current->next;
    }

    free(current->next);
    current->next = NULL;
}