#include <stdlib.h>

#include "lists.h"

/*
 *
 *******************
 *    Advanced     *
 *******************
 *
 */

struct list *list_insert(struct list *list, void *value, size_t index)
{
    if (list == NULL || index == 0)
    {
        struct list *new_elt = malloc(sizeof(struct list));
        new_elt->data = value;
        new_elt->next = list;
        return new_elt;
    }

    struct list *elt = list;

    for (size_t i = 0; i < index - 1; i++)
    {
        if (elt->next == NULL)
        {
            break;
        }
        elt = elt->next;
    }

    struct list *new_elt = malloc(sizeof(struct list));
    new_elt->data = value;
    new_elt->next = elt->next;
    elt->next = new_elt;

    return list;
}

struct list *list_remove(struct list *list, size_t index)
{
    struct list *elt = list;
    struct list *prev_elt;

    if (index == 0)
    {
        struct list *res = elt->next;
        free(elt);
        return res;
    }

    for (size_t i = 0; i < index; i++)
    {
        if (elt == NULL)
        {
            return list;
        }
        prev_elt = elt;
        elt = elt->next;
    }
    if (elt == NULL)
    {
        return list;
    }

    prev_elt->next = elt->next;
    free(elt);

    return list;
}

int list_find(struct list *list, void *value)
{
    if (list == NULL)
    {
        return -1;
    }

    int res = 0;
    while (list->data != value)
    {
        list = list->next;
        res++;
        if (list == NULL)
        {
            return -1;
        }
    }
    return res;
}

struct list *list_concat(struct list *list, struct list *list2)
{
    if (list == NULL)
    {
        return list2;
    }
    struct list *elt = list;
    while (elt->next != NULL)
    {
        elt = elt->next;
    }
    elt->next = list2;
    return list;
}