#include "ll.h"

#include <stddef.h>

void dlinkedlist_init(dlinkedlist **ll) {
    (*ll) = xcalloc(1, sizeof(**ll));
    
    (*ll)->start = NULL;
    (*ll)->end = NULL;
    (*ll)->size = 0;

    return;
}

void dlinkedlist_free(dlinkedlist **ll) {
    dllnode *p = (*ll)->start, *n;
    while(p != NULL) {
        n = p->next;
        
        if(p->dfreecb != NULL)
            p->dfreecb(p->data);
        free(p);

        p = n;
    }

    free(*ll);
    (*ll) = NULL;
    return;
}

int dlinkedlist_firstitem(dlinkedlist * const ll, void *data, int (*dfreecb)(void*)) {
    if(!ll)
        return -1;
    if(ll->size != 0)
        return 0;

    dllnode *n = xcalloc(1, sizeof(*n));
    n->next = NULL;
    n->prev = NULL;
    n->data = data;
    n->dfreecb = dfreecb;

    ll->start = n;
    ll->end = n;
    ll->size = 1;

    return 1;
}

int dlinkedlist_insert(dlinkedlist * const ll, void *data, int (*dfreecb)(void*)) {
    if(!ll)
        return -1;
    if(dlinkedlist_firstitem(ll, data, dfreecb) > 0)
        return 0;

    dllnode *n = xcalloc(1, sizeof(*n));
    n->data = data;
    n->dfreecb = dfreecb;
    n->prev = NULL;
    n->next = ll->start;

    ll->start->prev = n;
    ll->start = n;
    ll->size++;

    return 0;
}

int dlinkedlist_append(dlinkedlist * const ll, void *data, int (*dfreecb)(void*)) {
    if(!ll)
        return -1;
    if(dlinkedlist_firstitem(ll, data, dfreecb) > 0)
        return 0;

    dllnode *n = xcalloc(1, sizeof(*n));
    n->data = data;
    n->dfreecb = dfreecb;
    n->prev = ll->end;
    n->next = NULL;

    ll->end->next = n;
    ll->end = n;
    ll->size++;

    return 0;
}

dllnode *dlinkedlist_get(const dlinkedlist * const ll, size_t index) {
    if(index >= ll->size)
        return NULL;

    dllnode *p = ll->start;
    for(size_t i = 0; i < index && p != NULL; i++, p = p->next);

    return p;
}