#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dll.h"

#ifndef NULL
#define NULL (void *)0
#endif



DLLItem* makeDLLItem(char* data) {
    DLLItem *dlli = malloc(1 * sizeof(DLLItem));
    dlli->prev = NULL;
    dlli->next = NULL;
    dlli->payload = malloc((strlen(data)+1) * sizeof(char));
    strcpy(dlli->payload, data);
    return dlli;
}

DLL* makeDLL() {
    DLL *ret = malloc(1 * sizeof(DLL));
    ret->head = NULL;
    ret->tail = NULL;
    ret->count = 0;
    return ret;
}

void addDLLHead(DLL *dllC, char* data) {
    DLLItem *item = makeDLLItem(data);
    if (dllC->head == NULL)
    {
        dllC->head = item;
        dllC->tail = item;
        dllC->count = 1;
        return;
    }
    dllC->head->prev = item;
    item->next = dllC->head;
    dllC->head = item;
    dllC->count++;
}

void freeDLLItem(DLLItem *dlli) {
    free(dlli->payload);
    free(dlli);
}

char* removeTail(DLL *dll) {
    if (dll->count<=0)
        return NULL;
    dll->count--;
    DLLItem *itm = dll->tail;
    DLLItem *tprev = itm->prev;
    if (tprev==NULL) {
        dll->head = NULL;
        dll->tail = NULL;
        return NULL;
    }
    dll->tail = tprev;
    tprev->next = NULL;
    char *rtn = malloc((strlen(itm->payload) + 1) * sizeof(char));
    strcpy(rtn, itm->payload);
    freeDLLItem(itm);
    return rtn;
}

void printDLL(DLL *dll) {
    DLLItem *item = dll->head;
    while (item!=NULL) {
        printf("%s\n", item->payload);
        item = item->next;
    }
}

void freeDLL(DLL * dll) {
    DLLItem *item = dll->head;
    while (item!=NULL) {
        DLLItem * nextItem = item->next;
        freeDLLItem(item);
        item = nextItem;
        //item = item->next;
    }
    free(dll);
}

#ifndef DOTO
int main(int argc, char const *argv[])
{
    DLL *dll = makeDLL();
    addDLLHead(dll, "Geoff");
    addDLLHead(dll, "Deepak");
    addDLLHead(dll, "Dianna");
    printDLL(dll);
    char* cc = removeTail(dll);
    if (cc!=NULL) {
        printf("REMOVE %s\n", cc);
        free(cc);
    }
    printDLL(dll);
    freeDLL(dll);
    return 0;
}
#endif