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

void readfromkeyboard(Element_t *item)
{
    if(!item)
    {
        fprintf(stderr, "Nullpointer");
        exit(-1);
    }
    fprintf(stderr, "Waehle Song:");
    fgets(item->songtitle, 255, stdin);
    *strrchr(item->songtitle, '\n')=0;
    fprintf(stderr, "Waehle interpreter:");
    fgets(item->interpreter, 255, stdin);
    *strrchr(item->interpreter, '\n')=0;
}


Element_t *allocateElement()
{
    Element_t *elem = malloc(sizeof(Element_t));
    if (elem == 0)
    {
        fprintf(stderr, "Error:␣no␣memory␣available!\n");
        return 0;
    }
    readfromkeyboard(elem);
    elem->next = 0;
    return elem;
}

void freeList(Element_t **list)
{
    Element_t *next;
    Element_t *list2=*list;
    while (list2 != 0)
    {
        next = list2->next;
        free(list2);
        list2=next;
    }
    list2=0;


}

Element_t *insertLast(Element_t *list)
{
    Element_t *elem = allocateElement();
    if (list != 0)
        /* es wurde eine Liste uebergeben */
    {
        Element_t *end = find_end(list);
        /* Ende finden */
        end->next = elem;
        /* neues Element an das Ende anfuegen
        */
    }
    else
        list = elem;
    /* elem ist neue Liste */
    return list;

}


Element_t *find_end(Element_t *list)
{
    while (list->next != 0)
        list = list->next;
    return list;
}

void print_singleElement(Element_t *element)
{
    printf("%s-%s\n", element->songtitle, element->interpreter);

}

void print_entireList(Element_t *list)
{
    printf("-------Liste-------\n");
    long i=0;
    while(list)
    {
        i++;
        printf("%ld. ", i);
        print_singleElement(list);
        list = list->next;
    }
    printf("\nendd-------Liste-------");
}

/*void print_list(Element_t *list)
{
printf("----------␣Single␣Linked␣List␣---------\n");
while (list != 0)
{
printf("%ld\n", list->value);
list = list->next;
}
printf("---------------------------------------\n");
}
*/
void print_list_reverse(Element_t *list)
{
    if(list->next!=0)
        print_list_reverse(list->next);
    print_singleElement(list);
//list=list->next;
}
Element_t *elementAt(Element_t *list, long index)
{
    Element_t *l =list;
    long i;
    for(i=0; i<index-1; i++)
        l=l->next;
    return l;

}

long elementsCount(Element_t *list)
{
    if(list==0)
        return 0;
    long i=1;
    while(list->next)
    {
        list=list->next;
        i++;
    }
    return i;
}

Element_t *removeFirst(Element_t *list)
{
    Element_t  *begin = list;
    while (list != 0)
    {
        if (list->next != 0)
            /* Das gesuchte Element ist erreicht */
        {

            begin = list->next;
            /* Sichern des Rests der liste, falls */
            /* das erste Element geloescht wird */
            free(list);
            /* Element freigeben */
            return begin;
        }
        else
            /* nicht gefunden */
        {

            list = list->next;
        }
    }
    fprintf(stderr, "Error:␣element␣not␣found!\n");
    return begin;

}

void insertAt(Element_t *list, long insertAfter)
{
    Element_t *elem;
    if (list != 0)
    {
        list = elementAt(list,insertAfter);
        if (list != 0)
        {
            elem = allocateElement(); /* neues Element anlegen */
            if (elem == 0)
            {
                fprintf(stderr, "Error:␣no␣memory␣allocated␣for␣push_front!\n");
                // return list;
            }
            elem->next = list->next;
            /* Nachfolger von list als Nachfolger */
            /*
            von elem setzen */
            list->next = elem;
            /* elem als Nachfolger von list festlegen */
        }
        else
            fprintf(stderr, "Element␣not␣found\n");
    }

}

void print_list_random(Element_t *list)
{

    if( list->next)
    {
        if(rand()<266666)
        {
            print_list_random(list->next);
            fprintf(stdout, "%s\t%s\n", list->songtitle, list->interpreter);
        }
        else{
        fprintf(stdout, "%s\t%s\n", list->songtitle, list->interpreter);
        print_list_random(list->next);}
    }
    else{
    fprintf(stdout, "%s\t%s\n", list->songtitle, list->interpreter);
    }
}