#include "list.h"

/*      Fundamental      */
void initList(List * L)
{
    L->lin = NULL;
}

int lengthList(List * L)
{
    linkList tmp = L->lin;
    int i = 0;
    while (tmp)
    {
        i++;
        tmp = tmp->next;
    }

    return i;
}

bool locateElem(List * L, int * i, int e)
{
    linkList tmp = L->lin;
    *i = 1;
    while (tmp)
    {
        if (tmp->elem != e)
        {
            (*i)++;
            tmp = tmp->next;
        }
        else
            return true;
    }
    return false;
}

bool getElem(List * L, int i, int * e)
{
    linkList tmp = L->lin;

    for (int j = 1; j < i; j++)
        if(tmp->next)
            tmp = tmp->next;
        else
        {
            fprintf(stderr,"Location is out of range\n");
            return false;
        }
    *e = tmp->elem;
    return true;
}

bool insertElem(List * L, int i, int e)
{
    if (i <= 0)
    {
        fprintf(stderr,"Invalid location!\n");
        return false;
    }
    linkList scan = L->lin;
    linkList new = (Link *) malloc (sizeof(Link));

    new->elem = e;
    new->next = NULL;

    if (!L->lin)
    {
        L->lin = new;
        return true;
    }
    else
    {
        if (i == 1)
        {
            new->next = scan;
            L->lin = new;
        }
        else
        {
            int j = 2;
            while (j++ < i && scan->next)
                scan = scan->next;
            if (!scan->next && --j < i)
                printf("Location is beyond the list length, Append element\n");
            new->next = scan->next;
            scan->next = new;
        }
    }
    return true;
}

bool deleteElem(List * L, int i, int  * e)
{
    linkList tmp = L->lin;
    if (i == 1)
    {
        *e = tmp->elem;
        L->lin = L->lin->next;
        free(tmp);
        return true;
    }
    int j = 2;      // we need the one before the one needs delete
    while (j++ < i && tmp->next)
        tmp = tmp->next;
    if (!tmp->next)
    {
        fprintf(stderr,"location out of range\n");
        return false;
    }

    *e = tmp->next->elem;
    if (tmp->next)
    {
        linkList t = tmp->next;
        tmp->next = t->next;
        free(t);
    }
    else
        free(tmp);
    return true;
}

void printList(List * L)
{
    linkList tmp = L->lin;

    while (tmp)
    {
        printf("%d  ",tmp->elem);
        tmp = tmp->next;
    }
    putchar('\n');
}

void deleteList(List * L)
{
    linkList tmp = L->lin;
    linkList del;
    while (tmp)
    {
        del = tmp->next;
        free(tmp);
        tmp = del;
    }
}

/*      Homework      */
void deleteX(linkList * L, int e)
{
    linkList tmp = *L;

    if (!tmp->next)
        return;
    else
    {
        if (tmp->elem == e)
        {
            (*L) = (*L)->next;
            free(tmp);
            deleteX(&(*L)->next,e);
        }
        else if (tmp->next->elem == e)
        {
            linkList p = tmp->next;
            tmp->next = p->next;
            free(p);
            deleteX(&tmp,e);
        }
        else
            deleteX(&tmp->next,e);
    }
}