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*******************************************************************************/

#include <stdio.h>
struct Node
{
    void* key;
    struct Node* next;
    struct Node* pre;
};

struct List
{
    struct Node* end;
    struct Node* current;
    struct Node* start;
    int start_index;
    int end_index;
    int current_index;
};
struct Node arr2[100];
struct List arr1[5];
int head_free_index=0;
int node_free_index=0;;
struct List* ListCreate()
{
   struct List* ret;
   if(head_free_index+1>=5 || node_free_index+1>=100)
    return NULL;
    arr2[node_free_index].next=NULL;
   arr2[node_free_index].pre=NULL;
   arr2[node_free_index].key=NULL;
   arr1[head_free_index].start=&arr2[node_free_index];
   arr1[head_free_index].end=&arr2[node_free_index];
   arr1[head_free_index].current=&arr2[node_free_index];
   arr1[head_free_index].start_index=head_free_index;
   arr1[head_free_index].end_index=head_free_index;
   arr1[head_free_index].current_index=head_free_index;
   //if(arr1[head_free_index].start!=NULL) printf("hello");
   ret=&arr1[head_free_index];
   head_free_index++;
   node_free_index++;
  return ret;
}
int ListCount(struct List A)
{

    //A.start=arr1[0].start;
    //A.end=arr1[0].end;
    //A.current=arr1[0].current;
    int count=1;
    /*while( arr1[0].current->next!=NULL)
    {
        //printf("hello0000");
       count++;
       if (count>=2)break;
       struct Node temp;
       arr1[0].current=&temp;//arr1[0].current->next;
       //A=A.current->next;

    }*/
    int ind = A.end_index - A.start_index;

    //if(arr1[0].current->next!=NULL)printf("adad");
    return ind;
}
void* ListFirst(struct List A)
{
    A.current=A.start;
    return A.start;
}
void* ListLast(struct List A)
{
    A.current=A.end;
    return A.end;
}
void* ListNext(struct List A)
{
    if(A.current->next==NULL)
     return NULL;
    A.current=A.current->next;
    return A.current;
}
void* ListPrev(struct List A)
{
    if(A.current->pre==NULL)
        return NULL;
    A.current=A.current->pre;
    return A.current;
}
void* ListCurr(struct List A)
{
    return A.current;
}
int ListAdd(struct List A, void* item )
{
    struct Node newNode;
    newNode.key=item;
    if(node_free_index>=100)
    return -1;
    if(A.start->next==NULL&&A.start->pre==NULL)
    {
        //printf("hello");
        newNode.next=arr1[0].start;
        //if(arr1[0].start!=NULL)printf("fassafds");
        newNode.pre=NULL;
        arr1[0].start->pre=&newNode;
        arr1[0].start=&newNode;
        arr1[0].end=newNode.next;
        arr1[0].current=&newNode;
        node_free_index++;
        arr1[0].end_index++;
        node_free_index++;
        return 0;
        //if(arr1[0].current->next!=NULL)printf("asd");
    }
    else if(A.current==NULL && A.current->next!=NULL)
    {
        newNode.next=A.start;
        A.start->pre=&newNode;
        newNode.pre=NULL;
        A.start=&newNode;
        A.current=&newNode;
         //arr1[0].end_index++;
    }
    else if(A.current==NULL && A.current->pre!=NULL)
    {
        newNode.pre=A.end;
        A.end->next=&newNode;
        newNode.next=NULL;
        A.end=&newNode;
        A.current=&newNode;
        //arr1[0].end_index++;
    }
    else
    {
        newNode.next=A.current->next;
        A.current->next=&newNode;
        newNode.pre=A.current;
        newNode.next->pre=&newNode;
         arr1[0].end_index++;
    }
    for(int i=node_free_index;i>A.current_index;i--)
    {
        arr2[i].key=arr2[i-1].key;
        arr2[i].next=arr2[i-1].next;
        arr2[i].pre=arr2[i-1].pre;
    }
    for(int i=0;i<head_free_index;i++)
    {
        if(i!=0)
        arr1[i].start=arr1[i].start->next;
        arr1[i].end=arr1[i].end->next;
        arr1[i].current=arr1[i].current->next;
    }
    node_free_index++;
    //if(arr1[0].current->next!=NULL)printf("asd");
    return 0;
}
int ListInsert(struct List A, void* item)
{

}
int ListAppend (struct List A, void* item)
{
    struct Node newNode;
    newNode.key = item;
    if(node_free_index>=100)
        return -1;
    if(A.start->next==NULL&&A.start->pre==NULL)
    {
        newNode.next=arr1[0].start;
        newNode.pre=NULL;
        arr1[0].start->pre=&newNode;
        arr1[0].start=&newNode;
        arr1[0].end=newNode.next;
        arr1[0].current=&newNode;
        //node_free_index++;
        arr1[0].end_index++;
        node_free_index++;
        return 0;
    }
    else
    {
        newNode.pre=A.end;
        newNode.next=NULL;
        A.end->next=&newNode;
        A.end=&newNode;
    }
    for(int i=node_free_index;i>A.current_index;i--)
    {
        arr2[i].key=arr2[i-1].key;
        arr2[i].next=arr2[i-1].next;
        arr2[i].pre=arr2[i-1].pre;
    }
    for(int i=1;i<head_free_index;i++)
    {
        arr1[i].start=arr1[i].start->next;
        arr1[i].end=arr1[i].end->next;
        arr1[i].current=arr1[i].current->next;
    }
    node_free_index++;
    arr1[0].end_index++;
    return 0;

}
void* ListRemove(struct List A)
{
    if(A.current==A.end)
    {
        //printf("end");
        arr1[0].current->pre->next=NULL;
        arr1[0].end=arr1[0].end->pre;
        arr1[0].current->next=NULL;
        arr1[0].current->pre=NULL;
        struct Node* temp1=arr1[0].current;
        //detele A.current;
        arr1[0].end_index--;
        arr1[0].current=arr1[0].end;
        return temp1;
    }
    else if(A.current==A.start)
    {
        //printf("start");
        arr1[0].current->next->pre=NULL;
        arr1[0].start=arr1[0].start->next;
        arr1[0].current->next=NULL;
        arr1[0].current->pre=NULL;
        struct Node* temp2=arr1[0].current;
        //(A.current);
        arr1[0].current=arr1[0].start;
        arr1[0].start_index++;
        return temp2;
    }
    else
    {
        //printf("else");
        arr1[0].current->next->pre=arr1[0].current->pre;
        arr1[0].current->pre->next=arr1[0].current->next;
        struct Node* temp=arr1[0].current->next;
        arr1[0].current->next=NULL;
        arr1[0].current->pre=NULL;
        struct Node* temp3=arr1[0].current;
        //detele A.current;
        arr1[0].end_index--;
        arr1[0].current=temp;
        return temp3;
    }
}
void* ListTrim(struct List A)
{
    arr1[0].end->pre->next=NULL;
    struct Node* temp=arr1[0].end->pre;
    if(A.current==A.end) arr1[0].current=temp;
    arr1[0].end->pre=NULL;
    arr1[0].end->next=NULL;
    struct Node* ret=arr1[0].end;
    //delete A.end;
    arr1[0].end= temp;
    arr1[0].end_index--;
    return ret;
}
void* ListConcat(struct List A, struct List B)
{
    A.end->next = B.start;
    B.start = NULL;
    B.end = B.current = B.start;
    //Listfree B (but not yet made)
}
int main()
{
    arr1[0]=*ListCreate();
    //if(arr1[0].current!=NULL)printf("hello");
    struct List C;
    C.start=arr1[0].start;
    C.end=arr1[0].end;
    C.current=arr1[0].current;
    void* abc=NULL;

    int a = ListCount(arr1[0]);
    printf("%d \n", a);

    int ads= ListAdd(arr1[0],abc);
    //if(arr1[0].current->next!=NULL)printf("adsafafa");
    //printf("%d \n", ads);
    //if(arr1[0].current->next!=NULL)printf("adsafafa");
    a = ListCount(arr1[0]);
    printf("%d \n", a);

    void* gef = NULL;
    int blah =  ListAdd(arr1[0],gef);
    a = ListCount(arr1[0]);
    printf("%d \n", a);
    void* axe=ListRemove(arr1[0]);
    a = ListCount(arr1[0]);
    printf("%d \n", a);
    return 0;
}