/*
 * list.cpp
 *
 *  Created on: 03/mar/2015
 *      Author: andrea
 */

#include "list.h"

typedef struct node {
    struct node* prev;
    struct node* next;

    int value;
} node;

typedef struct list {
    struct node* head;
    struct node* end;
    int size;
} list;

struct list* newList(){
    list* l = malloc(sizeof(list));
    l->head = NULL;
    l->end = NULL;
    return l;
}

struct node* newNode(int value){
    node* n = malloc(sizeof(node));
    n->next = NULL;
    n->prev = NULL;
    n->value = value;
    return &n;
}

int addAfter(list* list, node* __new, node* prev){
    if ((list == NULL) || (node == NULL)){
        return -1;
    }

    if (list->head == NULL){    // Lista vuota
        list->head = node;
        list->end = node;
        __new->prev = NULL;
        __new->next = NULL;
    } else if (prev == NULL){   // In cima alla lista
        __new->next = list->head;
        __new->prev = list->head;
        list->head->prev = __new;
        list->head = __new;
    } else if (prev == list->end){ // In fondo alla lista
        __new->next = NULL;
        __new->prev = list->end;
        list->end->next = __new;
        list->end = __new;
    } else {
        __new->next = prev->next;
        __new->prev = prev;
        prev->next = __new;
        __new->next->prev = __new;
    }

    list->size++;

    return 0;
}

int addBefore(list* list, node* __new, node* next){
    if ((list == NULL) || (node == NULL)){
        return -1;
    }

    node* prev = NULL;
    if (next == NULL){
        prev = list->end;
    } else if (next == list->head){
        prev = NULL;
    } else {
        prev = next->prev;
    }

    return addAfter(list, __new, prev);
}

int removeNode(list* list, node* node){
    if (list == NULL || node == NULL){
        return -1;
    }

    if (node == list->head && node == list->end){
        list->head = NULL;
        list->end = NULL;
    } else if (node == list->head){ // Rimuovere primo elemento
        list->head = node->next;
        node->next->prev = list->head;
    } else if (node == list->end){  // Rimuovere l'ultimo elemento
        list->end = node->prev;
        node->prev->next = NULL;
    } else {                        // Rimuovere un nodo nel mezzo della lista
        node->prev->next = node->next;
        node->next->prev = node->prev;
    }

    free(node);

    return 0;
}