/**
 * @file lv_ll.c
 * Handle linked lists.
 * The nodes are dynamically allocated by the 'lv_mem' module,
 */

/*********************
 *      INCLUDES
 *********************/
#include <stdint.h>
#include <string.h>

#include "lv_ll.h"
#include "lv_mem.h"

/*********************
 *      DEFINES
 *********************/
#define LL_NODE_META_SIZE (sizeof(lv_ll_node_t*) + sizeof(lv_ll_node_t*))
#define LL_PREV_P_OFFSET(ll_p) (ll_p->n_size)
#define LL_NEXT_P_OFFSET(ll_p) (ll_p->n_size + sizeof(lv_ll_node_t*))

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/
static void node_set_prev(lv_ll_t * ll_p, lv_ll_node_t* act, lv_ll_node_t* prev);
static void node_set_next(lv_ll_t * ll_p, lv_ll_node_t* act, lv_ll_node_t* next);

/**********************
 *  STATIC VARIABLES
 **********************/

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

/**
 * Initialize linked list
 * @param ll_dsc pointer to ll_dsc variable
 * @param n_size the size of 1 node in bytes 
 */
void lv_ll_init(lv_ll_t * ll_p, uint32_t n_size)
{
    ll_p->head = NULL;
    ll_p->tail = NULL;

    if(n_size & 0b11) {
        n_size &= ~0b11;
        n_size += 4;
    }

    ll_p->n_size = n_size;   
}

/**
 * Add a new head to a linked list
 * @param ll_p pointer to linked list
 * @return pointer to the new head
 */
void * lv_ll_ins_head(lv_ll_t * ll_p)
{
    lv_ll_node_t* n_new;
    
    n_new = lv_mem_alloc(ll_p->n_size + LL_NODE_META_SIZE);
    
    if(n_new != NULL) { 
        node_set_prev(ll_p, n_new, NULL);           /*No prev. before the new head*/
        node_set_next(ll_p, n_new, ll_p->head);     /*After new comes the old head*/
        
        if(ll_p->head != NULL) { /*If there is old head then before it goes the new*/
            node_set_prev(ll_p, ll_p->head, n_new);
        }
        
        ll_p->head = n_new;         /*Set the new head in the dsc.*/
        if(ll_p->tail == NULL) {/*If there is no tail (1. node) set the tail too*/
            ll_p->tail = n_new;
        }
    }
    
    return n_new;
}

/**
 * Add a new tail to a linked list
 * @param ll_p pointer to linked list
 * @return pointer to the new tail
 */
void * lv_ll_ins_tail(lv_ll_t * ll_p)
{   
    lv_ll_node_t* n_new;
    
    n_new = lv_mem_alloc(ll_p->n_size + LL_NODE_META_SIZE);
    
    if(n_new != NULL) {
        node_set_next(ll_p, n_new, NULL); /*No next after the new tail*/
        node_set_prev(ll_p, n_new, ll_p->tail); /*The prev. before new is tho old tail*/
        if(ll_p->tail != NULL) {    /*If there is old tail then the new comes after it*/
            node_set_next(ll_p, ll_p->tail, n_new);
        }
        
        ll_p->tail = n_new;      /*Set the new tail in the dsc.*/
        if(ll_p->head == NULL) { /*If there is no head (1. node) set the head too*/
            ll_p->head = n_new;
        }
    }
    
    return n_new;
}


/**
 * Remove the node 'node_p' from 'll_p' linked list. 
 * It Dose not free the the memory of node.
 * @param ll_p pointer to the linked list of 'node_p'
 * @param node_p pointer to node in 'll_p' linked list
 */
void lv_ll_rem(lv_ll_t  * ll_p, void * node_p)
{
    if(lv_ll_get_head(ll_p) == node_p) {
        /*The new head will be the node after 'n_act'*/
        ll_p->head = lv_ll_get_next(ll_p, node_p);
        if(ll_p->head == NULL) {
            ll_p->tail = NULL;
        }
        else {
            node_set_prev(ll_p, ll_p->head, NULL);
        }   
    }
    else if(lv_ll_get_tail(ll_p) == node_p) {
        /*The new tail will be the  node before 'n_act'*/
        ll_p->tail = lv_ll_get_prev(ll_p, node_p);
        if(ll_p->tail == NULL) {
            ll_p->head = NULL;
        }
        else {
            node_set_next(ll_p, ll_p->tail, NULL);
        }
    }
    else
    {
        lv_ll_node_t* n_prev = lv_ll_get_prev(ll_p, node_p);
        lv_ll_node_t* n_next = lv_ll_get_next(ll_p, node_p);
        
        node_set_next(ll_p, n_prev, n_next);
        node_set_prev(ll_p, n_next, n_prev);
    }
}

/**
 * Remove and free all elements from a linked list. The list remain valid but become empty.
 * @param ll_p pointer to linked list
 */
void lv_ll_clear(lv_ll_t * ll_p)
{
	void * i;
	void * i_next;

	i = lv_ll_get_head(ll_p);
	i_next = NULL;

	while(i != NULL) {
		i_next = lv_ll_get_next(ll_p, i);

		lv_ll_rem(ll_p, i);
		lv_mem_free(i);

		i = i_next;
	}
}

/**
 * Move a node to a new linked list
 * @param ll_ori_p pointer to the original (old) linked list
 * @param ll_new_p pointer to the new linked list
 * @param node pointer to a node
 */
void lv_ll_chg_list(lv_ll_t * ll_ori_p, lv_ll_t * ll_new_p, void * node)
{
    lv_ll_rem(ll_ori_p, node);
    
    /*Set node as head*/
    node_set_prev(ll_new_p, node, NULL);      
    node_set_next(ll_new_p, node, ll_new_p->head);
    
    if(ll_new_p->head != NULL) { /*If there is old head then before it goes the new*/
        node_set_prev(ll_new_p, ll_new_p->head, node);
    }

    ll_new_p->head = node;        /*Set the new head in the dsc.*/
    if(ll_new_p->tail == NULL) {     /*If there is no tail (first node) set the tail too*/
        ll_new_p->tail = node;
    }
}

/**
 * Return with head node of the linked list
 * @param ll_p pointer to linked list
 * @return pointer to the head of 'll_p' 
 */
void * lv_ll_get_head(lv_ll_t * ll_p)
{   
    void * head = NULL;
    
    if(ll_p != NULL)    {
        head = ll_p->head;
    }
    
    return head;
}

/**
 * Return with tail node of the linked list
 * @param ll_p pointer to linked list
 * @return pointer to the head of 'll_p'
 */
void * lv_ll_get_tail(lv_ll_t * ll_p)
{
    void * tail = NULL;
    
    if(ll_p != NULL)    {
        tail = ll_p->tail;
    }
    
    return tail;
}

/**
 * Return with the pointer of the next node after 'n_act' 
 * @param ll_p pointer to linked list
 * @param n_act pointer a node 
 * @return pointer to the next node 
 */
void * lv_ll_get_next(lv_ll_t * ll_p, void * n_act)
{
    void * next = NULL;
 
    if(ll_p != NULL)    {
        lv_ll_node_t* n_act_d = n_act;
        memcpy(&next, n_act_d + LL_NEXT_P_OFFSET(ll_p), sizeof(void *));
    } 
    
    return next;
}

/**
 * Return with the pointer of the previous node after 'n_act' 
 * @param ll_p pointer to linked list
 * @param n_act pointer a node 
 * @return pointer to the previous node 
 */
void * lv_ll_get_prev(lv_ll_t * ll_p, void * n_act)
{
    void * prev = NULL;
 
    if(ll_p != NULL) {
        lv_ll_node_t* n_act_d = n_act;
        memcpy(&prev, n_act_d + LL_PREV_P_OFFSET(ll_p), sizeof(void *));
    }
    
    return prev;
}

void lv_ll_swap(lv_ll_t * ll_p, void * n1_p, void * n2_p)
{
    (void)(ll_p);
    (void)(n1_p);
    (void)(n2_p);
    /*TODO*/
}

/**********************
 *   STATIC FUNCTIONS
 **********************/

/**
 * Set the 'pervious node pointer' of a node 
 * @param ll_p pointer to linked list
 * @param act pointer to a node which prev. node pointer should be set
 * @param prev pointer to a node which should be the previous node before 'act'
 */
static void node_set_prev(lv_ll_t * ll_p, lv_ll_node_t* act, lv_ll_node_t* prev)
{
    memcpy(act + LL_PREV_P_OFFSET(ll_p), &prev, sizeof(lv_ll_node_t*));
}

/**
 * Set the 'next node pointer' of a node 
 * @param ll_p pointer to linked list
 * @param act pointer to a node which next node pointer should be set
 * @param next pointer to a node which should be the next node before 'act'
 */
static void node_set_next(lv_ll_t * ll_p, lv_ll_node_t* act, lv_ll_node_t* next)
{
    memcpy(act + LL_NEXT_P_OFFSET(ll_p), &next, sizeof(lv_ll_node_t*));
}