//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Authors:    spectral`                                                     //
//              NeoX                                                          //
//                                                                            //
//  Desc:       Doubly linked lists implementation                            //
//----------------------------------------------------------------------------//

#ifndef _KALLIST_H
#define _KALLIST_H

#ifdef _KALEID_KERNEL
#error "kallist.h - Not ready for kernel compilation"
#endif

#ifndef _KALASSRT_H
#include <common/kalassrt.h>
#endif

#ifndef _KALKERN_LOCKS_H
#include <kernel/kernlocks.h>
#endif

//
// XXX ¯\_(ツ)_/¯
//
void *malloc(long);
void free(void *);

#define AllocMemory malloc
#define FreeMemory free

//------------------------------------------//
//              Data structures             //
//------------------------------------------//

typedef struct sListHead_t {
    Lock_t                 *lock;
    unsigned long           length;
    struct sListNode_t     *first;
    struct sListNode_t     *last;
} ListHead_t;

typedef struct sListNode_t {
    void                   *data;
    ListHead_t             *head;
    struct sListNode_t     *prev;
    struct sListNode_t     *next;
} ListNode_t;

//------------------------------------------//
//                Functions                 //
//------------------------------------------//

//
// Create a list head with an extern lock
//
static inline ListHead_t
*CreateListHeadWithLock(Lock_t *lock)
{
    ListHead_t *head = AllocMemory(sizeof(ListHead_t));

    if (head == NULL) return NULL;

    head->first = head->last = NULL;
    head->length = 0;

    head->lock = lock;

    return head;
}

//
// Create a liste head
//
static inline ListHead_t
*CreateListHead(void)
{
    return CreateListHeadWithLock(NULL);
}

//
// Create a node
//
static inline ListNode_t
*CreateNode(void *data)
{
    ListNode_t *node = AllocMemory(sizeof(ListNode_t));

    if (node == NULL) return NULL;

    node->data = data;
    node->head = NULL;
    node->prev = node->next = NULL;

    return node;
}

//
// Prepend node at beginning of list
//
static inline ListHead_t
*PrependNode(ListHead_t *head, ListNode_t *node)
{
    KalAssert(head && node);

    node->head = head;
    node->prev = NULL;

    if (head->length > 0) {
        node->next = head->first;
        head->first->prev = node;
        head->first = node;
    }

    else {
        head->first = node;
        head->last  = node;
        node->next  = NULL;
    }

    head->length++;

    return head;
}

//
// Append node at end of list
//
static inline ListHead_t
*AppendNode(ListHead_t *head, ListNode_t *node)
{
    KalAssert(head && node);

    node->head = head;
    node->next = NULL;

    if (head->length > 0) {
        node->prev = head->last;
        head->last->next = node;
        head->last = node;
    }

    else {
        head->first = node;
        head->last  = node;
        node->prev  = NULL;
    }

    head->length++;

    return head;
}

//
// Insert node2 before node1
//
static inline ListHead_t
*AddNodeBefore(ListHead_t *head, ListNode_t *node1, ListNode_t *node2)
{
    KalAssert(head && node1 && node2 && node1->head == head);

    if (head->first == node1) {
        return PrependNode(head, node2);
    }

    node2->head = head;
    node2->next = node1;
    node2->prev = node1->prev;

    // node1->prev does exist
    // or node1 would be first
    node1->prev->next = node2;
    node1->prev = node2;

    head->length++;

    return head;
}

//
// Insert node2 after node1
//
static inline ListHead_t
*AddNodeAfter(ListHead_t *head, ListNode_t *node1, ListNode_t *node2)
{
    KalAssert(head && node1 && node2 && node1->head == head);

    if (head->last == node1) {
        return AppendNode(head, node2);
    }

    node2->head = head;
    node2->prev = node1;
    node2->next = node1->next;

    node1->next->prev = node2;
    node1->next = node2;

    head->length++;

    return head;
}

//
// Remove node of list (and frees it)
//
static inline ListHead_t
*RemoveNode(ListHead_t *head, ListNode_t *node)
{
    KalAssert(head && node && head->length > 0 && node->head == head);

    if (head->length == 1) {
        head->first = head->last = NULL;
        goto leave;
    }

    if (head->first == node) {
        head->first = node->next;
        node->next->prev = NULL;
    }

    else if (head->last == node) {
        head->last = node->prev;
        node->prev->next = NULL;
    }

    else {
        node->prev->next = node->next;
        node->next->prev = node->prev;
    }

leave:
    head->length--;
    FreeMemory(node);

    return head;
}

//
// Free a node
//
static inline void
DestroyNode(ListNode_t *node)
{
    KalAssert(node);
    FreeMemory(node);
}

//
// Free a list head
//
static inline void
DestroyListHead(ListHead_t *head)
{
    KalAssert(head);
    FreeMemory(head);
}

//
//  Access a node's data
//
#define GetNodeData(node, type) ((type)(node)->data)

//------------------------------------------//
//              End of header               //
//------------------------------------------//

#endif