#include "list.h"

#include "../db/assert.h"

#define OBJ_TO_NODE(list_, object_)                                                                \
    reinterpret_cast<Link*>(reinterpret_cast<u32>(object_) + (list_)->offset)

namespace nw4hbm {
    namespace ut {

        void List_Init(List* list, u16 offset) {
            NW4HBM_ASSERT_CHECK_NULL(41, list);
            list->headObject = NULL;
            list->tailObject = NULL;
            list->numObjects = 0;
            list->offset = offset;
        }

        static void SetFirstObject(List* list, void* object) {
            NW4HBM_ASSERT_CHECK_NULL(64, list);
            NW4HBM_ASSERT_CHECK_NULL(65, object);

            Link* link = OBJ_TO_NODE(list, object);

            link->nextObject = NULL;
            link->prevObject = NULL;
            list->headObject = object;
            list->tailObject = object;
            list->numObjects++;
        }

        void List_Append(List* list, void* object) {
            NW4HBM_ASSERT_CHECK_NULL(89, list);
            NW4HBM_ASSERT_CHECK_NULL(90, object);

            if (list->headObject == NULL) {
                SetFirstObject(list, object);
                return;
            }

            Link* link = OBJ_TO_NODE(list, object);

            link->prevObject = list->tailObject;
            link->nextObject = NULL;

            OBJ_TO_NODE(list, list->tailObject)->nextObject = object;

            list->tailObject = object;
            list->numObjects++;
        }

        void List_Remove(List* list, void* object) {
            NW4HBM_ASSERT_CHECK_NULL(203, list);
            NW4HBM_ASSERT_CHECK_NULL(204, object);

            Link* link = OBJ_TO_NODE(list, object);

            if (!link->prevObject) {
                list->headObject = link->nextObject;
            } else {
                OBJ_TO_NODE(list, link->prevObject)->nextObject = link->nextObject;
            }

            if (!link->nextObject) {
                list->tailObject = link->prevObject;
            } else {
                OBJ_TO_NODE(list, link->nextObject)->prevObject = link->prevObject;
            }

            link->prevObject = NULL;
            link->nextObject = NULL;

            list->numObjects--;
        }

        void* List_GetNext(const List* list, const void* object) {
            NW4HBM_ASSERT_CHECK_NULL(245, list);

            if (object == NULL) {
                return list->headObject;
            }

            return OBJ_TO_NODE(list, object)->nextObject;
        }

        void* List_GetNth(const List* list, u16 index) {
            int count = 0;
            Link* object = NULL;

            NW4HBM_ASSERT_CHECK_NULL(297, list);

            for (; (object = static_cast<Link*>(List_GetNext(list, object))); count++) {
                if (index == count) {
                    return object;
                }
            }

            return NULL;
        }

    }  // namespace ut
}  // namespace nw4hbm