/*
 * Copyright (C) 2023 Barry
 *
 * This file is part of Barry's Little Objects in C Library (libBLOC).
 *
 * libBLOC is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * libBLOC is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTIBILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * libBLOC.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <BLOC/object.h>
#include <BLOC/tree.h>
#include "../assert.h"
#include "tree.h"

/* Add a node to a tree recursively */
static struct TreeNode *
_tree_add_r(Tree *t, struct TreeNode *parent, struct TreeNode *child)
{
	/* Add to correct side */
	if (t->compare(parent->header.obj, child->header.obj) > 0) {
		if (!parent->left) {
			parent->left = child;

			child->header.prev = parent->header.prev;
			child->header.next = &parent->header;
			parent->header.prev = &child->header;
			if (child->header.prev)
				child->header.prev->next = &child->header;
			else
				t->header.start = &child->header;
		} else {
			parent->left = _tree_add_r(t, parent->left, child);
		}
	} else {
		if (!parent->right) {
			parent->right = child;

			child->header.next = parent->header.next;
			child->header.prev = &parent->header;
			parent->header.next = &child->header;
			if (child->header.next)
				child->header.next->prev = &child->header;
			else
				t->header.end = &child->header;
		} else {
			parent->right = _tree_add_r(t, parent->right, child);
		}
	}

	/* Balance */
	if (_tree_count(parent->right) > _tree_count(parent->left) + 1)
		return _tree_rotate_left(parent);
	if (_tree_count(parent->left) > _tree_count(parent->right) + 1)
		return _tree_rotate_right(parent);
	return parent;
}

/* Add an object to a tree */
void
tree_add(Tree *tree, void *obj)
{
	ASSERT(tree);
	ASSERT(obj);
	ASSERT(obj_verify(obj));
	if (tree->type && tree->type != obj_type(obj))
		return;

	struct TreeNode *node;
	node = malloc(sizeof(struct TreeNode));
	node->left = node->right = NULL;
	node->header.prev = node->header.next = NULL;
	node->header.obj = obj_get(obj);

	obj_lock(tree);
	tree->header.entries++;
	if (!tree->root) {
		tree->root = node;
		tree->header.start = tree->header.end = &node->header;
	} else {
		tree->root = _tree_add_r(tree, tree->root, node);
	}
	obj_unlock(tree);
}