#ifndef VIETER_TREE_BALANCING
#define VIETER_TREE_BALANCING

#include "vieter_tree_node.h"

/*
 * Check whether the given tree is a valid red-black tree.
 *
 * @param node root of the (sub)tree
 * @param passed_black_nodes how many black nodes the recursion has already seen
 * at this point. This should be initialized as 0 for the topmost call.
 * @param expected_black_nodes the correct amount of black nodes to expect when
 * a NULL child is encountered.
 * @return true if the tree is valid, false otherwise
 */
bool vieter_tree_node_validate(vieter_tree_node *node,
                               uint64_t passed_black_nodes,
                               uint64_t expected_black_nodes);

/*
 * Balance a path of 3 nodes into a complete binary tree, with a red root and
 * black children.
 */
vieter_tree_node *vieter_tree_node_balance(vieter_tree_node *node);

/*
 * Ensure the tree remains a valid red-black tree after having inserting the
 * node.
 */
void vieter_tree_node_balance_after_insert(vieter_tree_node *node);

/*
 * Remove the given node, ensuring the tree remains a valid red-black tree.
 *
 * @param node node to remove. This should have at most a single child. If node
 * isn't the root, this should be the right child, otherwise it can be either.
 * @return root of the subtree that this function operated on. This can
 * sometimes be the new root of the entire tree.
 */
vieter_tree_node *vieter_tree_node_remove_balanced(vieter_tree_node *node);

/*
 * Perform a tree rotation of the subtree with the given root.
 */
vieter_tree_node *vieter_tree_node_rotate(vieter_tree_node *old_root, bool dir);
#endif