#include "avl.h"
#include "algorithm"

int getHeight(AVL_tree *root) {
  if (!root)
    return 0;
  return root->height;
}

AVL_tree *rightRotate(AVL_tree *y) {
  AVL_tree *x = y->left;
  AVL_tree *T2 = x->right;

  x->right = y;
  y->left = T2;

  y->height = 1 + std::max(getHeight(y->left), getHeight(y->right));
  x->height = 1 + std::max(getHeight(x->left), getHeight(x->right));

  return x;
}

AVL_tree *leftRotate(AVL_tree *x) {
  AVL_tree *y = x->right;
  AVL_tree *T2 = y->left;

  y->left = x;
  x->right = T2;

  x->height = 1 + std::max(getHeight(x->left), getHeight(x->right));
  y->height = 1 + std::max(getHeight(y->left), getHeight(y->right));

  return y;
}

int getBalance(AVL_tree *root) {
  if (!root)
    return 0;
  return getHeight(root->left) - getHeight(root->right);
}

AVL_tree *insertAVL(AVL_tree *root, int value) {
  if (root == nullptr) {
    return new AVL_tree{value, nullptr, nullptr, 1};
  }

  if (value < root->info) {
    root->left = insertAVL(root->left, value);
  } else if (value > root->info) {
    root->right = insertAVL(root->right, value);
  } else {
    return root;
  }

  root->height = 1 + std::max(getHeight(root->left), getHeight(root->right));

  int balance = getBalance(root);

  if (balance > 1 && value < root->left->info) {
    return rightRotate(root);
  }

  if (balance < -1 && value > root->right->info) {
    return leftRotate(root);
  }

  if (balance > 1 && value > root->left->info) {
    root->left = leftRotate(root->left);
    return rightRotate(root);
  }

  if (balance < -1 && value < root->right->info) {
    root->right = rightRotate(root->right);
    return leftRotate(root);
  }

  return root;
}

void deleteAVL(AVL_tree *root){
    if (root != nullptr) {
      deleteAVL(root->left);
      deleteAVL(root->right);
      delete root;
    }
}