#pragma once

#include <queue>
#include <stack>

typedef enum AlgoVariant_E{
  Recursive,
  Iter,
}AlgoVariant;

template <class T>
class DopeBinTreeNode{
  DopeBinTreeNode<T>* left;
  DopeBinTreeNode<T>* right;
  T data;
public:
  DopeBinTreeNode(T data);
  ~DopeBinTreeNode();
  void SetLeft(DopeBinTreeNode<T>* newleft){left = newleft;}
  void SetRight(DopeBinTreeNode<T>* newright){right = newright;}
  DopeBinTreeNode<T>* GetLeft(){return left;}
  DopeBinTreeNode<T>* GetRight(){return right;}
  T GetData(){return data;}
};

template <class T>
class DopeBinTree{
  DopeBinTreeNode<T>* root;
  T* RecPreOrderTraversal(DopeBinTreeNode<T>* node, T* out);
  T* RecInOrderTraversal(DopeBinTreeNode<T>* node, T* out);
  T* RecPostOrderTraversal(DopeBinTreeNode<T>* node, T* out);
  void IterPreOrderTraversal(DopeBinTreeNode<T>* node, T* out);
  void IterInOrderTraversal(DopeBinTreeNode<T>* node, T* out);
  void IterPostOrderTraversal(DopeBinTreeNode<T>* node, T* out);
public:
  DopeBinTree(T data);
  DopeBinTree();
  ~DopeBinTree();
  void insert(T data);
  bool isEmpty();
  DopeBinTreeNode<T>* getRoot(){return root;}
  void PreOrderTraversal2Array(T* array, AlgoVariant variant);
  void InOrderTraversal2Array(T* array, AlgoVariant variant);
  void PostOrderTraversal2Array(T* array, AlgoVariant variant);
};

// Implementations ___________________________________________________
template <class T>
DopeBinTreeNode<T>::DopeBinTreeNode(T node_data):
  left(nullptr),
  right(nullptr),
  data(node_data)
{

}
template <class T>
DopeBinTreeNode<T>::~DopeBinTreeNode(){
  delete left;
  delete right;
}

template <class T>
DopeBinTree<T>::DopeBinTree(T data){
  root = new DopeBinTreeNode<T>(data);
}

template <class T>
DopeBinTree<T>::DopeBinTree():
  root(nullptr)
{

}

template <class T>
DopeBinTree<T>::~DopeBinTree(){
  if (root != nullptr){
    delete root;
  }

}

template <class T>
// Insert Breadth first
void DopeBinTree<T>::insert(T data){
  DopeBinTreeNode<T>* current_node = root;
  if (root == nullptr){
    root = new DopeBinTreeNode<T>(data);
  } else {
    auto new_node = new DopeBinTreeNode<T>(data);
    // Breadth first traversal
    std::queue<DopeBinTreeNode<T>*> q;
    q.push(root);
    while(!q.empty()){
      current_node = q.front();
      q.pop();
      if(current_node->GetLeft()){
        q.push(current_node->GetLeft());
      } else {
        current_node->SetLeft(new_node);
        break;
      }
      if(current_node->GetRight()){
        q.push(current_node->GetRight());
      } else {
        current_node->SetRight(new_node);
        break;
      }
    }
  }
}

template <class T>
bool DopeBinTree<T>::isEmpty(){
  if(root == nullptr){
    return true;
  } else {
    return false;
  }
}

template <class T>
T* DopeBinTree<T>::RecPreOrderTraversal(DopeBinTreeNode<T>* node, T* out){
  if (node == nullptr){
    return out--;
  }
  *out = node->GetData();
  out++;
  out = RecPreOrderTraversal(node->GetLeft(), out);
  out = RecPreOrderTraversal(node->GetRight(), out);
  return out;
}

template <class T>
T* DopeBinTree<T>::RecInOrderTraversal(DopeBinTreeNode<T>* node, T* out){
  if (node == nullptr){
    return out--;
  }

  out = RecInOrderTraversal(node->GetLeft(), out);
  *out = node->GetData();
  out++;
  out = RecInOrderTraversal(node->GetRight(), out);
  return out;
}

template <class T>
T* DopeBinTree<T>::RecPostOrderTraversal(DopeBinTreeNode<T>* node, T* out){
  if (node == nullptr){
    return out--;
  }
  out = RecPostOrderTraversal(node->GetLeft(), out);
  out = RecPostOrderTraversal(node->GetRight(), out);
  *out = node->GetData();
  out++;
  return out;
}

template <class T>
void DopeBinTree<T>::IterPreOrderTraversal(DopeBinTreeNode<T>* node, T* out){
  std::stack<DopeBinTreeNode<T>*> s = {};
  s.push(node);

  while(s.empty() == false){
    node = s.top();
    s.pop();
    *out = node->GetData();
    out++;
    if(node->GetRight()){
      s.push(node->GetRight());
    }
    if(node->GetLeft()){
      s.push(node->GetLeft());
    }
  }
}

template <class T>
void DopeBinTree<T>::IterInOrderTraversal(DopeBinTreeNode<T>* node, T* out){
  std::stack<DopeBinTreeNode<T>*> s = {};

  while (!s.empty() || node){
    while(node != nullptr){
      s.push(node);
      node = node->GetLeft();
    }
    node = s.top();
    s.pop();
    *out = node->GetData();
    out++;
    node = node->GetRight();
  }

}

template <class T>
void DopeBinTree<T>::IterPostOrderTraversal(DopeBinTreeNode<T>* node, T* out){
  std::stack<DopeBinTreeNode<T>*> s_tmp = {};
  std::stack<DopeBinTreeNode<T>*> s_fin = {};

  s_tmp.push(node);
  while(!s_tmp.empty()){
    node = s_tmp.top();
    s_tmp.pop();
    s_fin.push(node);

    if(node->GetLeft()){
      s_tmp.push(node->GetLeft());
    }
    if(node->GetRight()){
      s_tmp.push(node->GetRight());
    }
  }

  while(!s_fin.empty()){
    node = s_fin.top();
    s_fin.pop();
    *out = node->GetData();
    out++;
  }
}

/**
 *  \brief PreOrderTraversal2Array
 *
 *  Binary tree traversal that visits the root node, then the left
 *  sub-tree, and then the right-subtree.
 *
 *  \param The output array
 *  \param The algorithm variant
 *  \return return type
 */
template <class T>
void DopeBinTree<T>::PreOrderTraversal2Array(T* array, AlgoVariant variant){
  int index = 0;
  DopeBinTreeNode<T>* node = root;
  switch(variant){
  case AlgoVariant::Recursive:
    RecPreOrderTraversal(node, &array[index]);
    return;
  case AlgoVariant::Iter:
    IterPreOrderTraversal(node, &array[index]);
    return;
  default:
    return;
  }
}

/**
 *  \brief InOrderTraversal2Array
 *
 *  Binary tree traversal that traverses the left sub-tree, then
 *  visits the root node, then the right-subtree.
 *
 *  \param The output array
 *  \param The algorithm variant
 *  \return return type
 */
template <class T>
void DopeBinTree<T>::InOrderTraversal2Array(T* array, AlgoVariant variant){
  int index = 0;
  DopeBinTreeNode<T>* node = root;
  switch(variant){
  case AlgoVariant::Recursive:
    RecInOrderTraversal(node, &array[index]);
    return;
  case AlgoVariant::Iter:
    IterInOrderTraversal(node, &array[index]);
    return;
  default:
    return;
  }
}


/**
 *  \brief PostOrderTraversal2Array
 *
 *  Binary tree traversal that visits left-subtree, right subtree, and
 *  then the root node.
 *
 *  \param The output array
 *  \param The algorithm variant
 *  \return return type
 */
template <class T>
void DopeBinTree<T>::PostOrderTraversal2Array(T* array, AlgoVariant variant){
  int index = 0;
  DopeBinTreeNode<T>* node = root;

  switch(variant){
  case AlgoVariant::Recursive:
    RecPostOrderTraversal(node, &array[index]);
    return;
  case AlgoVariant::Iter:
    IterPostOrderTraversal(node, &array[index]);
    return;
  default:
    return;
  }
}