// Binary tree abstract base class
// Created by Iurii Tatishchev
// Modified by: Iurii Tatishchev

#ifndef _BINARY_TREE
#define _BINARY_TREE

#include "BinaryNode.h"

template<class ItemType>
class BinaryTree {
protected:
    BinaryNode<ItemType> *rootPtr;        // ptr to root node
    int count;                             // number of nodes in tree

public:
    // "admin" functions
    BinaryTree() {
        rootPtr = nullptr;
        count = 0;
    }

    BinaryTree(const BinaryTree<ItemType> &tree) {}

    virtual ~BinaryTree() { destroyTree(rootPtr); }

    // common functions for all binary trees
    bool isEmpty() const { return count == 0; }

    int getCount() const { return count; }

    void clear() {
        destroyTree(rootPtr);
        rootPtr = nullptr;
        count = 0;
    }

    void preOrder(void visit(ItemType &)) const { _preorder(visit, rootPtr); }

    void inOrder(void visit(ItemType &)) const { _inorder(visit, rootPtr); }

    void postOrder(void visit(ItemType &)) const { _postorder(visit, rootPtr); }
    // void printTree(void visit(ItemType &, int)) const{_printTree(visit, rootPtr, 1);}

    // abstract functions to be implemented by derived class
    virtual bool insert(const ItemType &newData) = 0;
    //virtual bool remove(const ItemType &data) = 0;
    //virtual bool search(const ItemType &target, ItemType & returnedItem) const = 0;

private:
    // delete all nodes from the tree
    void destroyTree(BinaryNode<ItemType> *nodePtr);

    // internal traverse
    void _preorder(void visit(ItemType &), BinaryNode<ItemType> *nodePtr) const;

    void _inorder(void visit(ItemType &), BinaryNode<ItemType> *nodePtr) const;

    void _postorder(void visit(ItemType &), BinaryNode<ItemType> *nodePtr) const;
    // void _printTree(void visit(ItemType &, int), BinaryNode<ItemType>* nodePtr, int level) const;

};

// Destroy the entire tree
template<class ItemType>
void BinaryTree<ItemType>::destroyTree(BinaryNode<ItemType> *nodePtr) {
    if (nodePtr) // != NULL
    {
        destroyTree(nodePtr->getLeftPtr());
        destroyTree(nodePtr->getRightPtr());
        // cout << "DEBUG - Destructor: Now deleting " << nodePtr->getItem().getName() << endl;
        delete nodePtr;
    }
}

// Preorder Traversal
template<class ItemType>
void BinaryTree<ItemType>::_preorder(void visit(ItemType &), BinaryNode<ItemType> *nodePtr) const {
    if (nodePtr == nullptr) return;

    ItemType item = nodePtr->getItem();
    visit(item);
    _preorder(visit, nodePtr->getLeftPtr());
    _preorder(visit, nodePtr->getRightPtr());

}

// Inorder Traversal
template<class ItemType>
void BinaryTree<ItemType>::_inorder(void visit(ItemType &), BinaryNode<ItemType> *nodePtr) const {
    if (nodePtr) // != NULL
    {
        ItemType item = nodePtr->getItem();
        _inorder(visit, nodePtr->getLeftPtr());
        visit(item);
        _inorder(visit, nodePtr->getRightPtr());
    }
}

// Postorder Traversal
template<class ItemType>
void BinaryTree<ItemType>::_postorder(void visit(ItemType &), BinaryNode<ItemType> *nodePtr) const {
    if (nodePtr == nullptr) return;

    _postorder(visit, nodePtr->getLeftPtr());
    _postorder(visit, nodePtr->getRightPtr());
    ItemType item = nodePtr->getItem();
    visit(item);
}

#endif