#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "stack.h"
#include "bintree.h"


//TODO: binären Suchbaum implementieren
/*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),           Done
    * `clearTree`: gibt den gesamten Baum frei (rekursiv),                      Done
    * `treeSize`: zählt die Knoten im Baum (rekursiv),                          Done
    * `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. Done */  


    static StackNode    *stackRoot  = NULL;


    TreeNode        *addToTree          (TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate);
    void            *nextTreeData       (TreeNode *root);
    void            clearTree           (TreeNode *root);
    unsigned int    treeSize            (const TreeNode *root);

    // self declared functions
    TreeNode        *addToTreeRec       (TreeNode *currentNode, TreeNode *newNode, CompareFctType compareFct, int *isDuplicate, const int root);
    void            clearTreeRec        (TreeNode *currentNode);
    void            clearNode           (TreeNode *node);
    int             treeSizeRec         (const TreeNode *currentNode);
    void            *nextTreeDataRec    (TreeNode *node, StackNode *stack);


// Adds a copy of data's pointer destination to the tree using compareFct for ordering. Accepts duplicates
// if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).

//      returned Value is new root
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{
    // create a node
    TreeNode *newNode;


    newNode         = calloc(1, sizeof(TreeNode));
    newNode->data   = calloc(1, dataSize);
    newNode->left   = NULL;
    newNode->right  = NULL;
    memcpy(newNode->data, data, dataSize);


    return addToTreeRec(root, newNode, compareFct, isDuplicate, 1);
}


TreeNode *addToTreeRec(TreeNode *currentNode, TreeNode *newNode, CompareFctType compareFct, int *isDuplicate, const int root)
{
    /*if ((currentNode == NULL))
    {
        if ((isDuplicate == NULL) || root)
        {
            return newNode;
        }
        else
        {
            return currentNode;
        }
    }
    */


// Mögliche Ergänzung --------------------------
if (currentNode == NULL)
{
    if (isDuplicate != NULL)
        *isDuplicate = 0;

    return newNode;
}
//--------------------------------

    else if ((compareFct(currentNode->data, newNode->data) < 0))
    {
        currentNode->left   = addToTreeRec(currentNode->left, newNode, compareFct, isDuplicate, 0);
    }
    else if ((compareFct(currentNode->data, newNode->data) > 0))
    {
        currentNode->right  = addToTreeRec(currentNode->right, newNode, compareFct, isDuplicate, 0);
    }
    else if ((compareFct(currentNode->data, newNode->data) == 0))
    {
        if (isDuplicate == NULL)
        {
            currentNode->left = addToTreeRec(currentNode->left, newNode, compareFct, isDuplicate, 0);
        }
        else
        {
            *isDuplicate = 1;
        }
    }


    return currentNode;
}
 

// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
// Use your implementation of a stack to organize the iterator. Push the root node and all left nodes first. On returning the next element,
// push the top node and push all its left nodes.

// Needs stack!!
//      Stack functions: push(), pop(), top(), clearStack()
void *nextTreeData(TreeNode *root)
{
    void *pointerToReturn = NULL;

    if (root != NULL)
    {
        // Add tree to stack so that bigest entry is ontop
        stackRoot       = nextTreeDataRec(root, stackRoot);
        pointerToReturn = stackRoot;
    }
    else
    {
        // return current top entry and then pop that top entry
        pointerToReturn = top(stackRoot);
        stackRoot       = pop(stackRoot);
    }

    
    return pointerToReturn;
}


void *nextTreeDataRec(TreeNode *tree, StackNode *stack)
{
    if (tree != NULL)
    {
        stack = nextTreeDataRec (tree->left, stack);
        stack = push            (stack, tree->data);
        stack = nextTreeDataRec (tree->right, stack);
    }


    return stack;
}


// Releases all memory resources (including data copies).
void clearTree(TreeNode *root)
{
    clearTreeRec(root);
}


void clearTreeRec(TreeNode *currentNode)
{
    if (currentNode != NULL)
    {
        clearTree(currentNode->left);
        clearTree(currentNode->right);
        clearNode(currentNode);
    }
}


void clearNode(TreeNode *node)
{
    free(node->data);
    node->data  = NULL;

    node->left  = NULL;
    node->right = NULL;

    free(node);
    node        = NULL;
}


// Returns the number of entries in the tree given by root.
unsigned int treeSize(const TreeNode *root)
{   
    unsigned int amountOfNodes = 0;

    
    amountOfNodes = treeSizeRec(root);


    return amountOfNodes;
}


int treeSizeRec(const TreeNode *currentNode)
{
    int nodeCount = 0;


    if (currentNode != NULL)
    {
        nodeCount += treeSizeRec(currentNode->left);
        nodeCount += treeSizeRec(currentNode->right);
        return nodeCount + 1;
    }

    return nodeCount;
}