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

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

// 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).
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{
    if (isDuplicate)
        *isDuplicate = 0;

    if (root == NULL)
    {
        TreeNode *newNode = (TreeNode *)malloc(sizeof(TreeNode));
        if (!newNode)
        {
            return NULL;
        }
        newNode->data = malloc(dataSize);
        if (!newNode->data)
        {
            free(newNode);
            return NULL;
        }

        memcpy(newNode->data, data, dataSize);
        newNode->left = NULL;
        newNode->right = NULL;
        return newNode;
    }

    int cmp = compareFct(data, root->data);

    if (cmp < 0)
    {
        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
    }
    else if (cmp > 0)
    {
        root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
    }
    else
    {

        if (isDuplicate)
        {
            *isDuplicate = 1; // ignorieren
            return root;
        }
        else
        {
            // Duplikate erlaubt -> nach rechts
            root->right = addToTree(root->right, data, dataSize, compareFct, NULL);
        }
    }
    return root;
}

// 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.
static StackNode *iterator = NULL;
void *nextTreeData(TreeNode *root)
{
      if (root != NULL)
    {
        clearStack(iterator);
        iterator = NULL;

        // Root + alle linken Nachfolger pushen
        TreeNode *current = root;
        while (current != NULL)
        {
            iterator = push(iterator, current);
            current = current->left;
        }
    }

    // Wenn Stack leer -> fertig
    if (iterator == NULL)
    {   
        return NULL;
    }
     

    // Top-Node holen
    TreeNode *node = (TreeNode *)top(iterator);
    iterator = pop(iterator);

    // rechten Teilbaum + linke Kette pushen
    TreeNode *right = node->right;
    while (right != NULL)
    {
        iterator = push(iterator, right);
        right = right->left;
    }

    return node->data;
}

// Releases all memory resources (including data copies).
void clearTree(TreeNode *root)
{
    if (root != NULL)
    {
        clearTree(root->left);
        clearTree(root->right);

        free(root->data);
        free(root);
    }
}

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

    return 1 + treeSize(root->left) + treeSize(root->right);
}