#include <string.h>
#include "stack.h"
#include "bintree.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)
{
  //*******************  Prüfen ob wir kein Nullzeiger oder Null speicher haben
    if (root == NULL) {
        // Kein Knoten vorhanden : neuer Knoten wird erstellt
        TreeNode *node = malloc(sizeof(TreeNode));
        if (!node)
          return NULL;
        node->data = malloc(dataSize);
        if (!node->data) {
            free(node);
            return NULL;
        }
  //*******************   Ende von Prüfungen

        memcpy(node->data, data, dataSize);
        node->left = NULL;
        node->right = NULL;

        if (isDuplicate != NULL)
          *isDuplicate = 0;
        return node;
    }

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

    if (cmp == 0) {
        if (isDuplicate)
          *isDuplicate = 1;
        return root;  // Ignorieren, keine Änderung
    }

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

    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.
void *nextTreeData(TreeNode *root) {

    // static stack : wie strtok interner Zustand
    static StackNode *stack = NULL;

    if (root != NULL) {
        // neuer Durchlauf : alten Stack löschen
        clearStack(stack);
        stack = NULL;

        // alle linken Knoten pushen
        TreeNode *curr = root;
        while (curr != NULL) {
            stack = push(stack, curr);
            curr = curr->left;
        }
    }

    if (stack == NULL)
        return NULL;   // nichts mehr da

    // obersten Knoten holen
    TreeNode *node = (TreeNode *) top(stack);
    stack = pop(stack);

    // rechten Teilbaum durchsuchen (und alle linken davon)
    TreeNode *curr = node->right;
    while (curr != NULL) {
        stack = push(stack, curr);
        curr = curr->left;
    }

    return node->data;
}


// Releases all memory resources (including data copies).
void clearTree(TreeNode *root) {
    if (root == NULL)
        return;
//erstens in die tiefsten Ebenen gehen
    clearTree(root->left);
    clearTree(root->right);
// dann zeiger auf Datei löschen
    free(root->data);
//Und am ende element des Baums löschen
    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);
}