#include "bintree.h"
#include "stack.h"
#include <string.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. */

// typedef int (*CompareFctType)(const void *arg1, const void *arg2);
//  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 *node = malloc(sizeof(TreeNode));
    node->data = malloc(dataSize);
    memcpy(node->data, data, dataSize);
    node->left = NULL;
    node->right = NULL;
    return node;
  }

  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 {
    // Duplikat
    if (isDuplicate) {
      *isDuplicate = 1;
    }
  }
  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 StackNode *stack = NULL;

  // Neue Iteration starten
  if (root != NULL) {
    clearStack(&stack);

    TreeNode *curr = root;

    // Alle linken Kinder pushen
    while (curr != NULL) {
      stack = push(stack, curr);
      curr = curr->left;
    }
  }

  // Wenn leer → fertig
  if (stack == NULL)
    return NULL;

  // Oberstes Element lesen
  TreeNode *node = (TreeNode *)stack->data;
  stack = pop(stack);

  // Jetzt den rechten Teilbaum verarbeiten
  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;

  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);
}