// SPDX-License-Identifier: GPL-3.0-or-later
#include <iostream>
#include <sstream>
#include <stack>

#include "node.h"

unsigned int node::node_id = 0;

node::node(const std::string &name) : name(name) {
  node_id++;
  if (name.empty()) {
    std::stringstream node_sm;
    node_sm << "node_" << node_id;
    this->name = node_sm.str();
  }
}

node::~node() {
  std::cout << "enter ~node() of \"" << get_name() << "\"" << std::endl;
  this->destroy = true;
  for (node *child : children) {
    if (!child->destroy) {
      delete child;
    }
  }
  std::cout << "leave ~node() of \"" << get_name() << "\"" << std::endl;
}

std::string node::get_name() const { return name; }

void node::set_name(const std::string& new_name) { this->name = new_name; }

std::size_t node::get_nr_children() const { return children.size(); }

node *node::get_child(std::size_t i) const { return children[i]; }

void node::add_child(node *child) { children.push_back(child); }

void node::print(std::ostream &str, unsigned int depth) const {
  str << std::string(depth, '\t') << get_name() << std::endl;
  for (node *child : children) {
    child->print(str, depth + 1);
  }
}

std::string node::print_recursive(unsigned int depth,
                                  std::set<const node *> visited) const {
  std::stringstream output;
  output << std::string(depth, '\t') << get_name();
  visited.insert(this);
  for (const node *child : children) {
    // std::set::contains is only implemented in C++20
    if (visited.find(child) == visited.end()) {
      output << std::endl << child->print_recursive(depth + 1, visited);
    } else {
      output << " [↝ " << child->get_name() << "]";
    }
  }
  if (depth == 0)
    output << std::endl;
  return output.str();
}

std::string node::print_iterative() const {
  std::stringstream output;
  std::stack<std::pair<const node *, unsigned int>> stack;
  stack.push({this, 0});
  std::set<const node *> visited = {};

  while (!stack.empty()) {
    const node *n = nullptr;
    unsigned int depth;
    std::tie(n, depth) = stack.top();
    stack.pop();
    if (visited.find(n) == visited.end()) {
      if (n != this)
        output << std::endl;
      output << std::string(depth, '\t') << n->get_name();
      // Complex iteration (not default vector iteration) is necessary,
      // to achieve the same output as the recursive approach.
      // Otherwise, the order of the children is reversed (due to LIFO).
      for (std::size_t i = n->get_nr_children(); i > 0; i--) {
        stack.push({n->get_child(i - 1), depth + 1});
      }
    } else {
      output << " [↝ " << n->get_name() << "]";
    }
    visited.insert(n);
  }
  output << std::endl;
  return output.str();
}

std::ostream &operator<<(std::ostream &os, node &n) {
  n.print(os);
  return os;
}

node *create_complete_tree(std::size_t nr_child_nodes,
                           unsigned int tree_depth) {
  node *n = new node();
  if (tree_depth > 1) {
    for (std::size_t i = 0; i < nr_child_nodes; i++) {
      n->add_child(create_complete_tree(nr_child_nodes, tree_depth - 1));
    }
  }
  return n;
}