#pragma once

#include "Visitor.h"

#include <functional> // for std::reference_wrapper
#include <list>
#include <ostream>

namespace ChimeraTK {

  // Forward declarations
  class VariableNetworkNode;

  /**
   * @brief A helper class to replace the output stream temporarily
   *
   * This is a helper class that is used in the Graphviz dumper to be able to dump
   * the nodes to a stringstream instead of directly to the file.
   *
   * Ideally, the pushStream()/popStream() functions should be called in pairs but
   * popStream() will do nothing if the stack is empty.
   */
  class PushableStream {
   public:
    PushableStream(std::ostream& stream) : _streamStack{stream} {}
    virtual ~PushableStream() {}

    void pushStream(std::ostream& stream) { _streamStack.push_back(stream); }

    std::ostream& stream() { return _streamStack.back().get(); }

    void popStream() {
      if(_streamStack.size() == 1) return;

      _streamStack.pop_back();
    }

   private:
    std::list<std::reference_wrapper<std::ostream>> _streamStack;
  };

  /**
   * @brief The VariableNetworkNodeDumpingVisitor class
   *
   * This class is serving as one of the base classes for the Graphviz dumper as
   * well as the textual dumper providing detailed information about a node.
   */
  class VariableNetworkNodeDumpingVisitor : public Visitor<VariableNetworkNode>, public PushableStream {
   public:
    /**
     * @brief VariableNetworkNodeDumpingVisitor::VariableNetworkNodeDumpingVisitor
     * @param stream instance of std::ostream to write to
     * @param separator the separator to use
     *
     * Separator is used to be able to use the function in the Graphviz and
     * textual connection dumper. We are using newlines for Graphviz, and space
     * for textual
     */
    VariableNetworkNodeDumpingVisitor(std::ostream& stream, const std::string& separator);
    virtual ~VariableNetworkNodeDumpingVisitor() {}

    /**
     * @brief dispatch
     * @param t Node to visit
     *
     * Visitor function for VariableNetworkNode. Will dump a verbose description
     * of the node
     */
    void dispatch(const VariableNetworkNode& t);

   private:
    std::string _separator;
  };

} // namespace ChimeraTK