#pragma once

#include "generator/osm_element.hpp"

#include "base/assert.hpp"
#include "base/string_utils.hpp"

#include <functional>
#include <string>

class XMLSource
{
public:
  using Emitter = std::function<void(OsmElement *)>;

  XMLSource(Emitter fn) : m_emitter(fn) {}

  void CharData(std::string const &) {}

  void AddAttr(std::string const & key, std::string const & value)
  {
    if (!m_current)
      return;

    if (key == "id")
      CHECK(strings::to_uint64(value, m_current->id), ("Unknown element with invalid id:", value));
    else if (key == "lon")
      CHECK(strings::to_double(value, m_current->lon), ("Bad node lon:", value));
    else if (key == "lat")
      CHECK(strings::to_double(value, m_current->lat), ("Bad node lat:", value));
    else if (key == "ref")
      CHECK(strings::to_uint64(value, m_current->ref), ("Bad node ref in way:", value));
    else if (key == "k")
      m_current->k = value;
    else if (key == "v")
      m_current->v = value;
    else if (key == "type")
      m_current->memberType = OsmElement::StringToEntityType(value);
    else if (key == "role")
      m_current->role = value;
  }

  bool Push(std::string const & tagName)
  {
    ASSERT_GREATER_OR_EQUAL(tagName.size(), 2, ());

    // As tagKey we use first two char of tag name.
    OsmElement::EntityType tagKey =
        OsmElement::EntityType(*reinterpret_cast<uint16_t const *>(tagName.data()));

    switch (++m_depth)
    {
    case 1:
      m_current = nullptr;
      break;
    case 2:
      m_current = &m_parent;
      m_current->type = tagKey;
      break;
    default:
      m_current = &m_child;
      m_current->type = tagKey;
      break;
    }
    return true;
  }

  void Pop(std::string const & v)
  {
    switch (--m_depth)
    {
    case 0:
      break;

    case 1:
      m_emitter(m_current);
      m_parent.Clear();
      break;

    default:
      switch (m_child.type)
      {
      case OsmElement::EntityType::Member:
        m_parent.AddMember(m_child.ref, m_child.memberType, m_child.role);
        break;
      case OsmElement::EntityType::Tag:
        m_parent.AddTag(m_child.k, m_child.v);
        break;
      case OsmElement::EntityType::Nd:
        m_parent.AddNd(m_child.ref);
        break;
      default:
        break;
      }
      m_current = &m_parent;
      m_child.Clear();
    }
  }

private:
  OsmElement m_parent;
  OsmElement m_child;

  size_t m_depth = 0;
  OsmElement * m_current = nullptr;

  Emitter m_emitter;
};