#include <filesystem>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <map>
#include <sstream>
#include <stdexcept>
#include <string_view>
#include <variant>

#include "heading.h"
#include "scene.h"

Scene::Scene(const std::filesystem::path& path) {
  std::ifstream input(path.c_str());
  std::string line;
  bool section_started = false;
  Heading cur_heading;
  std::ostringstream cur_value;
  bool value_started = false;
  auto handle_end_of_section = [&]() {
    section_started = false;
    value_started = false;

    if (cur_heading.type() == "sub_resource") {
      sub_resources_[std::get<int>(cur_heading.GetKeyval("id"))] = {
          cur_heading, cur_value.str()};
    } else {
      other_.emplace_back(cur_heading, cur_value.str());
    }

    cur_value = {};
  };
  while (std::getline(input, line)) {
    if (section_started && (line.empty() || line[0] == '[')) {
      handle_end_of_section();
    }
    if (!line.empty() && line[0] == '[') {
      Heading heading(line);
      if (heading.type() == "gd_scene") {
        file_descriptor_ = heading;
      } else if (heading.type() == "ext_resource") {
        ext_resources_[std::get<int>(heading.GetKeyval("id"))] = heading;
      } else {
        cur_heading = heading;
        section_started = true;
      }
    } else if (!line.empty()) {
      if (value_started) {
        cur_value << std::endl;
      } else {
        value_started = true;
      }
      cur_value << line;
    }
  }
  if (section_started) {
    handle_end_of_section();
  }

  for (const auto& [id, stuff] : sub_resources_) {
    if (id >= next_sub_id_) {
      next_sub_id_ = id + 1;
    }
  }
}

int Scene::AddSubResource(const Script& script) {
  int new_id = next_sub_id_++;

  std::ostringstream resource_contents;
  for (const auto& [variable, value] : script.exports()) {
    resource_contents << variable << " = SubResource( " << value << " )"
                      << std::endl;
  }
  resource_contents << "script/source = " << std::quoted(script.ToString());

  Heading heading;
  heading.set_type("sub_resource");
  heading.SetKeyval("type", "GDScript");
  heading.SetKeyval("id", new_id);

  sub_resources_[new_id] = {heading, resource_contents.str()};

  return new_id;
}

void Scene::RemoveExtResource(int id) { ext_resources_.erase(id); }

void Scene::ReplaceScriptReferences(int ext_id, int sub_id) {
  auto replace_refs = [&](std::string& text) {
    std::ostringstream search_str;
    search_str << "ExtResource( " << ext_id << " )";
    std::string search = search_str.str();

    std::ostringstream new_text;
    std::string_view corpus = text;
    int location;
    while ((location = corpus.find(search)) != std::string_view::npos) {
      new_text << corpus.substr(0, location) << "SubResource( " << sub_id
               << " )";
      corpus.remove_prefix(location + search.size());
    }
    new_text << corpus;

    text = new_text.str();
  };

  for (auto& [id, stuff] : sub_resources_) {
    auto& [heading, text] = stuff;
    replace_refs(text);
  }

  for (auto& [heading, text] : other_) {
    replace_refs(text);
  }
}

std::string Scene::ToString() const {
  std::ostringstream output;
  output << file_descriptor_.ToString() << std::endl;

  for (const auto& [id, heading] : ext_resources_) {
    output << heading.ToString();
  }

  output << std::endl;

  for (const auto& [id, resource] : sub_resources_) {
    const auto& [heading, value] = resource;
    output << heading.ToString() << value << std::endl << std::endl;
  }

  for (const auto& [heading, value] : other_) {
    output << heading.ToString() << value << std::endl << std::endl;
  }

  return output.str();
}