text: /*****************************************************************************************
   *                                                                                       *
   * OpenSpace                                                                             *
   *                                                                                       *
   * Copyright (c) 2014-2021                                                               *
   *                                                                                       *
   * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
   * software and associated documentation files (the "Software"), to deal in the Software *
   * without restriction, including without limitation the rights to use, copy, modify,    *
   * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
   * permit persons to whom the Software is furnished to do so, subject to the following   *
   * conditions:                                                                           *
   *                                                                                       *
   * The above copyright notice and this permission notice shall be included in all copies *
   * or substantial portions of the Software.                                              *
   *                                                                                       *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
   * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
   * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
   * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
   * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
   * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
   ****************************************************************************************/
  
  #include <modules/server/include/topics/luascripttopic.h>
  
  #include <modules/server/include/jsonconverters.h>
  #include <modules/server/include/connection.h>
  #include <openspace/json.h>
  #include <openspace/engine/globals.h>
  #include <openspace/scripting/scriptengine.h>
  #include <ghoul/logging/logmanager.h>
  #include <ghoul/misc/dictionary.h>
  
  namespace {
      constexpr const char* KeyScript = "script";
      constexpr const char* KeyFunction = "function";
      constexpr const char* KeyArguments = "arguments";
      constexpr const char* KeyReturn = "return";
      constexpr const char* _loggerCat = "LuaScriptTopic";
  
      std::string formatLua(const nlohmann::json::const_iterator& it);
  
      std::string escapeLuaString(const std::string& s) {
          std::string output;
          for (const char& c : s) {
              switch (c) {
                  case '\a': output += "\\\a"; break;
                  case '\b': output += "\\\b"; break;
                  case '\f': output += "\\\f"; break;
                  case '\n' : output += "\\\n"; break;
                  case '\r' : output += "\\\r"; break;
                  case '\t' : output += "\\\t"; break;
                  case '\v' : output += "\\\v"; break;
                  case '\\' : output += "\\\\"; break;
                  case '"' : output += "\\\""; break;
                  case '\'' : output += "\\'"; break;
                  default: output += c;
              }
          }
          return output;
      }
  
      std::string formatLuaString(const std::string& s) {
          return "\"" + escapeLuaString(s) + "\"";
      }
  
      std::string formatKeyValuePair(const nlohmann::json::const_iterator& it) {
          return "[" + formatLuaString(it.key()) + "] = " + formatLua(it);
      }
  
      std::string formatObjectAsLuaTable(const nlohmann::json& json) {
          std::string output = "{";
          auto it = json.begin();
          for (size_t i = 0; i < json.size(); ++i, ++it) {
              output += formatKeyValuePair(it);
              if (i < json.size() - 1) {
                  output += ",";
              }
          }
          return output + "}";
      }
  
      std::string formatArrayAsLuaTable(const nlohmann::json& json) {
          std::string output = "{";
          auto it = json.begin();
          for (size_t i = 0; i < json.size(); ++i, ++it) {
              output += formatLua(it);
              if (i < json.size() - 1) {
                  output += ",";
              }
          }
          return output + "}";
      }
  
      std::string formatLua(const nlohmann::json::const_iterator& it) {
          if (it->is_object()) {
              return formatObjectAsLuaTable(it->get<nlohmann::json>());
          }
          if (it->is_array()) {
              return formatArrayAsLuaTable(it->get<nlohmann::json>());
          }
          if (it->is_number()) {
              return fmt::format("{}", it->get<double>());
          }
          if (it->is_string()) {
              return formatLuaString(it->get<std::string>());
          }
          if (it->is_boolean()) {
              return it->get<bool>() ? "true" : "false";
          }
          if (it->is_null()) {
              return "nil";
          }
          throw ghoul::lua::LuaFormatException("Format error.");
      }
  
      std::string generateScript(const std::string& function,
                                 const std::vector<std::string>& args)
      {
          std::string script = "return " + function + "(";
          auto it = args.begin();
          for (size_t i = 0; i < args.size(); ++i, ++it) {
              script += *it;
              if (i < args.size() - 1) {
                  script += ",";
              }
          }
          return script + ")";
      }
  
  
  } // namespace
  
  namespace openspace {
  
  void LuaScriptTopic::handleJson(const nlohmann::json& json) {
      try {
          nlohmann::json::const_iterator script = json.find(KeyScript);
          nlohmann::json::const_iterator function = json.find(KeyFunction);
  
          if (script != json.end() && script->is_string()) {
              std::string luaScript = script->get<std::string>();
              nlohmann::json::const_iterator ret = json.find(KeyReturn);
              bool shouldReturn = (ret != json.end()) &&
                                   ret->is_boolean() &&
                                   ret->get<bool>();
  
              runScript(luaScript, shouldReturn);
          }
          else if (function != json.end() && function->is_string()) {
              std::string luaFunction = function->get<std::string>();
              nlohmann::json::const_iterator ret = json.find(KeyReturn);
              bool shouldReturn = (ret != json.end()) &&
                                   ret->is_boolean() &&
                                   ret->get<bool>();
  
              nlohmann::json::const_iterator args = json.find(KeyArguments);
              if (!args->is_array()) {
                  return;
              }
  
              std::vector<std::string> formattedArgs;
              formattedArgs.reserve(args->size());
              for (auto it = args->begin(); it != args->end(); ++it) {
                  formattedArgs.push_back(formatLua(it));
              }
  
              std::string luaScript = generateScript(luaFunction, formattedArgs);
              runScript(luaScript, shouldReturn);
          }
      }
      catch (const std::out_of_range& e) {
          LERROR("Could not run script -- key or value is missing in payload");
          LERROR(e.what());
      }
  }
  
  void LuaScriptTopic::runScript(std::string script, bool shouldReturn) {
      scripting::ScriptEngine::ScriptCallback callback;
      if (shouldReturn) {
          callback = [this](ghoul::Dictionary data) {
              if (_connection) {
                  nlohmann::json j = data;
                  _connection->sendJson(wrappedPayload(j));
                  _waitingForReturnValue = false;
              }
          };
          _waitingForReturnValue = true;
      }
      else {
          _waitingForReturnValue = false;
      }
  
      global::scriptEngine->queueScript(
          std::move(script),
          scripting::ScriptEngine::RemoteScripting::No,
          callback
      );
  }
  
  bool LuaScriptTopic::isDone() const {
      return !_waitingForReturnValue;
  }
  
  } // namespace openspace
  