// Copyright satoren
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#pragma once

#include <string>

#include "kaguya/config.hpp"
#include "kaguya/type.hpp"

namespace kaguya {
inline const char *get_error_message(lua_State *state) {
  if (lua_type(state, -1) == LUA_TSTRING) {
    const char *message = lua_tostring(state, -1);
    return message ? message : "unknown error";
  } else {
    return "unknown error";
  }
}
inline int lua_pcall_wrap(lua_State *state, int argnum, int retnum) {
  int result = lua_pcall(state, argnum, retnum, 0);
  return result;
}

struct ErrorHandler {
  typedef standard::function<void(int, const char *)> function_type;

  static bool handle(const char *message, lua_State *state) {
    function_type handler = getHandler(state);
    if (handler) {
      handler(0, message);
      return true;
    }
    return false;
  }
  static bool handle(int status_code, const char *message, lua_State *state) {
    function_type handler = getHandler(state);
    if (handler) {
      handler(status_code, message);
      return true;
    }
    return false;
  }
  static bool handle(int status_code, lua_State *state) {
    function_type handler = getHandler(state);
    if (handler) {
      handler(status_code, get_error_message(state));
      return true;
    }
    return false;
  }

  static function_type getHandler(lua_State *state) {
    function_type *funptr = getFunctionPointer(state);
    if (funptr) {
      return *funptr;
    }
    return function_type();
  }

  static void unregisterHandler(lua_State *state) {
    if (state) {
      function_type *funptr = getFunctionPointer(state);
      if (funptr) {
        *funptr = function_type();
      }
    }
  }
  static void registerHandler(lua_State *state, function_type f) {
    if (state) {
      function_type *funptr = getFunctionPointer(state);
      if (!funptr) {
        util::ScopedSavedStack save(state);
        lua_pushlightuserdata(state, handlerRegistryKey());
        void *ptr = lua_newuserdata(
            state, sizeof(function_type)); // dummy data for gc call
        funptr = new (ptr) function_type();

        // create function_type metatable
        lua_newtable(state);
        lua_pushcclosure(state, &error_handler_cleanner, 0);
        lua_setfield(state, -2, "__gc");
        lua_pushvalue(state, -1);
        lua_setfield(state, -1, "__index");
        lua_setmetatable(state, -2);

        lua_rawset(state, LUA_REGISTRYINDEX);
      }
      *funptr = f;
    }
  }

  static void throwDefaultError(int status, const char *message = 0) {
    switch (status) {
    case LUA_ERRSYNTAX:
      throw LuaSyntaxError(status, message ? std::string(message)
                                           : "unknown syntax error");
    case LUA_ERRRUN:
      throw LuaRuntimeError(status, message ? std::string(message)
                                            : "unknown runtime error");
    case LUA_ERRMEM:
      throw LuaMemoryError(status, message ? std::string(message)
                                           : "lua memory allocation error");
    case LUA_ERRERR:
      throw LuaErrorRunningError(status, message
                                             ? std::string(message)
                                             : "unknown error running error");
#if LUA_VERSION_NUM >= 502
    case LUA_ERRGCMM:
      throw LuaGCError(status,
                       message ? std::string(message) : "unknown gc error");
#endif
    default:
      throw LuaUnknownError(status, message ? std::string(message)
                                            : "lua unknown error");
    }
  }

private:
  static void *handlerRegistryKey() {
    static void *key;
    return key;
  }
  static function_type *getFunctionPointer(lua_State *state) {
    if (state) {
      util::ScopedSavedStack save(state);
      lua_pushlightuserdata(state, handlerRegistryKey());
      lua_rawget(state, LUA_REGISTRYINDEX);
      function_type *ptr = (function_type *)lua_touserdata(state, -1);
      return ptr;
    }
    return 0;
  }

  ErrorHandler() {}

  ErrorHandler(const ErrorHandler &);
  ErrorHandler &operator=(const ErrorHandler &);

  static int error_handler_cleanner(lua_State *state) {
    function_type *ptr = (function_type *)lua_touserdata(state, 1);
    ptr->~function_type();
    return 0;
  }
};

namespace except {
inline void OtherError(lua_State *state, const std::string &message) {
  if (ErrorHandler::handle(message.c_str(), state)) {
    return;
  }
}
inline void typeMismatchError(lua_State *state, const std::string &message) {
  if (ErrorHandler::handle(message.c_str(), state)) {
    return;
  }
}
inline void memoryError(lua_State *state, const char *message) {
  if (ErrorHandler::handle(message, state)) {
    return;
  }
}
inline bool checkErrorAndThrow(int status, lua_State *state) {
  if (status != 0 && status != LUA_YIELD) {
    ErrorHandler::handle(status, state);

    return false;
  }
  return true;
}
}
}