// Handle errors with a Lua function, defined in lua-env.lua
#include "luainterp.hpp"
#include "BlHooks.hpp"
#include "lauxlib.h"
#include "lua.h"
#include <cstring>

int bll_error_handler(lua_State *L) {
  lua_getfield(L, LUA_GLOBALSINDEX, "_bllua_on_error");
  if (!lua_isfunction(L, -1)) {
    BlPrintf("  Lua error handler: _bllua_on_error not defined.");
    lua_pop(L, 1);
    return 1;
  }

  // move function to before arg
  int hpos = lua_gettop(L) - 1;
  lua_insert(L, hpos);

  lua_pcall(L, 1, 1, 0);
  return 1;
}
int bll_pcall(lua_State *L, int nargs, int nret) {
  // calculate stack position for message handler
  int hpos = lua_gettop(L) - nargs;
  // push custom error message handler
  lua_pushcfunction(L, bll_error_handler);
  // move it before function and arguments
  lua_insert(L, hpos);
  // call lua_pcall function with custom handler
  int ret = lua_pcall(L, nargs, nret, hpos);
  // remove custom error message handler from stack
  lua_remove(L, hpos);
  return ret;
}

// Display the last Lua error in the BL console
void bll_printError(lua_State *L, const char *operation, const char *item) {
  // error_handler(L);
  BlPrintf("\x03Lua error: %s", lua_tostring(L, -1));
  BlPrintf("\x03  (%s: %s)", operation, item);
  lua_pop(L, 1);
}

// Eval a string of Lua code
bool bll_LuaEval(lua_State *L, const char *str) {
  if (luaL_loadbuffer(L, str, strlen(str), "input") || bll_pcall(L, 0, 1)) {
    bll_printError(L, "eval", str);
    return false;
  }
  return true;
}

// Convert a Lua stack entry into a string for providing to TS
// Use static buffer to avoid excessive malloc
char bll_arg_buffer[BLL_ARG_COUNT][BLL_ARG_MAX];
bool bll_toarg(lua_State *L, char *buf, int i, bool err) {
  if (lua_isstring(L, i)) {
    const char *str = lua_tostring(L, i);
    if (strlen(str) >= BLL_ARG_MAX) {
      if (err)
        luaL_error(L, "argument to TS is too long - max length is 8192");
      return true;
    } else {
#ifdef _MSC_VER
      strncpy_s(buf, BLL_ARG_MAX, str, _TRUNCATE);
#else
      strncpy(buf, str, BLL_ARG_MAX - 1);
      buf[BLL_ARG_MAX - 1] = '\0';
#endif
      return false;
    }
  } else {
    if (err)
      luaL_error(L, "argument to TS must be a string");
    return true;
  }
}