#include "exception.hpp"

#include "windows.h"

#include <llarp/util/str.hpp>

#include <array>

namespace llarp::win32

{
  error::error(std::string msg) : error{GetLastError(), std::move(msg)}
  {}
  error::error(DWORD err, std::string msg)
      : std::runtime_error{fmt::format("{}: {} (code={})", msg, error_to_string(err), err)}
  {}
  std::string
  error_to_string(DWORD err)
  {
    // mostly yoinked from https://stackoverflow.com/a/45565001
    LPTSTR psz{nullptr};
    const DWORD cchMsg = FormatMessage(
        FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_ALLOCATE_BUFFER,
        nullptr,
        err,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        reinterpret_cast<LPTSTR>(&psz),
        0,
        nullptr);

    if (cchMsg <= 0)
    {
      // cannot get message for error, reset the last error here so it does not propagate
      ::SetLastError(0);
      return "unknown error";
    }

    auto deleter = [](void* p) { ::LocalFree(p); };
    std::unique_ptr<TCHAR, decltype(deleter)> ptrBuffer{psz, deleter};
    return std::string{ptrBuffer.get(), cchMsg};
  }
}  // namespace llarp::win32