/*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#pragma once
#include <folly/dynamic.h>

namespace facebook {
namespace xplat {

namespace detail {

template <typename R, typename M, typename... T>
R jsArg1(const folly::dynamic &arg, M asFoo, const T &...desc) {
  try {
    return (arg.*asFoo)();
  } catch (const folly::TypeError &ex) {
    throw JsArgumentException(folly::to<std::string>(
        "Error converting javascript arg ", desc..., " to C++: ", ex.what()));
  } catch (const std::range_error &ex) {
    throw JsArgumentException(folly::to<std::string>(
        "Could not convert argument ",
        desc...,
        " to required type: ",
        ex.what()));
  }
}

} // namespace detail

template <typename R, typename... T>
R jsArg(
    const folly::dynamic &arg,
    R (folly::dynamic::*asFoo)() const,
    const T &...desc) {
  return detail::jsArg1<R>(arg, asFoo, desc...);
}

template <typename R, typename... T>
R jsArg(
    const folly::dynamic &arg,
    R (folly::dynamic::*asFoo)() const &,
    const T &...desc) {
  return detail::jsArg1<R>(arg, asFoo, desc...);
}

template <typename T>
// NOLINTNEXTLINE (T62192316)
typename detail::is_dynamic<T>::type &jsArgAsDynamic(T &&args, size_t n) {
  try {
    return args[n];
  } catch (const std::out_of_range &ex) {
    // Use 1-base counting for argument description.
    throw JsArgumentException(folly::to<std::string>(
        "JavaScript provided ",
        args.size(),
        " arguments for C++ method which references at least ",
        n + 1,
        " arguments: ",
        ex.what()));
  }
}

template <typename R>
R jsArgN(
    const folly::dynamic &args,
    size_t n,
    R (folly::dynamic::*asFoo)() const) {
  return jsArg(jsArgAsDynamic(args, n), asFoo, n);
}
template <typename R>
R jsArgN(
    const folly::dynamic &args,
    size_t n,
    R (folly::dynamic::*asFoo)() const &) {
  return jsArg(jsArgAsDynamic(args, n), asFoo, n);
}

namespace detail {

// This is a helper for jsArgAsArray and jsArgAsObject.

template <typename T>
typename detail::is_dynamic<T>::type &jsArgAsType(
    T &&args,
    size_t n,
    const char *required,
    bool (folly::dynamic::*isFoo)() const) {
  T &ret = jsArgAsDynamic(args, n);
  if ((ret.*isFoo)()) {
    return ret;
  }

  // Use 1-base counting for argument description.
  throw JsArgumentException(folly::to<std::string>(
      "Argument ",
      n + 1,
      " of type ",
      ret.typeName(),
      " is not required type ",
      required));
}

} // end namespace detail

template <typename T>
typename detail::is_dynamic<T>::type &jsArgAsArray(T &&args, size_t n) {
  return detail::jsArgAsType(args, n, "Array", &folly::dynamic::isArray);
}

template <typename T>
typename detail::is_dynamic<T>::type &jsArgAsObject(T &&args, size_t n) {
  return detail::jsArgAsType(args, n, "Object", &folly::dynamic::isObject);
}

} // namespace xplat
} // namespace facebook