#ifndef THIRD_PARTY_GBMCWEB_REDFISH_CORE_INCLUDE_UTILS_JSON_UTILS_H_
#define THIRD_PARTY_GBMCWEB_REDFISH_CORE_INCLUDE_UTILS_JSON_UTILS_H_

/*
// Copyright (c) 2018 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/

#include <algorithm>
#include <array>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <limits>
#include <optional>
#include <span>  // NOLINT
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <variant>
#include <vector>

#include "http_request.hpp"
#include "http_response.hpp"
#include "logging.hpp"
#include "human_sort.hpp"
#include "error_messages.hpp"
#include <nlohmann/json.hpp>

// IWYU pragma: no_include <stdint.h>
// IWYU pragma: no_forward_declare crow::Request

namespace redfish {

namespace json_util {

/**
 * @brief Processes request to extract JSON from its body. If it fails, adds
 *       MalformedJSON message to response and ends it.
 *
 * @param[io]  res       Response object
 * @param[in]  req       Request object
 * @param[out] reqJson   JSON object extracted from request's body
 *
 * @return true if JSON is valid, false when JSON is invalid and response has
 *         been filled with message and ended.
 */
bool processJsonFromRequest(crow::Response& res, const crow::Request& req,
                            nlohmann::json& reqJson);
namespace details {

template <typename Type>
struct IsOptional : std::false_type {};

template <typename Type>
struct IsOptional<std::optional<Type>> : std::true_type {};

template <typename Type>
struct IsVector : std::false_type {};

template <typename Type>
struct IsVector<std::vector<Type>> : std::true_type {};

template <typename Type>
struct IsStdArray : std::false_type {};

template <typename Type, std::size_t size>
struct IsStdArray<std::array<Type, size>> : std::true_type {};

enum class UnpackErrorCode : std::uint8_t { success, invalidType, outOfRange };

template <typename ToType, typename FromType>
bool checkRange(const FromType& from, std::string_view key) {
  if (from > std::numeric_limits<ToType>::max()) {
    BMCWEB_LOG_DEBUG << "Value for key " << key
                     << " was greater than max: " << __PRETTY_FUNCTION__;
    return false;
  }
  if (from < std::numeric_limits<ToType>::lowest()) {
    BMCWEB_LOG_DEBUG << "Value for key " << key
                     << " was less than min: " << __PRETTY_FUNCTION__;
    return false;
  }
  if constexpr (std::is_floating_point_v<ToType>) {
    if (std::isnan(from)) {
      BMCWEB_LOG_DEBUG << "Value for key " << key << " was NAN";
      return false;
    }
  }

  return true;
}

template <typename Type>
UnpackErrorCode unpackValueWithErrorCode(nlohmann::json& jsonValue,
                                         std::string_view key, Type& value) {
  UnpackErrorCode ret = UnpackErrorCode::success;

  if constexpr (std::is_floating_point_v<Type>) {
    double helper = 0;
    double* jsonPtr = jsonValue.get_ptr<double*>();

    if (jsonPtr == nullptr) {
      int64_t* intPtr = jsonValue.get_ptr<int64_t*>();
      if (intPtr != nullptr) {
        helper = static_cast<double>(*intPtr);
        jsonPtr = &helper;
      }
    }
    if (jsonPtr == nullptr) {
      return UnpackErrorCode::invalidType;
    }
    if (!checkRange<Type>(*jsonPtr, key)) {
      return UnpackErrorCode::outOfRange;
    }
    value = static_cast<Type>(*jsonPtr);
  } else if constexpr (std::is_signed_v<Type>) {
    int64_t* jsonPtr = jsonValue.get_ptr<int64_t*>();
    if (jsonPtr == nullptr) {
      return UnpackErrorCode::invalidType;
    }
    if (!checkRange<Type>(*jsonPtr, key)) {
      return UnpackErrorCode::outOfRange;
    }
    value = static_cast<Type>(*jsonPtr);
  } else if constexpr ((std::is_unsigned_v<Type>) &&
                       (!std::is_same_v<bool, Type>)) {
    uint64_t* jsonPtr = jsonValue.get_ptr<uint64_t*>();
    if (jsonPtr == nullptr) {
      return UnpackErrorCode::invalidType;
    }
    if (!checkRange<Type>(*jsonPtr, key)) {
      return UnpackErrorCode::outOfRange;
    }
    value = static_cast<Type>(*jsonPtr);
  } else if constexpr (std::is_same_v<nlohmann::json, Type>) {
    value = std::move(jsonValue);
  } else {
    using JsonType = std::add_const_t<std::add_pointer_t<Type>>;
    JsonType jsonPtr = jsonValue.get_ptr<JsonType>();
    if (jsonPtr == nullptr) {
      BMCWEB_LOG_DEBUG << "Value for key " << key
                       << " was incorrect type: " << jsonValue.type_name();
      return UnpackErrorCode::invalidType;
    }
    value = std::move(*jsonPtr);
  }
  return ret;
}

template <typename Type>
bool unpackValue(nlohmann::json& jsonValue, std::string_view key,
                 crow::Response& res, Type& value) {
  bool ret = true;

  if constexpr (IsOptional<Type>::value) {
    value.emplace();
    ret = unpackValue<typename Type::value_type>(jsonValue, key, res, *value) &&
          ret;
  } else if constexpr (IsStdArray<Type>::value) {
    if (!jsonValue.is_array()) {
      messages::propertyValueTypeError(
          res,
          res.jsonValue.dump(2, ' ', true,
                             nlohmann::json::error_handler_t::replace),
          key);
      return false;
    }
    if (jsonValue.size() != value.size()) {
      messages::propertyValueTypeError(
          res,
          res.jsonValue.dump(2, ' ', true,
                             nlohmann::json::error_handler_t::replace),
          key);
      return false;
    }
    size_t index = 0;
    for (const auto& val : jsonValue.items()) {
      ret = unpackValue<typename Type::value_type>(val.value(), key, res,
                                                   value[index++]) &&
            ret;
    }
  } else if constexpr (IsVector<Type>::value) {
    if (!jsonValue.is_array()) {
      messages::propertyValueTypeError(
          res,
          res.jsonValue.dump(2, ' ', true,
                             nlohmann::json::error_handler_t::replace),
          key);
      return false;
    }

    for (const auto& val : jsonValue.items()) {
      value.emplace_back();
      ret = unpackValue<typename Type::value_type>(val.value(), key, res,
                                                   value.back()) &&
            ret;
    }
  } else {
    UnpackErrorCode ec = unpackValueWithErrorCode(jsonValue, key, value);
    if (ec != UnpackErrorCode::success) {
      if (ec == UnpackErrorCode::invalidType) {
        messages::propertyValueTypeError(
            res,
            jsonValue.dump(2, ' ', true,
                           nlohmann::json::error_handler_t::replace),
            key);
      } else if (ec == UnpackErrorCode::outOfRange) {
        messages::propertyValueNotInList(
            res,
            jsonValue.dump(2, ' ', true,
                           nlohmann::json::error_handler_t::replace),
            key);
      }
      return false;
    }
  }

  return ret;
}

template <typename Type>
bool unpackValue(nlohmann::json& jsonValue, std::string_view key, Type& value) {
  bool ret = true;
  if constexpr (IsOptional<Type>::value) {
    value.emplace();
    ret = unpackValue<typename Type::value_type>(jsonValue, key, *value) && ret;
  } else if constexpr (IsStdArray<Type>::value) {
    if (!jsonValue.is_array()) {
      return false;
    }
    if (jsonValue.size() != value.size()) {
      return false;
    }
    size_t index = 0;
    for (const auto& val : jsonValue.items()) {
      ret = unpackValue<typename Type::value_type>(val.value(), key,
                                                   value[index++]) &&
            ret;
    }
  } else if constexpr (IsVector<Type>::value) {
    if (!jsonValue.is_array()) {
      return false;
    }

    for (const auto& val : jsonValue.items()) {
      value.emplace_back();
      ret = unpackValue<typename Type::value_type>(val.value(), key,
                                                   value.back()) &&
            ret;
    }
  } else {
    UnpackErrorCode ec = unpackValueWithErrorCode(jsonValue, key, value);
    if (ec != UnpackErrorCode::success) {
      return false;
    }
  }

  return ret;
}
}  // namespace details

// clang-format off
using UnpackVariant = std::variant<
    uint8_t*,
    uint16_t*,
    int16_t*,
    uint32_t*,
    int32_t*,
    uint64_t*,
    int64_t*,
    bool*,
    double*,
    std::string*,
    nlohmann::json*,
    std::vector<uint8_t>*,
    std::vector<uint16_t>*,
    std::vector<int16_t>*,
    std::vector<uint32_t>*,
    std::vector<int32_t>*,
    std::vector<uint64_t>*,
    std::vector<int64_t>*,
    // std::vector<bool>*,
    std::vector<double>*,
    std::vector<std::string>*,
    std::vector<nlohmann::json>*,
    std::optional<uint8_t>*,
    std::optional<uint16_t>*,
    std::optional<int16_t>*,
    std::optional<uint32_t>*,
    std::optional<int32_t>*,
    std::optional<uint64_t>*,
    std::optional<int64_t>*,
    std::optional<bool>*,
    std::optional<double>*,
    std::optional<std::string>*,
    std::optional<nlohmann::json>*,
    std::optional<std::vector<uint8_t>>*,
    std::optional<std::vector<uint16_t>>*,
    std::optional<std::vector<int16_t>>*,
    std::optional<std::vector<uint32_t>>*,
    std::optional<std::vector<int32_t>>*,
    std::optional<std::vector<uint64_t>>*,
    std::optional<std::vector<int64_t>>*,
    // std::optional<std::vector<bool>>*,
    std::optional<std::vector<double>>*,
    std::optional<std::vector<std::string>>*,
    std::optional<std::vector<nlohmann::json>>*
>;
// clang-format on

struct PerUnpack {
  std::string_view key;
  UnpackVariant value;
  bool complete = false;
};

inline bool readJsonHelper(nlohmann::json& jsonRequest, crow::Response& res,
                           std::span<PerUnpack> toUnpack) {
  bool result = true;
  nlohmann::json::object_t* obj =
      jsonRequest.get_ptr<nlohmann::json::object_t*>();
  if (obj == nullptr) {
    BMCWEB_LOG_DEBUG << "Json value is not an object";
    messages::unrecognizedRequestBody(res);
    return false;
  }
  for (auto& item : *obj) {
    size_t unpackIndex = 0;
    for (; unpackIndex < toUnpack.size(); unpackIndex++) {
      PerUnpack& unpackSpec = toUnpack[unpackIndex];
      std::string_view key = unpackSpec.key;
      size_t keysplitIndex = key.find('/');
      std::string_view leftover;
      if (keysplitIndex != std::string_view::npos) {
        leftover = key.substr(keysplitIndex + 1);
        key = key.substr(0, keysplitIndex);
      }

      if (key != item.first || unpackSpec.complete) {
        continue;
      }

      // Sublevel key
      if (!leftover.empty()) {
        // Include the slash in the key so we can compare later
        key = unpackSpec.key.substr(0, keysplitIndex + 1);
        nlohmann::json j;
        result =
            details::unpackValue<nlohmann::json>(item.second, key, res, j) &&
            result;
        if (!result) {
          return result;
        }

        std::vector<PerUnpack> nextLevel;
        for (PerUnpack& p : toUnpack) {
          if (!p.key.starts_with(key)) {
            continue;
          }
          std::string_view thisLeftover = p.key.substr(key.size());
          nextLevel.push_back({thisLeftover, p.value, false});
          p.complete = true;
        }

        result = readJsonHelper(j, res, nextLevel) && result;
        break;
      }

      result = std::visit(
                   [&item, &unpackSpec, &res](auto&& val) {
                     using ContainedT =
                         std::remove_pointer_t<std::decay_t<decltype(val)>>;
                     return details::unpackValue<ContainedT>(
                         item.second, unpackSpec.key, res, *val);
                   },
                   unpackSpec.value) &&
               result;

      unpackSpec.complete = true;
      break;
    }

    if (unpackIndex == toUnpack.size()) {
      messages::propertyUnknown(res, item.first);
      result = false;
    }
  }

  for (PerUnpack& perUnpack : toUnpack) {
    if (!perUnpack.complete) {
      bool isOptional = std::visit(
          [](auto&& val) {
            using ContainedType =
                std::remove_pointer_t<std::decay_t<decltype(val)>>;
            return details::IsOptional<ContainedType>::value;
          },
          perUnpack.value);
      if (isOptional) {
        continue;
      }
      messages::propertyMissing(res, perUnpack.key);
      result = false;
    }
  }
  return result;
}

inline void packVariant(std::span<PerUnpack> /*toPack*/) {}

template <typename FirstType, typename... UnpackTypes>
void packVariant(std::span<PerUnpack> toPack, std::string_view key,
                 FirstType& first, UnpackTypes&&... in) {
  if (toPack.empty()) {
    return;
  }
  toPack[0].key = key;
  toPack[0].value = &first;
  // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-array-to-pointer-decay)
  packVariant(toPack.subspan(1), std::forward<UnpackTypes&&>(in)...);
}

template <typename FirstType, typename... UnpackTypes>
bool readJson(nlohmann::json& jsonRequest, crow::Response& res,
              std::string_view key, FirstType&& first, UnpackTypes&&... in) {
  const std::size_t n = sizeof...(UnpackTypes) + 2;
  std::array<PerUnpack, n / 2> toUnpack2;
  packVariant(toUnpack2, key, first, std::forward<UnpackTypes&&>(in)...);
  return readJsonHelper(jsonRequest, res, toUnpack2);
}

inline std::optional<nlohmann::json> readJsonPatchHelper(
    const crow::Request& req, crow::Response& res) {
  nlohmann::json jsonRequest;
  if (!json_util::processJsonFromRequest(res, req, jsonRequest)) {
    BMCWEB_LOG_DEBUG << "Json value not readable";
    return std::nullopt;
  }
  nlohmann::json::object_t* object =
      jsonRequest.get_ptr<nlohmann::json::object_t*>();
  if (object == nullptr || object->empty()) {
    BMCWEB_LOG_DEBUG << "Json value is empty";
    messages::emptyJSON(res);
    return std::nullopt;
  }
  std::erase_if(*object,
                [](const std::pair<std::string, nlohmann::json>& item) {
                  return item.first.starts_with("@odata.");
                });
  if (object->empty()) {
    //  If the update request only contains OData annotations, the service
    //  should return the HTTP 400 Bad Request status code with the
    //  NoOperation message from the Base Message Registry, ...
    messages::noOperation(res);
    return std::nullopt;
  }

  return {std::move(jsonRequest)};
}

template <typename... UnpackTypes>
bool readJsonPatch(const crow::Request& req, crow::Response& res,
                   std::string_view key, UnpackTypes&&... in) {
  std::optional<nlohmann::json> jsonRequest = readJsonPatchHelper(req, res);
  if (jsonRequest == std::nullopt) {
    return false;
  }

  return readJson(*jsonRequest, res, key, std::forward<UnpackTypes&&>(in)...);
}

/* readJsonAction
 *
 * returns false if argument parsing failed
 */

template <typename... UnpackTypes>
bool readJsonAction(const crow::Request& req, crow::Response& res,
                    const char* key, UnpackTypes&&... in) {
  nlohmann::json jsonRequest;
  if (!json_util::processJsonFromRequest(res, req, jsonRequest)) {
    BMCWEB_LOG_DEBUG << "Json value not readable";
    return false;
  }
  return readJson(jsonRequest, res, key, std::forward<UnpackTypes&&>(in)...);
}

// Sort the JSON array by |element[key]|.
// Each element shall contains |key| and the corresponding value shall be of
// type |nlohmann::json::string_t|; otherwise, returns false.
// For wehther sorting is performed, please refer to the following:
// if the all objects in the array either "have the key and the key value is
// string" or "the first key in the object has a value that is string", sorting
// will be performed, otherwise  not. the array of mixed key and no key objects
// will be sorted as follows:
// 1. Elements without |key| are smaller than elements with |key|.
// 2. For elements without |key|, the order is based on first_key then
// |element[first_key]|.
// 3. For elements with same |key|, the order is based on
// |element[key]|.
// Altough we can safely assume that each element[key] is string based
// on current usage. In production usage of the function, each element will have
// the target key and the corresponding value is string based on current usage.
inline bool sortJsonArrayByKey(const std::string& key,
                               nlohmann::json::array_t& array) {
  bool succeeded = false;

  // only if all elements have the key and the key value is string, the sort is
  // deemed successful.
  if (std::all_of(array.begin(), array.end(), [&key](const nlohmann::json& a) {
        auto it = a.find(key);
        if (it == a.end()) {
          return false;
        }
        const nlohmann::json::string_t* v =
            it->get_ptr<const nlohmann::json::string_t*>();
        if (v == nullptr) {
          return false;
        }
        return true;
      })) {
    succeeded = true;
  }

  // If the array is a mixture of objects with and without the target key,
  // sorting is performed only if the first key in the object without key or
  // target key in object have a string value.
  if (!std::all_of(array.begin(), array.end(), [&key](const nlohmann::json& a) {
        auto it = a.find(key);
        if (it != a.end()) {
          return it->get_ptr<const nlohmann::json::string_t*>() != nullptr;
        }
        const nlohmann::json::string_t* v =
            a.begin()->get_ptr<const nlohmann::json::string_t*>();
        return v != nullptr;
      })) {
    // If the first key of the object doesn't have a string value, no
    // sorting is performed.
    return false;
  }

  std::sort(array.begin(), array.end(),
            [comparator = AlphanumLess<nlohmann::json::string_t>(), &key](
                const nlohmann::json& a, const nlohmann::json& b) mutable {
              auto aIt = a.find(key);
              auto bIt = b.find(key);
              if (aIt == a.end() && bIt == b.end()) {
                // If both arrays don't have the key, compare the first key of
                // the object then value
                auto akey = a.begin().key();
                auto aValue = a.begin().value();
                auto bkey = b.begin().key();
                auto bValue = b.begin().value();
                if (!comparator(akey, bkey) && !comparator(bkey, akey)) {
                  return comparator(aValue, bValue);
                }
                return comparator(akey, bkey);
              }

              // If one object doesn't have the key, the other one is larger.
              if (aIt == a.end()) {
                return true;
              }
              if (bIt == b.end()) {
                return false;
              }

              // If both objects have the key, compare the value.
              const nlohmann::json::string_t* nameA =
                  aIt->get_ptr<const nlohmann::json::string_t*>();
              const nlohmann::json::string_t* nameB =
                  bIt->get_ptr<const nlohmann::json::string_t*>();
              return comparator(*nameA, *nameB);
            });

  return succeeded;
}

}  // namespace json_util
}  // namespace redfish

#endif  // THIRD_PARTY_GBMCWEB_REDFISH_CORE_INCLUDE_UTILS_JSON_UTILS_H_