/**
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 "DiskSpaceWatchdog.h"

#include "core/Property.h"
#include "core/logging/Logger.h"
#include "properties/Configure.h"
#include "utils/file/PathUtils.h"

namespace org {
namespace apache {
namespace nifi {
namespace minifi {

namespace {
namespace chr = std::chrono;

utils::optional<chr::milliseconds> time_string_to_milliseconds(const std::string& str) {
  uint64_t millisec_value{};
  const bool success = core::Property::getTimeMSFromString(str, millisec_value);
  if (!success) return utils::nullopt;
  return utils::make_optional(chr::milliseconds{millisec_value});
}

template<typename T, typename = typename std::enable_if<std::is_integral<T>::value>::type>
utils::optional<T> data_size_string_to_int(const std::string& str) {
  T result{};
  // actually aware of data units like B, kB, MB, etc.
  const bool success = core::Property::StringToInt(str, result);
  if (!success) return utils::nullopt;
  return utils::make_optional(result);
}


}  // namespace

namespace disk_space_watchdog {
Config read_config(const Configure& conf) {
  const auto interval_ms = conf.get(Configure::minifi_disk_space_watchdog_interval) | utils::flatMap(time_string_to_milliseconds);
  const auto stop_bytes = conf.get(Configure::minifi_disk_space_watchdog_stop_threshold) | utils::flatMap(data_size_string_to_int<std::uintmax_t>);
  const auto restart_bytes = conf.get(Configure::minifi_disk_space_watchdog_restart_threshold) | utils::flatMap(data_size_string_to_int<std::uintmax_t>);
  if (restart_bytes < stop_bytes) { throw std::runtime_error{"disk space watchdog stop threshold must be <= restart threshold"}; }
  constexpr auto mebibytes = 1024 * 1024;
  return {
      interval_ms.value_or(chr::seconds{15}),
      stop_bytes.value_or(100 * mebibytes),
      restart_bytes.value_or(150 * mebibytes)
  };
}


std::vector<std::uintmax_t> check_available_space(const std::vector<std::string>& paths, core::logging::Logger* logger) {
  std::vector<std::uintmax_t> result;
  result.reserve(paths.size());
  std::transform(std::begin(paths), std::end(paths), std::back_inserter(result), [logger](const std::string& path) {
    std::error_code ec;
    const auto result = utils::file::space(path.c_str(), ec);
    if (ec && logger) {
      logger->log_info("Couldn't check disk space at %s: %s (ignoring)", path, ec.message());
    } else if (logger) {
      logger->log_trace("%s available space: %zu bytes", path, gsl::narrow_cast<size_t>(result.available));
    }
    return result.available;
  });
  return result;
}

}  // namespace disk_space_watchdog
}  // namespace minifi
}  // namespace nifi
}  // namespace apache
}  // namespace org