// Copyright 2020 Google LLC
//
// 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
//
//     https://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 "core/options.h"

#include <string>

namespace location {
namespace nearby {
namespace connections {

// Verify if  ConnectionOptions is in a not-initialized (Empty) state.
bool ConnectionOptions::Empty() const { return strategy.IsNone(); }

// Bring  ConnectionOptions to a not-initialized (Empty) state.
void ConnectionOptions::Clear() { strategy.Clear(); }

// Returns a copy and normalizes allowed mediums:
// (1) If is_out_of_band_connection is true, verifies that there is only one
//     medium allowed, defaulting to only Bluetooth if unspecified.
// (2) If no mediums are allowed, allow all mediums.
ConnectionOptions ConnectionOptions::CompatibleOptions() const {
  ConnectionOptions result = *this;

  // Out-of-band connections initiate connections via an injected endpoint
  // rather than through the normal discovery flow. These types of connections
  // can only be injected via a single medium.
  if (is_out_of_band_connection) {
    int num_enabled = result.allowed.Count(true);

    // Default to allow only Bluetooth if no single medium is specified.
    if (num_enabled != 1) {
      result.allowed.SetAll(false);
      result.allowed.bluetooth = true;
    }
    return result;
  }

  // Normal connections (i.e., not out-of-band) connections can specify
  // multiple mediums. If none are specified, default to allowing all mediums.
  if (!allowed.Any(true)) result.allowed.SetAll(true);
  return result;
}

std::vector<Medium> ConnectionOptions::GetMediums() const {
  return allowed.GetMediums(true);
}

// This call follows the standard Microsoft calling pattern of calling first
// to get the size of the array. Caller then allocates memory for the array,
// and makes this call again to copy the array into the provided location.
void ConnectionOptions::GetMediums(
    location::nearby::proto::connections::Medium* mediums,
    uint32_t* mediumsSize) {
  auto size = GetMediums().size();

  // Caller is seeking the size of mediums
  if (mediums == nullptr) {
    *mediumsSize = size;
    return;
  }

  // Caller has not specified enough memory
  if (*mediumsSize < size) {
    mediums = nullptr;    // ensure nullptr return
    *mediumsSize = size;  // update the size to indicate the correct size
    return;
  }

  for (uint32_t i = 0; i < size; i++) {
    // Construct an array at the given location
    mediums[i] = GetMediums().at(i);
  }
}

}  // namespace connections
}  // namespace nearby
}  // namespace location