// Copyright 2022 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.

#ifndef THIRD_PARTY_NEARBY_INTERNAL_DATA_DATA_SET_H_
#define THIRD_PARTY_NEARBY_INTERNAL_DATA_DATA_SET_H_

#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "absl/functional/any_invocable.h"
#include "absl/strings/string_view.h"

namespace nearby::data {

enum class InitStatus {
  kOK = 0,
  kNotInitialized = 1,
  kError = 2,
  kCorrupt = 3,
  kInvalidOperation = 4,
  kMaxValue = kInvalidOperation
};

template <typename T>
class DataSet {
 public:
  using KeyEntryVector = std::vector<std::pair<std::string, T>>;

  virtual ~DataSet() = default;

  // Asynchronously initializes the object, which must have been created by the
  // DataManager::GetDataSet<T> function. `callback` will be invoked on the
  // calling thread when complete.
  virtual void Initialize(absl::AnyInvocable<void(InitStatus) &&> callback) = 0;

  // Asynchronously loads all entries from the database and invokes `callback`
  // when complete.
  virtual void LoadEntries(
      absl::AnyInvocable<void(bool, std::unique_ptr<std::vector<T>>) &&>
          callback) = 0;

  // Asynchronously loads an entry from the database with key `key` and invokes
  // `callback` when complete.
  virtual void LoadEntry(
      absl::string_view key,
      absl::AnyInvocable<void(bool, std::unique_ptr<T>) &&> callback) = 0;

  // Asynchronously saves `entries_to_save` and deletes entries from
  // `keys_to_remove` from the database. `callback` will be invoked on the
  // calling thread when complete. `entries_to_save` and `keys_to_remove` must
  // be non-null.
  virtual void UpdateEntries(
      std::unique_ptr<KeyEntryVector> entries_to_save,
      std::unique_ptr<std::vector<std::string>> keys_to_remove,
      absl::AnyInvocable<void(bool) &&> callback) = 0;

  // Asynchronously destroys the database. Use this call only if the database
  // needs to be destroyed for this particular profile.
  virtual void Destroy(absl::AnyInvocable<void(bool) &&> callback) = 0;
};

}  // namespace nearby::data

#endif  // THIRD_PARTY_NEARBY_INTERNAL_DATA_DATA_SET_H_