// 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_CEL_CPP_BASE_ATTRIBUTE_SET_H_

#define THIRD_PARTY_CEL_CPP_BASE_ATTRIBUTE_SET_H_

#include "absl/container/btree_set.h"

#include "absl/types/span.h"

#include "base/attribute.h"

namespace google::api::expr::runtime {

class AttributeUtility;

}  // namespace google::api::expr::runtime

namespace cel {

class UnknownValue;

namespace base_internal {

class UnknownSet;

}

// AttributeSet is a container for CEL attributes that are identified as

// unknown during expression evaluation.

class AttributeSet final {

 private:

  using Container = absl::btree_set<Attribute>;

 public:

  using value_type = typename Container::value_type;

  using size_type = typename Container::size_type;

  using iterator = typename Container::const_iterator;

  using const_iterator = typename Container::const_iterator;

  AttributeSet() = default;

  AttributeSet(const AttributeSet&) = default;

  AttributeSet(AttributeSet&&) = default;

  AttributeSet& operator=(const AttributeSet&) = default;

  AttributeSet& operator=(AttributeSet&&) = default;

  explicit AttributeSet(absl::Span<const Attribute> attributes) {

    for (const auto& attr : attributes) {

      Add(attr);

    }

  }

  AttributeSet(const AttributeSet& set1, const AttributeSet& set2)

      : attributes_(set1.attributes_) {

    for (const auto& attr : set2.attributes_) {

      Add(attr);

    }

  }

  iterator begin() const { return attributes_.begin(); }

  const_iterator cbegin() const { return attributes_.cbegin(); }

  iterator end() const { return attributes_.end(); }

  const_iterator cend() const { return attributes_.cend(); }

  size_type size() const { return attributes_.size(); }

  bool empty() const { return attributes_.empty(); }

  bool operator==(const AttributeSet& other) const {

    return this == &other || attributes_ == other.attributes_;

  }

  bool operator!=(const AttributeSet& other) const {

    return !operator==(other);

  }

  static AttributeSet Merge(const AttributeSet& set1,

                            const AttributeSet& set2) {

    return AttributeSet(set1, set2);

  }

 private:

  friend class google::api::expr::runtime::AttributeUtility;

  friend class UnknownValue;

  friend class base_internal::UnknownSet;

  void Add(const Attribute& attribute) { attributes_.insert(attribute); }

  void Add(const AttributeSet& other) {

    for (const auto& attribute : other) {

      Add(attribute);

    }

  }

  // Attribute container.

  Container attributes_;

};

}  // namespace cel

#endif  // THIRD_PARTY_CEL_CPP_BASE_ATTRIBUTE_SET_H_