/*
 * Copyright 2018 Google
 *
 * 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.
 */

#ifndef FIRESTORE_CORE_SRC_CREDENTIALS_USER_H_
#define FIRESTORE_CORE_SRC_CREDENTIALS_USER_H_

#if defined(__OBJC__)
#import <Foundation/Foundation.h>
#include "Firestore/core/src/util/string_apple.h"
#endif  // defined(__OBJC__)

#include <string>

#include "absl/strings/string_view.h"

namespace firebase {
namespace firestore {
namespace credentials {

/**
 * Simple wrapper around a nullable UID. Mostly exists to make code more
 * readable and for compatibility with other clients where map keys cannot be
 * null.
 */
class User {
 public:
  /** Construct an unauthenticated user. */
  User();

  /** Construct an authenticated user with the given UID. */
  explicit User(std::string uid);

  const std::string& uid() const {
    return uid_;
  }

  // PORTING NOTE: Here use more clear naming is_authenticated() instead of
  // is_unauthenticated().
  bool is_authenticated() const {
    return is_authenticated_;
  }

  /** Returns an unauthenticated instance. */
  static const User& Unauthenticated();

#if defined(__OBJC__)
  /**
   * Returns an authenticated user if uid is non-nil, otherwise an
   * unauthenticated user.
   */
  static User FromUid(NSString* _Nullable uid) {
    if (uid == nil) {
      return Unauthenticated();
    } else {
      return User{util::MakeString(uid)};
    }
  }
#endif  // defined(__OBJC__)

  User(const User& other) = default;
  User& operator=(const User& other) = default;

  friend bool operator==(const User& lhs, const User& rhs);

 private:
  std::string uid_;
  bool is_authenticated_;
};

inline bool operator==(const User& lhs, const User& rhs) {
  return lhs.is_authenticated_ == rhs.is_authenticated_ &&
         (!lhs.is_authenticated_ || lhs.uid_ == rhs.uid_);
}

inline bool operator!=(const User& lhs, const User& rhs) {
  return !(lhs == rhs);
}

// Specializations of std::hash is prohibited. We define a hash function to be
// passed through manually.
struct HashUser {
  inline int64_t operator()(const User& user) const {
    return std::hash<std::string>{}(user.uid());
  }
};

}  // namespace credentials
}  // namespace firestore
}  // namespace firebase

#endif  // FIRESTORE_CORE_SRC_CREDENTIALS_USER_H_
