// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_DNS_PUBLIC_DOH_PROVIDER_ENTRY_H_
#define NET_DNS_PUBLIC_DOH_PROVIDER_ENTRY_H_

#include <set>
#include <string>
#include <vector>

#include "base/feature_list.h"
#include "base/strings/string_piece.h"
#include "net/base/ip_address.h"
#include "net/base/net_export.h"
#include "net/dns/public/dns_over_https_server_config.h"
#include "third_party/abseil-cpp/absl/types/optional.h"

namespace net {

// Provider ids for usage in histograms. Entries should not be renumbered and
// numeric values should never be reused. Please keep in sync with
// "DohProviderId" in src/tools/metrics/histograms/enums.xml.
enum class DohProviderIdForHistogram {
  kCustom = 0,
  kCleanBrowsingFamily = 1,
  kCloudflare = 2,
  kGoogle = 3,
  kIij = 4,
  kQuad9Secure = 5,
  kDnsSb = 6,
  kCznic = 7,
  kNextDns = 8,
  kOpenDns = 9,
  kAlekBergNl = 10,
  kMaxValue = kAlekBergNl,
};

// Represents insecure DNS, DoT, and DoH services run by the same provider.
// These entries are used to support upgrade from insecure DNS or DoT services
// to associated DoH services in automatic mode and to populate the dropdown
// menu for secure mode.
//
// To be eligible for auto-upgrade, an entry must have a non-empty `ip_strs` or
// non-empty `dns_over_tls_hostnames`. To be eligible for the dropdown menu, the
// entry must have non-empty `ui_name` and `privacy_policy`. If
// `display_globally` is true, the entry is eligible to be displayed globally in
// the dropdown menu. If `display_globally` is false, `display_countries` should
// contain the two-letter ISO 3166-1 country codes, if any, where the entry is
// eligible for being displayed in the dropdown menu.
//
// If `feature` is disabled, the entry is eligible for neither auto-upgrade nor
// the dropdown menu.
struct NET_EXPORT DohProviderEntry {
 public:
  using List = std::vector<const DohProviderEntry*>;

  enum class LoggingLevel {
    // Indicates the normal amount of logging, monitoring, and metrics.
    kNormal,

    // Indicates that a provider is of extra interest and eligible for
    // additional logging, monitoring, and metrics.
    kExtra,
  };

  std::string provider;
  const base::Feature& feature;
  // A provider_id_for_histogram is required for entries that are intended to
  // be visible in the UI.
  absl::optional<DohProviderIdForHistogram> provider_id_for_histogram;
  std::set<IPAddress> ip_addresses;
  std::set<std::string> dns_over_tls_hostnames;
  DnsOverHttpsServerConfig doh_server_config;
  std::string ui_name;
  std::string privacy_policy;
  bool display_globally;
  std::set<std::string> display_countries;
  LoggingLevel logging_level;

  // Returns the full list of DoH providers. A subset of this list may be used
  // to support upgrade in automatic mode or to populate the dropdown menu for
  // secure mode.
  static const List& GetList();

  static DohProviderEntry ConstructForTesting(
      std::string provider,
      const base::Feature* feature,
      absl::optional<DohProviderIdForHistogram> provider_id_for_histogram,
      std::set<base::StringPiece> ip_strs,
      std::set<std::string> dns_over_tls_hostnames,
      std::string dns_over_https_template,
      std::string ui_name,
      std::string privacy_policy,
      bool display_globally,
      std::set<std::string> display_countries,
      LoggingLevel logging_level = LoggingLevel::kNormal);

  // Entries are neither copyable nor moveable. This allows tests to construct a
  // List but ensures that `const DohProviderEntry*` is a safe type for
  // application code.
  DohProviderEntry(DohProviderEntry& other) = delete;
  DohProviderEntry(DohProviderEntry&& other) = delete;

  ~DohProviderEntry();

 private:
  DohProviderEntry(
      std::string provider,
      // Disallow implicit copying of the `feature` parameter because there
      // cannot be more than one `base::Feature` for a given feature name.
      const base::Feature* feature,
      absl::optional<DohProviderIdForHistogram> provider_id_for_histogram,
      std::set<base::StringPiece> ip_strs,
      std::set<std::string> dns_over_tls_hostnames,
      std::string dns_over_https_template,
      std::string ui_name,
      std::string privacy_policy,
      bool display_globally,
      std::set<std::string> display_countries,
      LoggingLevel logging_level);
};

}  // namespace net

#endif  // NET_DNS_PUBLIC_DOH_PROVIDER_ENTRY_H_