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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROMEOS_ASH_COMPONENTS_REPORT_DEVICE_METRICS_CHURN_ACTIVE_STATUS_H_
#define CHROMEOS_ASH_COMPONENTS_REPORT_DEVICE_METRICS_CHURN_ACTIVE_STATUS_H_
#include <bitset>
#include <optional>
#include "base/component_export.h"
#include "base/memory/raw_ptr.h"
#include "base/time/time.h"
#include "chromeos/ash/components/report/prefs/fresnel_pref_names.h"
#include "chromeos/ash/components/report/proto/fresnel_service.pb.h"
class PrefService;
namespace ash {
namespace system {
class StatisticsProvider;
} // namespace system
namespace report::device_metrics {
// Manage information about the number of active months and the months since
// the device's inception, using specific bit sizes for each.
// Provide the methods for calculating churn analysis metadata.
class COMPONENT_EXPORT(CHROMEOS_ASH_COMPONENTS_REPORT) ActiveStatus {
public:
static constexpr int kInceptionYear = 2000;
static constexpr int kMonthCountBitSize = 10;
static constexpr int kActiveMonthsBitSize = 18;
static constexpr int kActiveStatusBitSize =
kMonthCountBitSize + kActiveMonthsBitSize;
// Calculate monthly and yearly churn for the 3 observation windows by
// checking active status at bits 1-3 (monthly) and bits 13-15 (yearly).
static constexpr int kMonthlyChurnOffset = 1;
static constexpr int kYearlyChurnOffset = 13;
// Track number of months from inception date in first 10 bits active status.
static constexpr char kActiveStatusInceptionDate[] =
"2000-01-01 00:00:00 GMT";
ActiveStatus() = delete;
explicit ActiveStatus(PrefService* local_state);
ActiveStatus(const ActiveStatus&) = delete;
ActiveStatus& operator=(const ActiveStatus&) = delete;
~ActiveStatus() = default;
// Accessor methods for the active status value stored in local state pref.
// This pref is used as the source of truth for this class.
int GetValue() const;
void SetValue(int val);
// Returns a copy of the 28 bit updated active status value which reflects
// the current month is also active.
std::optional<int> CalculateNewValue(base::Time ts) const;
// The inception month and the month count since inception are utilized to
// generate a fresh timestamp that signifies the presently active month.
std::optional<base::Time> GetCurrentActiveMonthTimestamp() const;
// Return necessary information used to send the churn cohort request.
std::optional<ChurnCohortMetadata> CalculateCohortMetadata(
base::Time active_ts) const;
// Return necessary information used to send the churn observation request,
// based on the local state last ping prefs.
// |period| is a value between [0,2].
// |period| = 0 indicates 3-month period starting current month.
// |period| = 1 indicates 3-month period starting last month.
// |period| = 2 indicates 3-month period starting two months ago.
std::optional<ChurnObservationMetadata> CalculateObservationMetadata(
base::Time active_ts,
int period) const;
private:
// Grant friend access for comprehensive testing of private/protected members.
friend class ActiveStatusTest;
// Return |kActiveStatusInceptionDate| as a GMT timestamp.
std::optional<base::Time> GetInceptionMonthTimestamp() const;
// Return the int representation of the known months since inception, based
// on the active status value in local state pref.
int GetMonthsSinceInception() const;
// Return the int representation of the known active month bits, based on the
// active status value in local state pref.
int GetActiveMonthBits() const;
// Check if device was active during a specific month in the past 18 months.
// |month_idx| is a value within the past 18 months, [0,17].
bool IsDeviceActiveInMonth(int month_idx) const;
// Helper to check if |active_ts| aligns with the first active month.
std::optional<bool> IsFirstActiveInCohort(base::Time active_ts) const;
// Used to read/write the latest active status value.
const raw_ptr<PrefService> local_state_;
// Singleton lives throughout class lifetime.
const raw_ptr<system::StatisticsProvider> statistics_provider_;
};
} // namespace report::device_metrics
} // namespace ash
#endif // CHROMEOS_ASH_COMPONENTS_REPORT_DEVICE_METRICS_CHURN_ACTIVE_STATUS_H_
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