// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef METRICS_DAEMON_H_
#define METRICS_DAEMON_H_

#include <dbus/dbus.h>
#include <glib.h>
#include <time.h>

class MetricsDaemon {

 public:
  MetricsDaemon()
      : network_state_(kUnknownNetworkState),
        network_state_last_(0),
        power_state_(kUnknownPowerState),
        screensaver_state_(kUnknownScreenSaverState),
        session_state_(kUnknownSessionState),
        user_active_(false),
        user_active_last_(0),
        daily_use_day_last_(0),
        usemon_interval_(0),
        usemon_source_(NULL) {}
  ~MetricsDaemon() {}

  // Does all the work. If |run_as_daemon| is true, daemonizes by
  // forking. If |testing| is true, logs the stats instead of sending
  // them to Chrome.
  void Run(bool run_as_daemon, bool testing);

 private:
  // The network states (see network_states.h).
  enum NetworkState {
    kUnknownNetworkState = -1, // Initial/unknown network state.
#define STATE(name, capname) kNetworkState ## capname,
#include "network_states.h"
    kNumberNetworkStates
  };

  // The power states (see power_states.h).
  enum PowerState {
    kUnknownPowerState = -1, // Initial/unknown power state.
#define STATE(name, capname) kPowerState ## capname,
#include "power_states.h"
    kNumberPowerStates
  };

  // The screen-saver states (see screensaver_states.h).
  enum ScreenSaverState {
    kUnknownScreenSaverState = -1, // Initial/unknown screen-saver state.
#define STATE(name, capname) kScreenSaverState ## capname,
#include "screensaver_states.h"
    kNumberScreenSaverStates
  };

  // The user session states (see session_states.h).
  enum SessionState {
    kUnknownSessionState = -1, // Initial/unknown user session state.
#define STATE(name, capname) kSessionState ## capname,
#include "session_states.h"
    kNumberSessionStates
  };

  // Data record for aggregating daily usage.
  class UseRecord {
   public:
    UseRecord() : day_(0), seconds_(0) {}
    int day_;
    int seconds_;
  };

  // D-Bus message match strings.
  static const char* kDBusMatches_[];

  // Array of network states.
  static const char* kNetworkStates_[kNumberNetworkStates];

  // Array of power states.
  static const char* kPowerStates_[kNumberPowerStates];

  // Array of screen-saver states.
  static const char* kScreenSaverStates_[kNumberScreenSaverStates];

  // Array of user session states.
  static const char* kSessionStates_[kNumberSessionStates];

  // Initializes.
  void Init(bool testing);

  // Creates the event loop and enters it.
  void Loop();

  // D-Bus filter callback.
  static DBusHandlerResult MessageFilter(DBusConnection* connection,
                                         DBusMessage* message,
                                         void* user_data);

  // Processes network state change.
  void NetStateChanged(const char* state_name, time_t now);

  // Given the state name, returns the state id.
  NetworkState LookupNetworkState(const char* state_name);

  // Processes power state change.
  void PowerStateChanged(const char* state_name, time_t now);

  // Given the state name, returns the state id.
  PowerState LookupPowerState(const char* state_name);

  // Processes screen-saver state change.
  void ScreenSaverStateChanged(const char* state_name, time_t now);

  // Given the state name, returns the state id.
  ScreenSaverState LookupScreenSaverState(const char* state_name);

  // Processes user session state change.
  void SessionStateChanged(const char* state_name, time_t now);

  // Given the state name, returns the state id.
  SessionState LookupSessionState(const char* state_name);

  // Updates the user-active state to |active| and logs the usage data
  // since the last update. If the user has just become active,
  // reschedule the daily use monitor for more frequent updates --
  // this is followed by an exponential back-off (see UseMonitor).
  void SetUserActiveState(bool active, time_t now);

  // Updates the daily usage file, if necessary, by adding |seconds|
  // of active use to the |day| since Epoch. If there's usage data for
  // day in the past in the usage file, that data is sent to UMA and
  // removed from the file. If there's already usage data for |day| in
  // the usage file, the |seconds| are accumulated.
  void LogDailyUseRecord(int day, int seconds);

  // Callbacks for the daily use monitor. The daily use monitor uses
  // LogDailyUseRecord to aggregate current usage data and send it to
  // UMA, if necessary. It also reschedules itself using an
  // exponentially bigger interval (up to a certain maximum) -- so
  // usage is monitored less frequently with longer active use.
  static gboolean UseMonitorStatic(gpointer data);
  bool UseMonitor();

  // Schedules or reschedules a daily use monitor for |interval|
  // seconds from now. |backoff| mode is used by the use monitor to
  // reschedule itself. If there's a monitor scheduled already and
  // |backoff| is false, unschedules it first. Doesn't schedule a
  // monitor for more than kUseMonitorIntervalMax seconds in the
  // future (see metrics_daemon.cc). Returns true if a new use monitor
  // was scheduled, false otherwise (note that if |backoff| is false a
  // new use monitor will always be scheduled).
  bool ScheduleUseMonitor(int interval, bool backoff);

  // Unschedules a scheduled use monitor, if any.
  void UnscheduleUseMonitor();

  // Sends a stat to Chrome for transport to UMA (or prints it for
  // testing). See MetricsLibrary::SendToChrome in metrics_library.h
  // for a description of the arguments.
  void PublishMetric(const char* name, int sample,
                     int min, int max, int nbuckets);

  // Testing mode.
  bool testing_;

  // Current network state.
  NetworkState network_state_;

  // Timestamps last network state update.
  time_t network_state_last_;

  // Current power state.
  PowerState power_state_;

  // Current screen-saver state.
  ScreenSaverState screensaver_state_;

  // Current user session state.
  SessionState session_state_;

  // Is the user currently active: power is on, user session has
  // started, screen is not locked.
  bool user_active_;

  // Timestamps last user active update.
  time_t user_active_last_;

  // Last stored daily use day (since epoch).
  int daily_use_day_last_;

  // Sleep period until the next daily usage aggregation performed by
  // the daily use monitor (see ScheduleUseMonitor).
  int usemon_interval_;

  // Scheduled daily use monitor source (see ScheduleUseMonitor).
  GSource* usemon_source_;
};

#endif  // METRICS_DAEMON_H_