// 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.

#include "metrics_daemon.h"
#include "metrics_library.h"

#include <dbus/dbus-glib-lowlevel.h>
#include <sys/file.h>

#include <base/eintr_wrapper.h>
#include <base/logging.h>

#define SAFE_MESSAGE(e) (e.message ? e.message : "unknown error")
#define DBUS_IFACE_CONNMAN_MANAGER "org.moblin.connman.Manager"
#define DBUS_IFACE_POWER_MANAGER "org.chromium.Power.Manager"
#define DBUS_IFACE_SCREENSAVER_MANAGER "org.chromium.ScreenSaver.Manager"
#define DBUS_IFACE_SESSION_MANAGER "org.chromium.SessionManagerInterface"

// File to aggregate daily usage before sending to UMA.
// TODO(petkov): This file should probably live in a user-specific stateful
// location, e.g., /home/chronos/user.
static const char kDailyUseRecordFile[] = "/var/log/metrics/daily-usage";

static const int kSecondsPerMinute = 60;
static const int kMinutesPerHour = 60;
static const int kHoursPerDay = 24;
static const int kMinutesPerDay = kHoursPerDay * kMinutesPerHour;
static const int kSecondsPerDay = kMinutesPerDay * kSecondsPerMinute;

// The daily use monitor is scheduled to a 1-minute interval after
// initial user activity and then it's exponentially backed off to
// 10-minute intervals. Although not required, the back off is
// implemented because the histogram buckets are spaced exponentially
// anyway and to avoid too frequent metrics daemon process wake-ups
// and file I/O.
static const int kUseMonitorIntervalInit = 1 * kSecondsPerMinute;
static const int kUseMonitorIntervalMax = 10 * kSecondsPerMinute;

// static metrics parameters.
const char MetricsDaemon::kMetricDailyUseTimeName[] =
    "Logging.DailyUseTime";
const int MetricsDaemon::kMetricDailyUseTimeMin = 1;
const int MetricsDaemon::kMetricDailyUseTimeMax = kMinutesPerDay;
const int MetricsDaemon::kMetricDailyUseTimeBuckets = 50;

const char MetricsDaemon::kMetricTimeToNetworkDropName[] =
    "Network.TimeToDrop";
const int MetricsDaemon::kMetricTimeToNetworkDropMin = 1;
const int MetricsDaemon::kMetricTimeToNetworkDropMax =
    8 /* hours */ * kMinutesPerHour * kSecondsPerMinute;
const int MetricsDaemon::kMetricTimeToNetworkDropBuckets = 50;

// static
const char* MetricsDaemon::kDBusMatches_[] = {
  "type='signal',"
  "sender='org.moblin.connman',"
  "interface='" DBUS_IFACE_CONNMAN_MANAGER "',"
  "path='/',"
  "member='StateChanged'",

  "type='signal',"
  "interface='" DBUS_IFACE_POWER_MANAGER "',"
  "path='/',"
  "member='PowerStateChanged'",

  "type='signal',"
  "interface='" DBUS_IFACE_SCREENSAVER_MANAGER "',"
  "path='/',"
  "member='LockStateChanged'",

  "type='signal',"
  "sender='org.chromium.SessionManager',"
  "interface='" DBUS_IFACE_SESSION_MANAGER "',"
  "path='/org/chromium/SessionManager',"
  "member='SessionStateChanged'",
};

// static
const char* MetricsDaemon::kNetworkStates_[] = {
#define STATE(name, capname) #name,
#include "network_states.h"
};

// static
const char* MetricsDaemon::kPowerStates_[] = {
#define STATE(name, capname) #name,
#include "power_states.h"
};

// static
const char* MetricsDaemon::kScreenSaverStates_[] = {
#define STATE(name, capname) #name,
#include "screensaver_states.h"
};

// static
const char* MetricsDaemon::kSessionStates_[] = {
#define STATE(name, capname) #name,
#include "session_states.h"
};

void MetricsDaemon::Run(bool run_as_daemon) {
  Init(false);
  if (!run_as_daemon || daemon(0, 0) == 0) {
    Loop();
  }
}

void MetricsDaemon::Init(bool testing) {
  testing_ = testing;
  daily_use_record_file_ = kDailyUseRecordFile;

  // Don't setup D-Bus and GLib in test mode.
  if (testing)
    return;

  g_thread_init(NULL);
  g_type_init();
  dbus_g_thread_init();

  DBusError error;
  dbus_error_init(&error);

  DBusConnection *connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
  LOG_IF(FATAL, dbus_error_is_set(&error)) <<
      "No D-Bus connection: " << SAFE_MESSAGE(error);

  dbus_connection_setup_with_g_main(connection, NULL);

  // Registers D-Bus matches for the signals we would like to catch.
  for (unsigned int m = 0; m < sizeof(kDBusMatches_) / sizeof(char *); m++) {
    const char* match = kDBusMatches_[m];
    DLOG(INFO) << "adding dbus match: " << match;
    dbus_bus_add_match(connection, match, &error);
    LOG_IF(FATAL, dbus_error_is_set(&error)) <<
        "unable to add a match: " << SAFE_MESSAGE(error);
  }

  // Adds the D-Bus filter routine to be called back whenever one of
  // the registered D-Bus matches is successful. The daemon is not
  // activated for D-Bus messages that don't match.
  CHECK(dbus_connection_add_filter(connection, MessageFilter, this, NULL));
}

void MetricsDaemon::Loop() {
  GMainLoop* loop = g_main_loop_new(NULL, false);
  g_main_loop_run(loop);
}

// static
DBusHandlerResult MetricsDaemon::MessageFilter(DBusConnection* connection,
                                               DBusMessage* message,
                                               void* user_data) {
  time_t now = time(NULL);
  DLOG(INFO) << "message intercepted @ " << now;

  int message_type = dbus_message_get_type(message);
  if (message_type != DBUS_MESSAGE_TYPE_SIGNAL) {
    DLOG(WARNING) << "unexpected message type " << message_type;
    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
  }

  // Signal messages always have interfaces.
  const char* interface = dbus_message_get_interface(message);
  CHECK(interface != NULL);

  MetricsDaemon* daemon = static_cast<MetricsDaemon*>(user_data);

  DBusMessageIter iter;
  dbus_message_iter_init(message, &iter);
  if (strcmp(interface, DBUS_IFACE_CONNMAN_MANAGER) == 0) {
    CHECK(strcmp(dbus_message_get_member(message),
                 "StateChanged") == 0);

    char *state_name;
    dbus_message_iter_get_basic(&iter, &state_name);
    daemon->NetStateChanged(state_name, now);
  } else if (strcmp(interface, DBUS_IFACE_POWER_MANAGER) == 0) {
    CHECK(strcmp(dbus_message_get_member(message),
                 "PowerStateChanged") == 0);

    char *state_name;
    dbus_message_iter_get_basic(&iter, &state_name);
    daemon->PowerStateChanged(state_name, now);
  } else if (strcmp(interface, DBUS_IFACE_SCREENSAVER_MANAGER) == 0) {
    CHECK(strcmp(dbus_message_get_member(message),
                 "LockStateChanged") == 0);

    char *state_name;
    dbus_message_iter_get_basic(&iter, &state_name);
    daemon->ScreenSaverStateChanged(state_name, now);
  } else if (strcmp(interface, DBUS_IFACE_SESSION_MANAGER) == 0) {
    CHECK(strcmp(dbus_message_get_member(message),
                 "SessionStateChanged") == 0);

    char *state_name;
    dbus_message_iter_get_basic(&iter, &state_name);
    daemon->SessionStateChanged(state_name, now);
  } else {
    DLOG(WARNING) << "unexpected interface: " << interface;
    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
  }

  return DBUS_HANDLER_RESULT_HANDLED;
}

void MetricsDaemon::NetStateChanged(const char* state_name, time_t now) {
  DLOG(INFO) << "network state: " << state_name;

  NetworkState state = LookupNetworkState(state_name);

  // Logs the time in seconds between the network going online to
  // going offline (or, more precisely, going not online) in order to
  // measure the mean time to network dropping. Going offline as part
  // of suspend-to-RAM is not logged as network drop -- the assumption
  // is that the message for suspend-to-RAM comes before the network
  // offline message which seems to and should be the case.
  if (state != kNetworkStateOnline &&
      network_state_ == kNetworkStateOnline &&
      power_state_ != kPowerStateMem) {
    int online_time = static_cast<int>(now - network_state_last_);
    PublishMetric(kMetricTimeToNetworkDropName, online_time,
                  kMetricTimeToNetworkDropMin,
                  kMetricTimeToNetworkDropMax,
                  kMetricTimeToNetworkDropBuckets);
  }

  network_state_ = state;
  network_state_last_ = now;
}

MetricsDaemon::NetworkState
MetricsDaemon::LookupNetworkState(const char* state_name) {
  for (int i = 0; i < kNumberNetworkStates; i++) {
    if (strcmp(state_name, kNetworkStates_[i]) == 0) {
      return static_cast<NetworkState>(i);
    }
  }
  DLOG(WARNING) << "unknown network connection state: " << state_name;
  return kUnknownNetworkState;
}

void MetricsDaemon::PowerStateChanged(const char* state_name, time_t now) {
  DLOG(INFO) << "power state: " << state_name;
  power_state_ = LookupPowerState(state_name);

  if (power_state_ != kPowerStateOn)
    SetUserActiveState(false, now);
}

MetricsDaemon::PowerState
MetricsDaemon::LookupPowerState(const char* state_name) {
  for (int i = 0; i < kNumberPowerStates; i++) {
    if (strcmp(state_name, kPowerStates_[i]) == 0) {
      return static_cast<PowerState>(i);
    }
  }
  DLOG(WARNING) << "unknown power state: " << state_name;
  return kUnknownPowerState;
}

void MetricsDaemon::ScreenSaverStateChanged(const char* state_name,
                                            time_t now) {
  DLOG(INFO) << "screen-saver state: " << state_name;
  screensaver_state_ = LookupScreenSaverState(state_name);
  SetUserActiveState(screensaver_state_ == kScreenSaverStateUnlocked, now);
}

MetricsDaemon::ScreenSaverState
MetricsDaemon::LookupScreenSaverState(const char* state_name) {
  for (int i = 0; i < kNumberScreenSaverStates; i++) {
    if (strcmp(state_name, kScreenSaverStates_[i]) == 0) {
      return static_cast<ScreenSaverState>(i);
    }
  }
  DLOG(WARNING) << "unknown screen-saver state: " << state_name;
  return kUnknownScreenSaverState;
}

void MetricsDaemon::SessionStateChanged(const char* state_name,
                                        time_t now) {
  DLOG(INFO) << "user session state: " << state_name;
  session_state_ = LookupSessionState(state_name);
  SetUserActiveState(session_state_ == kSessionStateStarted, now);
}

MetricsDaemon::SessionState
MetricsDaemon::LookupSessionState(const char* state_name) {
  for (int i = 0; i < kNumberSessionStates; i++) {
    if (strcmp(state_name, kSessionStates_[i]) == 0) {
      return static_cast<SessionState>(i);
    }
  }
  DLOG(WARNING) << "unknown user session state: " << state_name;
  return kUnknownSessionState;
}

void MetricsDaemon::SetUserActiveState(bool active, time_t now) {
  DLOG(INFO) << "user: " << (active ? "active" : "inactive");

  // Calculates the seconds of active use since the last update and
  // the day since Epoch, and logs the usage data.
  int seconds = user_active_ ? (now - user_active_last_) : 0;
  int day = now / kSecondsPerDay;
  LogDailyUseRecord(day, seconds);

  // Schedules a use monitor on inactive->active transitions and
  // unschedules it on active->inactive transitions.
  if (!user_active_ && active)
    ScheduleUseMonitor(kUseMonitorIntervalInit, /* backoff */ false);
  else if (user_active_ && !active)
    UnscheduleUseMonitor();

  // Remembers the current active state and the time of the last
  // activity update.
  user_active_ = active;
  user_active_last_ = now;
}

void MetricsDaemon::LogDailyUseRecord(int day, int seconds) {
  // If there's no new active use today and the last record in the
  // usage aggregation file is today, there's nothing to do.
  if (seconds == 0 && day == daily_use_day_last_)
    return;

  DLOG(INFO) << "day: " << day << " usage: " << seconds << " seconds";
  int fd = HANDLE_EINTR(open(daily_use_record_file_,
                             O_RDWR | O_CREAT,
                             S_IRUSR | S_IWUSR));
  if (fd < 0) {
    PLOG(WARNING) << "Unable to open the daily use file";
    return;
  }

  bool same_day = false;
  UseRecord record;
  if (HANDLE_EINTR(read(fd, &record, sizeof(record))) == sizeof(record)) {
    if (record.day_ == day) {
      // If there's an existing record for today, aggregates the usage
      // time.
      same_day = true;
      record.seconds_ += seconds;
    } else {
      // If there's an existing record for a day in the past, rounds
      // the usage to the nearest minute and sends it to UMA.
      int minutes =
          (record.seconds_ + kSecondsPerMinute / 2) / kSecondsPerMinute;
      PublishMetric(kMetricDailyUseTimeName, minutes,
                    kMetricDailyUseTimeMin,
                    kMetricDailyUseTimeMax,
                    kMetricDailyUseTimeBuckets);

      // Truncates the usage file to ensure that no duplicate usage is
      // sent to UMA.
      PLOG_IF(WARNING, HANDLE_EINTR(ftruncate(fd, 0)) != 0);
    }
  }

  // Updates the use record in the daily usage file if there's new
  // usage today.
  if (seconds > 0) {
    if (!same_day) {
      record.day_ = day;
      record.seconds_ = seconds;
    }
    // else an already existing record for the same day will be
    // overwritten with updated usage below.

    PLOG_IF(WARNING, HANDLE_EINTR(lseek(fd, 0, SEEK_SET)) != 0);
    PLOG_IF(WARNING,
            HANDLE_EINTR(write(fd, &record, sizeof(record))) !=
            sizeof(record));
  }

  HANDLE_EINTR(close(fd));

  // Remembers the day of the use record in the usage aggregation file
  // to reduce file I/O. This is not really useful now but potentially
  // allows frequent LogDailyUseRecord calls with no unnecessary I/O
  // overhead.
  daily_use_day_last_ = day;
}

// static
gboolean MetricsDaemon::UseMonitorStatic(gpointer data) {
  return static_cast<MetricsDaemon*>(data)->UseMonitor() ? TRUE : FALSE;
}

bool MetricsDaemon::UseMonitor() {
  SetUserActiveState(user_active_, time(NULL));

  // If a new monitor source/instance is scheduled, returns false to
  // tell GLib to destroy this monitor source/instance. Returns true
  // otherwise to keep calling back this monitor.
  return !ScheduleUseMonitor(usemon_interval_ * 2, /* backoff */ true);
}

bool MetricsDaemon::ScheduleUseMonitor(int interval, bool backoff)
{
  if (testing_)
    return false;

  // Caps the interval -- the bigger the interval, the more active use
  // time will be potentially dropped on system shutdown.
  if (interval > kUseMonitorIntervalMax)
    interval = kUseMonitorIntervalMax;

  if (backoff) {
    // Back-off mode is used by the use monitor to reschedule itself
    // with exponential back-off in time. This mode doesn't create a
    // new timeout source if the new interval is the same as the old
    // one. Also, if a new timeout source is created, the old one is
    // not destroyed explicitly here -- it will be destroyed by GLib
    // when the monitor returns FALSE (see UseMonitor and
    // UseMonitorStatic).
    if (interval == usemon_interval_)
      return false;
  } else {
    UnscheduleUseMonitor();
  }

  // Schedules a new use monitor for |interval| seconds from now.
  DLOG(INFO) << "scheduling use monitor in " << interval << " seconds";
  usemon_source_ = g_timeout_source_new_seconds(interval);
  g_source_set_callback(usemon_source_, UseMonitorStatic, this,
                        NULL); // No destroy notification.
  g_source_attach(usemon_source_,
                  NULL); // Default context.
  usemon_interval_ = interval;
  return true;
}

void MetricsDaemon::UnscheduleUseMonitor() {
  // If there's a use monitor scheduled already, destroys it.
  if (usemon_source_ == NULL)
    return;

  DLOG(INFO) << "destroying use monitor";
  g_source_destroy(usemon_source_);
  usemon_source_ = NULL;
  usemon_interval_ = 0;
}

void MetricsDaemon::PublishMetric(const char* name, int sample,
                                  int min, int max, int nbuckets) {
  LOG(INFO) << "received metric: " << name << " " << sample << " "
            << min << " " << max << " " << nbuckets;
  if (!testing_) {
    MetricsLibrary::SendToChrome(name, sample, min, max, nbuckets);
  }
}