/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */

/* 
 * Copyright 2013 Red Hat, Inc.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * Adapted from gnome-session/gnome-session/gs-idle-monitor.c and
 *         from gnome-desktop/libgnome-desktop/gnome-idle-monitor.c
 */

/**
 * SECTION:idle-monitor
 * @title: MetaIdleMonitor
 * @short_description: Mutter idle counter (similar to X's IDLETIME)
 */

#include "config.h"

#include <string.h>
#include <clutter/clutter.h>
#include <X11/Xlib.h>
#include <X11/extensions/sync.h>

#include <meta/util.h>
#include <meta/main.h>
#include <meta/meta-idle-monitor.h>
#include "meta-idle-monitor-private.h"
#include "meta-idle-monitor-dbus.h"
#include "display-private.h"

G_STATIC_ASSERT(sizeof(unsigned long) == sizeof(gpointer));

struct _MetaIdleMonitor
{
  GObject parent_instance;

  GHashTable  *watches;
  GHashTable  *alarms;
  int          device_id;

  /* X11 implementation */
  Display     *display;
  int          sync_event_base;
  XSyncCounter counter;
  XSyncAlarm   user_active_alarm;

  /* Wayland implementation */
  guint64      last_event_time;
};

struct _MetaIdleMonitorClass
{
  GObjectClass parent_class;
};

typedef struct
{
  MetaIdleMonitor          *monitor;
  guint	                    id;
  MetaIdleMonitorWatchFunc  callback;
  gpointer		    user_data;
  GDestroyNotify            notify;
  guint64                   timeout_msec;

  /* x11 */
  XSyncAlarm                xalarm;
  int                       idle_source_id;

  /* wayland */
  GSource                  *timeout_source;
} MetaIdleMonitorWatch;

enum
{
  PROP_0,
  PROP_DEVICE_ID,
  PROP_LAST,
};

static GParamSpec *obj_props[PROP_LAST];

G_DEFINE_TYPE (MetaIdleMonitor, meta_idle_monitor, G_TYPE_OBJECT)

static MetaIdleMonitor *device_monitors[256];
static int              device_id_max;

static void
fire_watch (MetaIdleMonitorWatch *watch)
{
  MetaIdleMonitor *monitor;
  guint id;
  gboolean is_user_active_watch;

  monitor = watch->monitor;
  g_object_ref (monitor);

  if (watch->idle_source_id)
    {
      g_source_remove (watch->idle_source_id);
      watch->idle_source_id = 0;
    }

  id = watch->id;
  is_user_active_watch = (watch->timeout_msec == 0);

  if (watch->callback)
    watch->callback (monitor, id, watch->user_data);

  if (is_user_active_watch)
    meta_idle_monitor_remove_watch (monitor, id);

  g_object_unref (monitor);
}

static gint64
_xsyncvalue_to_int64 (XSyncValue value)
{
  return ((guint64) XSyncValueHigh32 (value)) << 32
    | (guint64) XSyncValueLow32 (value);
}

#define GUINT64_TO_XSYNCVALUE(value, ret) XSyncIntsToValue (ret, (value) & 0xFFFFFFFF, ((guint64)(value)) >> 32)

static XSyncAlarm
_xsync_alarm_set (MetaIdleMonitor	*monitor,
		  XSyncTestType          test_type,
		  guint64                interval,
		  gboolean               want_events)
{
  XSyncAlarmAttributes attr;
  XSyncValue	     delta;
  guint		     flags;

  flags = XSyncCACounter | XSyncCAValueType | XSyncCATestType |
    XSyncCAValue | XSyncCADelta | XSyncCAEvents;

  XSyncIntToValue (&delta, 0);
  attr.trigger.counter = monitor->counter;
  attr.trigger.value_type = XSyncAbsolute;
  attr.delta = delta;
  attr.events = want_events;

  GUINT64_TO_XSYNCVALUE (interval, &attr.trigger.wait_value);
  attr.trigger.test_type = test_type;
  return XSyncCreateAlarm (monitor->display, flags, &attr);
}

static void
ensure_alarm_rescheduled (Display    *dpy,
			  XSyncAlarm  alarm)
{
  XSyncAlarmAttributes attr;

  /* Some versions of Xorg have an issue where alarms aren't
   * always rescheduled. Calling XSyncChangeAlarm, even
   * without any attributes, will reschedule the alarm. */
  XSyncChangeAlarm (dpy, alarm, 0, &attr);
}

static void
set_alarm_enabled (Display    *dpy,
		   XSyncAlarm  alarm,
		   gboolean    enabled)
{
  XSyncAlarmAttributes attr;
  attr.events = enabled;
  XSyncChangeAlarm (dpy, alarm, XSyncCAEvents, &attr);
}

static void
check_x11_watch (gpointer data,
                 gpointer user_data)
{
  MetaIdleMonitorWatch *watch = data;
  XSyncAlarm alarm = (XSyncAlarm) user_data;

  if (watch->xalarm != alarm)
    return;

  fire_watch (watch);
}

static void
meta_idle_monitor_handle_xevent (MetaIdleMonitor       *monitor,
                                 XSyncAlarmNotifyEvent *alarm_event)
{
  XSyncAlarm alarm;
  GList *watches;
  gboolean has_alarm;

  if (alarm_event->state != XSyncAlarmActive)
    return;

  alarm = alarm_event->alarm;

  has_alarm = FALSE;

  if (alarm == monitor->user_active_alarm)
    {
      set_alarm_enabled (monitor->display,
                         alarm,
                         FALSE);
      has_alarm = TRUE;
    }
  else if (g_hash_table_contains (monitor->alarms, (gpointer) alarm))
    {
      ensure_alarm_rescheduled (monitor->display,
                                alarm);
      has_alarm = TRUE;
    }

  if (has_alarm)
    {
      watches = g_hash_table_get_values (monitor->watches);

      g_list_foreach (watches, check_x11_watch, (gpointer) alarm);
      g_list_free (watches);
    }
}

void
meta_idle_monitor_handle_xevent_all (XEvent *xevent)
{
  int i;

  for (i = 0; i <= device_id_max; i++)
    if (device_monitors[i])
      meta_idle_monitor_handle_xevent (device_monitors[i], (XSyncAlarmNotifyEvent*)xevent);
}

static char *
counter_name_for_device (int device_id)
{
  if (device_id > 0)
    return g_strdup_printf ("DEVICEIDLETIME %d", device_id);

  return g_strdup ("IDLETIME");
}

static XSyncCounter
find_idletime_counter (MetaIdleMonitor *monitor)
{
  int		      i;
  int		      ncounters;
  XSyncSystemCounter *counters;
  XSyncCounter        counter = None;
  char               *counter_name;

  counter_name = counter_name_for_device (monitor->device_id);
  counters = XSyncListSystemCounters (monitor->display, &ncounters);
  for (i = 0; i < ncounters; i++)
    {
      if (counters[i].name != NULL && strcmp (counters[i].name, counter_name) == 0)
        {
          counter = counters[i].counter;
          break;
        }
    }
  XSyncFreeSystemCounterList (counters);
  g_free (counter_name);

  return counter;
}

static guint32
get_next_watch_serial (void)
{
  static guint32 serial = 0;
  g_atomic_int_inc (&serial);
  return serial;
}

static void
idle_monitor_watch_free (MetaIdleMonitorWatch *watch)
{
  MetaIdleMonitor *monitor;

  if (watch == NULL)
    return;

  monitor = watch->monitor;
  g_object_ref (monitor);

  if (watch->idle_source_id)
    {
      g_source_remove (watch->idle_source_id);
      watch->idle_source_id = 0;
    }

  if (watch->notify != NULL)
    watch->notify (watch->user_data);

  if (watch->xalarm != monitor->user_active_alarm &&
      watch->xalarm != None)
    {
      XSyncDestroyAlarm (monitor->display, watch->xalarm);
      g_hash_table_remove (monitor->alarms, (gpointer) watch->xalarm);
    }

  if (watch->timeout_source != NULL)
    g_source_destroy (watch->timeout_source);

  g_object_unref (monitor);
  g_slice_free (MetaIdleMonitorWatch, watch);
}

static void
init_xsync (MetaIdleMonitor *monitor)
{
  monitor->counter = find_idletime_counter (monitor);
  /* IDLETIME counter not found? */
  if (monitor->counter == None)
    {
      meta_warning ("IDLETIME counter not found\n");
      return;
    }

  monitor->user_active_alarm = _xsync_alarm_set (monitor, XSyncNegativeTransition, 1, FALSE);
}

static void
meta_idle_monitor_dispose (GObject *object)
{
  MetaIdleMonitor *monitor;

  monitor = META_IDLE_MONITOR (object);

  g_clear_pointer (&monitor->watches, g_hash_table_destroy);
  g_clear_pointer (&monitor->alarms, g_hash_table_destroy);

  if (monitor->user_active_alarm != None)
    {
      XSyncDestroyAlarm (monitor->display, monitor->user_active_alarm);
      monitor->user_active_alarm = None;
    }

  G_OBJECT_CLASS (meta_idle_monitor_parent_class)->dispose (object);
}

static void
meta_idle_monitor_get_property (GObject    *object,
                                guint       prop_id,
                                GValue     *value,
                                GParamSpec *pspec)
{
  MetaIdleMonitor *monitor = META_IDLE_MONITOR (object);

  switch (prop_id)
    {
    case PROP_DEVICE_ID:
      g_value_set_int (value, monitor->device_id);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
meta_idle_monitor_set_property (GObject      *object,
                                guint         prop_id,
                                const GValue *value,
                                GParamSpec   *pspec)
{
  MetaIdleMonitor *monitor = META_IDLE_MONITOR (object);
  switch (prop_id)
    {
    case PROP_DEVICE_ID:
      monitor->device_id = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
meta_idle_monitor_constructed (GObject *object)
{
  MetaIdleMonitor *monitor = META_IDLE_MONITOR (object);

  if (!meta_is_wayland_compositor ())
    {
      monitor->display = meta_get_display ()->xdisplay;
      init_xsync (monitor);
    }
}

static void
meta_idle_monitor_class_init (MetaIdleMonitorClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->dispose = meta_idle_monitor_dispose;
  object_class->constructed = meta_idle_monitor_constructed;
  object_class->get_property = meta_idle_monitor_get_property;
  object_class->set_property = meta_idle_monitor_set_property;

  /**
   * MetaIdleMonitor:device_id:
   *
   * The device to listen to idletime on.
   */
  obj_props[PROP_DEVICE_ID] =
    g_param_spec_int ("device-id",
                      "Device ID",
                      "The device to listen to idletime on",
                      0, 255, 0,
                      G_PARAM_STATIC_STRINGS | G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY);
  g_object_class_install_property (object_class, PROP_DEVICE_ID, obj_props[PROP_DEVICE_ID]);
}

static void
meta_idle_monitor_init (MetaIdleMonitor *monitor)
{
  monitor->watches = g_hash_table_new_full (NULL,
                                                  NULL,
                                                  NULL,
                                                  (GDestroyNotify)idle_monitor_watch_free);

  monitor->alarms = g_hash_table_new (NULL, NULL);
}

static void
ensure_device_monitor (int device_id)
{
  if (device_monitors[device_id])
    return;

  device_monitors[device_id] = g_object_new (META_TYPE_IDLE_MONITOR, "device-id", device_id, NULL);
  device_id_max = MAX (device_id_max, device_id);
}

/* FIXME -- destroy device monitors at some point */
G_GNUC_UNUSED static void
destroy_device_monitor (int device_id)
{
  g_clear_object (&device_monitors[device_id]);
  if (device_id == device_id_max)
    device_id_max--;
}

/**
 * meta_idle_monitor_get_core:
 *
 * Returns: (transfer none): the #MetaIdleMonitor that tracks the server-global
 * idletime for all devices. To track device-specific idletime,
 * use meta_idle_monitor_get_for_device().
 */
MetaIdleMonitor *
meta_idle_monitor_get_core (void)
{
  ensure_device_monitor (0);
  return device_monitors[0];
}

/**
 * meta_idle_monitor_get_for_device:
 * @device_id: the device to get the idle time for.
 *
 * Returns: (transfer none): a new #MetaIdleMonitor that tracks the
 * device-specific idletime for @device. To track server-global idletime
 * for all devices, use meta_idle_monitor_get_core().
 */
MetaIdleMonitor *
meta_idle_monitor_get_for_device (int device_id)
{
  g_return_val_if_fail (device_id > 0 && device_id < 256, NULL);

  ensure_device_monitor (device_id);
  return device_monitors[device_id];
}

static gboolean
wayland_dispatch_timeout (GSource     *source,
                          GSourceFunc  callback,
                          gpointer     user_data)
{
  MetaIdleMonitorWatch *watch = user_data;

  fire_watch (watch);
  g_source_set_ready_time (watch->timeout_source, -1);
  return TRUE;
}

static GSourceFuncs wayland_source_funcs = {
  NULL, /* prepare */
  NULL, /* check */
  wayland_dispatch_timeout,
  NULL, /* finalize */
};

static gboolean
fire_watch_idle (gpointer data)
{
  MetaIdleMonitorWatch *watch = data;

  watch->idle_source_id = 0;
  fire_watch (watch);

  return FALSE;
}

static MetaIdleMonitorWatch *
make_watch (MetaIdleMonitor           *monitor,
            guint64                    timeout_msec,
	    MetaIdleMonitorWatchFunc   callback,
	    gpointer                   user_data,
	    GDestroyNotify             notify)
{
  MetaIdleMonitorWatch *watch;

  watch = g_slice_new0 (MetaIdleMonitorWatch);
  watch->monitor = monitor;
  watch->id = get_next_watch_serial ();
  watch->callback = callback;
  watch->user_data = user_data;
  watch->notify = notify;
  watch->timeout_msec = timeout_msec;

  if (meta_is_wayland_compositor ())
    {
      if (timeout_msec != 0)
        {
          GSource *source = g_source_new (&wayland_source_funcs, sizeof (GSource));

          g_source_set_callback (source, NULL, watch, NULL);
          g_source_set_ready_time (source, monitor->last_event_time + timeout_msec * 1000);
          g_source_attach (source, NULL);
          g_source_unref (source);

          watch->timeout_source = source;
        }
    }
  else if (monitor->user_active_alarm != None)
    {
      if (timeout_msec != 0)
        {
          watch->xalarm = _xsync_alarm_set (monitor, XSyncPositiveTransition, timeout_msec, TRUE);

          g_hash_table_add (monitor->alarms, (gpointer) watch->xalarm);

          if (meta_idle_monitor_get_idletime (monitor) > (gint64)timeout_msec)
            watch->idle_source_id = g_idle_add (fire_watch_idle, watch);
        }
      else
        {
          watch->xalarm = monitor->user_active_alarm;

          set_alarm_enabled (monitor->display, monitor->user_active_alarm, TRUE);
        }
    }

  g_hash_table_insert (monitor->watches,
                       GUINT_TO_POINTER (watch->id),
                       watch);
  return watch;
}

/**
 * meta_idle_monitor_add_idle_watch:
 * @monitor: A #MetaIdleMonitor
 * @interval_msec: The idletime interval, in milliseconds
 * @callback: (allow-none): The callback to call when the user has
 *     accumulated @interval_msec milliseconds of idle time.
 * @user_data: (allow-none): The user data to pass to the callback
 * @notify: A #GDestroyNotify
 *
 * Returns: a watch id
 *
 * Adds a watch for a specific idle time. The callback will be called
 * when the user has accumulated @interval_msec milliseconds of idle time.
 * This function will return an ID that can either be passed to
 * meta_idle_monitor_remove_watch(), or can be used to tell idle time
 * watches apart if you have more than one.
 *
 * Also note that this function will only care about positive transitions
 * (user's idle time exceeding a certain time). If you want to know about
 * when the user has become active, use
 * meta_idle_monitor_add_user_active_watch().
 */
guint
meta_idle_monitor_add_idle_watch (MetaIdleMonitor	       *monitor,
                                  guint64	                interval_msec,
                                  MetaIdleMonitorWatchFunc      callback,
                                  gpointer			user_data,
                                  GDestroyNotify		notify)
{
  MetaIdleMonitorWatch *watch;

  g_return_val_if_fail (META_IS_IDLE_MONITOR (monitor), 0);
  g_return_val_if_fail (interval_msec > 0, 0);

  watch = make_watch (monitor,
                      interval_msec,
                      callback,
                      user_data,
                      notify);

  return watch->id;
}

/**
 * meta_idle_monitor_add_user_active_watch:
 * @monitor: A #MetaIdleMonitor
 * @callback: (allow-none): The callback to call when the user is
 *     active again.
 * @user_data: (allow-none): The user data to pass to the callback
 * @notify: A #GDestroyNotify
 *
 * Returns: a watch id
 *
 * Add a one-time watch to know when the user is active again.
 * Note that this watch is one-time and will de-activate after the
 * function is called, for efficiency purposes. It's most convenient
 * to call this when an idle watch, as added by
 * meta_idle_monitor_add_idle_watch(), has triggered.
 */
guint
meta_idle_monitor_add_user_active_watch (MetaIdleMonitor          *monitor,
                                         MetaIdleMonitorWatchFunc  callback,
                                         gpointer		   user_data,
                                         GDestroyNotify	           notify)
{
  MetaIdleMonitorWatch *watch;

  g_return_val_if_fail (META_IS_IDLE_MONITOR (monitor), 0);

  watch = make_watch (monitor,
                      0,
                      callback,
                      user_data,
                      notify);

  return watch->id;
}

/**
 * meta_idle_monitor_remove_watch:
 * @monitor: A #MetaIdleMonitor
 * @id: A watch ID
 *
 * Removes an idle time watcher, previously added by
 * meta_idle_monitor_add_idle_watch() or
 * meta_idle_monitor_add_user_active_watch().
 */
void
meta_idle_monitor_remove_watch (MetaIdleMonitor *monitor,
                                guint	         id)
{
  g_return_if_fail (META_IS_IDLE_MONITOR (monitor));

  g_object_ref (monitor);
  g_hash_table_remove (monitor->watches,
                       GUINT_TO_POINTER (id));
  g_object_unref (monitor);
}

static gint64
meta_idle_monitor_get_idletime_wayland (MetaIdleMonitor *monitor)
{
  return (g_get_monotonic_time () - monitor->last_event_time) / 1000;
}

static gint64
meta_idle_monitor_get_idletime_x11 (MetaIdleMonitor *monitor)
{
  XSyncValue value;

  if (!XSyncQueryCounter (monitor->display, monitor->counter, &value))
    return -1;

  return _xsyncvalue_to_int64 (value);
}

/**
 * meta_idle_monitor_get_idletime:
 * @monitor: A #MetaIdleMonitor
 *
 * Returns: The current idle time, in milliseconds, or -1 for not supported
 */
gint64
meta_idle_monitor_get_idletime (MetaIdleMonitor *monitor)
{
  if (meta_is_wayland_compositor ())
    return meta_idle_monitor_get_idletime_wayland (monitor);
  else
    return meta_idle_monitor_get_idletime_x11 (monitor);
}

typedef struct {
  MetaIdleMonitor *monitor;
  GList *fired_watches;
} CheckWaylandClosure;

static gboolean
check_wayland_watch (gpointer key,
                     gpointer value,
                     gpointer user_data)
{
  MetaIdleMonitorWatch *watch = value;
  CheckWaylandClosure *closure = user_data;
  gboolean steal;

  if (watch->timeout_msec == 0)
    {
      closure->fired_watches = g_list_prepend (closure->fired_watches, watch);
      steal = TRUE;
    }
  else
    {
      g_source_set_ready_time (watch->timeout_source,
                               closure->monitor->last_event_time +
                               watch->timeout_msec * 1000);
      steal = FALSE;
    }

  return steal;
}

static void
fire_wayland_watch (gpointer watch,
                    gpointer data)
{
  fire_watch (watch);
}

void
meta_idle_monitor_reset_idletime (MetaIdleMonitor *monitor)
{
  CheckWaylandClosure closure;

  monitor->last_event_time = g_get_monotonic_time ();

  closure.monitor = monitor;
  closure.fired_watches = NULL;
  g_hash_table_foreach_steal (monitor->watches, check_wayland_watch, &closure);

  g_list_foreach (closure.fired_watches, fire_wayland_watch, NULL);
  g_list_free (closure.fired_watches);
}