/*
 * Copyright 2014 Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 3, as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranties of
 * MERCHANTABILITY, SATISFACTORY QUALITY, 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/>.
 *
 * Authors:
 *   Charles Kerr <charles.kerr@canonical.com>
 */

#include "dbus-battery.h"
#include "dbus-shared.h"
#include "notifier.h"

#include <libnotify/notify.h>

#include <glib/gi18n.h>
#include <gio/gio.h>

#define HINT_INTERACTIVE "x-canonical-switch-to-application"

G_DEFINE_TYPE(IndicatorPowerNotifier,
              indicator_power_notifier,
              G_TYPE_OBJECT)

/**
***  GObject Properties
**/

enum
{
  PROP_0,
  PROP_BATTERY,
  PROP_IS_WARNING,
  PROP_POWER_LEVEL,
  LAST_PROP
};

#define PROP_BATTERY_NAME "battery"
#define PROP_IS_WARNING_NAME "is-warning"
#define PROP_POWER_LEVEL_NAME "power-level"

static GParamSpec * properties[LAST_PROP];

static int instance_count = 0;

/**
***
**/

struct _IndicatorPowerNotifierPrivate
{
  /* The battery we're currently watching.
     This may be a physical battery or it may be an aggregated
     battery from multiple batteries present on the device.
     See indicator_power_service_choose_primary_device() and
     bug #880881 */
  IndicatorPowerDevice * battery;
  PowerLevel power_level;
  gboolean discharging;

  NotifyNotification* notify_notification;
  gboolean is_warning;

  GDBusConnection * bus;
  DbusBattery * dbus_battery; /* com.canonical.indicator.power.Battery skeleton */
  GBinding * is_warning_binding; /* pushes our property to dbus_battery */
  GBinding * power_level_binding; /* pushes our property to dbus_battery */
};

typedef IndicatorPowerNotifierPrivate priv_t;

static void set_is_warning_property (IndicatorPowerNotifier*,
                                     gboolean is_warning);

static void set_power_level_property (IndicatorPowerNotifier*,
                                      PowerLevel power_level);

/***
****  Notifications
***/

static void
notification_clear (IndicatorPowerNotifier * self)
{
  priv_t * p = self->priv;

  if (p->notify_notification != NULL)
    {
      set_is_warning_property (self, FALSE);

      notify_notification_clear_actions(p->notify_notification);
      g_signal_handlers_disconnect_by_data(p->notify_notification, self);
      g_clear_object(&p->notify_notification);
    }
}

static void
notification_show(IndicatorPowerNotifier * self)
{
  priv_t * p;
  char * body;
  GError * error;

  notification_clear (self);

  p = self->priv;

  /* create the notification */
  body = g_strdup_printf(_("%.0f%% charge remaining"),
                         indicator_power_device_get_percentage(p->battery));
  p->notify_notification = notify_notification_new(_("Battery Low"), body, NULL);
  notify_notification_set_hint(p->notify_notification,
                               HINT_INTERACTIVE,
                               g_variant_new_boolean(TRUE));
  g_signal_connect_swapped(p->notify_notification, "closed",
                           G_CALLBACK(notification_clear), self);

  /* show the notification */
  error = NULL;
  notify_notification_show(p->notify_notification, &error);
  if (error != NULL)
    {
      g_critical("Unable to show snap decision for '%s': %s", body, error->message);
      g_error_free(error);
    }
  else
    {
      set_is_warning_property (self, TRUE);
    }

  g_free (body);
}

/***
****
***/

static void
on_battery_property_changed (IndicatorPowerNotifier * self)
{
  priv_t * p;
  PowerLevel old_power_level;
  PowerLevel new_power_level;
  gboolean old_discharging;
  gboolean new_discharging;

  g_return_if_fail(INDICATOR_IS_POWER_NOTIFIER(self));
  g_return_if_fail(INDICATOR_IS_POWER_DEVICE(self->priv->battery));

  p = self->priv;

  old_power_level = p->power_level;
  new_power_level = indicator_power_notifier_get_power_level (p->battery);

  old_discharging = p->discharging;
  new_discharging = indicator_power_device_get_state(p->battery) == UP_DEVICE_STATE_DISCHARGING;

  /* pop up a 'low battery' notification if either:
     a) it's already discharging, and its PowerLevel worsens, OR
     b) it's already got a bad PowerLevel and its state becomes 'discharging */
  if ((new_discharging && (new_power_level > old_power_level)) ||
      ((new_power_level != POWER_LEVEL_OK) && new_discharging && !old_discharging))
    {
      notification_show (self);
    }
  else
    {
      notification_clear (self);
    }

  set_power_level_property (self, new_power_level);
  p->discharging = new_discharging;
}

/***
****  GObject virtual functions
***/

static void
my_get_property (GObject     * o,
                 guint         property_id,
                 GValue      * value,
                 GParamSpec  * pspec)
{
  IndicatorPowerNotifier * self = INDICATOR_POWER_NOTIFIER (o);
  priv_t * p = self->priv;

  switch (property_id)
    {
      case PROP_BATTERY:
        g_value_set_object (value, p->battery);
        break;

      case PROP_POWER_LEVEL:
        g_value_set_int (value, p->power_level);
        break;

      case PROP_IS_WARNING:
        g_value_set_boolean (value, p->is_warning);
        break;

      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (o, property_id, pspec);
    }
}

static void
my_set_property (GObject       * o,
                 guint           property_id,
                 const GValue  * value,
                 GParamSpec    * pspec)
{
  IndicatorPowerNotifier * self = INDICATOR_POWER_NOTIFIER (o);

  switch (property_id)
    {
      case PROP_BATTERY:
        indicator_power_notifier_set_battery (self, g_value_get_object(value));
        break;

      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (o, property_id, pspec);
    }
}

/* read-only property, so not implemented in my_set_property() */
static void
set_is_warning_property (IndicatorPowerNotifier * self, gboolean is_warning)
{
  priv_t * p = self->priv;

  if (p->is_warning != is_warning)
    {
      p->is_warning = is_warning;

      g_object_notify_by_pspec (G_OBJECT(self), properties[PROP_IS_WARNING]);
    }
}

/* read-only property, so not implemented in my_set_property() */
static void
set_power_level_property (IndicatorPowerNotifier * self, PowerLevel power_level)
{
  priv_t * p = self->priv;

  if (p->power_level != power_level)
    {
      p->power_level = power_level;

      g_object_notify_by_pspec (G_OBJECT(self), properties[PROP_POWER_LEVEL]);
    }
}

static void
my_dispose (GObject * o)
{
  IndicatorPowerNotifier * self = INDICATOR_POWER_NOTIFIER(o);
  priv_t * p = self->priv;

  indicator_power_notifier_set_bus (self, NULL);
  notification_clear (self);
  g_clear_object (&p->power_level_binding);
  g_clear_object (&p->is_warning_binding);
  g_clear_object (&p->dbus_battery);
  indicator_power_notifier_set_battery (self, NULL);

  G_OBJECT_CLASS (indicator_power_notifier_parent_class)->dispose (o);
}

static void
my_finalize (GObject * o G_GNUC_UNUSED)
{
  /* FIXME: This is an awkward place to put this. 
     Ordinarily something like this would go in main(), but we need libnotify
     to clean itself up before shutting down the bus in the unit tests as well. */
  if (!--instance_count)
    notify_uninit();
}

/***
****  Instantiation
***/

static void
indicator_power_notifier_init (IndicatorPowerNotifier * self)
{
  priv_t * p;

  p = G_TYPE_INSTANCE_GET_PRIVATE (self,
                                   INDICATOR_TYPE_POWER_NOTIFIER,
                                   IndicatorPowerNotifierPrivate);
  self->priv = p;

  /* bind the read-only properties so they'll get pushed to the bus */

  p->dbus_battery = dbus_battery_skeleton_new ();

  p->is_warning_binding = g_object_bind_property (self,
                                                  PROP_IS_WARNING_NAME,
                                                  p->dbus_battery,
                                                  PROP_IS_WARNING_NAME,
                                                  G_BINDING_SYNC_CREATE);

  p->power_level_binding = g_object_bind_property (self,
                                                   PROP_POWER_LEVEL_NAME,
                                                   p->dbus_battery,
                                                   PROP_POWER_LEVEL_NAME,
                                                   G_BINDING_SYNC_CREATE);

  if (!instance_count++)
    {
      if (!notify_init("indicator-power-service"))
        {
          g_critical("Unable to initialize libnotify! Notifications might not be shown.");
        }
    }
}

static void
indicator_power_notifier_class_init (IndicatorPowerNotifierClass * klass)
{
  GObjectClass * object_class = G_OBJECT_CLASS (klass);

  object_class->dispose = my_dispose;
  object_class->finalize = my_finalize;
  object_class->get_property = my_get_property;
  object_class->set_property = my_set_property;

  g_type_class_add_private (klass, sizeof (IndicatorPowerNotifierPrivate));

  properties[PROP_0] = NULL;

  properties[PROP_BATTERY] = g_param_spec_object (
    PROP_BATTERY_NAME,
    "Battery",
    "The current battery",
    G_TYPE_OBJECT,
    G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);

  properties[PROP_POWER_LEVEL] = g_param_spec_int (
    PROP_POWER_LEVEL_NAME,
    "Power Level",
    "The battery's power level",
    POWER_LEVEL_OK,
    POWER_LEVEL_CRITICAL,
    POWER_LEVEL_OK,
    G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

  properties[PROP_IS_WARNING] = g_param_spec_boolean (
    PROP_IS_WARNING_NAME,
    "Is Warning",
    "Whether or not we're currently warning the user about a low battery",
    FALSE,
    G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

  g_object_class_install_properties (object_class, LAST_PROP, properties);
}

/***
****  Public API
***/

IndicatorPowerNotifier *
indicator_power_notifier_new (void)
{
  GObject * o = g_object_new (INDICATOR_TYPE_POWER_NOTIFIER, NULL);

  return INDICATOR_POWER_NOTIFIER (o);
}

void
indicator_power_notifier_set_battery (IndicatorPowerNotifier * self,
                                      IndicatorPowerDevice   * battery)
{
  priv_t * p;

  g_return_if_fail(INDICATOR_IS_POWER_NOTIFIER(self));
  g_return_if_fail((battery == NULL) || INDICATOR_IS_POWER_DEVICE(battery));
  g_return_if_fail((battery == NULL) || (indicator_power_device_get_kind(battery) == UP_DEVICE_KIND_BATTERY));

  p = self->priv;

  if (p->battery == battery)
    return;

  if (p->battery != NULL)
    {
      g_signal_handlers_disconnect_by_data (p->battery, self);
      g_clear_object (&p->battery);
      set_power_level_property (self, POWER_LEVEL_OK);
      notification_clear (self);
    }

  if (battery != NULL)
    {
      p->battery = g_object_ref (battery);
      g_signal_connect_swapped (p->battery, "notify::"INDICATOR_POWER_DEVICE_PERCENTAGE,
                                G_CALLBACK(on_battery_property_changed), self);
      g_signal_connect_swapped (p->battery, "notify::"INDICATOR_POWER_DEVICE_STATE,
                                G_CALLBACK(on_battery_property_changed), self);
      on_battery_property_changed (self);
    }
}

void
indicator_power_notifier_set_bus (IndicatorPowerNotifier * self,
                                  GDBusConnection        * bus)
{
  priv_t * p;
  GDBusInterfaceSkeleton * skel;

  g_return_if_fail(INDICATOR_IS_POWER_NOTIFIER(self));
  g_return_if_fail((bus == NULL) || G_IS_DBUS_CONNECTION(bus));

  p = self->priv;

  if (p->bus == bus)
    return;

  skel = G_DBUS_INTERFACE_SKELETON(p->dbus_battery);

  if (p->bus != NULL)
    {
      if (skel != NULL)
        g_dbus_interface_skeleton_unexport (skel);

      g_clear_object (&p->bus);
    }

  if (bus != NULL)
    {
      GError * error;

      p->bus = g_object_ref (bus);

      error = NULL;
      g_dbus_interface_skeleton_export(skel,
                                       bus,
                                       BUS_PATH"/Battery",
                                       &error);
      if (error != NULL)
        {
          g_warning ("Unable to export LowBattery properties: %s", error->message);
          g_error_free (error);
        }
    }
}

PowerLevel
indicator_power_notifier_get_power_level (IndicatorPowerDevice * battery)
{
  static const double percent_critical = 2.0;
  static const double percent_very_low = 5.0;
  static const double percent_low = 10.0;
  gdouble p;
  PowerLevel ret;

  g_return_val_if_fail(battery != NULL, POWER_LEVEL_OK);
  g_return_val_if_fail(indicator_power_device_get_kind(battery) == UP_DEVICE_KIND_BATTERY, POWER_LEVEL_OK);

  p = indicator_power_device_get_percentage(battery);

  if (p <= percent_critical)
    ret = POWER_LEVEL_CRITICAL;
  else if (p <= percent_very_low)
    ret = POWER_LEVEL_VERY_LOW;
  else if (p <= percent_low)
    ret = POWER_LEVEL_LOW;
  else
    ret = POWER_LEVEL_OK;

  return ret;
}