/*
 * Copyright 2013 Canonical Ltd.
 *
 * 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; version 3.
 *
 * 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/>.
 *
 * Authors:
 *   Charles Kerr <charles.kerr@canonical.com>
 *   Robert Ancell <robert.ancell@canonical.com>
 */


/**
 * Bluetooth implementaion which uses org.bluez on DBus
 */
public class Bluez: Bluetooth, Object
{
  uint name_watch_id = 0;
  uint next_device_id = 1;
  ObjectManager manager;
  const string BLUEZ_BUSNAME = "org.bluez";

  private bool _powered = false;

  private bool powered {
    get { return _powered; }
    set { _powered = value; update_enabled(); }
  }

  private KillSwitch killswitch = new RfKillSwitch ();

  private DBusConnection bus = null;

  /* maps an org.bluez.Adapter1's object_path to the BluezAdapter proxy */
  private HashTable<ObjectPath,BluezAdapter> path_to_adapter_proxy;

  /* maps an org.bluez.Device1's object_path to the BluezDevice proxy */
  private HashTable<ObjectPath,BluezDevice> path_to_device_proxy;

  /* maps an org.bluez.Device1's object_path to our arbitrary unique id */
  private HashTable<ObjectPath,uint> path_to_id;

  /* maps our arbitrary unique id to an org.bluez.Device's object path */
  private HashTable<uint,ObjectPath> id_to_path;

  /* maps our arbitrary unique id to a Bluetooth.Device struct for public consumption */
  private HashTable<uint,Device> id_to_device;

  public Bluez (KillSwitch? killswitch)
  {
    init_bluez_state_vars ();

    if ((killswitch != null) && (killswitch.is_valid()))
      {
        this.killswitch = killswitch;
        killswitch.notify["blocked"].connect (() => update_enabled());
        update_enabled ();
      }

    name_watch_id = Bus.watch_name(BusType.SYSTEM,
                                   BLUEZ_BUSNAME,
                                   BusNameWatcherFlags.AUTO_START,
                                   on_bluez_appeared,
                                   on_bluez_vanished);
  }

  ~Bluez()
  {
    Bus.unwatch_name(name_watch_id);
  }

  private void on_bluez_appeared (DBusConnection connection, string name, string name_owner)
  {
    debug(@"$name owned by $name_owner, setting up bluez proxies");

    bus = connection;

    init_bluez_state_vars();
    reset_manager();
  }

  private void on_bluez_vanished (DBusConnection connection, string name)
  {
    debug(@"$name vanished from the bus");

    reset_bluez();
  }

  private void init_bluez_state_vars ()
  {
    id_to_path = new HashTable<uint,ObjectPath> (direct_hash, direct_equal);
    id_to_device = new HashTable<uint,Device> (direct_hash, direct_equal);
    path_to_id = new HashTable<ObjectPath,uint> (str_hash, str_equal);
    path_to_adapter_proxy = new HashTable<ObjectPath,BluezAdapter> (str_hash, str_equal);
    path_to_device_proxy = new HashTable<ObjectPath,BluezDevice> (str_hash, str_equal);
  }

  private void reset_bluez ()
  {
    init_bluez_state_vars ();

    devices_changed ();
    update_combined_adapter_state ();
    update_connected ();
    update_enabled ();
  }

  private void reset_manager()
  {
    try
      {
        manager = bus.get_proxy_sync (BLUEZ_BUSNAME, "/");

        // Find the adapters and watch for changes
        manager.interfaces_added.connect ((object_path, interfaces_and_properties) => {
          var iter = HashTableIter<string, HashTable<string, Variant>> (interfaces_and_properties);
          string name;
          while (iter.next (out name, null))
            {
              if (name == "org.bluez.Adapter1")
                update_adapter (object_path);
              if (name == "org.bluez.Device1")
                update_device (object_path);
            }
        });
        manager.interfaces_removed.connect ((object_path, interfaces) => {
            foreach (var interface in interfaces) {
              if (interface == "org.bluez.Adapter1")
                adapter_removed (object_path);
              if (interface == "org.bluez.Device1")
                device_removed (object_path);
            }
        });
        var objects = manager.get_managed_objects ();
        var object_iter = HashTableIter<ObjectPath, HashTable<string, HashTable<string, Variant>>> (objects);
        ObjectPath object_path;
        HashTable<string, HashTable<string, Variant>> interfaces_and_properties;
        while (object_iter.next (out object_path, out interfaces_and_properties))
          {
            var iter = HashTableIter<string, HashTable<string, Variant>> (interfaces_and_properties);
            string name;
            while (iter.next (out name, null)) {
              if (name == "org.bluez.Adapter1")
                update_adapter (object_path);
              if (name == "org.bluez.Device1")
                update_device (object_path);
            }
          }
      }
    catch (Error e)
      {
        critical (@"$(e.message)");
      }
  }

  ////
  ////  Adapter Upkeep
  ////

  private void update_adapter (ObjectPath object_path)
  {
    debug(@"bluez5 calling update_adapter for $object_path");

    // Create a proxy if we don't have one
    var adapter_proxy = path_to_adapter_proxy.lookup (object_path);
    if (adapter_proxy == null)
      {
        try {
          adapter_proxy = bus.get_proxy_sync (BLUEZ_BUSNAME, object_path);
        } catch (Error e) {
          critical (@"$(e.message)");
          return;
        }
        path_to_adapter_proxy.insert (object_path, adapter_proxy);
        adapter_proxy.g_properties_changed.connect(() => update_adapter (object_path));
      }

    update_combined_adapter_state ();
  }

  private void adapter_removed (ObjectPath object_path)
  {
    path_to_adapter_proxy.remove (object_path);
    update_combined_adapter_state ();
  }

  private void update_combined_adapter_state ()
  {
    var is_discoverable = false;
    var is_powered = false;
    var is_supported = false;

    var iter = HashTableIter<ObjectPath,BluezAdapter> (path_to_adapter_proxy);
    BluezAdapter adapter_proxy;
    while (iter.next (null, out adapter_proxy))
      {
        var v = adapter_proxy.get_cached_property ("Discoverable");
        if (!is_discoverable)
          is_discoverable = (v != null) && v.get_boolean ();

        v = adapter_proxy.get_cached_property ("Powered");
        if (!is_powered)
          is_powered = (v != null) && v.get_boolean ();

        is_supported = true;
      }

    discoverable = is_discoverable;
    powered = is_powered;
    supported = is_supported;
  }

  ////
  ////  bluetooth device UUIDs
  ////

  private static uint16 get_uuid16_from_uuid_string (string uuid)
  {
    uint16 uuid16;

    string[] tokens = uuid.split ("-", 1);
    if (tokens.length > 0)
      uuid16 = (uint16) uint64.parse ("0x"+tokens[0]);
    else
      uuid16 = 0;

    return uuid16;
  }

  // A device supports file transfer if OBEXObjectPush is in its uuid list
  private bool device_supports_file_transfer (uint16[] uuids)
  {
    foreach (var uuid16 in uuids)
      if (uuid16 == 0x1105) // OBEXObjectPush
        return true;

    return false;
  }

  // A device supports browsing if OBEXFileTransfer is in its uuid list
  private bool device_supports_browsing (uint16[] uuids)
  {
    foreach (var uuid16 in uuids)
      if (uuid16 == 0x1106) // OBEXFileTransfer
        return true;

    return false;
  }

  ////
  ////  Device Upkeep
  ////

  /* Update our public Device struct from the org.bluez.Device's properties.
   *
   * This is called when we first walk through bluez' Devices on startup,
   * when the org.bluez.Adapter gets a new device,
   * and when a device's properties change s.t. we need to rebuild the proxy.
   */
  private void update_device (ObjectPath object_path)
  {
    debug(@"bluez5 calling update_device for $object_path");

    // Create a proxy if we don't have one
    var device_proxy = path_to_device_proxy.lookup (object_path);
    if (device_proxy == null)
      {
        try {
          device_proxy = bus.get_proxy_sync (BLUEZ_BUSNAME, object_path);
        } catch (Error e) {
          critical (@"$(e.message)");
          return;
        }

        path_to_device_proxy.insert (object_path, device_proxy);
        device_proxy.g_properties_changed.connect(() => update_device (object_path));
      }

    // look up our id for this device.
    // if we don't have one yet, create one.
    var id = path_to_id.lookup (object_path);
    if (id == 0)
      {
        id = next_device_id ++;
        id_to_path.insert (id, object_path);
        path_to_id.insert (object_path, id);
      }

    // look up the device's type
    Device.Type type;
    var v = device_proxy.get_cached_property ("Class");
    if (v == null)
      type = Device.Type.OTHER;
    else
      type = Device.class_to_device_type (v.get_uint32());

    // look up the device's human-readable name
    v = device_proxy.get_cached_property ("Alias");
    if (v == null)
      v = device_proxy.get_cached_property ("Name");
    var name = v == null ? _("Unknown") : v.get_string ();

    // look up the device's bus address
    v = device_proxy.get_cached_property ("Address");
    var address = v == null ? null : v.get_string ();

    // look up the device's bus address
    v = device_proxy.get_cached_property ("Icon");
    var icon = new ThemedIcon (v != null ? v.get_string() : "unknown");

    // look up the device's Connected flag
    v = device_proxy.get_cached_property ("Connected");
    var is_connected = (v != null) && v.get_boolean ();

    // derive the uuid-related attributes we care about
    v = device_proxy.get_cached_property ("UUIDs");
    uint16[] uuids = {};
    if (v != null)
    {
        string[] uuid_strings = v.dup_strv ();
        foreach (var s in uuid_strings)
            uuids += get_uuid16_from_uuid_string (s);
    }
    var supports_browsing = device_supports_browsing (uuids);
    var supports_file_transfer = device_supports_file_transfer (uuids);

    id_to_device.insert (id, new Device (id,
                                         type,
                                         name,
                                         address,
                                         icon,
                                         true,
                                         is_connected,
                                         supports_browsing,
                                         supports_file_transfer));

    devices_changed ();
    update_connected ();
  }

  private void device_removed (ObjectPath path)
  {
    var id = path_to_id.lookup (path);
    path_to_id.remove (path);
    id_to_path.remove (id);
    id_to_device.remove (id);

    devices_changed ();
  }

  /* update the 'enabled' property by looking at the killswitch state
     and the 'powered' property state */
  void update_enabled ()
  {
    var blocked = (killswitch != null) && killswitch.blocked;
    debug (@"in upate_enabled, powered is $powered, blocked is $blocked");
    enabled = powered && !blocked;
  }

  private bool have_connected_device ()
  {
    var devices = get_devices();

    foreach (var device in devices)
      if (device.is_connected)
        return true;

    return false;
  }

  private void update_connected ()
  {
    connected = have_connected_device ();
  }

  ////
  ////  Public API
  ////

  public void set_device_connected (uint id, bool connected)
  {
    var device = id_to_device.lookup (id);
    var path = id_to_path.lookup (id);
    var proxy = (path != null) ? path_to_device_proxy.lookup (path) : null;

    if ((device != null)
        && (device.is_connected != connected))
      {
        try
          {
            if (connected)
              proxy.connect_ ();
            else
              proxy.disconnect_ ();
          }
        catch (Error e)
          {
            debug (@"$path org.bluez.Device1 connect/disconnect failed: $(e.message)");
          }

        update_connected ();
      }
  }

  public void try_set_discoverable (bool b)
  {
    if (discoverable != b)
      {
        var iter = HashTableIter<ObjectPath,BluezAdapter> (path_to_adapter_proxy);
        ObjectPath object_path;
        BluezAdapter adapter_proxy;
        while (iter.next (out object_path, out adapter_proxy))
          adapter_proxy.call.begin ("org.freedesktop.DBus.Properties.Set",
                                    new Variant ("(ssv)", "org.bluez.Adapter1", "Discoverable", new Variant.boolean (b)),
                                    DBusCallFlags.NONE, -1);
      }
  }

  public List<unowned Device> get_devices ()
  {
    return id_to_device.get_values();
  }

  public bool supported { get; protected set; default = false; }
  public bool discoverable { get; protected set; default = false; }
  public bool enabled { get; protected set; default = false; }
  public bool connected { get; protected set; default = false; }

  public void try_set_enabled (bool b)
  {
    if (killswitch != null)
      {
        debug (@"setting killswitch blocked to $(!b)");
        killswitch.try_set_blocked (!b);
      }
    else
      {
        var iter = HashTableIter<ObjectPath,BluezAdapter> (path_to_adapter_proxy);
        ObjectPath object_path;
        BluezAdapter adapter_proxy;
        while (iter.next (out object_path, out adapter_proxy))
          adapter_proxy.call.begin ("org.freedesktop.DBus.Properties.Set",
                                    new Variant ("(ssv)", "org.bluez.Adapter1", "Powered", new Variant.boolean (b)),
                                    DBusCallFlags.NONE, -1);
      }
  }
}

[DBus (name = "org.freedesktop.DBus.ObjectManager")]
private interface ObjectManager : Object {
  [DBus (name = "GetManagedObjects")]
  public abstract HashTable<ObjectPath, HashTable<string, HashTable<string, Variant>>> get_managed_objects() throws DBusError, IOError;

  [DBus (name = "InterfacesAdded")]
  public signal void interfaces_added(ObjectPath object_path, HashTable<string, HashTable<string, Variant>> interfaces_and_properties);

  [DBus (name = "InterfacesRemoved")]
  public signal void interfaces_removed(ObjectPath object_path, string[] interfaces);
}

[DBus (name = "org.bluez.Adapter1")]
private interface BluezAdapter : DBusProxy {
}

[DBus (name = "org.bluez.Device1")]
private interface BluezDevice : DBusProxy {
  [DBus (name = "Connect")]
  public abstract void connect_() throws DBusError, IOError;

  [DBus (name = "Disconnect")]
  public abstract void disconnect_() throws DBusError, IOError;
}