{ Copyleft implementation of TTrayIcon for
  Unity applications indicators
  Created 2015 by Anthony Walter sysrpl@gmail.com }

unit UnityWSCtrls;

interface

{$mode delphi}
uses
  GLib2, Gtk2, Gdk2Pixbuf,
  Classes, SysUtils, dynlibs,
  Graphics, Controls, Forms, ExtCtrls, WSExtCtrls, LCLType;

{ TUnityWSCustomTrayIcon is the class for tray icons on systems
  running the Unity desktop environment.

  Unity allows only AppIndicator objects in its tray. These objects
  have the following reduced functionality:

  Tooltips are not allowed
  Icons do not receive mouse events
  Indicators display a menu when clicked by any mouse button

  See also: http://www.markshuttleworth.com/archives/347
  "Clicking on an indicator will open its menu..."
  "There’ll be no ability for arbitrary applications to define arbitrary
   behaviours to arbitrary events on indicators"

  Personal observations:

  A popup menu is required always
  You can only create one AppIndicator per appplication
  You cannot use a different popupmenu once one has been used }

type
  TUnityWSCustomTrayIcon = class(TWSCustomTrayIcon)
  published
    class function Hide(const ATrayIcon: TCustomTrayIcon): Boolean; override;
    class function Show(const ATrayIcon: TCustomTrayIcon): Boolean; override;
    class procedure InternalUpdate(const ATrayIcon: TCustomTrayIcon); override;
    class function GetPosition(const {%H-}ATrayIcon: TCustomTrayIcon): TPoint; override;
  end;

{ UnityAppIndicatorInit returns true if appindicator libraries can be loaded }

function UnityAppIndicatorInit: Boolean;

implementation

const
  libappindicator = 'libappindicator.so.1';

{const
  APP_INDICATOR_SIGNAL_NEW_ICON = 'new-icon';
  APP_INDICATOR_SIGNAL_NEW_ATTENTION_ICON = 'new-attention-icon';
  APP_INDICATOR_SIGNAL_NEW_STATUS = 'new-status';
  APP_INDICATOR_SIGNAL_NEW_LABEL = 'new-label';
  APP_INDICATOR_SIGNAL_CONNECTION_CHANGED = 'connection-changed';
  APP_INDICATOR_SIGNAL_NEW_ICON_THEME_PATH = 'new-icon-theme-path';
}
type
  TAppIndicatorCategory = (
    APP_INDICATOR_CATEGORY_APPLICATION_STATUS,
    APP_INDICATOR_CATEGORY_COMMUNICATIONS,
    APP_INDICATOR_CATEGORY_SYSTEM_SERVICES,
    APP_INDICATOR_CATEGORY_HARDWARE,
    APP_INDICATOR_CATEGORY_OTHER
  );

  TAppIndicatorStatus = (
    APP_INDICATOR_STATUS_PASSIVE,
    APP_INDICATOR_STATUS_ACTIVE,
    APP_INDICATOR_STATUS_ATTENTION
  );

  PAppIndicator = Pointer;

var
  { GlobalAppIndicator creation routines }
  app_indicator_get_type: function: GType; cdecl;
  app_indicator_new: function(id, icon_name: PGChar; category: TAppIndicatorCategory): PAppIndicator; cdecl;
  app_indicator_new_with_path: function(id, icon_name: PGChar; category: TAppIndicatorCategory; icon_theme_path: PGChar): PAppIndicator; cdecl;
  { Set properties }
  app_indicator_set_status: procedure(self: PAppIndicator; status: TAppIndicatorStatus); cdecl;
  app_indicator_set_attention_icon: procedure(self: PAppIndicator; icon_name: PGChar); cdecl;
  app_indicator_set_menu: procedure(self: PAppIndicator; menu: PGtkMenu); cdecl;
  app_indicator_set_icon: procedure(self: PAppIndicator; icon_name: PGChar); cdecl;
  app_indicator_set_label: procedure(self: PAppIndicator; _label, guide: PGChar); cdecl;
  app_indicator_set_icon_theme_path: procedure(self: PAppIndicator; icon_theme_path: PGChar); cdecl;
  app_indicator_set_ordering_index: procedure(self: PAppIndicator; ordering_index: guint32); cdecl;
  { Get properties }
  app_indicator_get_id: function(self: PAppIndicator): PGChar; cdecl;
  app_indicator_get_category: function(self: PAppIndicator): TAppIndicatorCategory; cdecl;
  app_indicator_get_status: function(self: PAppIndicator): TAppIndicatorStatus; cdecl;
  app_indicator_get_icon: function(self: PAppIndicator): PGChar; cdecl;
  app_indicator_get_icon_theme_path: function(self: PAppIndicator): PGChar; cdecl;
  app_indicator_get_attention_icon: function(self: PAppIndicator): PGChar; cdecl;
  app_indicator_get_menu: function(self: PAppIndicator): PGtkMenu; cdecl;
  app_indicator_get_label: function(self: PAppIndicator): PGChar; cdecl;
  app_indicator_get_label_guide: function(self: PAppIndicator): PGChar; cdecl;
  app_indicator_get_ordering_index: function(self: PAppIndicator): guint32; cdecl;

{ TUnityTrayIconHandle }

type
  TUnityTrayIconHandle = class
  private
    FTrayIcon: TCustomTrayIcon;
    FName: string;
    FIconName: string;
  public
    constructor Create(TrayIcon: TCustomTrayIcon);
    destructor Destroy; override;
    procedure Update;
  end;

{ It seems to me, and please tell me otherwise if untrue, that the only way
  to load icons for AppIndicator is through files }

const
  IconThemePath = '/tmp/appindicators/';
  IconType = 'png';

{ It seems to me, and please tell me otherwise if untrue, that you can only
  create one working AppIndicator for your program over its lifetime }

var
  GlobalAppIndicator: PAppIndicator;
  GlobalIcon: Pointer;
  GlobalIconPath: string;

constructor TUnityTrayIconHandle.Create(TrayIcon: TCustomTrayIcon);
var
  NewIcon: Pointer;
begin
  inherited Create;
  FTrayIcon := TrayIcon;
  FName := 'app-' + IntToHex(IntPtr(Application), SizeOf(IntPtr) * 2);
  NewIcon := {%H-}Pointer(FTrayIcon.Icon.Handle);
  if NewIcon = nil then
    NewIcon := {%H-}Pointer(Application.Icon.Handle);
  if NewIcon <> GlobalIcon then
  begin
    GlobalIcon := NewIcon;
    ForceDirectories(IconThemePath);
    FIconName := FName + '-' + IntToHex({%H-}IntPtr(GlobalIcon), SizeOf(GlobalIcon) * 2);
    if FileExists(GlobalIconPath) then
      DeleteFile(GlobalIconPath);
    GlobalIconPath := IconThemePath + FIconName + '.' + IconType;
    gdk_pixbuf_save(GlobalIcon, PChar(GlobalIconPath), IconType, nil);
    if GlobalAppIndicator <> nil then
      app_indicator_set_icon(GlobalAppIndicator, PChar(FIconName));
  end
  else
    FIconName := FName + '-' + IntToHex({%H-}IntPtr(GlobalIcon), SizeOf(GlobalIcon) * 2);
  { Only the first created AppIndicator is functional }
  if GlobalAppIndicator = nil then
    { It seems that icons can only come from files :( }
    GlobalAppIndicator := app_indicator_new_with_path(PChar(FName), PChar(FIconName),
      APP_INDICATOR_CATEGORY_APPLICATION_STATUS, IconThemePath);
  Update;
end;

destructor TUnityTrayIconHandle.Destroy;
begin
  { Hide the global AppIndicator }
  app_indicator_set_status(GlobalAppIndicator, APP_INDICATOR_STATUS_PASSIVE);
  inherited Destroy;
end;

procedure TUnityTrayIconHandle.Update;
var
  NewIcon: Pointer;
begin
  NewIcon := {%H-}Pointer(FTrayIcon.Icon.Handle);
  if NewIcon = nil then
    NewIcon := {%H-}Pointer(Application.Icon.Handle);
  if NewIcon <> GlobalIcon then
  begin
    GlobalIcon := NewIcon;
    FIconName := FName + '-' + IntToHex({%H-}IntPtr(GlobalIcon), SizeOf(GlobalIcon) * 2);
    ForceDirectories(IconThemePath);
    if FileExists(GlobalIconPath) then
      DeleteFile(GlobalIconPath);
    GlobalIconPath := IconThemePath + FIconName + '.' + IconType;
    gdk_pixbuf_save(GlobalIcon, PChar(GlobalIconPath), IconType, nil);
    { Again it seems that icons can only come from files }
    app_indicator_set_icon(GlobalAppIndicator, PChar(FIconName));
  end;
  { It seems to me you can only set the menu once for an AppIndicator }
  if (app_indicator_get_menu(GlobalAppIndicator) = nil) and (FTrayIcon.PopUpMenu <> nil) then
    app_indicator_set_menu(GlobalAppIndicator, {%H-}PGtkMenu(FTrayIcon.PopUpMenu.Handle));
  app_indicator_set_status(GlobalAppIndicator, APP_INDICATOR_STATUS_ACTIVE);
end;

{ TUnityWSCustomTrayIcon }

class function TUnityWSCustomTrayIcon.Hide(const ATrayIcon: TCustomTrayIcon): Boolean;
var
  T: TUnityTrayIconHandle;
begin
  if ATrayIcon.Handle <> 0 then
  begin
    T := TUnityTrayIconHandle(ATrayIcon.Handle);
    ATrayIcon.Handle := 0;
    T.Free;
  end;
  Result := True;
end;

class function TUnityWSCustomTrayIcon.Show(const ATrayIcon: TCustomTrayIcon): Boolean;
var
  T: TUnityTrayIconHandle;
begin
  if ATrayIcon.Handle = 0 then
  begin
    T := TUnityTrayIconHandle.Create(ATrayIcon);
    ATrayIcon.Handle := HWND(T);
  end;
  Result := True;
end;

class procedure TUnityWSCustomTrayIcon.InternalUpdate(const ATrayIcon: TCustomTrayIcon);
var
  T: TUnityTrayIconHandle;
begin
  if ATrayIcon.Handle <> 0 then
  begin
    T := TUnityTrayIconHandle(ATrayIcon.Handle);
    T.Update;
  end;
end;

class function TUnityWSCustomTrayIcon.GetPosition(const ATrayIcon: TCustomTrayIcon): TPoint;
begin
  Result := Point(0, 0);
end;

{ UnityAppIndicatorInit }

var
  Loaded: Boolean;
  Initialized: Boolean;

function UnityAppIndicatorInit: Boolean;
var
  Module: HModule;

  function TryLoad(const ProcName: string; var Proc: Pointer): Boolean;
  begin
    Proc := GetProcAddress(Module, ProcName);
    Result := Proc <> nil;
  end;

begin
  Result := False;
  if Loaded then
    Exit(Initialized);
  Loaded:= True;
  if GetEnvironmentVariable('XDG_CURRENT_DESKTOP') <> 'Unity' then
  begin
    Initialized := False;
    Exit;
  end;
  if Initialized then
    Exit(True);
  Module := LoadLibrary(libappindicator);
  if Module = 0 then
    Exit;
  Result :=
    TryLoad('app_indicator_get_type', @app_indicator_get_type) and
    TryLoad('app_indicator_new', @app_indicator_new) and
    TryLoad('app_indicator_new_with_path', @app_indicator_new_with_path) and
    TryLoad('app_indicator_set_status', @app_indicator_set_status) and
    TryLoad('app_indicator_set_attention_icon', @app_indicator_set_attention_icon) and
    TryLoad('app_indicator_set_menu', @app_indicator_set_menu) and
    TryLoad('app_indicator_set_icon', @app_indicator_set_icon) and
    TryLoad('app_indicator_set_label', @app_indicator_set_label) and
    TryLoad('app_indicator_set_icon_theme_path', @app_indicator_set_icon_theme_path) and
    TryLoad('app_indicator_set_ordering_index', @app_indicator_set_ordering_index) and
    TryLoad('app_indicator_get_id', @app_indicator_get_id) and
    TryLoad('app_indicator_get_category', @app_indicator_get_category) and
    TryLoad('app_indicator_get_status', @app_indicator_get_status) and
    TryLoad('app_indicator_get_icon', @app_indicator_get_icon) and
    TryLoad('app_indicator_get_icon_theme_path', @app_indicator_get_icon_theme_path) and
    TryLoad('app_indicator_get_attention_icon', @app_indicator_get_attention_icon) and
    TryLoad('app_indicator_get_menu', @app_indicator_get_menu) and
    TryLoad('app_indicator_get_label', @app_indicator_get_label) and
    TryLoad('app_indicator_get_label_guide', @app_indicator_get_label_guide) and
    TryLoad('app_indicator_get_ordering_index', @app_indicator_get_ordering_index);
  Initialized := Result;
end;

initialization
  GlobalAppIndicator := nil;
  GlobalIconPath := '';
finalization
  if FileExists(GlobalIconPath) then
    DeleteFile(GlobalIconPath);
  if GlobalAppIndicator <> nil then
    g_object_unref(GlobalAppIndicator);
end.