------------------------------------------------------------------------------
--                                  G P S                                   --
--                                                                          --
--                     Copyright (C) 2009-2018, AdaCore                     --
--                                                                          --
-- This is free software;  you can redistribute it  and/or modify it  under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  This software is distributed in the hope  that it will be useful, --
-- but WITHOUT ANY WARRANTY;  without even the implied warranty of MERCHAN- --
-- TABILITY 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  distributed  with  this  software;   see  file --
-- COPYING3.  If not, go to http://www.gnu.org/licenses for a complete copy --
-- of the license.                                                          --
------------------------------------------------------------------------------

with Gdk;               use Gdk;
with Gdk.Cursor;        use Gdk.Cursor;
with Gdk.Event;         use Gdk.Event;
with Gdk.Types;         use Gdk.Types;
with Gdk.Window;        use Gdk.Window;

with Gtk.Handlers;
with Gtk.Enums;  use Gtk.Enums;
with Gtk.Widget; use Gtk.Widget;

with Gtkada.Handlers; use Gtkada.Handlers;

with GNATCOLL.Traces;   use GNATCOLL.Traces;
with Src_Editor_Buffer; use Src_Editor_Buffer;
with GNATCOLL.VFS;      use GNATCOLL.VFS;

with Src_Editor_Buffer.Hyper_Mode; use Src_Editor_Buffer.Hyper_Mode;
with Gtk.Text_Iter; use Gtk.Text_Iter;

with GPS.Kernel.Hyper_Mode; use GPS.Kernel.Hyper_Mode;

package body Src_Editor_View.Hyper_Mode is

   Me : constant Trace_Handle := Create
     ("GPS.SOURCE_EDITOR.HYPER_MODE", GNATCOLL.Traces.Off);

   ---------------
   -- Callbacks --
   ---------------

   function Button_Press_Event_Cb
     (Widget : access Gtk_Widget_Record'Class;
      Event  : Gdk_Event) return Boolean;

   function Motion_Notify_Event_Cb
     (Widget : access Gtk_Widget_Record'Class;
      Event  : Gdk_Event) return Boolean;

   -----------------------
   -- Local subprograms --
   -----------------------

   procedure Hyper_Mode_Enter (Widget : access Gtk_Widget_Record'Class);
   --  Put View in hyper mode

   procedure Hyper_Mode_Leave (Widget : access Gtk_Widget_Record'Class);
   --  Leave hyper mode

   function Name (View : Source_View) return String;
   --  Return a name for View, for debugging purposes

   procedure Highlight_On (View : Source_View; X, Y : Gint);
   --  Highlight text at position X, Y

   ----------
   -- Name --
   ----------

   function Name (View : Source_View) return String is
   begin
      return (+Base_Name (Source_Buffer (Get_Buffer (View)).Get_Filename));
   end Name;

   ----------------------
   -- Hyper_Mode_Enter --
   ----------------------

   procedure Hyper_Mode_Enter (Widget : access Gtk_Widget_Record'Class) is
      View   : constant Source_View   := Source_View (Widget);
   begin
      if View.Hyper_Mode then
         return;
      end if;

      View.Hyper_Mode := True;
      View.Cursor_Needs_Change := True;

      if Active (Me) then
         Trace (Me, "HYPER MODE ENTER " & Name (View));
      end if;

      Hyper_Mode_Enter (Source_Buffer (Get_Buffer (View)));

      --  Connect the motion handler
      View.Hyper_Mode_Motion_Handler :=
        Return_Callback.Connect
          (View, Signal_Motion_Notify_Event,
           Marsh => Return_Callback.To_Marshaller
             (Motion_Notify_Event_Cb'Access),
           After => False);

      --  Connect to a button press on the view

      View.Hyper_Mode_Button_Handler :=
        Return_Callback.Connect
          (View, Signal_Button_Press_Event,
           Marsh => Return_Callback.To_Marshaller
             (Button_Press_Event_Cb'Access),
           After => False);
   end Hyper_Mode_Enter;

   ----------------------
   -- Hyper_Mode_Leave --
   ----------------------

   Text_View_Cursor : Gdk.Gdk_Cursor;
   --  This is set as a global variable in order to avoid memory leaks.
   --  See comments in body of GUI_Utils.Set_Busy_Cursor.

   procedure Hyper_Mode_Leave (Widget : access Gtk_Widget_Record'Class) is
      View   : constant Source_View   := Source_View (Widget);
   begin
      if not View.Hyper_Mode then
         return;
      end if;

      View.Hyper_Mode := False;

      if Active (Me) then
         Trace (Me, "HYPER MODE LEAVE " & Name (View));
      end if;

      if Text_View_Cursor = null then
         Gdk_New (Text_View_Cursor, Xterm);
      end if;

      if not In_Destruction (View)
        and then not View.Cursor_Needs_Change
      then
         Set_Cursor (Get_Window (View, Text_Window_Text), Text_View_Cursor);
      end if;

      View.Cursor_Needs_Change := False;

      Hyper_Mode_Leave (Source_Buffer (Get_Buffer (View)));

      --  Disconnect the motion handler
      Gtk.Handlers.Disconnect (View, View.Hyper_Mode_Motion_Handler);
      View.Hyper_Mode_Motion_Handler :=
        (Gtk.Handlers.Null_Handler_Id, null);

      --  Disconnect the button handler
      Gtk.Handlers.Disconnect (View, View.Hyper_Mode_Button_Handler);
      View.Hyper_Mode_Button_Handler :=
        (Gtk.Handlers.Null_Handler_Id, null);
   end Hyper_Mode_Leave;

   -------------------------
   -- Activate_Hyper_Mode --
   -------------------------

   procedure Activate_Hyper_Mode (View : access Source_View_Record) is
   begin
      Enable_Hyper_Mode (Kernel              => View.Kernel,
                         Widget              => Gtk_Widget (View),
                         On_Hyper_Mode_Enter => Hyper_Mode_Enter'Access,
                         On_Hyper_Mode_Leave => Hyper_Mode_Leave'Access);
   end Activate_Hyper_Mode;

   ---------------------------
   -- Button_Press_Event_Cb --
   ---------------------------

   function Button_Press_Event_Cb
     (Widget : access Gtk_Widget_Record'Class;
      Event  : Gdk_Event) return Boolean
   is
      View      : constant Source_View   := Source_View (Widget);
      Button    : Guint;
   begin
      if not View.Hyper_Mode then
         return False;
      end if;

      Button := Get_Button (Event);

      if Button not in 1 .. 2 then
         return False;
      end if;

      declare
         X, Y : Gint;
      begin
         Get_Pointer (View, X, Y);
         Highlight_On (View, X, Y);
      end;

      Hyper_Mode_Click_On
        (Source_Buffer (Get_Buffer (View)),
         Project   => Get_Project (View),
         Alternate => Button = 2);

      return True;
   exception
      when E : others =>
         Trace (Me, E);
         return False;
   end Button_Press_Event_Cb;

   ------------------
   -- Highlight_On --
   ------------------

   procedure Highlight_On (View : Source_View; X, Y : Gint) is
      Line, Column : Gint;
      Iter         : Gtk_Text_Iter;
      Out_Of_Bounds : Boolean := False;
   begin
      Window_To_Buffer_Coords
        (View,
         X - Get_Border_Window_Size (View, Text_Window_Left),
         Y - Get_Border_Window_Size (View, Text_Window_Top),
         Line, Column, Out_Of_Bounds);
      Get_Iter_At_Line_Offset
        (Source_Buffer (Get_Buffer (View)), Iter, Line, Column);

      if Out_Of_Bounds then
         Remove_Highlight (Source_Buffer (Get_Buffer (View)));
      else
         Hyper_Mode_Highlight_On (Source_Buffer (Get_Buffer (View)), Iter);
      end if;
   end Highlight_On;

   ----------------------------
   -- Motion_Notify_Event_Cb --
   ----------------------------

   function Motion_Notify_Event_Cb
     (Widget : access Gtk_Widget_Record'Class;
      Event  : Gdk_Event) return Boolean
   is
      View  : constant Source_View := Source_View (Widget);
      X, Y  : Gint;

   begin
      if Active (Me) then
         Trace (Me, "motion_notify " & Name (View));
      end if;

      --  Safety check, just in case we left hyper mode while GPS did not have
      --  the focus
      if (Get_State (Event) and Control_Mask) = 0 then
         Hyper_Mode_Leave (Widget);
         return False;
      end if;

      if View.Cursor_Needs_Change then
         Set_Cursor (Get_Window (View, Text_Window_Text), null);
         View.Cursor_Needs_Change := False;
      end if;

      --  Call Get_Pointer first, since Gtk+ is waiting for this call in order
      --  to be able to propagate further "motion_notify" events.
      Get_Pointer (View, X, Y);

      if not View.Hyper_Mode then
         return False;
      end if;

      Highlight_On (View, X, Y);

      return False;
   exception
      when E : others =>
         Trace (Me, E);
         return False;
   end Motion_Notify_Event_Cb;

end Src_Editor_View.Hyper_Mode;
