<?xml version="1.0" encoding="UTF-8"?>
<protocol name="xdg_toplevel_drag_v1">

  <copyright>
    Copyright 2023 David Redondo

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice (including the next
    paragraph) shall be included in all copies or substantial portions of the
    Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
  </copyright>

  <interface name="xdg_toplevel_drag_manager_v1" version="1">
    <description summary="Move a window during a drag">
      This protocol enhances normal drag and drop with the ability to move a
      window at the same time. This allows having detachable parts of a window
      that when dragged out of it become a new window and can be dragged over
      an existing window to be reattached.

      A typical workflow would be when the user starts dragging on top of a
      detachable part of a window, the client would create a wl_data_source and
      a xdg_toplevel_drag_v1 object and start the drag as normal via
      wl_data_device.start_drag. Once the client determines that the detachable
      window contents should be detached from the originating window, it creates
      a new xdg_toplevel with these contents and issues a
      xdg_toplevel_drag_v1.attach request before mapping it. From now on the new
      window is moved by the compositor during the drag as if the client called
      xdg_toplevel.move.

      Dragging an existing window is similar. The client creates a
      xdg_toplevel_drag_v1 object and attaches the existing toplevel before
      starting the drag.

      Clients use the existing drag and drop mechanism to detect when a window
      can be docked or undocked. If the client wants to snap a window into a
      parent window it should delete or unmap the dragged top-level. If the
      contents should be detached again it attaches a new toplevel as described
      above. If a drag operation is cancelled without being dropped, clients
      should revert to the previous state, deleting any newly created windows
      as appropriate. When a drag operation ends as indicated by
      wl_data_source.dnd_drop_performed the dragged toplevel window's final
      position is determined as if a xdg_toplevel_move operation ended.

      Warning! The protocol described in this file is currently in the testing
      phase. Backward compatible changes may be added together with the
      corresponding interface version bump. Backward incompatible changes can
      only be done by creating a new major version of the extension.
    </description>

    <enum name="error">
      <entry name="invalid_source" value="0"
             summary="data_source already used for toplevel drag"/>
    </enum>

    <request name="destroy" type="destructor">
      <description summary="destroy the xdg_toplevel_drag_manager_v1 object">
        Destroy this xdg_toplevel_drag_manager_v1 object. Other objects,
        including xdg_toplevel_drag_v1 objects created by this factory, are not
        affected by this request.
      </description>
    </request>

    <request name="get_xdg_toplevel_drag">
      <description summary="get an xdg_toplevel_drag for a wl_data_source">
        Create an xdg_toplevel_drag for a drag and drop operation that is going
        to be started with data_source.

        This request can only be made on sources used in drag-and-drop, so it
        must be performed before wl_data_device.start_drag. Attempting to use
        the source other than for drag-and-drop such as in
        wl_data_device.set_selection will raise an invalid_source error.

        Destroying data_source while a toplevel is attached to the
        xdg_toplevel_drag is undefined.
      </description>

      <arg name="id" type="new_id" interface="xdg_toplevel_drag_v1"/>
      <arg name="data_source" type="object" interface="wl_data_source"/>
    </request>
  </interface>

  <interface name="xdg_toplevel_drag_v1" version="1">
    <description summary="Object representing a toplevel move during a drag">
    </description>

    <enum name="error">
      <entry name="toplevel_attached" value="0"
             summary="valid toplevel already attached"/>
      <entry name="ongoing_drag" value="1"
             summary="drag has not ended" />
    </enum>

    <request name="destroy" type="destructor">
      <description summary="destroy an xdg_toplevel_drag_v1 object">
        Destroy this xdg_toplevel_drag_v1 object. This request must only be
        called after the underlying wl_data_source drag has ended, as indicated
        by the dnd_drop_performed or cancelled events. In any other case an
        ongoing_drag error is raised.
      </description>
    </request>

    <request name="attach">
      <description summary="Move a toplevel with the drag operation">
        Request that the window will be moved with the cursor during the drag
        operation. The offset is a hint to the compositor how the toplevel
        should be positioned relative to the cursor hotspot in surface local
        coordinates. For example it might only be used when an unmapped window
        is attached. The attached window does not participate in the selection
        of the drag target.

        If the toplevel is unmapped while it is attached, it is automatically
        detached from the drag. In this case this request has to be called again
        if the window should be attached after it is remapped.

        This request can be called multiple times but issuing it while a
        toplevel with an active role is attached raises a toplevel_attached
        error.
      </description>

      <arg name="toplevel" type="object" interface="xdg_toplevel"/>
      <arg name="x_offset" type="int" summary="dragged surface x offset"/>
      <arg name="y_offset" type="int" summary="dragged surface y offset"/>
    </request>

  </interface>
</protocol>

