"""
This plugin improves the behavior of Left and Right arrow keys
when navigating in a tree, for instance the project explorer.

It brings a behavior similar to the Windows default, that is:
  - Right expands the current node, and then selects its first child
    The Down key does not expand before it moves the cursor down.

  - Left collapse the current node if it is expanded otherwise it moves
    the cursor to the parent node.
"""

import GPS
from gs_utils import interactive
from gi.repository import Gtk


logger = GPS.Logger("treemove")


def current_tree():
    """Return the current tree widget and path that has the focus or None"""
    for widget in Gtk.Window.list_toplevels():
        if widget.is_active():
            result = widget.get_focus()
            if isinstance(result, Gtk.TreeView):
                # Disable these actions for the call graph tree
                if "Call Graph" in result.get_name():
                    return None
                else:
                    return result, result.get_cursor()[0]
            return None
    return None


@interactive(
    category="General", filter=lambda x: current_tree() is not None, key="Left"
)
def move_cursor_up_or_collapse():
    tree, path = current_tree()
    if tree and path:
        if tree.row_expanded(path):
            # The current cursor is on an expanded row, so collapse
            # the row
            logger.log("collapse row %s" % path)
            tree.collapse_row(path)
        else:
            # The current cursor is not on an expanded row so try to
            # to move up to the parent node.
            path.up()
        if path:
            # Check that path is valid as path.up on the root
            # node might return an invalid path ?
            tree.set_cursor(path, tree.get_column(0))


@interactive(
    category="General", filter=lambda x: current_tree() is not None, key="Right"
)
def expand_and_move_cursor_down():
    tree, path = current_tree()
    if tree and path:
        logger.log("expand row %s" % path)
        if tree.row_expanded(path):
            path.down()
        else:
            tree.expand_row(path, False)
        tree.set_cursor(path, tree.get_column(0))
