from .mode import Mode
from .opengl_widget import set_current_points, set_drawing_event
from .points import PointSet

# Size of point for drawing
__POINT_SIZE = 8

# There are a lot of module-global variables being used because of the
# nature of state management in OpenGL.
__point_set = PointSet(__POINT_SIZE)

def __refresh_point_list(ctx):
    """
    Refreshes the point list display.

    @param ctx A handle to the window context.
    """
    # In order to make some guarantees and avoid duplicate
    # data we will clear the point list widget and re-populate
    # it using the current __point_set.
    ctx.point_list_widget.clear()

    for p in __point_set.points:
        ctx.point_list_widget.addItem("({}, {})".format(p.x, p.y))


def __handle_add_point(ctx, event):
    """
    Event handler for the add point mode.

    Sets the drawing mode for the OpenGL Widget using
    `set_drawing_mode`, converts a point to our point
    representation, and adds it to the list.

    @param ctx A context handle to the main window.
    @param event The click event.
    """
    global __point_set

    # No attribute at the moment.
    __point_set.add_point(event.x(), event.y())

    __refresh_point_list(ctx)

    set_drawing_event(event)
    set_current_points(__point_set)

    ctx.opengl_widget.update()
    ctx.point_list_widget.update()


def __handle_edit_point(ctx, event):
    # TODO: This function and delete definitely need to make sure they are
    #       on a point we have.
    #
    # Since points are unique consider a hashmap of points to make O(1)
    # lookups for addition and deletion. This list can be maintained here
    # in this module. It should be a dictionary - from point to
    # attributes in the case of algorithms that require points to have
    # weights or something.
    #
    # Should move the associated point in the list to the new location if
    # applicable.

    # Store old x, y from event
    set_drawing_event(event)
    ctx.update()
    # after this remove the point from the list

def __handle_move_points(ctx, event):
    # TODO: Should move the associated points in the list to the new location.
    # Store list of old points that are captured

    set_drawing_event(event)
    ctx.update()
    # Find and move all points from the old list to their new locations

def __handle_delete_point(ctx, event):
    set_drawing_event(event)

    __point_set.remove_point(event.x(), event.y())

    __refresh_point_list(ctx)

    ctx.opengl_widget.update()
    ctx.point_list_widget.update()

# Simple dispatcher to make it easy to dispatch the right mode
# function when the OpenGL window is clicked.
MODE_HANDLER_MAP = {
    Mode.OFF: lambda: None,
    Mode.ADD: __handle_add_point,
    Mode.EDIT: __handle_edit_point,
    Mode.MOVE: __handle_move_points,
    Mode.DELETE: __handle_delete_point
}