""" Defines the DataPrinter tool class.
"""

from __future__ import print_function

# Enthought library imports
from traits.api import Str
from enable.api import BaseTool

# Chaco imports
from chaco.base_xy_plot import BaseXYPlot


class DataPrinter(BaseTool):
    """ Simple listener tool that prints the (x,y) data space position of the
    point under the cursor.
    """

    #: This tool is a listener and does not display anything
    visible = False

    #: Turn off drawing, because the tool prints to stdout.
    draw_mode = "none"

    #: The string to format the (x,y) value in data space.
    format = Str("(%.3f, %.3f)")

    def normal_mouse_move(self, event):
        """ Handles the mouse being moved in the 'normal' state.

        Prints the data space position of the current mouse position.
        """
        plot = self.component
        if plot is not None:
            if isinstance(plot, BaseXYPlot):
                text = self._build_text_from_event(event)
                print(text)
            else:
                msg = "dataprinter: don't know how to handle plots of type {}"
                print(msg.format(plot.__class__.__name__))
        return

    def _build_text_from_event(self, event):
        """ Build the text to display from the mouse event.
        """
        plot = self.component
        ndx = plot.map_index((event.x, event.y), index_only=True)
        x = plot.index.get_data()[ndx]
        y = plot.value.get_data()[ndx]
        return self.format % (x, y)