# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!

""" Defines the PointMarker tool class.
"""


# Major library imports
from numpy import array, take, transpose

# Enthought library imports
from enable.api import BaseTool, ColorTrait
from traits.api import Enum, Float


class PointMarker(BaseTool):
    """This tool looks at an XY plot's index data source and draws a
    line corresponding to the index indicated by the "selections" metadata.
    """

    #: The axis that this tool is parallel to.
    axis = Enum("index", "value")

    #: This tool is visible (overrides BaseTool).
    visible = True
    #: This tool is drawn as an overlay (overrides BaseTool).
    draw_mode = "overlay"

    # TODO:STYLE

    #: The color of the line.
    color = ColorTrait("red")
    #: The width of the line, in pixels.
    line_width = Float(1.0)

    def draw(self, gc, view_bounds=None):
        """Draws this tool on a graphics context.

        Implements BaseTool.
        """
        # Draw the component in interactive mode
        plot = self.component
        if plot is not None:
            # selections should be a list of indices on the datasource
            indices = getattr(plot, self.axis).metadata["selections"]

            if len(indices) == 0:
                return

            index_pts = take(plot.index.get_data(), indices)
            value_pts = take(plot.value.get_data(), indices)
            data_pts = transpose(array((index_pts, value_pts)))
            screen_pts = plot.map_screen(data_pts)

            if self.axis == "index":
                if plot.orientation == "h":
                    self._draw_vertical_lines(gc, screen_pts)
                else:
                    self._draw_horizontal_lines(gc, screen_pts)
            else:  # self.axis == "value"
                if plot.orientation == "h":
                    self._draw_horizontal_lines(gc, screen_pts)
                else:
                    self._draw_vertical_lines(gc, screen_pts)

    # ------------------------------------------------------------------------
    # Private methods
    # ------------------------------------------------------------------------

    def _draw_vertical_lines(self, gc, points):
        with gc:
            gc.set_stroke_color(self.color_)
            for pt in points:
                gc.move_to(int(pt[0]) + 0.5, self.component.y)
                gc.line_to(int(pt[0]) + 0.5, self.component.y2)
            gc.stroke_path()

    def _draw_horizontal_lines(self, gc, points):
        with gc:
            gc.set_stroke_color(self.color_)
            for pt in points:
                gc.move_to(self.component.x, int(pt[1]) + 0.5)
                gc.line_to(self.component.x2, int(pt[1]) + 0.5)
            gc.stroke_path()