# (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!

"""
Test cases for the LinePlot's hittest() function
"""

import unittest
from numpy import arange, array, linalg
from chaco.api import (
    ArrayDataSource,
    ArrayPlotData,
    Plot,
    LinearMapper,
    DataRange1D,
)


class HittestTestCase(unittest.TestCase):
    def make_plot(self, orientation):
        # make some data points
        x = arange(3)
        x = ArrayDataSource(x, sort_order="ascending")
        y = array([2, 0, 1])

        # Plot the data
        pd = ArrayPlotData(x=x, y=y)

        plot = Plot(pd, orientation=orientation)
        line_plot = plot.plot(("x", "y"))[0]

        # Construct a fake screen space for the plots
        # otherwise would need to actually display the plots to get this
        index_mapper = LinearMapper(
            data_range=DataRange1D(low=0, high=2), high_pos=380, low_pos=20
        )
        value_mapper = LinearMapper(
            data_range=DataRange1D(low=0, high=2), high_pos=380, low_pos=20
        )
        plot.index_mapper = index_mapper
        plot.value_mapper = value_mapper
        line_plot.index_mapper = index_mapper
        line_plot.value_mapper = value_mapper

        return plot, line_plot

    def test_horizontal(self):
        plot, line_plot = self.make_plot("h")

        self._test_plot(plot, line_plot, point=[0.5, 1])
        self._test_plot(plot, line_plot, point=[1, 0])

    def test_vertical(self):
        plot, line_plot = self.make_plot("v")

        self._test_plot(plot, line_plot, point=[0.5, 1])
        self._test_plot(plot, line_plot, point=[1, 0])

    def _test_plot(self, plot, line_plot, point):
        threshold = 2  # In pixels

        screen_pt = plot.map_screen(point).flatten()
        result = line_plot.hittest(screen_pt, threshold=threshold)

        self.assertTrue(result is not None)

        # Check that the result is close by threshold in screenspace
        screen_result = plot.map_screen(result)

        self.assertTrue(linalg.norm(screen_pt - screen_result) < threshold)

        # check the return_distance = True case:
        x, y, d = line_plot.hittest(
            screen_pt, threshold=threshold, return_distance=True
        )
        self.assertEqual(x, result[0])
        self.assertEqual(y, result[1])
        self.assertTrue(d < threshold)