import unittest

import numpy as np

from damaris.data.DamarisFFT import DamarisFFT


class TestDamarisFFT(unittest.TestCase):
    @staticmethod
    def make_fft():
        fft = DamarisFFT()
        fft.sampling_rate = 100.0
        fft.x = np.arange(10, dtype="float32") / 100.0
        fft.y = [np.arange(10, dtype="float32")]
        fft.xlabel = "Time / s"
        return fft

    def test_clip_without_arguments_is_placeholder(self):
        """clip() without arguments returns self unchanged (placeholder use)."""
        fft = self.make_fft()
        self.assertIs(fft.clip(), fft)
        self.assertEqual(len(fft.x), 10)
        np.testing.assert_array_equal(fft.y[0], np.arange(10, dtype="float32"))

    def test_clip_swaps_reversed_bounds(self):
        fft = self.make_fft()
        fft.clip(start=0.05, stop=0.01)
        expected_x = (np.arange(10, dtype="float32") / 100.0)[1:5]
        np.testing.assert_array_equal(fft.x, expected_x)
        np.testing.assert_array_equal(fft.y[0], np.arange(1, 5, dtype="float32"))

    def test_clip_single_bound(self):
        fft = self.make_fft()
        fft.clip(start=0.02)
        self.assertEqual(len(fft.x), 7)
        self.assertEqual(len(fft.y[0]), 7)

    def test_clip_too_close_raises(self):
        fft = self.make_fft()
        self.assertRaises(ValueError, fft.clip, 0.021, 0.029)


if __name__ == "__main__":
    unittest.main()