#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
The calibration test suite.
"""
import os

import numpy as np

from obspy import read
from obspy.signal.calibration import rel_calib_stack
from obspy.core.util.misc import TemporaryWorkingDirectory


class TestCalibration():
    """
    Calibration test case
    """
    def test_relcal_sts2_vs_unknown(self, testdata):
        """
        Test relative calibration of unknown instrument vs STS2 in the same
        time range. Window length is set to 20 s, smoothing rate to 10.
        """
        st1 = read(testdata['ref_STS2'])
        st2 = read(testdata['ref_unknown'])
        calfile = testdata['STS2_simp.cal']

        with TemporaryWorkingDirectory():
            freq, amp, phase = rel_calib_stack(st1, st2, calfile, 20,
                                               smooth=10, save_data=True)
            assert os.path.isfile("0438.EHZ.20.resp")
            assert os.path.isfile("STS2.refResp")
            freq_, amp_, phase_ = np.loadtxt("0438.EHZ.20.resp", unpack=True)
            assert np.allclose(freq, freq_, rtol=1e-8, atol=1e-8)
            assert np.allclose(amp, amp_, rtol=1e-8, atol=1e-8)
            assert np.allclose(phase, phase_, rtol=1e-8, atol=1e-8)

        # read in the reference responses
        un_resp = np.loadtxt(testdata['unknown.resp'])
        kn_resp = np.loadtxt(testdata['STS2.refResp'])

        # bug resolved with 2f9876d, arctan was used which maps to
        # [-pi/2, pi/2]. arctan2 or np.angle shall be used instead
        # correct the test data by hand
        un_resp[:, 2] = np.unwrap(un_resp[:, 2] * 2) / 2
        if False:
            import matplotlib.pyplot as plt
            plt.plot(freq, un_resp[:, 2], 'b', label='reference', alpha=.8)
            plt.plot(freq, phase, 'r', label='new', alpha=.8)
            plt.xlim(-10, None)
            plt.legend()
            plt.show()

        # test if freq, amp and phase match the reference values
        np.testing.assert_array_almost_equal(freq, un_resp[:, 0],
                                             decimal=4)
        np.testing.assert_array_almost_equal(freq, kn_resp[:, 0],
                                             decimal=4)
        np.testing.assert_array_almost_equal(amp, un_resp[:, 1],
                                             decimal=4)
        # TODO: unknown why the first frequency mismatches so much
        np.testing.assert_array_almost_equal(phase[1:], un_resp[1:, 2],
                                             decimal=4)

    def test_relcal_using_traces(self, testdata):
        """
        Tests using traces instead of stream objects as input parameters.
        """
        st1 = read(testdata['ref_STS2'])
        st2 = read(testdata['ref_unknown'])
        calfile = testdata['STS2_simp.cal']
        # stream
        freq, amp, phase = rel_calib_stack(st1, st2, calfile, 20, smooth=10,
                                           save_data=False)
        # traces
        freq2, amp2, phase2 = rel_calib_stack(st1[0], st2[0], calfile, 20,
                                              smooth=10, save_data=False)
        np.testing.assert_array_almost_equal(freq, freq2, decimal=4)
        np.testing.assert_array_almost_equal(amp, amp2, decimal=4)
        np.testing.assert_array_almost_equal(phase, phase2, decimal=4)

    def test_relcal_different_overlaps(self, testdata):
        """
        Tests using different window overlap percentages.

        Regression test for bug #1821.
        """
        st1 = read(testdata['ref_STS2'])
        st2 = read(testdata['ref_unknown'])
        calfile = testdata['STS2_simp.cal']

        def median_amplitude_plateau(freq, amp):
            # resulting response is pretty much flat in this frequency range
            return np.median(amp[(freq >= 0.3) & (freq <= 3)])

        # correct results using default overlap fraction of 0.5
        freq, amp, phase = rel_calib_stack(
            st1, st2, calfile, 20, smooth=10, overlap_frac=0.5,
            save_data=False)
        amp_expected = median_amplitude_plateau(freq, amp)
        for overlap in np.linspace(0.1, 0.9, 5):
            freq2, amp2, phase2 = rel_calib_stack(
                st1, st2, calfile, 20, smooth=10, overlap_frac=overlap,
                save_data=False)
            amp_got = median_amplitude_plateau(freq2, amp2)
            percentual_difference = abs(
                (amp_expected - amp_got) / amp_expected)
            # make sure results are close for any overlap choice
            assert percentual_difference < 0.01

    def test_relcal_using_dict(self, testdata):
        """
        Tests using paz dictionary instead of a gse2 file.
        """
        st1 = read(testdata['ref_STS2'])
        st2 = read(testdata['ref_unknown'])
        calfile = testdata['STS2_simp.cal']
        calpaz = dict()
        calpaz['poles'] = [-0.03677 + 0.03703j, -0.03677 - 0.03703j]
        calpaz['zeros'] = [0 + 0j, 0 - 0j]
        calpaz['sensitivity'] = 1500

        # stream
        freq, amp, phase = rel_calib_stack(st1, st2, calfile, 20, smooth=10,
                                           save_data=False)
        # traces
        freq2, amp2, phase2 = rel_calib_stack(st1, st2, calpaz, 20,
                                              smooth=10, save_data=False)
        np.testing.assert_array_almost_equal(freq, freq2, decimal=4)
        np.testing.assert_array_almost_equal(amp, amp2, decimal=4)
        np.testing.assert_array_almost_equal(phase, phase2, decimal=4)
