#!/usr/bin/env python
#
# Copyright 2008,2010,2012,2013 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
#

from gnuradio import gr, gr_unittest, filter, blocks

import cmath
import math


def fir_filter(x, taps, decim=1):
    y = []
    x2 = (len(taps) - 1) * [0, ] + x
    for i in range(0, len(x), decim):
        yi = 0
        for j in range(len(taps)):
            yi += taps[len(taps) - 1 - j] * x2[i + j]
        y.append(yi)
    return y


def sig_source_s(samp_rate, freq, amp, N):
    t = [float(x) / samp_rate for x in range(N)]
    y = [int(100 * math.sin(2. * math.pi * freq * x)) for x in t]
    return y


def sig_source_c(samp_rate, freq, amp, N):
    t = [float(x) / samp_rate for x in range(N)]
    y = [math.cos(2. * math.pi * freq * x) +
         1j * math.sin(2. * math.pi * freq * x) for x in t]
    return y


def mix(lo, data):
    y = [lo_i * data_i for lo_i, data_i in zip(lo, data)]
    return y


class test_freq_xlating_filter(gr_unittest.TestCase):

    def setUp(self):
        self.tb = gr.top_block()

    def tearDown(self):
        self.tb = None

    def generate_ccf_source(self):
        self.fs = fs = 1
        self.fc = fc = 0.3
        self.bw = bw = 0.1
        self.taps = filter.firdes.low_pass(1, fs, bw, bw / 4)
        times = list(range(1024))
        self.src_data = [
            cmath.exp(-2j * cmath.pi * fc / fs * (t / 100.0)) for t in times]

    def generate_ccc_source(self):
        self.fs = fs = 1
        self.fc = fc = 0.3
        self.bw = bw = 0.1
        self.taps = filter.firdes.complex_band_pass(
            1, fs, -bw / 2, bw / 2, bw / 4)
        times = list(range(1024))
        self.src_data = [
            cmath.exp(-2j * cmath.pi * fc / fs * (t / 100.0)) for t in times]

    def assert_fft_ok(self, expected_result, result_data):
        expected_result = expected_result[:len(result_data)]
        self.assertComplexTuplesAlmostEqual2(expected_result, result_data,
                                             abs_eps=1e-9, rel_eps=2e-3)

    def test_fft_filter_ccf_001(self):
        self.generate_ccf_source()

        decim = 1
        lo = sig_source_c(self.fs, -self.fc, 1, len(self.src_data))
        despun = mix(lo, self.src_data)
        expected_data = fir_filter(despun, self.taps, decim)

        src = blocks.vector_source_c(self.src_data)
        op = filter.freq_xlating_fft_filter_ccc(
            decim, self.taps, self.fc, self.fs)
        dst = blocks.vector_sink_c()
        self.tb.connect(src, op, dst)
        self.tb.run()
        result_data = dst.data()
        self.assert_fft_ok(expected_data, result_data)

    def test_fft_filter_ccf_002(self):
        self.generate_ccf_source()

        decim = 4
        lo = sig_source_c(self.fs, -self.fc, 1, len(self.src_data))
        despun = mix(lo, self.src_data)
        expected_data = fir_filter(despun, self.taps, decim)

        src = blocks.vector_source_c(self.src_data)
        op = filter.freq_xlating_fft_filter_ccc(
            decim, self.taps, self.fc, self.fs)
        dst = blocks.vector_sink_c()
        self.tb.connect(src, op, dst)
        self.tb.run()
        result_data = dst.data()
        self.assert_fft_ok(expected_data, result_data)

    def test_fft_filter_ccc_001(self):
        self.generate_ccc_source()

        decim = 1
        lo = sig_source_c(self.fs, -self.fc, 1, len(self.src_data))
        despun = mix(lo, self.src_data)
        expected_data = fir_filter(despun, self.taps, decim)

        src = blocks.vector_source_c(self.src_data)
        op = filter.freq_xlating_fft_filter_ccc(
            decim, self.taps, self.fc, self.fs)
        dst = blocks.vector_sink_c()
        self.tb.connect(src, op, dst)
        self.tb.run()
        result_data = dst.data()
        self.assert_fft_ok(expected_data, result_data)

    def test_fft_filter_ccc_002(self):
        self.generate_ccc_source()

        decim = 4
        lo = sig_source_c(self.fs, -self.fc, 1, len(self.src_data))
        despun = mix(lo, self.src_data)
        expected_data = fir_filter(despun, self.taps, decim)

        src = blocks.vector_source_c(self.src_data)
        op = filter.freq_xlating_fft_filter_ccc(
            decim, self.taps, self.fc, self.fs)
        dst = blocks.vector_sink_c()
        self.tb.connect(src, op, dst)
        self.tb.run()
        result_data = dst.data()
        self.assert_fft_ok(expected_data, result_data)


if __name__ == '__main__':
    gr_unittest.run(test_freq_xlating_filter)
