#!/usr/bin/python3
#
# Copyright 2013 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
#

from gnuradio import gr, filter
from gnuradio import analog
from gnuradio import blocks
from gnuradio import eng_notation
from gnuradio.eng_arg import eng_float, intx
from argparse import ArgumentParser
import sys
import numpy

try:
    from matplotlib import pyplot
except ImportError:
    print("Error: could not from matplotlib import pyplot (http://matplotlib.sourceforge.net/)")
    sys.exit(1)

class example_fir_filter_fff(gr.top_block):
    def __init__(self, N, fs, bw, tw, atten, D):
        gr.top_block.__init__(self)

        self._nsamps = N
        self._fs = fs
        self._bw = bw
        self._tw = tw
        self._at = atten
        self._decim = D
        taps = filter.firdes.low_pass_2(1, self._fs, self._bw, self._tw, self._at)
        print("Num. Taps: ", len(taps))

        self.src  = analog.noise_source_f(analog.GR_GAUSSIAN, 1)
        self.head = blocks.head(gr.sizeof_float, self._nsamps)

        self.filt0 = filter.fir_filter_fff(self._decim, taps)

        self.vsnk_src = blocks.vector_sink_f()
        self.vsnk_out = blocks.vector_sink_f()

        self.connect(self.src, self.head, self.vsnk_src)
        self.connect(self.head, self.filt0, self.vsnk_out)

def main():
    parser = ArgumentParser(conflict_handler="resolve")
    parser.add_argument("-N", "--nsamples", type=int, default=10000,
                      help="Number of samples to process [default=%(default)r]")
    parser.add_argument("-s", "--samplerate", type=eng_float, default=8000,
                      help="System sample rate [default=%(default)r]")
    parser.add_argument("-B", "--bandwidth", type=eng_float, default=1000,
                      help="Filter bandwidth [default=%(default)r]")
    parser.add_argument("-T", "--transition", type=eng_float, default=100,
                      help="Transition band [default=%(default)r]")
    parser.add_argument("-A", "--attenuation", type=eng_float, default=80,
                      help="Stopband attenuation [default=%(default)r]")
    parser.add_argument("-D", "--decimation", type=int, default=1,
                      help="Decmation factor [default=%(default)r]")
    args = parser.parse_args()

    put = example_fir_filter_fff(args.nsamples,
                                 args.samplerate,
                                 args.bandwidth,
                                 args.transition,
                                 args.attenuation,
                                 args.decimation)
    put.run()

    data_src = numpy.array(put.vsnk_src.data())
    data_snk = numpy.array(put.vsnk_out.data())

    # Plot the signals PSDs
    nfft = 1024
    f1 = pyplot.figure(1, figsize=(12,10))
    s1 = f1.add_subplot(1,1,1)
    s1.psd(data_src, NFFT=nfft, noverlap=nfft / 4,
           Fs=args.samplerate)
    s1.psd(data_snk, NFFT=nfft, noverlap=nfft / 4,
           Fs=args.samplerate)

    f2 = pyplot.figure(2, figsize=(12,10))
    s2 = f2.add_subplot(1,1,1)
    s2.plot(data_src)
    s2.plot(data_snk.real, 'g')

    pyplot.show()

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        pass

