#!/usr/bin/env python
#
# Adds additional components to the input file, which is
# an array of complex floats, and save it as a new file
#
# Licence: see LICENCE file

import numpy as np
import matplotlib.pyplot as pp
import sys

if len(sys.argv) != 3:
    print("Usage")
    print(" script <filename_input> <filename_output>")
    print(" input and output files are fc64 format")
    sys.exit(1)

file_in = sys.argv[1]
file_out = sys.argv[2]


# Simulate the channel with several components,
# shifted by some number of samples and multiplied by
# the amplitude
#
# The (0, 1.0) component is always present
CIR = [(14, 0.4), (25, 0.3)]

print("Simulate channel {}".format(CIR))

maxdelay = max(delay for delay, ampl in CIR)


original_iq = np.fromfile(file_in, np.complex64)

original_iq_extended = np.append(original_iq, np.zeros(maxdelay, dtype=np.complex64))

channel_out = original_iq_extended

for delay, ampl in CIR:
    print("Add component {}".format(delay))
    channel_out += np.append(np.zeros(delay, dtype=np.complex64), ampl * original_iq_extended[:-delay])


# The simulated channel output is in channel_out

channel_out.tofile(file_out)