"""
Embedded Python Blocks:

Each time this file is saved, GRC will instantiate the first class it finds
to get ports and parameters of your block. The arguments to __init__  will
be the parameters. All of them are required to have default values!
"""

import numpy as np
from gnuradio import gr


class blk(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block
    """Embedded Python Block example - a simple multiply const"""

    def __init__(self, center_freq=1850e6, fft_size=1024, freq_range=5e6):  # only default arguments here
        """arguments to this function show up as parameters in GRC"""
        gr.sync_block.__init__(
            self,
            name='Embedded Python Block',   # will show up in GRC
            in_sig=[np.short],
            out_sig=[np.float32]
        )
        # if an attribute with the same name as a parameter is found,
        # a callback is registered (properties work, too).
        self.center_freq = center_freq
        self.fft_size = fft_size
        self.freq_range = freq_range

    def work(self, input_items, output_items):
        if (input_items[0] >= (self.fft_size/2)).all():
            output_items[0][:] = (self.freq_range * (input_items[0] - self.fft_size/2) / self.fft_size + self.center_freq - self.freq_range/2) / 1e6
        else:
            output_items[0][:] = (self.freq_range * input_items[0] / self.fft_size + self.center_freq) / 1e6
        return len(output_items[0])