"""
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
import pmt
global param_1

class my_block(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block
    """my msg splitter"""

    def __init__(self, LO_1=1.0):
        gr.sync_block.__init__(self, 
                 name = "Message splitter",
                 in_sig = None,
                 out_sig = None)
        self.message_port_register_in(pmt.intern('msg_in'))
        self.message_port_register_out(pmt.intern('LO_1'))
        #self.message_port_register_out(pmt.intern('LO_2'))
        self.set_msg_handler(pmt.intern('msg_in'), self.handle_msg)
        # if an attribute with the same name as a parameter is found,
        # a callback is registered (properties work, too).
        self.param_1= LO_1
        #self.param_2= LO_2
        
    def handle_msg(self, msg):
        print ("in--> ", (msg), pmt.cdr(msg))
        #freq_in_tag = pmt.car(msg)
        freq_in_value = pmt.to_double(pmt.cdr(msg))
        new_freq = freq_in_value - self.param_1 + 0.5
        #new_freq = freq_in_value
        #new_msg = pmt.set_cdr(msg, pmt.from_double(new_freq))
        x = pmt.string_to_symbol("freq")
        y = pmt.from_double(new_freq)
        new_msg = pmt.cons(x, y)
        print ("out--> ", new_msg, freq_in_value)
                
        self.message_port_pub(pmt.intern('LO_1'), msg)
        #self.message_port_pub(pmt.intern('LO_2'), new_msg)
        

    def work(self, input_items, output_items):
        output_items[0][:] = input_items[0]
        return len(output_items[0])