#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Tue Dec 15 18:29:22 2020

@author: DJ2LS
"""


import ctypes
from ctypes import *
import pathlib

import binascii #required for string.to_bytes() function
import sys


def main():
    
    modem = FreeDV() #Load FreeDV Class as "modem"
      
    modem.Demodulate()

class FreeDV():
    
    def __init__(self):
        
        self.mode = 12 # define mode

        libname = pathlib.Path().absolute() / "libcodec2.so"
        self.c_lib = ctypes.CDLL(libname) # Load FreeDV shared libary
        
        self.freedv = self.c_lib.freedv_open(self.mode) #Set FreeDV waveform ( 10,11,12 --> DATA1-3 )
        
        self.bytes_per_frame = int(self.c_lib.freedv_get_bits_per_modem_frame(self.freedv)/8)  #get bytes per frame from selected waveform
        self.payload_per_frame = self.bytes_per_frame -2 #get frame payload because of 2byte CRC16 checksum
        self.n_max_modem_samples = self.c_lib.freedv_get_n_max_modem_samples(self.freedv)
        self.nin = self.c_lib.freedv_nin(self.freedv)
    
        print("N MAX MODEM SAMPLES: " + str(self.n_max_modem_samples))
        print("NIN:                 " + str(self.nin))
        print("BYTES PER FRAME:     " + str(self.bytes_per_frame))
        print("---------------------------------")
        
    # MODULATION-IN OBJECT   
    def ModulationIn(self):
        return (c_short * (self.n_max_modem_samples))  ##

    
    # Pointer for changing buffer data type 
    def FrameBytes(self):
        return (c_ubyte * self.bytes_per_frame)

        
    # Modulate function which returns modulated data   
    def Demodulate(self):
        

        nin = self.c_lib.freedv_nin(self.freedv)
        #while (self.c_lib.freedv_nin(self.freedv) == nin):
        #while sys.stdin.buffer != 0:
        while True:
            
            samples = self.c_lib.freedv_nin(self.freedv)*2 ### MIT DER *2 funktioniert das irgendwie recht zuverlässig bei mode 5! Bei Mode 12 auch
            data_in = sys.stdin.buffer.read(samples)
  
         
            #buffer = bytearray(len(self.ModulationIn()())*sizeof(c_short)) # create empty byte array  
            #buffer = bytearray(len(self.ModulationIn()())*self.n_max_modem_samples) # create empty byte array 
            buffer = bytearray(self.n_max_modem_samples*2) # N MAX SAMPLES * 2
            buffer[:len(data_in)] = data_in # copy across what we have
         
            self.ModulationIn()() #Create new ModulationIn Object
            modulation = self.ModulationIn()# get an empty modulation array
            modulation = modulation.from_buffer_copy(buffer) # copy buffer across and get a pointer to it.
            bytes_out = self.FrameBytes()() # initilize a pointer to where bytes will be outputed

            nbytes = self.c_lib.freedv_rawdatarx(self.freedv, bytes_out, data_in) # Demodulated data and get number of demodulated bytes
            #self.nin = self.c_lib.freedv_nin(self.freedv)


            # ------------- SOME DEBUGGING OUTPUT
            #print("INPUT PARSER:      " + str(samples))            
            #print("INPUT LENGTH:      " + str(len(data_in)))
            #print("BUFFER LENGTH:     " + str(len(buffer)))
            #print("MODULATION LENGTH: " + str(len(modulation)))
            
            #sync_state = self.c_lib.freedv_get_sync(self.freedv)
            #if sync_state > 0:
            #    print("SYNC")
            #else:
            #    print("NO SYNC")
            # -------------
            
            
            
            # print data to terminal if nbytes == bytes_per_frame for selected mode
            if nbytes == self.bytes_per_frame:
                print(bytes(bytes_out))
                self.c_lib.freedv_set_sync(self.freedv, 0)                      
                
            
            #Stop loop until data input is empty
            #if len(data_in) == 0:
            #    False





main()