#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import ctypes
from ctypes import *
import sys
import pathlib
from enum import Enum
import numpy as np

print("loading codec2 module", file=sys.stderr)


# Enum for codec2 modes
class FREEDV_MODE(Enum):
    datac0 = 14
    datac1 = 10
    datac3 = 12
    
def FREEDV_GET_MODE(mode):
    return FREEDV_MODE[mode].value

class audio_buffer:
    # a buffer of int16 samples, using a fixed length numpy array self.buffer for storage
    # self.nbuffer is the current number of samples in the buffer
    def __init__(self, size):
        print("create audio_buffer: ", size)
        self.size = size
        self.buffer = np.zeros(size, dtype=np.int16)
        self.nbuffer = 0
    def push(self,samples):
        # add samples at the end of the buffer
        assert self.nbuffer+len(samples) <= self.size
        self.buffer[self.nbuffer:self.nbuffer+len(samples)] = samples
        self.nbuffer += len(samples)
    def pop(self,size):
        # remove samples from the start of the buffer
        self.nbuffer -= size;
        self.buffer[:self.nbuffer] = self.buffer[size:size+self.nbuffer]
        assert self.nbuffer >= 0
               
# LOAD FREEDV
libname = "libcodec2.so"
api = ctypes.CDLL(libname)


# ctypes function init        

api.freedv_open.argype = [c_int]
api.freedv_open.restype = c_void_p

api.freedv_get_bits_per_modem_frame.argtype = [c_void_p]
api.freedv_get_bits_per_modem_frame.restype = c_int

api.freedv_nin.argtype = [c_void_p]
api.freedv_nin.restype = c_int

api.freedv_rawdatarx.argtype = [c_void_p, c_char_p, c_char_p]
api.freedv_rawdatarx.restype = c_int

api.freedv_rawdatatx.argtype = [c_void_p, c_char_p, c_char_p]
api.freedv_rawdatatx.restype = c_int

api.freedv_rawdatapostambletx.argtype = [c_void_p, c_char_p, c_char_p]
api.freedv_rawdatapostambletx.restype = c_int

api.freedv_rawdatapreambletx.argtype = [c_void_p, c_char_p, c_char_p]
api.freedv_rawdatapreambletx.restype = c_int

api.freedv_get_n_max_modem_samples.argtype = [c_void_p]
api.freedv_get_n_max_modem_samples.restype = c_int

api.freedv_set_frames_per_burst.argtype = [c_void_p, c_int]
api.freedv_set_frames_per_burst.restype = c_void_p
      
api.freedv_get_rx_status.argtype = [c_void_p]
api.freedv_get_rx_status.restype = c_int  

api.freedv_get_modem_stats.argtype = [c_void_p, c_void_p, c_void_p]
api.freedv_get_modem_stats.restype = c_int

api.freedv_get_n_tx_postamble_modem_samples.argtype = [c_void_p]
api.freedv_get_n_tx_postamble_modem_samples.restype = c_int 

api.freedv_get_n_tx_preamble_modem_samples.argtype = [c_void_p]
api.freedv_get_n_tx_preamble_modem_samples.restype = c_int 

api.freedv_get_n_tx_modem_samples.argtype = [c_void_p]
api.freedv_get_n_tx_modem_samples.restype = c_int 

api.freedv_get_n_max_modem_samples.argtype = [c_void_p]
api.freedv_get_n_max_modem_samples.restype = c_int 

api.FREEDV_FS_8000 = 8000
api.FREEDV_MODE_DATAC1 = 10
api.FREEDV_MODE_DATAC3 = 12
api.FREEDV_MODE_DATAC0 = 14

# Return code flags for freedv_get_rx_status() function
api.FREEDV_RX_TRIAL_SYNC = 0x1       # demodulator has trial sync
api.FREEDV_RX_SYNC       = 0x2       # demodulator has sync
api.FREEDV_RX_BITS       = 0x4       # data bits have been returned
api.FREEDV_RX_BIT_ERRORS = 0x8       # FEC may not have corrected all bit errors (not all parity checks OK)

api.rx_sync_flags_to_text = [
    "----",
    "---T",
    "--S-",
    "--ST",
    "-B--",
    "-B-T",
    "-BS-",
    "-BST",
    "E---",
    "E--T",
    "E-S-",
    "E-ST",
    "EB--",
    "EB-T",
    "EBS-",
    "EBST"]


# resampler ---------------------------------------------------------

api.FDMDV_OS_48         = 6                                       # oversampling rate
api.FDMDV_OS_TAPS_48K   = 48                                      # number of OS filter taps at 48kHz
api.FDMDV_OS_TAPS_48_8K = (api.FDMDV_OS_TAPS_48K/api.FDMDV_OS_48) # number of OS filter taps at 8kHz
api.fdmdv_8_to_48_short.argtype = [c_void_p, c_void_p, c_int]
api.fdmdv_48_to_8_short.argtype = [c_void_p, c_void_p, c_int]