import os
import time
import struct
import socket
import pyodbc
import logging
import datetime

UDP_IP = '192.168.10.2'
UDP_PORT = 4007


def rawbytes(s):
    """
    Convert a string to raw bytes without encoding
    Used to convert the encoded string message for the radio into a byte array
    """
    outlist = []
    for cp in s:
        num = ord(cp)
        if num < 255:
            outlist.append(struct.pack('B', num))
        elif num < 65535:
            outlist.append(struct.pack('>H', num))
        else:
            b = (num & 0xFF0000) >> 16
            H = num & 0xFFFF
            outlist.append(struct.pack('>bH', b, H))
    return b''.join(outlist)


def decode_message(message):
    """
    decode the string message coming from the radio
    """
    # header = message[:message.index(b'\n')]
    header = message[:6]
    ret = message[6:].replace(b'\x00', b'')
    return header, ret.decode(errors='ignore').strip()


def recv_message(cursor, conn, udp_ip=UDP_IP, udp_port=UDP_PORT):
    """
    listen for messages then generate ack and send it
    """
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind((udp_ip, udp_port))
    while True:
        data, addr = sock.recvfrom(1024)
        header, decoded_message = decode_message(data)
        if len(header) == 6:
            print('Recieved {} from {}:{}'.format(
                decoded_message, addr[0], addr[1]))
            # time.sleep(1)
            send_ack(generate_ack(header), sock, addr[0], addr[1])
            push_to_db(cursor, conn, decoded_message, addr[0])


def push_to_db(cursor, conn, decoded_message, radio_id):
    cursor.execute('insert into messages (radio_id, message_type, message_text, timestamp) values(?, ?, ?, ?)',
                   205, 'Text', decoded_message, datetime.datetime.now())
    conn.commit()


def generate_ack(header):
    """
    generate ack for message
    """
    msg_header_2 = bin(header[5])[2:]
    extension = 0

    if msg_header_2[1:3] != '00':
        extension = 1
        seq_extension = msg_header_2[1:3]
        ack_header_3 = '0{}00000'.format(seq_extension)
        ack_message_size = '0000000000000100'
    else:
        ack_header_3 = ''
        ack_message_size = '0000000000000011'

    seq_num = bin(header[4])[2:][3:]
    ack_header_1 = '10011111'
    ack_header_2 = '{}00{}'.format(extension, seq_num)
    address_size = '00000000'
    print(ack_message_size[:8], ack_message_size[8:], ack_header_1,
          address_size, ack_header_2, ack_header_3)
    s = ack_message_size + ack_header_1 + address_size + ack_header_2 + ack_header_3
    return bytes(int(s[i:i+8], 2) for i in range(0, len(s), 8))


def send_ack(ack, sock, udp_ip, udp_port):
    """
    send ack
    """
    print('Sending {} to {}:{}'.format(ack, udp_ip, udp_port))
    sock.sendto(ack, (udp_ip, udp_port))


def init_db():
    conn = pyodbc.connect('Driver={MariaDB};'
                          'Server=localhost;'
                          'Database=motoroladb;'
                          'UID=engineer;'
                          'PWD=motorolastore')
    cursor = conn.cursor()
    return conn, cursor


if __name__ == '__main__':
    conn, cursor = init_db()
    recv_message(cursor, conn)

#   00000000 00000011   10011111      00000000      000[10111]
#    [MESSAGE SIZE]    [HEADER 1]  [ADDRESS SIZE]  [HEADER 2]
#   00000000 00000011   10011111      00000000      000[01101]

#   00000010 00110100   11100000      00000000      100[10111] 0[00]00100

# If extension is indicated in message header, add extra header to ack and copy two extra seq num bits