#!/usr/bin/env python3
# Copyright (c) 2014-2016 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.

# A blocking example using python 2.7 can be obtained from the git history:
# https://github.com/bitcoin/bitcoin/blob/37a7fe9e440b83e2364d5498931253937abe9294/contrib/zmq/zmq_sub.py

import array
import binascii
import asyncio, zmq, zmq.asyncio
import signal
import struct
import sys

if not (sys.version_info.major >= 3 and sys.version_info.minor >= 4):
    print("This example only works with Python 3.4 and greater")
    exit(1)

port = 28332

class ZMQHandler():
    def __init__(self):
        self.loop = zmq.asyncio.install()
        self.zmqContext = zmq.asyncio.Context()

        self.zmqSubSocket = self.zmqContext.socket(zmq.SUB)
        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "hashblock")
        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "hashtx")
        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "rawblock")
        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "rawtx")
        self.zmqSubSocket.connect("tcp://127.0.0.1:%i" % port)

    @asyncio.coroutine
    def handle(self) :
        msg = yield from self.zmqSubSocket.recv_multipart()
        topic = msg[0]
        body = msg[1]
        sequence = "Unknown";
        if len(msg[-1]) == 4:
          msgSequence = struct.unpack('<I', msg[-1])[-1]
          sequence = str(msgSequence)
        if topic == b"hashblock":
            print('- HASH BLOCK ('+sequence+') -')
            print(binascii.hexlify(body))
        elif topic == b"hashtx":
            print('- HASH TX  ('+sequence+') -')
            print(binascii.hexlify(body))
        elif topic == b"rawblock":
            print('- RAW BLOCK HEADER ('+sequence+') -')
            print(binascii.hexlify(body[:80]))
        elif topic == b"rawtx":
            print('- RAW TX ('+sequence+') -')
            print(binascii.hexlify(body))
        # schedule ourselves to receive the next message
        asyncio.ensure_future(self.handle())

    def start(self):
        asyncio.ensure_future(self.handle())
        self.loop.run_forever()

    def stop(self):
        self.loop.stop()
        self.zmqContext.destroy()

daemon = ZMQHandler()
def signal_handler(num, frame):
    daemon.stop()
    exit(0)
signal.signal(signal.SIGINT, signal_handler)
daemon.start()