import os
import asyncio

import nats
from nats.errors import TimeoutError as NATSTimeoutError

NATS_SERVERS = os.getenv('NATS_URL', 'nats://localhost:4222').split(',')
NATS_TOKEN = os.getenv('NATS_TOKEN', '')

async def nats_subscribe(nc, subject):
    sub = await nc.subscribe(subject)
    while True:
        try:
            msg = await sub.next_msg(timeout=0.1)
            print(f"Received a message on '{msg.subject}': {msg.data}")
        except NATSTimeoutError:
            continue
        except KeyboardInterrupt:
            await sub.unsubscribe()
            return True

async def nats_publish(nc, subject, data):
    count = 0
    while True:
        try:
            print(f"Publishing a message on '{subject}': {data}_{count}")
            await nc.publish(subject, (f"{data}_{count}").encode())
            count += 1
            await asyncio.sleep(5)
        except KeyboardInterrupt:
            return True

async def main():
    print(f'Startting ...')
    print(f'NATS_SERVER: {NATS_SERVERS}')
    print(f'NATS_TOKEN: {NATS_TOKEN}')


    nc = await nats.connect(servers=NATS_SERVERS,
                            token=NATS_TOKEN)

    asyncio.create_task(nats_subscribe(nc, "greet.*"))
    asyncio.create_task(nats_publish(nc, "greet.bob", "hello_bob"))
    await asyncio.sleep(0.5)
    asyncio.create_task(nats_publish(nc, "greet.alice", "hello_alice"))


    while True:
        await asyncio.sleep(1)

    await nc.drain()




# Press the green button in the gutter to run the script.
if __name__ == '__main__':
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        pass

# See PyCharm help at https://www.jetbrains.com/help/pycharm/