#!/bin/python

# Ouroboros - Copyright (C) 2016 - 2026
#
# A simple echo application
#
#    Dimitri Staessens <dimitri@ouroboros.rocks>
#
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# notice, this list of conditions and the following disclaimer.
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"""A simple echo client/server example using Ouroboros flow event sets."""

# Standalone demo; intentionally duplicates oecho.py.
# pylint: disable=duplicate-code

from __future__ import annotations

import argparse

from ouroboros.dev import flow_accept, flow_alloc
from ouroboros.event import FEventQueue, FEventType, FlowSet


def client() -> None:
    """Send a message and print the echo reply."""
    with flow_alloc("oecho") as f:
        f.writeline("Hello, PyOuroboros!")
        print(f.readline())


def server() -> None:
    """Accept flows and echo back received messages using flow events."""
    print("Starting the server.")
    while True:
        with flow_accept() as f:
            print("New flow.")
            with FEventQueue() as fq, FlowSet([f]) as fs:
                fs.wait(fq)
                f2, t = fq.next()
            if t != FEventType.FLOW_PKT:
                continue
            line = f2.readline()
            print(f"Message from client is {line}")
            f2.writeline(line)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='A simple echo client/server')
    parser.add_argument('-l', '--listen', help='run as a server',
                        action='store_true')
    args = parser.parse_args()
    if args.listen:
        server()
    else:
        client()