#!/usr/bin/env python3
'''
    server.py
    Jeff Ondich, March 2026

    Very simple server based on Python's socket module.
'''

import sys
import socket

def run_server(host, port):
    server_socket = socket.socket()
    server_socket.bind((host, port))
    server_socket.listen(2)  # Listen for up to 2 clients simultaneously
    while True:
        connection, address = server_socket.accept()
        print(f'{address}: connection established')
        handle_connection_echo_protocol(connection, address)

def handle_connection_echo_protocol(connection, address):
    '''
        Implement an echo protocol. Note that if the connection.recv method
        returns a non-None value, it only guarantees the receipt of 1 byte.
        It might return everything the client has sent so far in a single
        call of connection.recv, or it might not.

        Since the echo protocol works just fine if you echo whatever bytes
        you get from the client whenever you get them, we don't worry about this
        connection.recv behavior here.

        Consider: what if your protocol has to process input one full line
        at a time? How would you structure your server input code in that case?
    '''
    while True:
        data = connection.recv(1024)
        if not data:
            break
        connection.send(data)
    connection.close()

if __name__ == '__main__':
    try:
        host = sys.argv[1]
        port = int(sys.argv[2])
    except:
        print(f'Usage: {sys.argv[0]} host port', file=sys.stderr)
        exit()

    run_server(host, port)