import socket
import sys


# DEFINE CONSTANTS
BUFFER_SIZE = 1024

# Check input arguments
if len(sys.argv) != 4:
    print("ERROR: Invalid input(s).")
    print("Usage:")
    print("\tpython fclient.py <server IP addr.> <server port> <filename>")
    sys.exit(1)

serverIp = sys.argv[1]

try:
    serverPort = int(sys.argv[2])
except ValueError:
    print("ERROR: server port must be between 1024 and 65535.")
    sys.exit(1)

fileName = sys.argv[3]
serverAddr = (serverIp, serverPort)

# Define socket
clientSocket = socket.socket(type=socket.SOCK_DGRAM)
clientSocket.bind(("0.0.0.0", 0))

# Start running the client
"""
SAMPLE CODE

This sample code sends a request packet to the server, then waits
indefinitely for any packets sent by the server, printing out the contents
upon receipt.

You may find useful this when you start writing your own code.
"""

print("Initiating request to server {}:{}".format(*serverAddr))
clientSocket.sendto(b"hello", serverAddr)
clientSocket.settimeout(1)  # allows for CTRL+C break out


while True:
    try:
        data, addr = clientSocket.recvfrom(BUFFER_SIZE)
    except socket.timeout:
        continue

    print("Rx: {} from {}".format(data, addr))