import sys
import time

from defective_socket import DefectiveTxSocket


# Define constants
BIT_ERROR_RATE = 0.1  # in percentage
BUFFER_SIZE = 1024

# Check input arguments
if len(sys.argv) != 2:
    print("ERROR: Invalid input(s).")
    print("Usage:")
    print("\tpython fserver.py <server port>")
    sys.exit(1)

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

# Define socket
serverSocket = DefectiveTxSocket(bindPort, BIT_ERROR_RATE)

print("Server listening on {}:{}".format("0.0.0.0", bindPort))

# Start running the server
"""
SAMPLE CODE

This sample code waits for a request packet from the client, and on receipt,
continuously sends out packets containing the string "hello"

You may find this useful when you start writing your own code. 
"""
data, clientAddr = serverSocket.recvfrom(BUFFER_SIZE)
print("Received request from {}:\n{}".format(clientAddr, data))

serverSocket.settimeout(1)  # allows for CTRL+C break out
while True:
    serverSocket.sendto(b"hello", clientAddr)
    time.sleep(1)