#! /usr/bin/env python

import sys
import getopt
import socket

def main(argv):
    """Parse command line arguements to transfer file"""
    #Attempt to parse command line args, catch error
    try:
        options, arguements = getopt.getopt(argv, "a:f:hp:svw", ["address=", "file=", "help", "port=", "send", "verbose", "wait"])
    except getopt.GetoptError:
        error("Incorrect arguements")

    #Parse getopt option, arguement tuples to a dictionary
    args = dict(options)

    #Store whether the command should be verbose
    global verbose_bool
    verbose_bool = "-v" in args.keys() or "--verbose" in args.keys()

    #Test for presence of a wait and/or send flag
    wait_bool = "-w" in args.keys() or "--wait" in args.keys()
    send_bool = "-s" in args.keys() or "--send" in args.keys()

    #Resolve script action from flags
    if wait_bool and send_bool:
        error("Cannot wait and send.")
    elif wait_bool:
        #Wait on the specified port
        port = args.get("-p") or args.get("--port")
        if port is None:
            error("Must specify port to wait on")
        wait(port)
    elif send_bool:
        #Retrieve the target address
        address = args.get("-a") or args.get("--address")
        if address is None:
            error("Must specify address to send to.")

        #Retrive port to transfer on
        port = args.get("-p") or args.get("--port")
        if port is None:
            error("Must specify port to transfer on")

        #Retrieve the filename
        filename = args.get("-f") or args.get("--file")
        if filename is None:
            error("Must specify file to send")

        #Send the file to the adress
        send(address, port, filename)
    elif "-h" in args.keys() or "--help" in args.keys():
        #Display usage and exit
        usage()
        sys.exit(0)
    else:
        error("Must send, wait, or help")

def wait(port):
    """Wait for a transfer on specified port"""

    print ("Waiting for connection on port", port + "...")

    #Establish server socket
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #Set up server socket
    server.bind(('', int(port))) #Bind socket to specified port
    server.listen(1) #Listen for up to 1 connection on bound port
    connection, address = server.accept() #On connection accept, store new connection and address
    print ("Connected to address", address)

    #Recieve the data
    if verbose_bool: print ("\nRecieving data")
    data = ""
    while True:
        new_data = connection.recv(512)
        if not new_data:
            break
        data += new_data
    if verbose_bool: print ("Data recieved")

    #Seperate filename and file content via delimeter
    delim_index = data.find("///")
    delim_end = delim_index + 3
    filename = data[:delim_index]
    file_content = data[delim_end:]

    #Save file
    if verbose_bool: print ("\nSaving file", filename)
    f = open(filename, "w")
    f.write(file_content)
    f.close()
    print ("File", filename, "saved")

    #Close connection"2

    if verbose_bool: print ("\nClosing connection")
    connection.close()

def send(address, port, filename):
    """Send a file to an address on specified port"""

    print ("Establishing connection on port", port)

    #Establish client socket
    client = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #Set up client socket
    client.connect((address, int(port)))
    print ("Connection established")

    #Read in file
    if verbose_bool: print ("\nReading file")
    try:
        f = open(filename, "r")
    except IOError:
        print ("Error: File", filename, "not found")
        client.close()
        sys.exit(1)
    file_content = f.read()
    f.close()
    if verbose_bool: print ("File read")

    #Format data for sending
    data = filename + "///" + file_content

    #Send data
    if verbose_bool: print ("\nSending", filename)
    while data:
        send_data = data[:512]
        data = data[512:]
        client.send(send_data)
    print ("Sent", filename)

    #Close client connection
    if verbose_bool: print ("\nClosing connection")
    client.close()

def error(msg):
    """Print an error message and usage, then quit"""
    print (msg, "\n")
    usage()
    sys.exit(2)

def usage():
    """Print script usage"""
    print ("Usage: sendfile [OPTION] ...")
    print ("Sends a file to another sendfile user on the other end.")
    print ("")
    print ("-a, --address    The adress to send to ")
    print ("-f, --file       Filename to send")
    print ("-h, --help       Print this usage and quit")
    print ("-p, --port       The port to send or wait on")
    print ("-s, --send       Flag telling sendfile to send")
    print ("-w, --wait       Flag telling sendfile to wait")

if __name__ == "__main__":
    main(sys.argv[1:])