#!/usr/bin/env python

# ultimately, this should provide an interactive cli for navigating confluent
# tree and doing console with a socket.  <ESC>]0;<string><BELL> can be used to
# present info such as whether it is in a console or other mode and, if in
# console, how many other connections are live and looking
# this means 'wcons' simply needs to make a terminal run and we'll take care of
# the title while providing more info
# this also means the socket interface needs to have ways to convey more
# interesting pieces of data (like concurrent connection count)
# socket will probably switch to a TLV scheme:
# 32 bit TL, 8 bits of type code and 24 bit size
# type codes:
# 0: string data
# 1: json data
# 24 bit size allows the peer to avoid having to do any particular parsing to
# understand message boundaries (which is a significant burden on the xCAT
# protocol)

# When in a console client mode, will recognize two escape sequences by
# default:
# Ctrl-E, c, ?: mimick conserver behavior
# ctrl-]: go to interactive prompt (telnet escape, but not telnet prompt)
# esc-( would interfere with normal esc use too much
# ~ I will not use for now...

import fcntl
import optparse
import os
import select
import socket
import ssl
import sys
import termios
import tty

SO_PASSCRED = 16
conserversequence = '\x05c' # ctrl-e, c

oldtcattr = termios.tcgetattr(sys.stdin.fileno())
server = None

def parseservervalue(serverstring):
    if serverstring.find(']:') != -1:
        server, port = serverstring[1:].split(']:')
    elif serverstring[0] == '[':
        server = serverstring[1:-1]
        port = 4001
    elif -1 != opts.server.find(':'):
        server, port = opts.server.split(":")
    else:
        server = serverstring
        port = 4001
    return (server, port)


def exit(code=0):
    termios.tcsetattr(sys.stdin.fileno(), termios.TCSANOW, oldtcattr)
    server.shutdown(socket.SHUT_RDWR)
    server.close()
    sys.exit(code)

def conserver_command(fh, command):
    while not command:
        ready, _, _ = select.select((fh,), (), (), 1)
        if ready:
            command += fh.read()
    if command[0] == '.':
        print("disconnect]\r")
        exit()
    elif command[0] == '?':
        print("help]\r")
        print(".    disconnect\r")
        print("<cr> abort command\r")
    elif command[0] == '\x0d':
        print("ignored]\r")
    else: #not a command at all..
        print("unknown -- use '?']\r")


def check_escape_seq(input, fh):
    while conserversequence.startswith(input):
        if input.startswith(conserversequence):  # We have full sequence
            sys.stdout.write("[")
            sys.stdout.flush()
            return conserver_command(fh, input[len(conserversequence):])
        ready, _, _ = select.select((fh,), (), (), 3)
        if not ready:  # 3 seconds of no typing
            break
        input += fh.read()
    return input


def connect_unix_server(sockpath):
    server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, SO_PASSCRED, 1)
    server.connect(sockpath)
    return server


def connect_tls_server(serverstring):
    host, port = parseservervalue(serverstring)
    for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
            socket.SOCK_STREAM):
        af, socktype, proto, cononname, sa = res
        try:
            server = socket.socket(af, socktype, proto)
        except:
            server = None
            continue
        try:
            server.settimeout(5)
            server.connect(sa)
        except:
            server.close()
            server = None
            continue
        break
    if server is None:
        sys.stderr.write("Failed to connect to %s\n" % serverstring)
        sys.exit(1)
    secserver = ssl.wrap_socket(server)
    return secserver

parser = optparse.OptionParser()
parser.add_option("-s", "--server", dest="server",
                  help="TLS server to connect to", metavar="SERVER:PORT")
parser.add_option("-u", "--unixsocket", dest="unixsock",
                  help="TLS server to connect to", metavar="UNIXDOMAINSOCKET")
opts, args =  parser.parse_args()
if opts.server:  # going over a TLS network
    server = connect_tls_server(opts.server)
elif opts.unixsock:
    server = connect_unix_server(opts.unixsock)

#Next stop, reading and writing from whichever of stdin and server goes first.
#see pyghmi code for solconnect.py

tty.setraw(sys.stdin.fileno())
fcntl.fcntl(sys.stdin.fileno(), fcntl.F_SETFL, os.O_NONBLOCK)
# clear on start can help with readable of TUI, but it
# can be annoying, so for now don't do it.
# sys.stdout.write('\x1b[H\x1b[J')
# sys.stdout.flush()
doexit = False
while not doexit:
    rdylist, _, _ = select.select((sys.stdin, server), (), (), 60)
    for fh in rdylist:
        if fh == server:
            #fh.read()
            data = fh.recv(16384)
            if data:
                sys.stdout.write(data)
                sys.stdout.flush()
            else:
                doexit = True
                sys.stdout.write("\r\n[remote disconnected]\r\n")
                break
        else:
            input = fh.read()
            input = check_escape_seq(input, fh)
            if input:
                server.sendall(input)
exit()