#!/usr/bin/env python
from __future__ import print_function

import argparse
import base64
import errno
import httplib
import json
import os
import platform
import random
import socket
import string
import subprocess
import sys
import tempfile
import thread
import time
import urllib2
import uuid


class NotAuthorizedException(Exception):
    pass

class RequestTooLargeException(Exception):
    pass


def id_generator(size=18, chars=string.ascii_letters + string.digits):
    return ''.join(random.choice(chars) for x in range(size))


def terminal_size():
    cols = subprocess.Popen('tput cols', shell=True, stdout=subprocess.PIPE)
    rows = subprocess.Popen('tput lines', shell=True, stdout=subprocess.PIPE)
    cols = int(cols.stdout.read().strip())
    rows = int(rows.stdout.read().strip())
    return {'cols': cols, 'rows': rows}


def post(conn, url, message, room, password):
    is_successful = lambda status: status >= 200 and status < 300
    headers = {'Content-type': 'application/json',
               'Authorization': password}
    data = json.dumps({'message': message, 'size': terminal_size()})
    try:
        conn.request('POST', '/%s' % room, data, headers)
        res = conn.getresponse()
        res.read()

        if res.status == 401:
            raise NotAuthorizedException()
        elif res.status == 413:
            raise RequestTooLargeException()
        else:
            return is_successful(res.status)
    except httplib.HTTPException:
        pass
    except socket.error as e:
        if e.errno != errno.ECONNREFUSED:
            raise e
        pass


def stream_file(path, url, room, password):
    retries = 3
    try:
        conn = httplib.HTTPSConnection(url)
        f = open(path, 'rb')
        success = True
        while success:
            time.sleep(1)
            # osx wants this because EOF is cached
            f.seek(0, os.SEEK_CUR)
            data = f.read()
            if not (data == ""):
                urlencoded = urllib2.quote(data)
                encoded_str = base64.b64encode(urlencoded)
                for _ in range(retries):
                    success = post(conn, url, encoded_str, room, password)
                    if success:
                        break
                    else:
                        time.sleep(1)
                        conn = httplib.HTTPSConnection(url)
        error('There was an error connecting to the server.')
    except NotAuthorizedException:
        error('You\'re not authorized to share on https://%s/%s.' % (url, room))
    except RequestTooLargeException:
        error('You\'ve wrote too much too fast. Please, slow down.')


def error(*args):
    print('\r\nERROR:', *args, file=sys.stderr)
    print('\rERROR: Exit shellshare and try again later.', file=sys.stderr)


def delete(url, room, password):
    headers = {'Authorization': password}
    try:
        conn = httplib.HTTPSConnection(url)
        conn.request('DELETE', '/%s' % room, {}, headers)
        res = conn.getresponse()
        res.read()
    except Exception:
        pass


def parse_args():
    description = 'Transmits the current shell to shellshare'
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument('-v', '--version', action='version',
                        version='%(prog)s 1.0.1')
    parser.add_argument('-s', '--server', dest='server',
                        help=('shellshare instance URL'
                              ' (default: shellshare.net)'),
                        default='shellshare.net')
    parser.add_argument('-r', '--room', dest='room',
                        help='room to share into (default: random room)',
                        default=id_generator())
    parser.add_argument('-p', '--password', dest='password',
                        help='room\'s broadcasting password (default: network card\'s MAC address)',
                        default=uuid.getnode())
    return parser.parse_args()


args = parse_args()
room = 'r/%s' % args.room
tmp = tempfile.NamedTemporaryFile()

if platform.system() == 'Darwin':
    shell_args = '-qt 0'
else:
    shell_args = '-qf'

size = terminal_size()
if (size['rows'] > 30 or size['cols'] > 160):
    print('Current terminal size is %dx%d.' % (size['rows'], size['cols']))
    print('It\'s too big to be viewed on smaller screens.')
    print('You can resize it anytime.')

print('Sharing terminal in https://%s/%s' % (args.server, room))
thread.start_new_thread(stream_file,
                        (tmp.name, args.server, room, args.password))
subprocess.call('script %s %s' % (shell_args, tmp.name), shell=True)
delete(args.server, room, args.password)
print('End of transmission.')