import pty
import os
import io
import sys
import struct
import fcntl
import termios
import tornado.websocket
import tornado.process
import tornado.ioloop
from subprocess import Popen
from app import url, Route

ioloop = tornado.ioloop.IOLoop.instance()


@url(r'/')
class Index(Route):
    def get(self):
        return self.render('index.html')


@url(r'/ws')
class TermWebSocket(Route, tornado.websocket.WebSocketHandler):

    def pty(self):
        pid, fd = pty.fork()
        if pid == 0:
            # Child
            try:
                fd_list = [int(i) for i in os.listdir('/proc/self/fd')]
            except OSError:
                fd_list = range(256)
            # Close all file descriptors other than
            # stdin, stdout, and stderr (0, 1, 2)
            for i in [i for i in fd_list if i > 2]:
                try:
                    os.close(i)
                except OSError:
                    pass
            env = os.environ
            env["TERM"] = "xterm"
            env["COLORTERM"] = "wsterm"
            command = os.getenv('SHELL')
            env["SHELL"] = command
            p = Popen(command, env=env)
            p.wait()
            self.log.info('Exiting...')
            sys.exit(0)
        else:
            self.pid = pid
            self.fd = fd
            self.log.debug('Adding handler')
            fcntl.fcntl(fd, fcntl.F_SETFL, os.O_NONBLOCK)

            # Set the size of the terminal window:
            s = struct.pack("HHHH", 80, 80, 0, 0)
            fcntl.ioctl(fd, termios.TIOCSWINSZ, s)

            self.reader = io.open(
                fd,
                'rt',
                buffering=1024,
                newline="",
                encoding='UTF-8',
                closefd=False,
                errors='handle_special'
            )
            self.writer = io.open(
                fd,
                'wt',
                buffering=1024,
                newline="",
                encoding='UTF-8',
                closefd=False
            )
            ioloop.add_handler(fd, self.shell, ioloop.READ)

    def open(self):
        self.log.info('Websocket opened')
        self.pty()

    def on_message(self, message):
        if message.startswith('RS|'):
            message = message[3:]
            cols, rows = map(int, message.split(','))
            s = struct.pack("HHHH", rows, cols, 0, 0)
            fcntl.ioctl(self.fd, termios.TIOCSWINSZ, s)
            self.log.info('SIZE (%d, %d)' % (cols, rows))
        elif message.startswith('SH|'):
            message = message[3:]
            self.log.info('WRIT<%r' % message)
            self.writer.write(message)
            self.writer.flush()

    def shell(self, fd, events):
        if events & ioloop.READ:
            self.log.info('shell %d: %d' % (fd, events))
            try:
                read = self.reader.read()
            except IOError:
                self.log.info('READ>%r' % read)
                self.write_message('Exited')
                return

            self.log.info('READ>%r' % read)
            self.write_message(read)

    def on_close(self):
        self.writer.write('')
        self.writer.flush()
        os.close(self.fd)
        os.waitpid(self.pid, 0)
        self.log.info('Websocket closed')