# Copyright 2014-2015 Canonical Limited.
#
# This file is part of charm-helpers.
#
# charm-helpers is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3 as
# published by the Free Software Foundation.
#
# charm-helpers is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.

"""Remote Python Debugger (pdb wrapper)."""

import pdb
import socket
import sys

__author__ = "Bertrand Janin <b@janin.com>"
__version__ = "0.1.3"


class Rpdb(pdb.Pdb):

    def __init__(self, addr="127.0.0.1", port=4444):
        """Initialize the socket and initialize pdb."""

        # Backup stdin and stdout before replacing them by the socket handle
        self.old_stdout = sys.stdout
        self.old_stdin = sys.stdin

        # Open a 'reusable' socket to let the webapp reload on the same port
        self.skt = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.skt.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
        self.skt.bind((addr, port))
        self.skt.listen(1)
        (clientsocket, address) = self.skt.accept()
        handle = clientsocket.makefile('rw')
        pdb.Pdb.__init__(self, completekey='tab', stdin=handle, stdout=handle)
        sys.stdout = sys.stdin = handle

    def shutdown(self):
        """Revert stdin and stdout, close the socket."""
        sys.stdout = self.old_stdout
        sys.stdin = self.old_stdin
        self.skt.close()
        self.set_continue()

    def do_continue(self, arg):
        """Stop all operation on ``continue``."""
        self.shutdown()
        return 1

    do_EOF = do_quit = do_exit = do_c = do_cont = do_continue