# @author Bob Ippolito
#
# Copyright (c) 2005-2006, Bob Ippolito
# Copyright (c) 2007, Linden Research, Inc.
# Copyright (c) 2008, Donovan Preston
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import socket
import sys
from code import InteractiveConsole

from eventlib import api
from eventlib.support import greenlets

try:
    sys.ps1
except AttributeError:
    sys.ps1 = '>>> '
try:
    sys.ps2
except AttributeError:
    sys.ps2 = '... '


class SocketConsole(greenlets.greenlet):
    def __init__(self, desc, hostport, locals):
        self.hostport = hostport
        self.locals = locals
        # mangle the socket
        self.desc = desc
        readline = desc.readline
        self.old = {}
        self.fixups = {
            'softspace': 0,
            'isatty': lambda: True,
            'flush': lambda: None,
            'readline': lambda *a: readline(*a).replace('\r\n', '\n'),
        }
        for key, value in self.fixups.items():
            if hasattr(desc, key):
                self.old[key] = getattr(desc, key)
            setattr(desc, key, value)

        greenlets.greenlet.__init__(self)

    def run(self):
        try:
            console = InteractiveConsole(self.locals)
            console.interact()
        finally:
            self.switch_out()
            self.finalize()

    def switch(self, *args, **kw):
        self.saved = sys.stdin, sys.stderr, sys.stdout
        sys.stdin = sys.stdout = sys.stderr = self.desc
        greenlets.greenlet.switch(self, *args, **kw)

    def switch_out(self):
        sys.stdin, sys.stderr, sys.stdout = self.saved

    def finalize(self):
        # restore the state of the socket
        for key in self.fixups:
            try:
                value = self.old[key]
            except KeyError:
                delattr(self.desc, key)
            else:
                setattr(self.desc, key, value)
        self.fixups.clear()
        self.old.clear()
        self.desc = None
        print("backdoor closed to %s:%s" % self.hostport)


def backdoor_server(server, locals=None):
    print("backdoor listening on %s:%s" % server.getsockname())
    try:
        try:
            while True:
                (conn, (host, port)) = server.accept()
                print("backdoor connected to %s:%s" % (host, port))
                fl = conn.makeGreenFile("rw")
                fl.newlines = '\n'
                greenlet = SocketConsole(fl, (host, port), locals)
                hub = api.get_hub()
                hub.schedule_call_global(0, greenlet.switch)
        except socket.error as e:
            # Broken pipe means it was shutdown
            if e[0] != 32:
                raise
    finally:
        server.close()


def backdoor(connection, locals=None):
    """ Use this with tcp_server like so:
        api.tcp_server(
                       api.tcp_listener(('127.0.0.1', 9000)),
                       backdoor.backdoor,
                       {})
    """
    (conn, addr) = connection 
    host, port = addr
    print("backdoor to %s:%s" % (host, port))
    fl = conn.makeGreenFile("rw")
    fl.newlines = '\n'
    greenlet = SocketConsole(fl, (host, port), locals)
    hub = api.get_hub()
    hub.schedule_call_global(0, greenlet.switch)
