# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""Implement standard (and unused) TCP protocols.

These protocols are either provided by inetd, or are not provided at all.
"""

# system imports
import time, struct
from zope.interface import implements

# twisted import
from twisted.internet import protocol, interfaces


class Echo(protocol.Protocol):
"""As soon as any data is received, write it back (RFC 862)"""

def dataReceived(self, data):
self.transport.write(data)


class Discard(protocol.Protocol):
"""Discard any received data (RFC 863)"""

def dataReceived(self, data):
# I'm ignoring you, nyah-nyah
pass


class Chargen(protocol.Protocol):
"""Generate repeating noise (RFC 864)"""
noise = r'@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ !"#$%&?'

implements(interfaces.IProducer)

def connectionMade(self):
self.transport.registerProducer(self, 0)

def resumeProducing(self):
self.transport.write(self.noise)

def pauseProducing(self):
pass

def stopProducing(self):
pass


class QOTD(protocol.Protocol):
"""Return a quote of the day (RFC 865)"""

def connectionMade(self):
self.transport.write(self.getQuote())
self.transport.loseConnection()

def getQuote(self):
"""Return a quote. May be overrriden in subclasses."""
return "An apple a day keeps the doctor away.\r\n"

class Who(protocol.Protocol):
"""Return list of active users (RFC 866)"""

def connectionMade(self):
self.transport.write(self.getUsers())
self.transport.loseConnection()

def getUsers(self):
"""Return active users. Override in subclasses."""
return "root\r\n"


class Daytime(protocol.Protocol):
"""Send back the daytime in ASCII form (RFC 867)"""

def connectionMade(self):
self.transport.write(time.asctime(time.gmtime(time.time())) + '\r\n')
self.transport.loseConnection()


class Time(protocol.Protocol):
"""Send back the time in machine readable form (RFC 868)"""

def connectionMade(self):
# is this correct only for 32-bit machines?
result = struct.pack("!i", int(time.time()))
self.transport.write(result)
self.transport.loseConnection()