import datetime, os.path, re, types
from base64 import b32decode, b32encode

from twisted.python import log
from twisted.application import service
from twisted.internet import defer, reactor
from foolscap import Tub, eventual
from allmydata import get_package_versions_string
from allmydata.util import log as tahoe_log
from allmydata.util import fileutil, iputil, observer, humanreadable
from allmydata.util.assertutil import precondition

# Just to get their versions:
import allmydata, pycryptopp, zfec

from foolscap.logging.publish import LogPublisher
# Add our application versions to the data that Foolscap's LogPublisher
# reports. Our __version__ attributes are actually instances of a "Version"
# class, so convert them into strings first.
LogPublisher.versions['allmydata'] = str(allmydata.__version__)
LogPublisher.versions['zfec'] = str(zfec.__version__)
LogPublisher.versions['pycryptopp'] = str(pycryptopp.__version__)

# group 1 will be addr (dotted quad string), group 3 if any will be portnum (string)
ADDR_RE=re.compile("^([1-9][0-9]*\.[1-9][0-9]*\.[1-9][0-9]*\.[1-9][0-9]*)(:([1-9][0-9]*))?$")


def formatTimeTahoeStyle(self, when):
    # we want UTC timestamps that look like:
    #  2007-10-12 00:26:28.566Z [Client] rnp752lz: 'client running'
    d = datetime.datetime.utcfromtimestamp(when)
    if d.microsecond:
        return d.isoformat(" ")[:-3]+"Z"
    else:
        return d.isoformat(" ") + ".000Z"

PRIV_README="""
This directory contains files which contain private data for the Tahoe node,
such as private keys.  On Unix-like systems, the permissions on this directory
are set to disallow users other than its owner from reading the contents of
the files.   See the 'configuration.txt' documentation file for details."""

class Node(service.MultiService):
    # this implements common functionality of both Client nodes and Introducer
    # nodes.
    NODETYPE = "unknown NODETYPE"
    PORTNUMFILE = None
    CERTFILE = "node.pem"
    LOCAL_IP_FILE = "advertised_ip_addresses"

    def __init__(self, basedir="."):
        service.MultiService.__init__(self)
        self.basedir = os.path.abspath(basedir)
        self._tub_ready_observerlist = observer.OneShotObserverList()
        fileutil.make_dirs(os.path.join(self.basedir, "private"), 0700)
        open(os.path.join(self.basedir, "private", "README"), "w").write(PRIV_README)
        certfile = os.path.join(self.basedir, "private", self.CERTFILE)
        self.tub = Tub(certFile=certfile)
        self.tub.setOption("logLocalFailures", True)
        self.tub.setOption("logRemoteFailures", True)
        self.nodeid = b32decode(self.tub.tubID.upper()) # binary format
        self.write_config("my_nodeid", b32encode(self.nodeid).lower() + "\n")
        self.short_nodeid = b32encode(self.nodeid).lower()[:8] # ready for printing
        assert self.PORTNUMFILE, "Your node.Node subclass must provide PORTNUMFILE"
        self._portnumfile = os.path.join(self.basedir, self.PORTNUMFILE)
        try:
            portnum = int(open(self._portnumfile, "rU").read())
        except (EnvironmentError, ValueError):
            portnum = 0
        self.tub.listenOn("tcp:%d" % portnum)
        # we must wait until our service has started before we can find out
        # our IP address and thus do tub.setLocation, and we can't register
        # any services with the Tub until after that point
        self.tub.setServiceParent(self)
        self.logSource="Node"

        AUTHKEYSFILEBASE = "authorized_keys."
        for f in os.listdir(self.basedir):
            if f.startswith(AUTHKEYSFILEBASE):
                keyfile = os.path.join(self.basedir, f)
                portnum = int(f[len(AUTHKEYSFILEBASE):])
                from allmydata import manhole
                m = manhole.AuthorizedKeysManhole(portnum, keyfile)
                m.setServiceParent(self)
                self.log("AuthorizedKeysManhole listening on %d" % portnum)

        self.setup_logging()
        self.log("Node constructed. " + get_package_versions_string())
        iputil.increase_rlimits()

    def get_config(self, name, required=False):
        """Get the (string) contents of a config file, or None if the file
        did not exist. If required=True, raise an exception rather than
        returning None. Any leading or trailing whitespace will be stripped
        from the data."""
        fn = os.path.join(self.basedir, name)
        try:
            return open(fn, "r").read().strip()
        except EnvironmentError:
            if not required:
                return None
            raise

    def write_private_config(self, name, value):
        """Write the (string) contents of a private config file (which is a
        config file that resides within the subdirectory named 'private'), and
        return it. Any leading or trailing whitespace will be stripped from
        the data.
        """
        privname = os.path.join(self.basedir, "private", name)
        open(privname, "w").write(value.strip())

    def get_or_create_private_config(self, name, default):
        """Try to get the (string) contents of a private config file (which
        is a config file that resides within the subdirectory named
        'private'), and return it. Any leading or trailing whitespace will be
        stripped from the data.

        If the file does not exist, try to create it using default, and
        then return the value that was written. If 'default' is a string,
        use it as a default value. If not, treat it as a 0-argument callable
        which is expected to return a string.
        """
        privname = os.path.join("private", name)
        value = self.get_config(privname)
        if value is None:
            if isinstance(default, (str, unicode)):
                value = default
            else:
                value = default()
            fn = os.path.join(self.basedir, privname)
            try:
                open(fn, "w").write(value)
            except EnvironmentError, e:
                self.log("Unable to write config file '%s'" % fn)
                self.log(e)
            value = value.strip()
        return value

    def write_config(self, name, value, mode="w"):
        """Write a string to a config file."""
        fn = os.path.join(self.basedir, name)
        try:
            open(fn, mode).write(value)
        except EnvironmentError, e:
            self.log("Unable to write config file '%s'" % fn)
            self.log(e)

    def startService(self):
        # Note: this class can be started and stopped at most once.
        self.log("Node.startService")
        try:
            os.chmod("twistd.pid", 0644)
        except EnvironmentError:
            pass
        # Delay until the reactor is running.
        eventual.eventually(self._startService)

    def _startService(self):
        precondition(reactor.running)
        self.log("Node._startService")

        service.MultiService.startService(self)
        d = defer.succeed(None)
        d.addCallback(lambda res: iputil.get_local_addresses_async())
        d.addCallback(self._setup_tub)
        def _ready(res):
            self.log("%s running" % self.NODETYPE)
            self._tub_ready_observerlist.fire(self)
            return self
        d.addCallback(_ready)
        d.addErrback(self._service_startup_failed)

    def _service_startup_failed(self, failure):
        self.log('_startService() failed')
        log.err(failure)
        print "Node._startService failed, aborting"
        print failure
        #reactor.stop() # for unknown reasons, reactor.stop() isn't working.  [ ] TODO
        self.log('calling os.abort()')
        log.msg('calling os.abort()')
        print "calling os.abort()"
        os.abort()

    def stopService(self):
        self.log("Node.stopService")
        d = self._tub_ready_observerlist.when_fired()
        def _really_stopService(ignored):
            self.log("Node._really_stopService")
            return service.MultiService.stopService(self)
        d.addCallback(_really_stopService)
        return d

    def shutdown(self):
        """Shut down the node. Returns a Deferred that fires (with None) when
        it finally stops kicking."""
        self.log("Node.shutdown")
        return self.stopService()

    def setup_logging(self):
        # we replace the formatTime() method of the log observer that twistd
        # set up for us, with a method that uses better timestamps.
        for o in log.theLogPublisher.observers:
            # o might be a FileLogObserver's .emit method
            if type(o) is type(self.setup_logging): # bound method
                ob = o.im_self
                if isinstance(ob, log.FileLogObserver):
                    newmeth = types.UnboundMethodType(formatTimeTahoeStyle, ob, ob.__class__)
                    ob.formatTime = newmeth
        # TODO: twisted >2.5.0 offers maxRotatedFiles=50

        self.tub.setOption("logport-furlfile",
                           os.path.join(self.basedir, "private","logport.furl"))
        self.tub.setOption("log-gatherer-furlfile",
                           os.path.join(self.basedir, "log_gatherer.furl"))
        self.tub.setOption("bridge-twisted-logs", True)

    def log(self, *args, **kwargs):
        return tahoe_log.msg(*args, **kwargs)

    def old_log(self, msg, src="", args=(), **kw):
        if src:
            logsrc = src
        else:
            logsrc = self.logSource
        if args:
            try:
                msg = msg % tuple(map(humanreadable.hr, args))
            except TypeError, e:
                msg = "ERROR: output string '%s' contained invalid %% expansion, error: %s, args: %s\n" % (`msg`, e, `args`)
        msg = self.short_nodeid + ": " + humanreadable.hr(msg)
        return log.callWithContext({"system":logsrc},
                                   tahoe_log.msg, msg, **kw)

    def _setup_tub(self, local_addresses):
        # we can't get a dynamically-assigned portnum until our Tub is
        # running, which means after startService.
        l = self.tub.getListeners()[0]
        portnum = l.getPortnum()
        # record which port we're listening on, so we can grab the same one next time
        open(self._portnumfile, "w").write("%d\n" % portnum)

        local_addresses = [ "%s:%d" % (addr, portnum,) for addr in local_addresses ]

        addresses = []
        try:
            for addrline in open(os.path.join(self.basedir, self.LOCAL_IP_FILE), "rU"):
                mo = ADDR_RE.search(addrline)
                if mo:
                    (addr, dummy, aportnum,) = mo.groups()
                    if aportnum is None:
                        aportnum = portnum
                    addresses.append("%s:%d" % (addr, int(aportnum),))
        except EnvironmentError:
            pass

        addresses.extend(local_addresses)

        location = ",".join(addresses)
        self.log("Tub location set to %s" % location)
        self.tub.setLocation(location)
        return self.tub

    def when_tub_ready(self):
        return self._tub_ready_observerlist.when_fired()

    def add_service(self, s):
        s.setServiceParent(self)
        return s