# -*- test-case-name: txweb2.test.test_log -*-
##
# Copyright (c) 2001-2004 Twisted Matrix Laboratories.
# Copyright (c) 2010-2017 Apple Inc. All rights reserved.
#
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# 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.
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# 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
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##

"""
Logging tools. This is still in flux (even moreso than the rest of web2).

NOTE: This is now using twext.python.log new-style logging and observers.
"""

import time
from twisted.internet import defer
from twext.python.log import Logger
from txweb2 import iweb, stream, resource
from zope.interface import implements, Attribute, Interface

log = Logger()


class _LogByteCounter(object):
    implements(stream.IByteStream)

    def __init__(self, stream, done):
        self.stream = stream
        self.done = done
        self.len = 0

    length = property(lambda self: self.stream.length)

    def _callback(self, data):
        if data is None:
            if self.done:
                done = self.done
                self.done = None
                done(True, self.len)
        else:
            self.len += len(data)
        return data

    def read(self):
        data = self.stream.read()
        if isinstance(data, defer.Deferred):
            return data.addCallback(self._callback)
        return self._callback(data)

    def close(self):
        if self.done:
            done = self.done
            self.done = None
            done(False, self.len)
        self.stream.close()


class ILogInfo(Interface):
    """Auxilliary information about the response useful for logging."""

    bytesSent = Attribute("Number of bytes sent.")
    responseCompleted = Attribute("Whether or not the response was completed.")
    secondsTaken = Attribute("Number of seconds taken to serve the request.")
    startTime = Attribute("Time at which the request started")


class LogInfo(object):
    implements(ILogInfo)

    responseCompleted = None
    secondsTaken = None
    bytesSent = None
    startTime = None


def logFilter(request, response, startTime=None):
    if startTime is None:
        startTime = time.time()

    def _log(success, length):
        loginfo = LogInfo()
        loginfo.bytesSent = length
        loginfo.responseCompleted = success
        loginfo.secondsTaken = time.time() - startTime

        if length:
            request.timeStamp("t-resp-wr")
        log.info(interface=iweb.IRequest, request=request, response=response,
                 loginfo=loginfo)
        # Or just...
        # ILogger(ctx).log(...) ?

    request.timeStamp("t-resp-gen")
    if response.stream:
        response.stream = _LogByteCounter(response.stream, _log)
    else:
        _log(True, 0)

    return response

logFilter.handleErrors = True


class LogWrapperResource(resource.WrapperResource):

    def hook(self, request):
        # Insert logger
        request.addResponseFilter(logFilter, atEnd=True, onlyOnce=True)

monthname = [None, 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
             'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']


class BaseCommonAccessLoggingObserver(object):
    """An abstract Twisted-based logger for creating access logs.

    Derived implementations of this class *must* implement the
    ``logMessage(message)`` method, which will send the message to an actual
    log/file or stream.
    """

    logFormat = '%s - %s [%s] "%s" %s %d "%s" "%s"'

    def logMessage(self, message):
        raise NotImplemented, 'You must provide an implementation.'

    def computeTimezoneForLog(self, tz):
        if tz > 0:
            neg = 1
        else:
            neg = 0
            tz = -tz
        h, rem = divmod(tz, 3600)
        m, rem = divmod(rem, 60)
        if neg:
            return '-%02d%02d' % (h, m)
        else:
            return '+%02d%02d' % (h, m)

    tzForLog = None
    tzForLogAlt = None

    def logDateString(self, when):
        logtime = time.localtime(when)
        Y, M, D, h, m, s = logtime[:6]

        if logtime.tm_isdst == 0:
            tz = self.tzForLog
            if tz is None:
                tz = self.computeTimezoneForLog(time.timezone)
                self.tzForLog = tz
        else:
            tz = self.tzForLogAlt
            if tz is None:
                tz = self.computeTimezoneForLog(time.altzone)
                self.tzForLogAlt = tz

        return '%02d/%s/%02d:%02d:%02d:%02d %s' % (
            D, monthname[M], Y, h, m, s, tz)

    def emit(self, eventDict):
        if eventDict.get('interface') is not iweb.IRequest:
            return

        request = eventDict['request']
        response = eventDict['response']
        loginfo = eventDict['loginfo']
        firstLine = '%s %s HTTP/%s' % (
            request.method,
            request.uri,
            '.'.join([str(x) for x in request.clientproto]))

        self.logMessage(
            '%s - %s [%s] "%s" %s %d "%s" "%s"' % (
                request.remoteAddr.host,
                # XXX: Where to get user from?
                "-",
                self.logDateString(
                    response.headers.getHeader('date', 0)),
                firstLine,
                response.code,
                loginfo.bytesSent,
                request.headers.getHeader('referer', '-'),
                request.headers.getHeader('user-agent', '-')
            )
        )

    def start(self):
        """Start observing log events."""
        # Use the root publisher to bypass log level filtering
        log.observer.addObserver(self.emit)

    def stop(self):
        """Stop observing log events."""
        log.observer.removeObserver(self.emit)


class FileAccessLoggingObserver(BaseCommonAccessLoggingObserver):
    """I log requests to a single logfile
    """

    def __init__(self, logpath):
        self.logpath = logpath

    def logMessage(self, message):
        self.f.write(message + '\n')

    def start(self):
        super(FileAccessLoggingObserver, self).start()
        self.f = open(self.logpath, 'a', 1)

    def stop(self):
        super(FileAccessLoggingObserver, self).stop()
        self.f.close()


class DefaultCommonAccessLoggingObserver(BaseCommonAccessLoggingObserver):
    """Log requests to default twisted logfile."""

    def logMessage(self, message):
        log.info(message)