"""twisted server for CubicWeb web instances

:organization: Logilab
:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__docformat__ = "restructuredtext en"

import sys
import os
import select
from time import mktime
from datetime import date, timedelta
from urlparse import urlsplit, urlunsplit
import hotshot

from twisted.application import service, strports
try:
    from twisted.scripts._twistd_unix import daemonize
except ImportError:
    pass
from twisted.internet import reactor, task, threads
from twisted.internet.defer import maybeDeferred
from twisted.web2 import channel, http, server, iweb
from twisted.web2 import static, resource, responsecode

from cubicweb import ObjectNotFound, CW_EVENT_MANAGER
from cubicweb.web import (AuthenticationError, NotFound, Redirect,
                          RemoteCallFailed, DirectResponse, StatusResponse,
                          ExplicitLogin)
from cubicweb.web.application import CubicWebPublisher

from cubicweb.etwist.request import CubicWebTwistedRequestAdapter


def start_task(interval, func):
    lc = task.LoopingCall(func)
    lc.start(interval)

def start_looping_tasks(repo):
    for interval, func, args in repo._looping_tasks:
        repo.info('starting twisted task %s with interval %.2fs',
                  func.__name__, interval)
        def catch_error_func(repo=repo, func=func, args=args):
            try:
                func(*args)
            except:
                repo.exception('error in looping task')
        start_task(interval, catch_error_func)
    # ensure no tasks will be further added
    repo._looping_tasks = ()

def host_prefixed_baseurl(baseurl, host):
    scheme, netloc, url, query, fragment = urlsplit(baseurl)
    netloc_domain = '.' + '.'.join(netloc.split('.')[-2:])
    if host.endswith(netloc_domain):
        netloc = host
    baseurl = urlunsplit((scheme, netloc, url, query, fragment))
    return baseurl


class LongTimeExpiringFile(static.File):
    """overrides static.File and sets a far futre ``Expires`` date
    on the resouce.

    versions handling is done by serving static files by different
    URLs for each version. For instance::

      http://localhost:8080/data-2.48.2/cubicweb.css
      http://localhost:8080/data-2.49.0/cubicweb.css
      etc.

    """
    def renderHTTP(self, request):
        def setExpireHeader(response):
            response = iweb.IResponse(response)
            # Don't provide additional resource information to error responses
            if response.code < 400:
                # the HTTP RFC recommands not going further than 1 year ahead
                expires = date.today() + timedelta(days=6*30)
                response.headers.setHeader('Expires', mktime(expires.timetuple()))
            return response
        d = maybeDeferred(super(LongTimeExpiringFile, self).renderHTTP, request)
        return d.addCallback(setExpireHeader)


class CubicWebRootResource(resource.PostableResource):
    addSlash = False

    def __init__(self, config, debug=None):
        self.appli = CubicWebPublisher(config, debug=debug)
        self.debugmode = debug
        self.config = config
        self.base_url = config['base-url'] or config.default_base_url()
        self.versioned_datadir = 'data%s' % config.instance_md5_version()
        assert self.base_url[-1] == '/'
        self.https_url = config['https-url']
        assert not self.https_url or self.https_url[-1] == '/'
        # when we have an in-memory repository, clean unused sessions every XX
        # seconds and properly shutdown the server
        if config.repo_method == 'inmemory':
            reactor.addSystemEventTrigger('before', 'shutdown',
                                          self.shutdown_event)
            # monkey patch start_looping_task to get proper reactor integration
            self.appli.repo.__class__.start_looping_tasks = start_looping_tasks
            if config.pyro_enabled():
                # if pyro is enabled, we have to register to the pyro name
                # server, create a pyro daemon, and create a task to handle pyro
                # requests
                self.pyro_daemon = self.appli.repo.pyro_register()
                self.pyro_listen_timeout = 0.02
                start_task(1, self.pyro_loop_event)
            self.appli.repo.start_looping_tasks()
        self.set_url_rewriter()
        CW_EVENT_MANAGER.bind('after-registry-reload', self.set_url_rewriter)
        interval = min(config['cleanup-session-time'] or 120,
                       config['cleanup-anonymous-session-time'] or 720) / 2.
        start_task(interval, self.appli.session_handler.clean_sessions)

    def set_url_rewriter(self):
        self.url_rewriter = self.appli.vreg['components'].select_object('urlrewriter')

    def shutdown_event(self):
        """callback fired when the server is shutting down to properly
        clean opened sessions
        """
        self.appli.repo.shutdown()

    def pyro_loop_event(self):
        """listen for pyro events"""
        try:
            self.pyro_daemon.handleRequests(self.pyro_listen_timeout)
        except select.error:
            return

    def locateChild(self, request, segments):
        """Indicate which resource to use to process down the URL's path"""
        if segments:
            if segments[0] == 'https':
                segments = segments[1:]
            if len(segments) >= 2:
                if segments[0] in (self.versioned_datadir, 'data', 'static'):
                    # Anything in data/, static/ is treated as static files
                    if segments[0] == 'static':
                        # instance static directory
                        datadir = self.config.static_directory
                    elif segments[1] == 'fckeditor':
                        fckeditordir = self.config.ext_resources['FCKEDITOR_PATH']
                        return static.File(fckeditordir), segments[2:]
                    else:
                        # cube static data file
                        datadir = self.config.locate_resource(segments[1])
                        if datadir is None:
                            return None, []
                    self.info('static file %s from %s', segments[-1], datadir)
                    if segments[0] == 'data':
                        return static.File(str(datadir)), segments[1:]
                    else:
                        return LongTimeExpiringFile(datadir), segments[1:]
                elif segments[0] == 'fckeditor':
                    fckeditordir = self.config.ext_resources['FCKEDITOR_PATH']
                    return static.File(fckeditordir), segments[1:]
        # Otherwise we use this single resource
        return self, ()

    def render(self, request):
        """Render a page from the root resource"""
        # reload modified files (only in development or debug mode)
        if self.config.mode == 'dev' or self.debugmode:
            self.appli.vreg.register_objects(self.config.vregistry_path())
        if self.config['profile']: # default profiler don't trace threads
            return self.render_request(request)
        else:
            return threads.deferToThread(self.render_request, request)

    def render_request(self, request):
        origpath = request.path
        host = request.host
        # dual http/https access handling: expect a rewrite rule to prepend
        # 'https' to the path to detect https access
        if origpath.split('/', 2)[1] == 'https':
            origpath = origpath[6:]
            request.uri = request.uri[6:]
            https = True
            baseurl = self.https_url or self.base_url
        else:
            https = False
            baseurl = self.base_url
        if self.config['use-request-subdomain']:
            baseurl = host_prefixed_baseurl(baseurl, host)
            self.warning('used baseurl is %s for this request', baseurl)
        req = CubicWebTwistedRequestAdapter(request, self.appli.vreg, https, baseurl)
        if req.authmode == 'http':
            # activate realm-based auth
            realm = self.config['realm']
            req.set_header('WWW-Authenticate', [('Basic', {'realm' : realm })], raw=False)
        try:
            self.appli.connect(req)
        except AuthenticationError:
            return self.request_auth(req)
        except Redirect, ex:
            return self.redirect(req, ex.location)
        if https and req.cnx.anonymous_connection:
            # don't allow anonymous on https connection
            return self.request_auth(req)
        if self.url_rewriter is not None:
            # XXX should occur before authentication?
            try:
                path = self.url_rewriter.rewrite(host, origpath, req)
            except Redirect, ex:
                return self.redirect(req, ex.location)
            request.uri.replace(origpath, path, 1)
        else:
            path = origpath
        if not path or path == "/":
            path = 'view'
        try:
            result = self.appli.publish(path, req)
        except DirectResponse, ex:
            return ex.response
        except StatusResponse, ex:
            return http.Response(stream=ex.content, code=ex.status,
                                 headers=req.headers_out or None)
        except RemoteCallFailed, ex:
            req.set_header('content-type', 'application/json')
            return http.Response(stream=ex.dumps(),
                                 code=responsecode.INTERNAL_SERVER_ERROR)
        except NotFound:
            result = self.appli.notfound_content(req)
            return http.Response(stream=result, code=responsecode.NOT_FOUND,
                                 headers=req.headers_out or None)
        except ExplicitLogin:  # must be before AuthenticationError
            return self.request_auth(req)
        except AuthenticationError:
            if self.config['auth-mode'] == 'cookie':
                # in cookie mode redirecting to the index view is enough :
                # either anonymous connection is allowed and the page will
                # be displayed or we'll be redirected to the login form
                msg = req._('you have been logged out')
                if req.https:
                    req._base_url =  self.base_url
                    req.https = False
                url = req.build_url('view', vid='index', __message=msg)
                return self.redirect(req, url)
            else:
                # in http we have to request auth to flush current http auth
                # information
                return self.request_auth(req, loggedout=True)
        except Redirect, ex:
            return self.redirect(req, ex.location)
        # request may be referenced by "onetime callback", so clear its entity
        # cache to avoid memory usage
        req.drop_entity_cache()
        return http.Response(stream=result, code=responsecode.OK,
                             headers=req.headers_out or None)

    def redirect(self, req, location):
        req.headers_out.setHeader('location', str(location))
        self.debug('redirecting to %s', location)
        # 303 See other
        return http.Response(code=303, headers=req.headers_out)

    def request_auth(self, req, loggedout=False):
        if self.https_url and req.base_url() != self.https_url:
            req.headers_out.setHeader('location', self.https_url + 'login')
            return http.Response(code=303, headers=req.headers_out)
        if self.config['auth-mode'] == 'http':
            code = responsecode.UNAUTHORIZED
        else:
            code = responsecode.FORBIDDEN
        if loggedout:
            if req.https:
                req._base_url =  self.base_url
                req.https = False
            content = self.appli.loggedout_content(req)
        else:
            content = self.appli.need_login_content(req)
        return http.Response(code, req.headers_out, content)

from twisted.python import failure
from twisted.internet import defer
from twisted.web2 import fileupload

# XXX set max file size to 100Mo: put max upload size in the configuration
# line below for twisted >= 8.0, default param value for earlier version
resource.PostableResource.maxSize = 100*1024*1024
def parsePOSTData(request, maxMem=100*1024, maxFields=1024,
                  maxSize=100*1024*1024):
    if request.stream.length == 0:
        return defer.succeed(None)

    ctype = request.headers.getHeader('content-type')

    if ctype is None:
        return defer.succeed(None)

    def updateArgs(data):
        args = data
        request.args.update(args)

    def updateArgsAndFiles(data):
        args, files = data
        request.args.update(args)
        request.files.update(files)

    def error(f):
        f.trap(fileupload.MimeFormatError)
        raise http.HTTPError(responsecode.BAD_REQUEST)

    if ctype.mediaType == 'application' and ctype.mediaSubtype == 'x-www-form-urlencoded':
        d = fileupload.parse_urlencoded(request.stream, keep_blank_values=True)
        d.addCallbacks(updateArgs, error)
        return d
    elif ctype.mediaType == 'multipart' and ctype.mediaSubtype == 'form-data':
        boundary = ctype.params.get('boundary')
        if boundary is None:
            return defer.fail(http.HTTPError(
                http.StatusResponse(responsecode.BAD_REQUEST,
                                    "Boundary not specified in Content-Type.")))
        d = fileupload.parseMultipartFormData(request.stream, boundary,
                                              maxMem, maxFields, maxSize)
        d.addCallbacks(updateArgsAndFiles, error)
        return d
    else:
        raise http.HTTPError(responsecode.BAD_REQUEST)

server.parsePOSTData = parsePOSTData


from logging import getLogger
from cubicweb import set_log_methods
set_log_methods(CubicWebRootResource, getLogger('cubicweb.twisted'))



def _gc_debug():
    import gc
    from pprint import pprint
    from cubicweb.appobject import AppObject
    gc.collect()
    count = 0
    acount = 0
    ocount = {}
    for obj in gc.get_objects():
        if isinstance(obj, CubicWebTwistedRequestAdapter):
            count += 1
        elif isinstance(obj, AppObject):
            acount += 1
        else:
            try:
                ocount[obj.__class__] += 1
            except KeyError:
                ocount[obj.__class__] = 1
            except AttributeError:
                pass
    print 'IN MEM REQUESTS', count
    print 'IN MEM APPOBJECTS', acount
    ocount = sorted(ocount.items(), key=lambda x: x[1], reverse=True)[:20]
    pprint(ocount)
    print 'UNREACHABLE', gc.garbage

def run(config, debug):
    # create the site
    root_resource = CubicWebRootResource(config, debug)
    website = server.Site(root_resource)
    # serve it via standard HTTP on port set in the configuration
    port = config['port'] or 8080
    reactor.listenTCP(port, channel.HTTPFactory(website))
    baseurl = config['base-url'] or config.default_base_url()
    logger = getLogger('cubicweb.twisted')
    logger.info('instance started on %s', baseurl)
    if not debug:
        daemonize()
        if config['pid-file']:
            # ensure the directory where the pid-file should be set exists (for
            # instance /var/run/cubicweb may be deleted on computer restart)
            piddir = os.path.dirname(config['pid-file'])
            if not os.path.exists(piddir):
                os.makedirs(piddir)
            file(config['pid-file'], 'w').write(str(os.getpid()))
    if config['profile']:
        prof = hotshot.Profile(config['profile'])
        prof.runcall(reactor.run)
    else:
        reactor.run()