#!/usr/bin/env python
#
# Author: Sascha Silbe <sascha-pgp@silbe.org> (OpenPGP signed mails only)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3
# as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from BaseHTTPServer import HTTPServer
from SocketServer import ThreadingMixIn
import cgi
import cStringIO as StringIO
import gzip
import logging
import optparse
import os
import ssl
import sys
import time
import urllib
from urlparse import urljoin, urlparse

__pychecker__ = 'no-miximport'
try:
    from pywebdav.lib import propfind
except ImportError:
    # pywebdav < 0.9.8
    __pychecker__ = 'no-reimport'
    from DAV import propfind
    from DAV.constants import COLLECTION, OBJECT
    from DAV.iface import dav_interface
    from DAV.errors import DAV_Error, DAV_NotFound, DAV_Requested_Range_Not_Satisfiable
    from DAVServer.fileauth import DAVAuthHandler
    from xml.parsers.expat import ExpatError
    _PYWEBDAV_BUGS = set(['PROPFIND_NS', 'ALLPROP_RECURSE'])
else:
    from pywebdav.lib.constants import COLLECTION, OBJECT
    from pywebdav.lib.iface import dav_interface
    from pywebdav.lib.errors import DAV_Error, DAV_NotFound, DAV_Requested_Range_Not_Satisfiable
    from pywebdav.lib.WebDAVServer import DAVRequestHandler as DAVAuthHandler
    __pychecker__ = 'no-reimport'
    from xml.parsers.expat import ExpatError
    _PYWEBDAV_BUGS = set(['ALLPROP_RECURSE', 'HTTP10_KEEPALIVE'])

if 'ALLPROP_RECURSE' in _PYWEBDAV_BUGS:
    import xml.dom.minidom
    domimpl = xml.dom.minidom.getDOMImplementation()


# from sugar.logger import trace

import fsemulation


DS_DBUS_SERVICE = 'org.laptop.sugar.DataStore'
DS_DBUS_INTERFACE1 = 'org.laptop.sugar.DataStore'
DS_DBUS_PATH1 = '/org/laptop/sugar/DataStore'
DS_DBUS_INTERFACE2 = 'org.laptop.sugar.DataStore2'
DS_DBUS_PATH2 = '/org/laptop/sugar/DataStore2'

SUGAR_NS = 'http://people.sugarlabs.org/silbe/webdavns/sugar'
#SCHEMA_NS = 'http://www.w3.org/2001/XMLSchema'
INVALID_XML_CHARS = [unichr(i) for i in range(0, 0x20)
                     if i not in [0x09, 0x0A, 0x0D]]
CHUNK_SIZE = 65536


log = None


class ThreadedHTTPServer(ThreadingMixIn, HTTPServer):
    """Handle requests in a separate thread."""


class PROPFIND(propfind.PROPFIND):
    __pychecker__ = 'no-override'

    if 'PROPFIND_NS' in _PYWEBDAV_BUGS:
        # pylint: disable=C0324,C0322
        def mk_propname_response(self,uri,propnames,doc):
            # copy of original, but with bug fix for multiple namespaces
            re=doc.createElement("D:response")

            # write href information
            uparts=urlparse(uri)
            fileloc=uparts[2]
            href=doc.createElement("D:href")
            huri=doc.createTextNode(uparts[0]+'://'+'/'.join(uparts[1:2]) + urllib.quote(fileloc))
            href.appendChild(huri)
            re.appendChild(href)

            ps=doc.createElement("D:propstat")
            nsnum=0

            for ns,plist in propnames.items():
                # write prop element
                pr=doc.createElement("D:prop")
                nsp="ns"+str(nsnum)
                pr.setAttribute("xmlns:"+nsp,ns)
                nsnum=nsnum+1

                # write propertynames
                for p in plist:
                    pe=doc.createElement(nsp+":"+p)
                    pr.appendChild(pe)

                ps.appendChild(pr)

            re.appendChild(ps)

            return re

    if 'ALLPROP_RECURSE' in _PYWEBDAV_BUGS:
        # work-around for Debian#710690

        def create_allprop(self):
            return self.create_prop(True)

        def create_prop(self, allprop=False):
            # create the document generator
            doc = domimpl.createDocument(None, "multistatus", None)
            ms = doc.documentElement
            ms.setAttribute("xmlns:D", "DAV:")
            ms.tagName = 'D:multistatus'

            if self._depth == "0":
                if allprop:
                    self.proplist = self._dataclass.get_propnames(self._uri)
                    self.namespaces = self.proplist.keys()
                gp, bp = self.get_propvalues(self._uri)
                res = self.mk_prop_response(self._uri, gp, bp, doc)
                ms.appendChild(res)

            elif self._depth == "1":
                if allprop:
                    self.proplist = self._dataclass.get_propnames(self._uri)
                    self.namespaces = self.proplist.keys()
                gp, bp = self.get_propvalues(self._uri)
                res = self.mk_prop_response(self._uri, gp, bp, doc)
                ms.appendChild(res)

                for newuri in self._dataclass.get_childs(self._uri):
                    if allprop:
                        self.proplist = self._dataclass.get_propnames(newuri)
                        self.namespaces = self.proplist.keys()
                    gp, bp = self.get_propvalues(newuri)
                    res = self.mk_prop_response(newuri, gp, bp, doc)
                    ms.appendChild(res)
            elif self._depth == 'infinity':
                uri_list = [self._uri]
                while uri_list:
                    uri = uri_list.pop()
                    if allprop:
                        self.proplist = self._dataclass.get_propnames(uri)
                        self.namespaces = self.proplist.keys()
                    gp, bp = self.get_propvalues(uri)
                    res = self.mk_prop_response(uri, gp, bp, doc)
                    ms.appendChild(res)
                    uri_childs = self._dataclass.get_childs(uri)
                    if uri_childs:
                        uri_list.extend(uri_childs)

            return doc.toxml(encoding="utf-8")


class WebdavResource(object):
    def __len__(self):
        raise NotImplementedError('Not implemented by subclass')

    def __iter__(self):
        raise NotImplementedError('Not implemented by subclass')

    def read(self, length=0):
        __pychecker__ = 'no-argsused'
        raise NotImplementedError('Not implemented by subclass')


class JournalObjectResource(WebdavResource):
    def __init__(self, fs_object):
        path = fs_object.get_data()
        if path:
            self._file = file(path)
            os.remove(path)
            self._size = os.fstat(self._file.fileno()).st_size
        else:
            self._file = None
            self._size = 0

    def __len__(self):
        return self._size

    def __iter__(self):
        while self._size:
            data = self._file.read(CHUNK_SIZE)
            if not data:
                break

            yield data

        if self._file is not None:
            self._file.close()
            self._file = None

    def read(self, length=0):
        return self._file.read(length or self._size)


class BufferResource(WebdavResource):
    def __init__(self):
        self._position = 0
        self._buffer = ''

    def __len__(self):
        return len(self._buffer)

    def __iter__(self):
        while self._position < len(self._buffer):
            yield self._buffer[self._position:self._position + CHUNK_SIZE]
            self._position += CHUNK_SIZE

    def read(self, length=0):
        old_position = self._position
        self._position += length or len(self._buffer)
        return self._buffer[old_position:self._position]


class ObjectListHtmlResource(BufferResource):

    def __init__(self, directory, footer=None):
        super(ObjectListHtmlResource, self).__init__()
        self._buffer = self._generate_html(directory, footer)

    def _generate_html(self, directory, footer=None):
        lines = ['<html>', '<head><title>Journal listing</title></head>',
                 '<body>','<table>', '<tr><th>Name</th></tr>']

        for name, fs_object in directory.readdir():
            if name == '.':
                continue

            lines.append(self._generate_html_entry(name, fs_object))

        lines += ['</table>']

        if isinstance(footer, list):
            lines += footer
        elif isinstance(footer, basestring):
            lines += [footer]

        lines += ['</html>']
        return '\n'.join(lines)

    def _generate_html_entry(self, name, fs_object):
        url = urllib.quote(name.encode('utf-8'))
        escaped_name = cgi.escape(name.encode('utf-8'))
        if isinstance(fs_object, fsemulation.Directory):
            return '<tr><td><a href="%s/">%s/</a></td></tr>' % (url,
                                                                escaped_name)
        else:
            return '<tr><td><a href="%s">%s</a></td></tr>' % (url,
                                                              escaped_name)



class JournalHandler(dav_interface):

    PROPS={"DAV:" : ('creationdate',
                     'getcontentlength',
                     'getcontenttype',
                     'getlastmodified',
                     'resourcetype')}

    def __init__(self, file_system, base_uri, verbose=False):
        self._fs = file_system
        # required by dav_interface resp. PROPFIND
        self.baseuri = base_uri
        self.baseurl = base_uri
        self.verbose = verbose

    def exists(self, uri):
        log.debug('exists %r', uri)
        try:
            self._lookup_uri(uri)
        except DAV_Error:
            return False
        else:
            return True

    def get_propnames(self, uri):
        log.debug('get_propnames %r', uri)
        props_by_ns = dict(self.PROPS)
        fs_object = self._lookup_uri(uri)
        if isinstance(fs_object, fsemulation.DSObject):
            props_by_ns[SUGAR_NS] = fs_object.list_properties()

        log.debug('props_by_ns=%r', props_by_ns)
        return props_by_ns

    def get_prop(self, uri, ns, propname):
        if ns != SUGAR_NS:
            return dav_interface.get_prop(self, uri, ns, propname)

        log.debug('get_prop %r %r %r', uri, ns, propname)
        fs_object = self._lookup_uri(uri)
        if isinstance(fs_object, fsemulation.DSObject):
            metadata = fs_object.get_properties([propname])
            if propname not in metadata:
                raise DAV_NotFound

            value = metadata[propname]
            if isinstance(value, unicode):
                if not [c for c in value if c in INVALID_XML_CHARS]:
                    return value
                else:
                    # contains control characters => return as binary string
                    # (base64 encoded)
                    value = value.encode('utf-8')

            # binary data (e.g. PNG previews)

            # FIXME: We can't add an XML element containing a text
            # node since the xml.dom.minidom implementation requires
            # the Document object for instantiating Nodes, but
            # propfind.PROPFIND does not pass the Document object down
            # (and there's not even private API to access it as it's a
            # local variable). So the only thing we can return is a
            # plain string.
            #element = document.Element('base64Binary', SCHEMA_NS)
            #text_node = document.createTextNode(value.encode('base64'))
            #element.appendChild(text_node)
            return 'base64:' + value.encode('base64')


        raise DAV_NotFound

    def get_childs(self, uri):
        """Return the child objects of the given URI as absolute URIs."""
        scheme, netloc = urlparse(str(uri))[:2]
        path = unicode(urlparse(str(uri))[2], 'utf-8').strip('/')
        log.debug('get_childs %r', uri)
        fs_object = self._lookup_uri(uri)
        if not isinstance(fs_object, fsemulation.Directory):
            # PROPFIND.create_prop() recurses over all entities without
            # checking is_collection() first.
            return []

        if path:
            path += u'/'
        return ['%s://%s/%s%s' % (scheme, netloc, path.encode('utf-8'),
                                      child_name.encode('utf-8'))
                for child_name in fs_object.listdir()
                if not child_name in ['.', '..']]

    def get_data(self, uri, byte_range=None):
        __pychecker__ = 'no-returnvalues'
        log.debug('get_data %r %r', uri, byte_range)
        fs_object = self._lookup_uri(uri)

        if isinstance(fs_object, fsemulation.Directory):
            return ObjectListHtmlResource(fs_object)
        else:
            return JournalObjectResource(fs_object)

    def _get_dav_resourcetype(self, uri):
        log.debug('_get_dav_resourcetype %r', uri)
        fs_object = self._lookup_uri(uri)
        if isinstance(fs_object, fsemulation.Directory):
            return COLLECTION
        else:
            return OBJECT

    def _get_dav_getcontentlength(self, uri):
        log.debug('_get_dav_getcontentlength %r', uri)
        fs_object = self._lookup_uri(uri)
        if isinstance(fs_object, fsemulation.DSObject):
            return str(fs_object.get_size())
        else:
            # In theory, we should return the size of the HTML block
            # we return on a GET request on this directory. However,
            # native WebDAV clients are usually not used to download
            # the GET representation of a collection and non-WebDAV
            # clients don't request a WebDAV listing containing this
            # property. So as it's expensive to calculate (we need to
            # construct the full HTML block to determine the length),
            # we just claim it is empty and hope nothing breaks.
            return '0'

    def _get_dav_getcontenttype(self, uri):
        log.debug('_get_dav_getcontenttype %r', uri)
        fs_object = self._lookup_uri(uri)
        if isinstance(fs_object, fsemulation.Directory):
            return 'text/html; charset=utf-8'
        elif isinstance(fs_object, fsemulation.DSObject):
            metadata = fs_object.get_properties(['mime_type'])
            return str(metadata.get('mime_type', 'application/octet-stream'))

        raise DAV_NotFound

    def get_creationdate(self, uri):
        log.debug('get_creationdate %r', uri)
        fs_object = self._lookup_uri(uri)
        if not isinstance(fs_object, fsemulation.DSObject):
            return time.time()

        props = fs_object.get_properties(['creation_time', 'timestamp'])
        try:
            return float(props['creation_time'])
        except (KeyError, ValueError, TypeError):
            pass

        try:
            return float(props['timestamp'])
        except (KeyError, ValueError, TypeError):
            return time.time()

    def get_lastmodified(self, uri):
        log.debug('get_lastmodified %r', uri)
        fs_object = self._lookup_uri(uri)
        if not isinstance(fs_object, fsemulation.DSObject):
            return time.time()

        props = fs_object.get_properties(['timestamp'])
        try:
            return float(props['timestamp'])
        except (KeyError, ValueError, TypeError):
            return time.time()

    def is_collection(self, uri):
        log.debug('is_collection %r', uri)
        fs_object = self._lookup_uri(uri)
        return isinstance(fs_object, fsemulation.Directory)

    def _lookup_uri(self, uri):
        path = unicode(urlparse(str(uri))[2], 'utf-8')
        return self._lookup_path(path)

    def _lookup_path(self, path):
        try:
            # WebDAV doesn't support symlinks :-/
            fs_object = self._fs.resolve(path, follow_links=True)
        except (IOError, ValueError):
            # FIXME: better error mapping
            raise DAV_NotFound

        return fs_object

    def _parse_range(self, byte_range, size):
        if not byte_range or not byte_range[0]:
            start = 0
        else:
            start = int(byte_range[0])

        if not byte_range or not byte_range[1]:
            end = size
        else:
            end = min(int(byte_range[1]), size)

        if start > size:
            raise DAV_Requested_Range_Not_Satisfiable

        return start, end


class _DummyConfigDAV:
    def __init__(self, **kw):
        self.__dict__.update(**kw)

    def getboolean(self, name):
        return (str(getattr(self, name, 0)) in ('1', "yes", "true", "on", "True"))


def setupDummyConfig(**kw):
    class DummyConfig:
        DAV = _DummyConfigDAV(**kw)
    return DummyConfig()


class RequestHandler(DAVAuthHandler):
    protocol_version = 'HTTP/1.1'

    # These class attributes need to be overridden at run-time.
    IFACE_CLASS = None
    _config = None

    if 'ALLPROP_RECURSE' in _PYWEBDAV_BUGS or 'PROPFIND_NS' in _PYWEBDAV_BUGS:
        # pylint: disable=W0402,W0404,C0324,W0612
        def do_PROPFIND(self):
            from string import atoi
            # exact copy of original, just to override the PROPFIND class

            dc = self.IFACE_CLASS

            # read the body containing the xml request
            # iff there is no body then this is an ALLPROP request
            body = None
            if 'Content-Length' in self.headers:
                l = self.headers['Content-Length']
                body = self.rfile.read(atoi(l))

            uri = urljoin(self.get_baseuri(dc), self.path)
            uri = urllib.unquote(uri)

            try:
                pf = PROPFIND(uri, dc, self.headers.get('Depth', 'infinity'), body)
            except ExpatError:
                # parse error
                return self.send_status(400)

            try:
                DATA = '%s\n' % pf.createResponse()
            except DAV_Error, (ec,dd):
                return self.send_status(ec)

            # work around MSIE DAV bug for creation and modified date
            # taken from Resource.py @ Zope webdav
            if (self.headers.get('User-Agent') ==
                'Microsoft Data Access Internet Publishing Provider DAV 1.1'):
                DATA = DATA.replace('<ns0:getlastmodified xmlns:ns0="DAV:">',
                                    '<ns0:getlastmodified xmlns:n="DAV:" '
                                    'xmlns:b="urn:uuid:'
                                    'c2f41010-65b3-11d1-a29f-00aa00c14882/" '
                                    'b:dt="dateTime.rfc1123">')
                DATA = DATA.replace('<ns0:creationdate xmlns:ns0="DAV:">',
                                    '<ns0:creationdate xmlns:n="DAV:" '
                                    'xmlns:b="urn:uuid:'
                                    'c2f41010-65b3-11d1-a29f-00aa00c14882/" '
                                    'b:dt="dateTime.tz">')

            self.send_body_chunks_if_http11(DATA, 207, 'Multi-Status',
                                            'Multiple responses')

    if 'HTTP10_KEEPALIVE' in _PYWEBDAV_BUGS:
        # work-around for Debian#710672

        def send_body(self, DATA, code=None, msg=None, desc=None,
                      ctype='application/octet-stream', headers={}):
            """ send a body in one part """
            __pychecker__ = 'no-argsused no-moddefvalue no-shadowbuiltin'
            log.debug("Use send_body method")

            if self.request_version != 'HTTP/1.1':
                headers.pop('Keep-Alive', None)
                headers.pop('Connection', None)

            self.send_response(code, message=msg)
            if 'Connection' not in headers:
                self.send_header("Connection", "close")
            self.send_header("Accept-Ranges", "bytes")

            self._send_dav_version()

            for a, v in headers.items():
                self.send_header(a, v)

            if DATA:
                if 'gzip' in self.headers.get('Accept-Encoding', '').split(',') \
                        and len(DATA) > self.encode_threshold:
                    buffer = StringIO.StringIO()
                    output = gzip.GzipFile(mode='wb', fileobj=buffer)
                    if isinstance(DATA, str) or isinstance(DATA, unicode):
                        output.write(DATA)
                    else:
                        for buf in DATA:
                            output.write(buf)
                    output.close()
                    buffer.seek(0)
                    DATA = buffer.getvalue()
                    self.send_header('Content-Encoding', 'gzip')

                self.send_header('Content-Length', len(DATA))
                self.send_header('Content-Type', ctype)
            else:
                self.send_header('Content-Length', 0)

            self.end_headers()
            if DATA:
                if isinstance(DATA, str) or isinstance(DATA, unicode):
                    log.debug("Don't use iterator")
                    self.wfile.write(DATA)
                else:
                    if self._config.DAV.getboolean('http_response_use_iterator'):
                        # Use iterator to reduce using memory
                        log.debug("Use iterator")
                        for buf in DATA:
                            self.wfile.write(buf)
                            self.wfile.flush()
                    else:
                        # Don't use iterator, it's a compatibility option
                        log.debug("Don't use iterator")
                        self.wfile.write(DATA.read())

    def log_message(self, format, *args):
        # pylint: disable=W0622
        log.info('%s - - [%s] %s', self.address_string(),
                 self.log_date_time_string(), format % args)


def main():
    global log

    parser = optparse.OptionParser()
    parser.add_option('-d', '--debug', action='store_true', default=False,
                      help='enable additional debugging output')
    parser.add_option('-H', '--host', default='localhost', metavar='HOST',
                      help='bind to HOST; use empty string to listen on all'
                      ' interfaces [default: %default]')
    parser.add_option('-p', '--port', default=8009, metavar='PORT', type='int',
                      help='listen on PORT [default: %default]')
    parser.add_option('-r', '--root-query', default="{'keep': '1'}",
                      metavar='QUERY', help='publish all data store entries'
                      ' matching the data store query QUERY'
                      ' [default: %default]')
    parser.add_option('-q', '--quiet', action='store_false', dest='verbose',
                      help='only output warnings and errors')
    parser.add_option('-v', '--verbose', action='store_true', default=True,
                      help='override a previous -q or --quiet option')
    parser.add_option('--private-key', metavar='FILE',
                      help='private key file for TLS (enables TLS)')
    parser.add_option('--certificate', metavar='FILE',
                      help='X.509 certificate file for TLS (required for TLS)')
    parser.add_option('--tls-protocol', metavar='MODE', default='TLSv1',
                      choices=('SSLv23', 'TLSv1'),
                      help='TLS protocol to use (affects compatibility with'
                      ' clients) [choices: %choices, default: %default]')
    parser.add_option('--ca-certificates', metavar='FILE',
                      help='X.509 CA certificates to verify client'
                      ' certificates against (required when requesting client'
                      ' certificates)')
    parser.add_option('--client-certificate', metavar='MODE', default='none',
                      choices=('none', 'optional', 'required'),
                      help='whether to request and/or require a client'
                      ' certificate [choices: %choices, default: %default]')
    options, args = parser.parse_args()
    if args:
        parser.error('extra arguments passed')
    if options.private_key and not options.certificate:
        parser.error('Need server certificate in TLS mode')
    if options.client_certificate != 'none' and not options.ca_certificates:
        parser.error('Need CA certificates when requesting client'
                     ' certificates')

    root_query = eval(options.root_query)

    if options.debug:
        logging.basicConfig(level=0)
    elif options.verbose:
        logging.basicConfig(level=logging.INFO)
    else:
        logging.basicConfig(level=logging.WARNING)
    log = logging.getLogger('journal2webdav')

    emulated_fs = fsemulation.FSEmulation(root_query)

    handler = RequestHandler
    if options.private_key:
        base_url = 'https://%s:%d' % (options.host, options.port)
    else:
        base_url = 'http://%s:%d' % (options.host, options.port)
    handler.IFACE_CLASS = JournalHandler(emulated_fs, base_url, options.debug)
    handler.DO_AUTH = False
    handler.IFACE_CLASS.mimecheck = True  # pylint: disable=W0201

    handler._config = setupDummyConfig(verbose=options.debug,
                                       port=options.port, host=options.host,
                                       noauth=True, chunked_http_response=True)

    runner = ThreadedHTTPServer((options.host, options.port), handler)
    if options.private_key:
        cert_reqs = getattr(ssl, 'CERT_' + options.client_certificate.upper())
        ssl_version = getattr(ssl, 'PROTOCOL_' + options.tls_protocol)
        runner.socket = ssl.wrap_socket(
            runner.socket, server_side=True, certfile=options.certificate,
            keyfile=options.private_key, ssl_version=ssl_version,
            ca_certs=options.ca_certificates, cert_reqs=cert_reqs)

    log.info('Server running on %s', base_url)
    try:
        runner.serve_forever()
    except KeyboardInterrupt:
        log.info('Killed by user')

    return 0


if __name__ == '__main__':
    sys.exit(main())