import email
import re
from rfc822 import parseaddr

from zope.interface import implements
from zope.app.annotation.interfaces import IAnnotations
from zope.app import zapi

from OFS.Folder import Folder
from DateTime import DateTime
from Acquisition import aq_get
from BTrees.OOBTree import OOBTree

from Products.CMFPlone.utils import base_hasattr
from plone.mail import decode_header

from Products.CMFCore.utils import getToolByName

from Products.MailBoxer.MailBoxerTools import convertHTML2Text

from Products.listen.interfaces import IMailMessage
from Products.listen.interfaces import ISearchableArchive
from Products.listen.interfaces import ISearchableMessage
from Products.listen.config import PROJECTNAME
from Products.listen.lib.browser_utils import encode
from Products.listen.content.mailboxer_tools import unpackMail

_marker = []

# split on whitespace
REF_REGEX = re.compile(r'\s+')
CHARSET_REGEX = re.compile(r'charset=([^;\s]+)')


# Perhaps we can be even simpler than Folder
# We need persistence, acquisition, and a few standard methods.  We need to
# enforce permission mappings defined on the parent, but no need for individual
# permissions or roles on mail objects.
class MailMessage(Folder):
    """ A Mailng list implementation
    """

    implements(IMailMessage)

    # Though this is not a CMF type the plone ui expects a portal_type
    meta_type = portal_type = "MailingListMessage"

    body = ''
    message_id = ''
    in_reply_to = ''
    references = ()
    other_headers = ()

    # Stop zope from complaining about 'security declaration for
    # nonexistent method', by ensuring that we have class attributes
    # with all the names listed in IMailMessage.
    from_addr = None
    subject = None
    date = None

    def __init__(self, id, from_addr, subject, date=None, **kwargs):
        self.from_addr = decode_header(from_addr)
        self.subject = decode_header(subject)
        # date is expected to be a DateTime or None
        if not isinstance(date, DateTime):
            self.date = DateTime(date)
        else:
            self.date = date

        sender_name = parseaddr(self.from_addr)[0]

        title_subj = len(self.subject) > 20 and (self.subject[:20]+' ...') \
                         or self.subject
        if sender_name:
            self.title = u"%s / %s" % (title_subj, sender_name)
        else:
            self.title= title_subj

        Folder.__init__(self, id)

    # Provide a Title to make plone happy
    def Title(self):
        """An encoded title"""
        return encode(self.title, self)

    def Description(self):
        """An encoded description"""
        return encode(self.body[:50] + ' ...', self)


class MailFromString(object):
    """An adapter for mail messages that allows them to parse the text of a
       mail message and set all properties appropriately.  Uses
       MailBoxerTools."""

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

    def createMailFromMessage(self, msg_string, attachments=False):
        context = self.context

        (TextBody, ContentType, HtmlBody, Attachments) = unpackMail(msg_string)
        if attachments:
            for file in Attachments:
                self.addAttachment(file['filename'],
                                   file['filebody'],
                                   file['maintype'] + '/' + file['subtype'])

        # This must be encoded text. Attempt to use specificed encoding to
        # convert to unicode, otherwise default to iso-8859-1, which is a
        # a reasonable superset of 7-bit ascii, and more common than utf-8
        # for email.  The RFCs indicate that no specified encoding means 7-bit
        # ascii, so this should be safe.
        encoding = 'iso-8859-1'
        # ContentType is only set for the TextBody
        if ContentType:
            body = TextBody
            # find charset
            encoding_match = CHARSET_REGEX.search(ContentType)
            if encoding_match:
                encoding = encoding_match.groups()[0]
        else:
            body = convertHTML2Text(HtmlBody)

        try:
            body = body.decode(encoding, 'replace')
        except LookupError:
            # The email specified an invalid encoding
            body = body.decode('iso-8859-1', 'replace')

        msg = email.message_from_string(msg_string)
        in_reply_to = msg.get('in-reply-to', context.in_reply_to).strip()
        references = msg.get('references', '').strip()
        # split references on whitespace
        if references:
            references = REF_REGEX.split(references)
        else:
            references = ()
        message_id = msg.get('message-id', context.message_id).strip()
        if not message_id:
            # XXX: This method is acquired inappropriately from the parent
            # MailBoxer for now
            message_id = context.uniqueMessageId()
        # Use a regexp to optionally pull in other headers
        other_headers = []
        # Attempt to acquire the headers regex from our MailingList
        headers_regexp = aq_get(context, 'headers', None)
        if headers_regexp is not None:
            if headers_regexp:
                for (key, value) in msg.items():
                    if (re.match(headers_regexp, key, re.IGNORECASE) and
                        key not in ['subject', 'date', 'from', 'in_reply_to',
                                    'references', 'message_id']):
                        other_headers.append((key, value.strip()))

        context.body = body
        context.in_reply_to = in_reply_to
        context.references = tuple(references)
        context.message_id = message_id
        context.other_headers = tuple(other_headers)

    def addAttachment(self, filename, content, mime_type):
        """Adds a zope file object as an attachemnt"""

        sub_type = mime_type.split('/')[-1]
        attach_id = DateTime().millis()
        # to be sure: test and search for a free id...
        while base_hasattr(self.context, "%s.%s" % (attach_id, sub_type)):
            attach_id = attach_id + 1
        self.context.manage_addFile("%s.%s" % (attach_id, sub_type),
                                    title=filename,
                                    file=content,
                                    content_type=mime_type)


class SearchableMessage(object):
    """An adapter providing the ISearchableMessage interface for MailMessages"""

    implements(ISearchableMessage)

    def __init__(self, context):
        self.context = context
        # This is called during message creation (e.g. from Application), so
        # context needs to be passed explicitly.
        self.search = zapi.getUtility(ISearchableArchive, context=context)
        self.annotations = IAnnotations(context)
        self.list_data = self.annotations.get(PROJECTNAME)
        self._refs_calculated = False
        if self.list_data is None:
            self.list_data = self.annotations[PROJECTNAME] = OOBTree()

    def SearchableText(self):
        """Returns body, subject, and from address."""
        context  = self.context
        return u' '.join([context.body, context.subject, context.from_addr])

    def isInitialMessage(self):
        """Returns True if the object has no references and is not in reply to
           any other messages."""
        context = self.context
        is_reply = (context.references or context.in_reply_to)
        if not is_reply:
            return True
        # Check that parent message exists, if not check to see if any
        # of the references exist.
        if not self.in_reply_to():
            return True
        return False

    def in_reply_to(self):
        """If the parent object is somehow missing check to see if any of the
           referred messages are available"""
        parent = self.list_data.get('index_parent', None)
        if parent:
            return parent
        context = self.context
        parent_message = self.search.resolveMessageId(context.in_reply_to)
        # Return True if parent message is not found in archive
        if parent_message is None:
            references = context.references and \
                         self.search.resolveMessageIds(context.references)
            if len(references):
                self.list_data['index_parent'] = references[-1].message_id
            else:
                self.list_data['index_parent'] = ''
        else:
            self.list_data['index_parent'] = context.in_reply_to
        return self.list_data['index_parent']

    def references(self):
        context = self.context
        list_data = self.list_data
        # This method is called multiple times during indexing, store the
        # result on the object and use it if available.
        if context.in_reply_to and not (self._refs_calculated
                                        or context.references):
            message = context
            parents = []
            # Walk the in_reply_to chain to build the references list
            while message is not None:
                parent = self.search.getParentMessage(message.message_id)
                if parent is not None:
                    parents.append(parent.message_id)
                message = parent
            # initial message should be on top per RFC
            parents.reverse()
            refs = tuple(parents)
            context.references = refs
        else:
            refs = context.references
        if refs and not self._refs_calculated:
            # If we want to be able to make a list of the threads most
            # recently responded to, the we need to also catalog the date of
            # response on the toplevel message.
            # This is an archive viewing optimization which should help
            # tremendously when archives get large, unfortunately it slows
            # down message archiving considerably.  Make sure we never double
            # count.
            # XXX: Setting attributes directly on the mail object is hacky,
            # but does this optimization info really belong in the schema?
            resolved_refs = self.search.resolveMessageIds(refs)
            if resolved_refs and not list_data.has_key('counted_on_parent'):
                # Get the first referenced message and assume it is the start
                # of the thread.
                try:
                    # use unrestricted get object to prevent unauthorized
                    # errors when posting through email
                    initial = resolved_refs[0]._unrestrictedGetObject()
                    annotations = IAnnotations(initial)
                    data = annotations[PROJECTNAME]
                    data['modification_date'] = context.date
                    # Set the count
                    data['responses'] = data.setdefault('responses', 0) + 1
                    self.search.indexNewMessage(initial)
                    # Set an attribute to prevent reupdating the parent, on
                    # reindex.
                    list_data['counted_on_parent'] = True
                except AttributeError:
                    # We can't do a getObject without a request
                    pass
        self._refs_calculated = True
        return refs

    def modification_date(self):
        return self.list_data.get('modification_date', None) or \
                                                        self.context.date
    def responses(self):
        return self.list_data.get('responses', None) or 0

    # Override getattr so that we provide access to the MailMessage properties
    def __getattr__(self, name, default=_marker):
        if default is _marker:
            return getattr(self.context, name)
        else:
            return getattr(self.context, name, default)
