import logging
from functools import singledispatch
from typing import Any
from typing import Dict
from urllib.parse import urlparse

from little_boxes import activitypub as ap

from config import BASE_URL
from config import DB
from core.meta import MetaKey
from core.meta import _meta
from core.meta import by_actor
from core.meta import by_type
from core.meta import in_inbox
from core.meta import not_undo
from core.tasks import Tasks

_logger = logging.getLogger(__name__)

_NewMeta = Dict[str, Any]

_LOCAL_NETLOC = urlparse(BASE_URL).netloc


def _is_from_outbox(activity: ap.BaseActivity) -> bool:
    return activity.id.startswith(BASE_URL)


def _is_local(url: str) -> bool:
    return urlparse(url).netloc == _LOCAL_NETLOC


def _flag_as_notification(activity: ap.BaseActivity, new_meta: _NewMeta) -> None:
    new_meta.update(
        {_meta(MetaKey.NOTIFICATION): True, _meta(MetaKey.NOTIFICATION_UNREAD): True}
    )
    return None


def _set_flag(meta: _NewMeta, meta_key: MetaKey, value: Any = True) -> None:
    meta.update({_meta(meta_key): value})
    return None


@singledispatch
def set_inbox_flags(activity: ap.BaseActivity, new_meta: _NewMeta) -> None:
    _logger.warning(f"skipping {activity!r}")
    return None


@set_inbox_flags.register
def _accept_set_inbox_flags(activity: ap.Accept, new_meta: _NewMeta) -> None:
    """Handle notifications for "accepted" following requests."""
    _logger.info(f"set_inbox_flags activity={activity!r}")
    # Check if this actor already follow us back
    follows_back = False
    follow_query = {
        **in_inbox(),
        **by_type(ap.ActivityType.FOLLOW),
        **by_actor(activity.get_actor()),
        **not_undo(),
    }
    raw_follow = DB.activities.find_one(follow_query)
    if raw_follow:
        follows_back = True

        DB.activities.update_many(
            follow_query, {"$set": {_meta(MetaKey.NOTIFICATION_FOLLOWS_BACK): True}}
        )

    # This Accept will be a "You started following $actor" notification
    _flag_as_notification(activity, new_meta)
    _set_flag(new_meta, MetaKey.GC_KEEP)
    _set_flag(new_meta, MetaKey.NOTIFICATION_FOLLOWS_BACK, follows_back)
    return None


@set_inbox_flags.register
def _follow_set_inbox_flags(activity: ap.Follow, new_meta: _NewMeta) -> None:
    """Handle notification for new followers."""
    _logger.info(f"set_inbox_flags activity={activity!r}")
    # Check if we're already following this actor
    follows_back = False
    accept_query = {
        **in_inbox(),
        **by_type(ap.ActivityType.ACCEPT),
        **by_actor(activity.get_actor()),
        **not_undo(),
    }
    raw_accept = DB.activities.find_one(accept_query)
    if raw_accept:
        follows_back = True

        DB.activities.update_many(
            accept_query, {"$set": {_meta(MetaKey.NOTIFICATION_FOLLOWS_BACK): True}}
        )

    # This Follow will be a "$actor started following you" notification
    _flag_as_notification(activity, new_meta)
    _set_flag(new_meta, MetaKey.GC_KEEP)
    _set_flag(new_meta, MetaKey.NOTIFICATION_FOLLOWS_BACK, follows_back)
    return None


@set_inbox_flags.register
def _like_set_inbox_flags(activity: ap.Like, new_meta: _NewMeta) -> None:
    _logger.info(f"set_inbox_flags activity={activity!r}")
    # Is it a Like of local acitivty/from the outbox
    if _is_from_outbox(activity.get_object()):
        # Flag it as a notification
        _flag_as_notification(activity, new_meta)

        # Cache the object (for display on the notifcation page)
        Tasks.cache_object(activity.id)

        # Also set the "keep mark" for the GC (as we want to keep it forever)
        _set_flag(new_meta, MetaKey.GC_KEEP)

    return None


@set_inbox_flags.register
def _announce_set_inbox_flags(activity: ap.Announce, new_meta: _NewMeta) -> None:
    _logger.info(f"set_inbox_flags activity={activity!r}")
    # Is it a Like of local acitivty/from the outbox
    if _is_from_outbox(activity.get_object()):
        # Flag it as a notification
        _flag_as_notification(activity, new_meta)

        # Also set the "keep mark" for the GC (as we want to keep it forever)
        _set_flag(new_meta, MetaKey.GC_KEEP)

    # Cache the object in all case (for display on the notifcation page **and** the stream page)
    Tasks.cache_object(activity.id)
    # Display it in the stream
    _set_flag(new_meta, MetaKey.STREAM)

    return None


@set_inbox_flags.register
def _undo_set_inbox_flags(activity: ap.Undo, new_meta: _NewMeta) -> None:
    _logger.info(f"set_inbox_flags activity={activity!r}")
    obj = activity.get_object()

    if obj.has_type(ap.ActivityType.FOLLOW):
        # Flag it as a noticiation (for the "$actor unfollowed you"
        _flag_as_notification(activity, new_meta)

        # Also set the "keep mark" for the GC (as we want to keep it forever)
        _set_flag(new_meta, MetaKey.GC_KEEP)

    return None


@set_inbox_flags.register
def _create_set_inbox_flags(activity: ap.Create, new_meta: _NewMeta) -> None:
    _logger.info(f"set_inbox_flags activity={activity!r}")
    obj = activity.get_object()

    _set_flag(new_meta, MetaKey.POLL_ANSWER, False)

    in_reply_to = obj.get_in_reply_to()

    # Check if it's a local reply
    if in_reply_to and _is_local(in_reply_to):
        # TODO(tsileo): fetch the reply to check for poll answers more precisely
        # reply_of = ap.fetch_remote_activity(in_reply_to)

        # Ensure it's not a poll answer
        if obj.name and not obj.content:
            _set_flag(new_meta, MetaKey.POLL_ANSWER)
            return None

        # Flag it as a notification
        _flag_as_notification(activity, new_meta)

        # Also set the "keep mark" for the GC (as we want to keep it forever)
        _set_flag(new_meta, MetaKey.GC_KEEP)

        return None

    # Check for mention
    for mention in obj.get_mentions():
        if mention.href and _is_local(mention.href):
            # Flag it as a notification
            _flag_as_notification(activity, new_meta)

            # Also set the "keep mark" for the GC (as we want to keep it forever)
            _set_flag(new_meta, MetaKey.GC_KEEP)

    if not in_reply_to:
        # A good candidate for displaying in the stream
        _set_flag(new_meta, MetaKey.STREAM)

    return None