#!/usr/bin/env python3

# Libervia plugin for XEP-0084
# Copyright (C) 2009-2022 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# 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 Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from typing import Optional, Dict, Any
from pathlib import Path
from base64 import b64decode, b64encode

from twisted.internet import defer
from twisted.words.protocols.jabber.xmlstream import XMPPHandler
from twisted.words.protocols.jabber import jid, error
from twisted.words.xish import domish
from zope.interface import implementer
from wokkel import disco, iwokkel, pubsub

from libervia.backend.core.constants import Const as C
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger
from libervia.backend.core.core_types import SatXMPPEntity
from libervia.backend.core import exceptions


log = getLogger(__name__)

IMPORT_NAME = "XEP-0084"

PLUGIN_INFO = {
    C.PI_NAME: "User Avatar",
    C.PI_IMPORT_NAME: IMPORT_NAME,
    C.PI_TYPE: C.PLUG_TYPE_XEP,
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0084"],
    C.PI_DEPENDENCIES: ["IDENTITY", "XEP-0060", "XEP-0163"],
    C.PI_MAIN: "XEP_0084",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""XEP-0084 (User Avatar) implementation"""),
}

NS_AVATAR = "urn:xmpp:avatar"
NS_AVATAR_METADATA = f"{NS_AVATAR}:metadata"
NS_AVATAR_DATA = f"{NS_AVATAR}:data"


class XEP_0084:
    namespace_metadata = NS_AVATAR_METADATA
    namespace_data = NS_AVATAR_DATA

    def __init__(self, host):
        log.info(_("XEP-0084 (User Avatar) plugin initialization"))
        host.register_namespace("avatar_metadata", NS_AVATAR_METADATA)
        host.register_namespace("avatar_data", NS_AVATAR_DATA)
        self.host = host
        self._p = host.plugins["XEP-0060"]
        self._i = host.plugins['IDENTITY']
        self._i.register(
            IMPORT_NAME,
            "avatar",
            self.get_avatar,
            self.set_avatar,
            priority=2000
        )
        host.plugins["XEP-0163"].add_pep_event(
            None, NS_AVATAR_METADATA, self._on_metadata_update
        )

    def get_handler(self, client):
        return XEP_0084_Handler()

    def _on_metadata_update(self, itemsEvent, profile):
        client = self.host.get_client(profile)
        defer.ensureDeferred(self.on_metadata_update(client, itemsEvent))

    async def on_metadata_update(
        self,
        client: SatXMPPEntity,
        itemsEvent: pubsub.ItemsEvent
    ) -> None:
        entity = client.jid.userhostJID()
        avatar_metadata = await self.get_avatar(client, entity)
        await self._i.update(client, IMPORT_NAME, "avatar", avatar_metadata, entity)

    async def get_avatar(
            self,
            client: SatXMPPEntity,
            entity_jid: jid.JID
        ) -> Optional[dict]:
        """Get avatar data

        @param entity: entity to get avatar from
        @return: avatar metadata, or None if no avatar has been found
        """
        service = entity_jid.userhostJID()
        # metadata
        try:
            items, __ = await self._p.get_items(
                client,
                service,
                NS_AVATAR_METADATA,
                max_items=1
            )
        except exceptions.NotFound:
            return None

        if not items:
            return None

        item_elt = items[0]
        try:
            metadata_elt = next(item_elt.elements(NS_AVATAR_METADATA, "metadata"))
        except StopIteration:
            log.warning(f"missing metadata element: {item_elt.toXml()}")
            return None

        for info_elt in metadata_elt.elements(NS_AVATAR_METADATA, "info"):
            try:
                metadata = {
                    "id": str(info_elt["id"]),
                    "size": int(info_elt["bytes"]),
                    "media_type": str(info_elt["type"])
                }
                avatar_id = metadata["id"]
                if not avatar_id:
                    raise ValueError
            except (KeyError, ValueError):
                log.warning(f"invalid <info> element: {item_elt.toXml()}")
                return None
            # FIXME: to simplify, we only handle image/png for now
            if metadata["media_type"] == "image/png":
                break
        else:
            # mandatory image/png is missing, or avatar is disabled
            # (https://xmpp.org/extensions/xep-0084.html#pub-disable)
            return None

        cache_data = self.host.common_cache.get_metadata(avatar_id)
        if not cache_data:
            try:
                data_items, __ = await self._p.get_items(
                    client,
                    service,
                    NS_AVATAR_DATA,
                    item_ids=[avatar_id]
                )
                data_item_elt = data_items[0]
            except (error.StanzaError, IndexError) as e:
                log.warning(
                    f"Can't retrieve avatar of {service.full()} with ID {avatar_id!r}: "
                    f"{e}"
                )
                return None
            try:
                avatar_buf = b64decode(
                    str(next(data_item_elt.elements(NS_AVATAR_DATA, "data")))
                )
            except Exception as e:
                log.warning(
                    f"invalid data element for {service.full()} with avatar ID "
                    f"{avatar_id!r}: {e}\n{data_item_elt.toXml()}"
                )
                return None
            with self.host.common_cache.cache_data(
                IMPORT_NAME,
                avatar_id,
                metadata["media_type"]
            ) as f:
                f.write(avatar_buf)
                cache_data = {
                    "path": Path(f.name),
                    "mime_type": metadata["media_type"]
                }

        return self._i.avatar_build_metadata(
                cache_data['path'], cache_data['mime_type'], avatar_id
        )

    def build_item_data_elt(self, avatar_data: Dict[str, Any]) -> domish.Element:
        """Generate the item for the data node

        @param avatar_data: data as build by identity plugin (need to be filled with
            "cache_uid" and "base64" keys)
        """
        data_elt = domish.Element((NS_AVATAR_DATA, "data"))
        data_elt.addContent(avatar_data["base64"])
        return pubsub.Item(id=avatar_data["cache_uid"], payload=data_elt)

    def build_item_metadata_elt(self, avatar_data: Dict[str, Any]) -> domish.Element:
        """Generate the item for the metadata node

        @param avatar_data: data as build by identity plugin (need to be filled with
            "cache_uid", "path", and "media_type" keys)
        """
        metadata_elt = domish.Element((NS_AVATAR_METADATA, "metadata"))
        info_elt = metadata_elt.addElement("info")
        # FIXME: we only fill required elements for now (see
        #        https://xmpp.org/extensions/xep-0084.html#table-1)
        info_elt["id"] = avatar_data["cache_uid"]
        info_elt["type"] = avatar_data["media_type"]
        info_elt["bytes"] = str(avatar_data["path"].stat().st_size)
        return pubsub.Item(id=self._p.ID_SINGLETON, payload=metadata_elt)

    async def set_avatar(
        self,
        client: SatXMPPEntity,
        avatar_data: Dict[str, Any],
        entity: jid.JID
    ) -> None:
        """Set avatar of the profile

        @param avatar_data(dict): data of the image to use as avatar, as built by
            IDENTITY plugin.
        @param entity(jid.JID): entity whose avatar must be changed
        """
        service = entity.userhostJID()

        # Data
        await self._p.create_if_new_node(
            client,
            service,
            NS_AVATAR_DATA,
            options={
                self._p.OPT_ACCESS_MODEL: self._p.ACCESS_OPEN,
                self._p.OPT_PERSIST_ITEMS: 1,
                self._p.OPT_MAX_ITEMS: 1,
            }
        )
        item_data_elt = self.build_item_data_elt(avatar_data)
        await self._p.send_items(client, service, NS_AVATAR_DATA, [item_data_elt])

        # Metadata
        await self._p.create_if_new_node(
            client,
            service,
            NS_AVATAR_METADATA,
            options={
                self._p.OPT_ACCESS_MODEL: self._p.ACCESS_OPEN,
                self._p.OPT_PERSIST_ITEMS: 1,
                self._p.OPT_MAX_ITEMS: 1,
            }
        )
        item_metadata_elt = self.build_item_metadata_elt(avatar_data)
        await self._p.send_items(client, service, NS_AVATAR_METADATA, [item_metadata_elt])


@implementer(iwokkel.IDisco)
class XEP_0084_Handler(XMPPHandler):

    def getDiscoInfo(self, requestor, service, nodeIdentifier=""):
        return [
            disco.DiscoFeature(NS_AVATAR_METADATA),
            disco.DiscoFeature(NS_AVATAR_DATA)
        ]

    def getDiscoItems(self, requestor, service, nodeIdentifier=""):
        return []