#!/usr/bin/env python3

# Libervia plugin for XEP-0084
# Copyright (C) 2009-2026 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 Any, Dict

from base64 import b64decode
from pathlib import Path

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 tx_xmpp import disco, itx_xmpp, 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:
        """Handle PEP avatar metadata update event.

        Parse metadata, fetch data if not cached, and update identity cache.
        """
        entity = itemsEvent.sender
        service = entity.userhostJID()

        items = itemsEvent.items
        if not items:
            return

        if items[0].name == "retract":
            log.debug(f"Avatar retracted for {entity.full()}")
            await self._i.update(client, IMPORT_NAME, "avatar", None, entity)
            return

        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

        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)
            log.debug(f"Avatar disabled for {entity.full()}")
            await self._i.update(client, IMPORT_NAME, "avatar", None, entity)
            return

        # Check if avatar is already cached
        try:
            cached = self.host.memory.get_entity_datum(client, entity, "avatar")
        except (KeyError, exceptions.UnknownEntityError):
            cached = None

        if cached is not None:
            cached_uid = cached.get("cache_uid") if isinstance(cached, dict) else None
            if cached_uid == avatar_id:
                log.debug(f"Avatar already cached for {entity.full()} (id={avatar_id})")
                return
            log.debug(
                f"Avatar changed for {entity.full()} (old={cached_uid}, new={avatar_id})"
            )

        # Fetch avatar data if not already cached
        cache_data = self.host.common_cache.get_metadata(avatar_id)
        if not cache_data:
            cache_data = await self._fetch_avatar_data(
                client, service, avatar_id, metadata["media_type"]
            )
            if cache_data is None:
                log.warning(f"Failed to fetch avatar data for {entity.full()}")
                return

        log.debug(f"Avatar updated for {entity.full()} (id={avatar_id})")
        avatar_metadata = self._i.avatar_build_metadata(
            cache_data["path"], cache_data["mime_type"], avatar_id
        )
        await self._i.update(client, IMPORT_NAME, "avatar", avatar_metadata, entity)

    async def _fetch_avatar_data(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        avatar_id: str,
        media_type: str,
    ) -> dict | None:
        """Fetch avatar data from PEP data node and cache it.

        @return: Cache data dict with path and mime_type, or None on failure.
        """
        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, media_type) as f:
            f.write(avatar_buf)
            return {"path": Path(f.name), "mime_type": media_type}

    async def get_avatar(self, client: SatXMPPEntity, entity_jid: jid.JID) -> dict | None:
        """Get avatar data from cache."""
        try:
            cached = self.host.memory.get_entity_datum(client, entity_jid, "avatar")
        except (KeyError, exceptions.UnknownEntityError):
            return None

        if not cached:
            return None

        cache_uid = cached.get("cache_uid")
        filename = cached.get("filename")
        if not cache_uid or not filename:
            return None

        try:
            self.host.common_cache.get_metadata(cache_uid)
        except Exception:
            return None

        return cached

    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(itx_xmpp.IDisco)
class XEP_0084_Handler(XMPPHandler):

    def getDiscoInfo(self, requestor, service, nodeIdentifier=""):
        # NS_AVATAR_METADATA is already advertised by ``add_pep_event``.
        # Only NS_AVATAR_DATA needs to be advertised here.
        return [
            disco.DiscoFeature(NS_AVATAR_DATA),
        ]

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