#!/usr/bin/env python3

# Libervia plugin for Pubsub Attachments
# 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 List, Tuple, Dict, Any, Callable, Optional

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

from sat.core.constants import Const as C
from sat.core.i18n import _
from sat.core.log import getLogger
from sat.core.core_types import SatXMPPEntity
from sat.core import exceptions
from sat.tools.common import uri, data_format, date_utils
from sat.tools.utils import xmpp_date


log = getLogger(__name__)

IMPORT_NAME = "PUBSUB_ATTACHMENTS"

PLUGIN_INFO = {
    C.PI_NAME: "Pubsub Attachments",
    C.PI_IMPORT_NAME: IMPORT_NAME,
    C.PI_TYPE: C.PLUG_TYPE_EXP,
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: [],
    C.PI_DEPENDENCIES: ["XEP-0060"],
    C.PI_MAIN: "PubsubAttachments",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Pubsub Attachments implementation"""),
}
NS_PREFIX = "urn:xmpp:pubsub-attachments:"
NS_PUBSUB_ATTACHMENTS = f"{NS_PREFIX}0"
NS_PUBSUB_ATTACHMENTS_SUM = f"{NS_PREFIX}summary:0"


class PubsubAttachments:
    namespace = NS_PUBSUB_ATTACHMENTS

    def __init__(self, host):
        log.info(_("Pubsub Attachments plugin initialization"))
        host.registerNamespace("pubsub-attachments", NS_PUBSUB_ATTACHMENTS)
        self.host = host
        self._p = host.plugins["XEP-0060"]
        self.handlers = {}
        host.trigger.add("XEP-0277_send", self.onMBSend)
        self.registerAttachmentHandler(
            "noticed", NS_PUBSUB_ATTACHMENTS, self.noticedGet, self.noticedSet
        )
        self.registerAttachmentHandler(
            "reaction", NS_PUBSUB_ATTACHMENTS, self.reactionGet, self.reactionSet
        )
        host.bridge.addMethod(
            "psAttachmentsGet",
            ".plugin",
            in_sign="sssasss",
            out_sign="(ss)",
            method=self._get,
            async_=True,
        )
        host.bridge.addMethod(
            "psAttachmentsSet",
            ".plugin",
            in_sign="ss",
            out_sign="",
            method=self._set,
            async_=True,
        )

    def getHandler(self, client):
        return PubsubAttachments_Handler()

    def registerAttachmentHandler(
        self,
        name: str,
        namespace: str,
        get_cb: Callable[
            [SatXMPPEntity, domish.Element, Dict[str, Any]],
            None],
        set_cb: Callable[
            [SatXMPPEntity, Dict[str, Any], Optional[domish.Element]],
            Optional[domish.Element]],
    ) -> None:
        """Register callbacks to handle an attachment

        @param name: name of the element
        @param namespace: namespace of the element
            (name, namespace) couple must be unique
        @param get: method to call when attachments are retrieved
            it will be called with (client, element, data) where element is the
            <attachments> element to parse, and data must be updated in place with
            parsed data
        @param set: method to call when the attachment need to be set or udpated
            it will be called with (client, data, former_elt of None if there was no
            former element). When suitable, ``operation`` should be used to check if we
            request an ``update`` or a ``replace``.
        """
        key = (name, namespace)
        if key in self.handlers:
            raise exceptions.ConflictError(
                f"({name}, {namespace}) attachment handlers are already registered"
            )
        self.handlers[(name, namespace)] = {
            "get": get_cb,
            "set": set_cb
        }

    def getAttachmentNodeName(self, service: jid.JID, node: str, item: str) -> str:
        """Generate name to use for attachment node"""
        target_item_uri = uri.buildXMPPUri(
            "pubsub",
            path=service.userhost(),
            node=node,
            item=item
        )
        return f"{NS_PUBSUB_ATTACHMENTS}/{target_item_uri}"

    def isAttachmentNode(self, node: str) -> bool:
        """Return True if node name is an attachment node"""
        return node.startswith(f"{NS_PUBSUB_ATTACHMENTS}/")

    def attachmentNode2Item(self, node: str) -> Tuple[jid.JID, str, str]:
        """Retrieve service, node and item from attachement node's name"""
        if not self.isAttachmentNode(node):
            raise ValueError("this is not an attachment node!")
        prefix_len = len(f"{NS_PUBSUB_ATTACHMENTS}/")
        item_uri = node[prefix_len:]
        parsed_uri = uri.parseXMPPUri(item_uri)
        if parsed_uri["type"] != "pubsub":
            raise ValueError(f"unexpected URI type, it must be a pubsub URI: {item_uri}")
        try:
            service = jid.JID(parsed_uri["path"])
        except RuntimeError:
            raise ValueError(f"invalid service in pubsub URI: {item_uri}")
        node = parsed_uri["node"]
        item = parsed_uri["item"]
        return (service, node, item)

    async def onMBSend(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        node: str,
        item: domish.Element,
        data: dict
    ) -> bool:
        """trigger to create attachment node on each publication"""
        node_config = await self._p.getConfiguration(client, service, node)
        attachment_node = self.getAttachmentNodeName(service, node, item["id"])
        # we use the same options as target node
        try:
            await self._p.createIfNewNode(
                client, service, attachment_node, options=dict(node_config)
            )
        except Exception as e:
            log.warning(f"Can't create attachment node {attachment_node}: {e}]")
        return True

    def items2attachmentData(
        self,
        client: SatXMPPEntity,
        items: List[domish.Element]
    ) -> List[Dict[str, Any]]:
        """Convert items from attachment node to attachment data"""
        list_data = []
        for item in items:
            try:
                attachments_elt = next(
                    item.elements(NS_PUBSUB_ATTACHMENTS, "attachments")
                )
            except StopIteration:
                log.warning(
                    "item is missing <attachments> elements, ignoring it: {item.toXml()}"
                )
                continue
            item_id = item["id"]
            publisher_s = item.getAttribute("publisher")
            # publisher is not filled by all pubsub service, so we can't count on it
            if publisher_s:
                publisher = jid.JID(publisher_s)
                if publisher.userhost() != item_id:
                    log.warning(
                        f"publisher {publisher.userhost()!r} doesn't correspond to item "
                        f"id {item['id']!r}, ignoring. This may be a hack attempt.\n"
                        f"{item.toXml()}"
                    )
                    continue
            try:
                jid.JID(item_id)
            except RuntimeError:
                log.warning(
                    "item ID is not a JID, this is not compliant and is ignored: "
                    f"{item.toXml}"
                )
                continue
            data = {
                "from": item_id
            }
            for handler in self.handlers.values():
                handler["get"](client, attachments_elt, data)
            if len(data) > 1:
                list_data.append(data)
        return list_data

    def _get(
        self,
        service_s: str,
        node: str,
        item: str,
        senders_s: List[str],
        extra_s: str,
        profile_key: str
    ) -> defer.Deferred:
        client = self.host.getClient(profile_key)
        extra = data_format.deserialise(extra_s)
        senders = [jid.JID(s) for s in senders_s]
        d = defer.ensureDeferred(
            self.getAttachments(client, jid.JID(service_s), node, item, senders)
        )
        d.addCallback(
            lambda ret:
            (data_format.serialise(ret[0]),
             data_format.serialise(ret[1]))
        )
        return d

    async def getAttachments(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        node: str,
        item: str,
        senders: Optional[List[jid.JID]],
        extra: Optional[dict] = None
    ) -> Tuple[List[Dict[str, Any]], dict]:
        if extra is None:
            extra = {}
        attachment_node = self.getAttachmentNodeName(service, node, item)
        item_ids = [e.userhost() for e in senders] if senders else None
        items, metadata = await self._p.getItems(
            client, service, attachment_node, item_ids=item_ids, extra=extra
        )
        list_data = self.items2attachmentData(client, items)

        return list_data, metadata

    def _set(
        self,
        attachments_s: str,
        profile_key: str
    ) -> None:
        client = self.host.getClient(profile_key)
        attachments = data_format.deserialise(attachments_s)  or {}
        return defer.ensureDeferred(self.setAttachments( client, attachments))

    async def setAttachments(
        self,
        client: SatXMPPEntity,
        data: Dict[str, Any]
    ) -> None:
        """Set or update attachments

        Former <attachments> element will be retrieved and updated. Individual
        attachments replace or update their elements individually, according to the
        "operation" key.

        "operation" key may be "update" or "replace", and defaults to update, it is only
        used in attachments where "update" makes sense (e.g. it's used for "reactions"
        but not for "noticed").

        @param data: microblog data data. Various keys (usually stored in
            data["extra"]) may be used depending on the attachments handlers
            registered. The keys "service", "node" and "id" MUST be set.
        """
        data.setdefault("extra", {})
        try:
            service = jid.JID(data["service"])
            node = data["node"]
            item = data["id"]
        except (KeyError, RuntimeError):
            raise ValueError(
                'data must have "service", "node" and "id" set'
            )
        attachment_node = self.getAttachmentNodeName(service, node, item)
        items, __ = await self._p.getItems(
            client, service, attachment_node, item_ids=[client.jid.userhost()]
        )
        if not items:
            # the item doesn't exist, we create a new one
            item_elt = pubsub.Item(client.jid.userhost())
            item_elt.addElement((NS_PUBSUB_ATTACHMENTS, "attachments"))
        else:
            item_elt = items[0]

        try:
            attachments_elt = next(
                item_elt.elements(NS_PUBSUB_ATTACHMENTS, "attachments")
            )
        except StopIteration:
            log.warning(
                f"no <attachments> element found, creating a new one: {item_elt.toXml()}"
            )
            attachments_elt = item_elt.addElement((NS_PUBSUB_ATTACHMENTS, "attachments"))

        for (name, namespace), handler in self.handlers.items():
            try:
                former_elt = next(attachments_elt.elements(namespace, name))
            except StopIteration:
                former_elt = None
            new_elt = handler["set"](client, data, former_elt)
            if new_elt != former_elt:
                if former_elt is not None:
                    attachments_elt.children.remove(former_elt)
                if new_elt is not None:
                    attachments_elt.addChild(new_elt)
        try:
            await self._p.sendItems(client, service, attachment_node, [item_elt])
        except error.StanzaError as e:
            if e.condition == "item-not-found":
                # the node doesn't exist, we can't publish attachments
                log.warning(
                    f"no attachment node found at {service} on {node!r} for item "
                    f"{item!r}, we can't update attachments."
                )
                raise exceptions.NotFound("No attachment node available")
            else:
                raise e

    async def subscribe(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        node: str,
        item: str,
    ) -> None:
        """Subscribe to attachment node targeting the item

        @param service: service of target item (will also be used for attachment node)
        @param node: node of target item (used to get attachment node's name)
        @param item: name of target item (used to get attachment node's name)
        """
        attachment_node = self.getAttachmentNodeName(service, node, item)
        await self._p.subscribe(client, service, attachment_node)


    def setTimestamp(self, attachment_elt: domish.Element, data: dict) -> None:
        """Check if a ``timestamp`` attribute is set, parse it, and fill data

        @param attachments_elt: element where the ``timestamp`` attribute may be set
        @param data: data specific to the attachment (i.e. not the whole microblog data)
            ``timestamp`` field will be set there if timestamp exists and is parsable
        """
        timestamp_raw = attachment_elt.getAttribute("timestamp")
        if timestamp_raw:
            try:
                timestamp = date_utils.date_parse(timestamp_raw)
            except date_utils.ParserError:
                log.warning(f"can't parse timestamp: {timestamp_raw}")
            else:
                data["timestamp"] = timestamp

    def noticedGet(
        self,
        client: SatXMPPEntity,
        attachments_elt: domish.Element,
        data: Dict[str, Any],
    ) -> None:
        try:
            noticed_elt = next(
                attachments_elt.elements(NS_PUBSUB_ATTACHMENTS, "noticed")
            )
        except StopIteration:
            pass
        else:
            noticed_data = {
                "noticed": True
            }
            self.setTimestamp(noticed_elt, noticed_data)
            data["noticed"] = noticed_data

    def noticedSet(
        self,
        client: SatXMPPEntity,
        data: Dict[str, Any],
        former_elt: Optional[domish.Element]
    ) -> Optional[domish.Element]:
        """add or remove a <noticed> attachment

        if data["noticed"] is True, element is added, if it's False, it's removed, and
        it's not present or None, the former element is kept.
        """
        noticed = data["extra"].get("noticed")
        if noticed is None:
            return former_elt
        elif noticed:
            return domish.Element(
                (NS_PUBSUB_ATTACHMENTS, "noticed"),
                attribs = {
                    "timestamp": xmpp_date()
                }
            )
        else:
            return None

    def reactionGet(
        self,
        client: SatXMPPEntity,
        attachments_elt: domish.Element,
        data: Dict[str, Any],
    ) -> None:
        try:
            reaction_elt = next(
                attachments_elt.elements(NS_PUBSUB_ATTACHMENTS, "reaction")
            )
        except StopIteration:
            pass
        else:
            reaction_data = {
                "reactions": str(reaction_elt)
            }
            self.setTimestamp(reaction_elt, reaction_data)
            data["reaction"] = reaction_data

    def reactionSet(
        self,
        client: SatXMPPEntity,
        data: Dict[str, Any],
        former_elt: Optional[domish.Element]
    ) -> Optional[domish.Element]:
        """update the <reaction> attachment"""
        reaction = data["extra"].get("reaction")
        if reaction is None:
            return former_elt
        operation_type = reaction.get("operation", "update")
        if operation_type == "update":
            reactions = "".join(
                set(str(former_elt or ""))
                | set(reaction.get("reactions") or "")
            )
        elif operation_type == "replace":
            reactions = reaction.get("reactions", "")
        else:
            raise exceptions.DataError(f"invalid reaction operation: {operation_type!r}")
        if reactions:
            reaction_elt = domish.Element(
                (NS_PUBSUB_ATTACHMENTS, "reaction"),
                attribs = {
                    "timestamp": xmpp_date()
                }
            )
            reaction_elt.addContent(reactions)
            return reaction_elt
        else:
            return None


@implementer(iwokkel.IDisco)
class PubsubAttachments_Handler(xmlstream.XMPPHandler):

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

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