#!/usr/bin/env python3

# SàT plugin for attaching files
# Copyright (C) 2009-2020 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 functools import partial
from pathlib import Path
from twisted.internet import defer
from sat.core.i18n import _
from sat.core.constants import Const as C
from sat.core.log import getLogger

log = getLogger(__name__)


PLUGIN_INFO = {
    C.PI_NAME: "File Attach",
    C.PI_IMPORT_NAME: "ATTACH",
    C.PI_TYPE: C.PLUG_TYPE_MISC,
    C.PI_DEPENDENCIES: ["UPLOAD"],
    C.PI_MAIN: "AttachPlugin",
    C.PI_HANDLER: "no",
    C.PI_DESCRIPTION: _("""Attachments handler"""),
}


class AttachPlugin:

    def __init__(self, host):
        log.info(_("plugin Attach initialization"))
        self.host = host
        self._u = host.plugins["UPLOAD"]
        host.trigger.add("sendMessage", self._sendMessageTrigger)

    def _attachFiles(self, client, data):
        # TODO: handle xhtml-im
        body_elt = next(data["xml"].elements((C.NS_CLIENT, "body")))
        for attachment in data["extra"][C.MESS_KEY_ATTACHMENTS]:
            body_elt.addContent(f'\n{attachment["url"]}')
        return data

    async def uploadFiles(self, client, data):
        uploads_d = []
        to_delete = []
        attachments = data["extra"]["attachments"]

        for attachment in attachments:
            try:
                path = Path(attachment["path"])
            except KeyError:
                log.warning("no path in attachment: {attachment}")
                to_delete.append(attachment)
                continue

            if "url" in attachment:
                log.warning("invalid attachment: unknown URL")
                to_delete.append(attachment)

            try:
                name = attachment["name"]
            except KeyError:
                name = attachment["name"] = path.name

            options = {}
            if client.encryption.isEncryptionRequested(data):
                # FIXME: we should not use implementation specific value here
                #   but for not it's the only file encryption method available with
                #   with upload.
                options['encryption'] = C.ENC_AES_GCM

            __, upload_d = await self._u.upload(
                client,
                filepath=path,
                filename=name,
            )
            uploads_d.append(upload_d)

        for attachment in to_delete:
            attachments.remove(attachment)

        upload_results = await defer.DeferredList(uploads_d)
        for idx, (success, ret) in enumerate(upload_results):
            attachment = attachments[idx]

            if not success:
                # ret is a failure here
                log.warning(f"error while uploading {attachment}: {ret}")
                continue

            attachment["url"] = ret

        return data

    def _uploadFiles(self, client, data):
        return defer.ensureDeferred(self.uploadFiles(client, data))

    def _sendMessageTrigger(
        self, client, mess_data, pre_xml_treatments, post_xml_treatments):
        if mess_data['extra'].get(C.MESS_KEY_ATTACHMENTS):
            pre_xml_treatments.addCallback(partial(self._uploadFiles, client))
            post_xml_treatments.addCallback(partial(self._attachFiles, client))
        return True