#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from twisted.internet import defer

from httppusher import HttpPusher
from synapse.push import PusherConfigException

from syutil.jsonutil import encode_canonical_json

import logging
import simplejson as json

logger = logging.getLogger(__name__)


class PusherPool:
    def __init__(self, _hs):
        self.hs = _hs
        self.store = self.hs.get_datastore()
        self.pushers = {}
        self.last_pusher_started = -1

        distributor = self.hs.get_distributor()
        distributor.observe(
            "user_presence_changed", self.user_presence_changed
        )

    @defer.inlineCallbacks
    def user_presence_changed(self, user, state):
        user_name = user.to_string()

        # until we have read receipts, pushers use this to reset a user's
        # badge counters to zero
        for p in self.pushers.values():
            if p.user_name == user_name:
                yield p.presence_changed(state)

    @defer.inlineCallbacks
    def start(self):
        pushers = yield self.store.get_all_pushers()
        for p in pushers:
            p['data'] = json.loads(p['data'])
        self._start_pushers(pushers)

    @defer.inlineCallbacks
    def add_pusher(self, user_name, profile_tag, kind, app_id,
                   app_display_name, device_display_name, pushkey, lang, data):
        # we try to create the pusher just to validate the config: it
        # will then get pulled out of the database,
        # recreated, added and started: this means we have only one
        # code path adding pushers.
        self._create_pusher({
            "user_name": user_name,
            "kind": kind,
            "profile_tag": profile_tag,
            "app_id": app_id,
            "app_display_name": app_display_name,
            "device_display_name": device_display_name,
            "pushkey": pushkey,
            "pushkey_ts": self.hs.get_clock().time_msec(),
            "lang": lang,
            "data": data,
            "last_token": None,
            "last_success": None,
            "failing_since": None
        })
        yield self._add_pusher_to_store(
            user_name, profile_tag, kind, app_id,
            app_display_name, device_display_name,
            pushkey, lang, data
        )

    @defer.inlineCallbacks
    def _add_pusher_to_store(self, user_name, profile_tag, kind, app_id,
                             app_display_name, device_display_name,
                             pushkey, lang, data):
        yield self.store.add_pusher(
            user_name=user_name,
            profile_tag=profile_tag,
            kind=kind,
            app_id=app_id,
            app_display_name=app_display_name,
            device_display_name=device_display_name,
            pushkey=pushkey,
            pushkey_ts=self.hs.get_clock().time_msec(),
            lang=lang,
            data=encode_canonical_json(data).decode("UTF-8"),
        )
        self._refresh_pusher((app_id, pushkey))

    def _create_pusher(self, pusherdict):
        if pusherdict['kind'] == 'http':
            return HttpPusher(
                self.hs,
                profile_tag=pusherdict['profile_tag'],
                user_name=pusherdict['user_name'],
                app_id=pusherdict['app_id'],
                app_display_name=pusherdict['app_display_name'],
                device_display_name=pusherdict['device_display_name'],
                pushkey=pusherdict['pushkey'],
                pushkey_ts=pusherdict['pushkey_ts'],
                data=pusherdict['data'],
                last_token=pusherdict['last_token'],
                last_success=pusherdict['last_success'],
                failing_since=pusherdict['failing_since']
            )
        else:
            raise PusherConfigException(
                "Unknown pusher type '%s' for user %s" %
                (pusherdict['kind'], pusherdict['user_name'])
            )

    @defer.inlineCallbacks
    def _refresh_pusher(self, app_id_pushkey):
        p = yield self.store.get_pushers_by_app_id_and_pushkey(
            app_id_pushkey
        )
        p['data'] = json.loads(p['data'])

        self._start_pushers([p])

    def _start_pushers(self, pushers):
        logger.info("Starting %d pushers", len(pushers))
        for pusherdict in pushers:
            p = self._create_pusher(pusherdict)
            if p:
                fullid = "%s:%s" % (pusherdict['app_id'], pusherdict['pushkey'])
                if fullid in self.pushers:
                    self.pushers[fullid].stop()
                self.pushers[fullid] = p
                p.start()

    @defer.inlineCallbacks
    def remove_pusher(self, app_id, pushkey):
        fullid = "%s:%s" % (app_id, pushkey)
        if fullid in self.pushers:
            logger.info("Stopping pusher %s", fullid)
            self.pushers[fullid].stop()
            del self.pushers[fullid]
        yield self.store.delete_pusher_by_app_id_pushkey(app_id, pushkey)