'''
This file is part of JANINE.

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

JANINE 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with JANINE.  If not, see <https://www.gnu.org/licenses/>.
'''

import os
import sys
import json
import configparser
import logging
import asyncio
from collections import namedtuple
from optparse import OptionParser

import aioxmpp
from aioxmpp.structs import PresenceShow

import requests

from janine.utils import find_one, make_msg, format_warning
from janine.sources import sources_from_config, MiscDataSources

log = logging.getLogger('janine')
log.setLevel(logging.INFO)
log.addHandler(logging.StreamHandler())

Warning_ = namedtuple('Warning_', ['id',
                                   'sent',
                                   'effective_from',
                                   'expires',
                                   'urgency',
                                   'sender',
                                   'headline',
                                   'description',
                                   'instruction',
                                   'landkreise'])


def stub_warning(id_):
    '''
    Returns a stubbed warning for loading warnings from disk.
    The only real attribute is the @id_ .
    '''
    return Warning_(id=id_,
                    sent='',
                    effective_from='',
                    expires='',
                    urgency='',
                    sender='',
                    headline='',
                    description='',
                    instruction='',
                    landkreise=[])

def to_warning(data):
    '''
    Returns a Warning given the raw data
    '''
    info = find_one(lambda x: 'headline' in x.keys(), data['info'])
    return Warning_(id=data['identifier'],
                    sent=data['sent'],
                    # Not all items have to have those
                    effective_from=info.get('effective', 'N/A'),
                    # Not all items have to have those
                    expires=info.get('expires', 'N/A'),
                    urgency=info['urgency'],
                    # Not all items have to have those
                    sender=info.get('senderName', 'N/A'),
                    headline=info['headline'],
                    description=info['description'],
                    instruction=info.get('instruction', ''),
                    landkreise=get_landkreise(data))

def get_landkreise(data):
    '''
    Returns the list of Landkreise relevant to the warning in @data
    '''
    info = find_one(lambda e: 'area' in e.keys(), data['info'])
    geocode = find_one(lambda e: 'geocode' in e.keys(), info['area'])

    # Note: Some items may have multiple Landkreise
    return list(map(lambda e: e['valueName'], geocode['geocode']))

def parse_data(text):
    '''
    Reads the remote response, parses it and returns a list of warnings.
    '''
    data = json.loads(text)
    return [to_warning(el) for el in data]

class WarningBot:
    '''
    This class represents the actual bot. The only things
    to be done is call connect() after creating an instance.
    '''
    def __init__(self, config_file):
        self._warnings0 = []
        self._warnings1 = []
        self._client = None
        self._warn_clients = {}
        self._refresh_timeout = 630 # 15min

        # Configuration stuff
        self._data_dir = ''
        self._client_store = ''
        self._warning_store = ''

        self._load_config(config_file)

    async def connect(self):
        '''
        Starts the "event loop" of the bot
        '''
        self._client = aioxmpp.PresenceManagedClient(
            self._jid,
            aioxmpp.make_security_layer(self._password))

        log.debug('Connecting to server')
        async with self._client.connected():
            log.info('Client connected to server')

            # In case you want a nice avatar
            if self._avatar:
                log.debug('Setting avatar')
                with open(self._avatar, 'rb') as avatar_file:
                    image_data = avatar_file.read()

                avatar_set = aioxmpp.avatar.AvatarSet()
                avatar_set.add_avatar_image('image/png', image_bytes=image_data)
                await (self._client.summon(aioxmpp.avatar.AvatarService)
                       .publish_avatar_set(avatar_set))
                log.info('Avatar set')

            # Set some presence information
            self._client.set_presence(
                aioxmpp.PresenceState(available=True,
                                      show=PresenceShow.CHAT),
                self._status)

            # Enable Carbons
            await self._client.summon(aioxmpp.CarbonsClient).enable()
            log.info('Message carbons enabled')

            # Register the message handler
            self._client.stream.register_message_callback(
                aioxmpp.MessageType.CHAT,
                None,
                self._handle_message)
            log.info('Message handler registered')

            # Start our fetch-send loop
            # NOTE: Originally, I wanted to use a cronjob and
            #       signal.signal(...) for this but you can't
            #       use async in event handlers
            loop = asyncio.get_event_loop()
            periodic = loop.create_task(self._periodic_requests())
            log.info('Periodic ticker started')
            await periodic

    def __is_message_valid(self, msg):
        '''
        Returns True on messages we want to handle. False otherwise.
        '''
        if msg.type_ != aioxmpp.MessageType.CHAT:
            return False

        if not msg.body:
            return False

        if msg.from_.domain != self._jid.domain and self._same_domain:
            return False

        return True

    def _handle_message(self, msg):
        # Handle cases we don't want to deal with
        if not self.__is_message_valid(msg):
            return

        # Send a deliverability receipt
        receipt = aioxmpp.mdr.compose_receipt(msg)
        self._client.enqueue(receipt)

        cmd_parts = str(msg.body.any()).split(' ')
        cmd = cmd_parts[0].lower()

        if cmd == 'subscribe':
            # Do we have a landkreis?
            if len(cmd_parts) < 2:
                self._client.enqueue(make_msg(
                    to=msg.from_,
                    body='Du hast keinen Landkreis angegeben'))
                return

            # Check if the entered Landkreis is valid
            landkreis = ' '.join(cmd_parts[1:])
            if not landkreis in self._channels:
                self._client.enqueue(make_msg(
                    to=msg.from_,
                    body='Der angegebene Landkreis ist ungültig'))
                return

            if landkreis not in self._warn_clients.keys():
                self._warn_clients[landkreis] = []
            self._warn_clients[landkreis].append(str(msg.from_.bare()))

            self._client.enqueue(make_msg(
                to=msg.from_,
                body=f'Du erhälst nun Nachrichten zu {landkreis} von mir'))

            with open(self._client_store, 'w') as clients_file:
                clients_file.write(json.dumps(self._warn_clients))

            # Send all known warnings for the landkreis to the user
            for warning in self._warnings0:
                if landkreis in warning.landkreise:
                    body = format_warning(warning)
                    self._client.enqueue(make_msg(
                        to=msg.from_,
                        body=body))

        elif cmd == 'unsubscribe':
            # Do we have a landkreis?
            if len(cmd_parts) < 2:
                self._client.enqueue(make_msg(
                    to=msg.from_,
                    body='Du hast keinen Landkreis angegeben'))
                return

            landkreis = ' '.join(cmd_parts[1:])
            if landkreis not in self._warn_clients:
                self._client.enqueue(make_msg(
                    to=msg.from_,
                    body=f'Du hast {landkreis} nicht abonniert'))
                return

            if str(msg.from_.bare()) in self._warn_clients[landkreis]:
                filter_ = lambda x: x != str(msg.from_.bare())
                self._warn_clients[landkreis] = list(filter(filter_,
                                                            self._warn_clients[landkreis]))
                self._client.enqueue(make_msg(
                    to=msg.from_,
                    body=f'Du erhälst keine Nachrichten zu {landkreis} mehr von mir'))

                if len(self._warn_clients[landkreis]) == 0:
                    del self._warn_clients[landkreis]
            else:
                self._client.enqueue(make_msg(
                    to=msg.from_,
                    body=f'Du hast {landkreis} nicht abonniert'))
        elif cmd == 'help':
            body = '''Verfügbare Befehle:

subscribe <Landkreis> - Abonniere einen Landkreis
unsubscribe <Landkreis> - Entferne das Abonnement zu einem Landkreis
help - Gebe diese Hilfe aus'''
            self._client.enqueue(make_msg(
                to=msg.from_,
                body=body))
        else:
            self._client.enqueue(make_msg(
                to=msg.from_,
                body='Diesen Befehl kenne ich nicht... Mit "help" kannst du alle Befehle sehen, die ich kenne.'))

    async def _periodic_requests(self):
        '''
        "Executes" every self._refresh_timeout seconds to fetch all
        configured warnings and send them to the users, if there are
        any new ones.
        '''
        while True:
            log.debug('Refreshing warning list')
            await self._fetch_warnings()

            # Flush the warnings to disk
            ids = [x.id for x in self._warnings0]
            with open(self._warnings_file, 'w') as warnings_file:
                warnings_file.write(json.dumps(ids))

            await asyncio.sleep(self._refresh_timeout)

    async def _fetch_warnings(self):
        '''
        Fetches all warnings and tries to find new ones
        to send notifications.
        '''
        self._warnings1 = self._warnings0
        self._warnings0 = []
        for source in self._sources:
            try:
                req = requests.get(source)
                self._warnings0 += parse_data(req.text)
            except urllib3.exceptions.MaxRetryError:
                log.warn('Connection timeout for request to %s', source)
                continue 

        # Find new warnings and send the new ones
        ids = [x.id for x in self._warnings1]
        for warning in self._warnings0:
            if warning.id in ids:
                continue

            # We need to use a set as a warning can apply to more than one
            # Landkreis
            if set(warning.landkreise).intersection(self._warn_clients.keys()):
                body = format_warning(warning)
                for landkreis in warning.landkreise:
                    for to in self._warn_clients.get(landkreis, []):
                        await self._client.send(make_msg(
                            aioxmpp.JID.fromstr(to),
                            body))

    def _load_config(self, config_file):
        # Load config
        config = configparser.ConfigParser()
        config.read(config_file)

        # Configure sources
        self._sources = sources_from_config(config)
        self._data_dir = config['General'].get('DataDir', '/etc/janine/data')
        self._refresh_timeout = int(config['General']['Timeout'])
        self._same_domain = config['General'].get('SameDomain', 'True') == 'True'

        # Persistent data
        ## Subscribed clients
        self._client_store = os.path.join(self._data_dir, 'clients.json')
        if os.path.exists(self._client_store):
            with open(self._client_store, 'r') as clients_file:
                self._warn_clients = json.loads(clients_file.read())
            log.info('Clients read from disk')
        else:
            with open(self._client_store, 'w') as clients_file:
                clients_file.write('{}')
            os.chmod(self._client_store, S_IRUSR | S_IWUSR)
            log.info('Clients file created with 0600')
        
        ## Warnings
        self._warnings_file = os.path.join(self._data_dir, 'warnings.json')
        if os.path.exists(self._warnings_file):
            with open(self._warnings_file, 'r') as warnings_file:
                self._warnings0 = list(map(stub_warning,
                                           json.loads(warnings_file.read())))
            log.info('Warnings read from disk')

        ## Landkreise
        self._channels = []
        self._channel_file = os.path.join(self._data_dir, 'channels.json')
        if not os.path.exists(self._channel_file):
            log.info('Requesting search channels')
            req = requests.get(MiscDataSources.channels())
            channels = json.loads(req.text)
            self._channels = list(map(lambda key: channels[key].get('NAME', ''),
                                      channels.keys()))

            try:
                with open(self._channel_file, 'w') as channel_file:
                    channel_file.write(json.dumps(self._channels))
            except Exception as err:
                log.error('Failed to cache channel data:')
                log.error(str(err))
        else:
            with open(self._channel_file, 'r') as channel_file:
                self._channels = json.loads(channel_file.read())
            log.info('Search channels read from disk')

        # Bot Config
        self._jid = aioxmpp.JID.fromstr(config['Bot']['JID'])
        self._password = config['Bot']['Password']
        self._avatar = config['Bot'].get('Avatar', None)
        self._status = config['Bot'].get('Status', 'Warnt dich vor Katastrophen')

def main():
    '''
    Main function.
    '''
    parser = OptionParser()
    parser.add_option('-d', '--debug', action='store_true', dest='debug', default=False)
    (options, args) = parser.parse_args()

    if options.debug:
        log.setLevel(logging.DEBUG)

    if len(args) != 0:
        config_file = args[0]
    else:
        config_file = '/etc/janine/janine.conf'

    bot = WarningBot(config_file)
    loop = asyncio.get_event_loop()
    loop.run_until_complete(bot.connect())
    loop.close()

if __name__ == '__main__':
    main()