from collections import defaultdict
from typing import Any, Dict, List
from urllib.parse import parse_qs

from .auth import async_anonymous_is_enabled
from .autoupdate import AutoupdateFormat
from .cache import element_cache, split_element_id
from .websocket import ProtocollAsyncJsonWebsocketConsumer, get_element_data


class SiteConsumer(ProtocollAsyncJsonWebsocketConsumer):
    """
    Websocket Consumer for the site.
    """

    groups = ['site']

    async def connect(self) -> None:
        """
        A user connects to the site.

        If it is an anonymous user and anonymous is disabled, the connection is closed.

        Sends the startup data to the user.
        """
        # self.scope['user'] is the full_data dict of the user. For an
        # anonymous user is it the dict {'id': 0}
        change_id = None
        if not await async_anonymous_is_enabled() and not self.scope['user']['id']:
            await self.close()
            return

        query_string = parse_qs(self.scope['query_string'])
        if b'change_id' in query_string:
            try:
                change_id = int(query_string[b'change_id'][0])
            except ValueError:
                await self.close()  # TODO: Find a way to send an error code
                return

        if b'autoupdate' in query_string and query_string[b'autoupdate'][0].lower() not in [b'0', b'off', b'false']:
            # a positive value in autoupdate. Start autoupdate
            await self.channel_layer.group_add('autoupdate', self.channel_name)

        await self.accept()

        if change_id is not None:
            try:
                data = await get_element_data(self.scope['user']['id'], change_id)
            except ValueError:
                # When the change_id is to big, do nothing
                pass
            else:
                await self.send_json(type='autoupdate', content=data)

    async def disconnect(self, close_code: int) -> None:
        """
        A user disconnects. Remove it from autoupdate.
        """
        await self.channel_layer.group_discard('autoupdate', self.channel_name)

    async def send_notify(self, event: Dict[str, Any]) -> None:
        """
        Send a notify message to the user.
        """
        user_id = self.scope['user']['id']

        out = []
        for item in event['incomming']:
            users = item.get('users')
            reply_channels = item.get('replyChannels')
            if ((isinstance(users, list) and user_id in users)
                    or (isinstance(reply_channels, list) and self.channel_name in reply_channels)
                    or users is None and reply_channels is None):
                item['senderReplyChannelName'] = event.get('senderReplyChannelName')
                item['senderUserId'] = event.get('senderUserId')
                out.append(item)

        if out:
            await self.send_json(type='notify', content=out)

    async def send_data(self, event: Dict[str, Any]) -> None:
        """
        Send changed or deleted elements to the user.
        """
        change_id = event['change_id']
        changed_elements, deleted_elements_ids = await element_cache.get_restricted_data(
            self.scope['user']['id'],
            change_id,
            max_change_id=change_id)

        deleted_elements: Dict[str, List[int]] = defaultdict(list)
        for element_id in deleted_elements_ids:
            collection_string, id = split_element_id(element_id)
            deleted_elements[collection_string].append(id)
        await self.send_json(type='autoupdate', content=AutoupdateFormat(
            changed=changed_elements,
            deleted=deleted_elements,
            from_change_id=change_id,
            to_change_id=change_id,
            all_data=False))