import logging

from typing import List

from .consts import ADAPTERS
from .worker import ServiceWorker

log = logging.getLogger(__name__)

_COLUMNS = {
    'timestamp': 'timestamp bigint',
    'status': 'status bool',
    'latency': 'latency bigint',
}


class ServiceManager:
    def __init__(self, app):
        self.app = app
        self.cfg = app.cfg
        self.conn = app.conn
        self.loop = app.loop

        self.workers = {}
        self.state = {}
        self.subscribers = {}

        self._start()

    def _make_db_table(self, name: str, service: dict):
        adapter = ADAPTERS[service['adapter']]

        columnstr = map(_COLUMNS.get, adapter.spec['db'])
        columnstr = ',\n'.join(columnstr)

        log.info(f'Making table for {name}')
        self.conn.executescript(f"""
        CREATE TABLE IF NOT EXISTS {name} (
        {columnstr}
        );
        """)

    def _start(self):
        for name, service in self.cfg.SERVICES.items():
            self._make_db_table(name, service)

            # spawn a service worker
            serv_worker = ServiceWorker(self, name, service)
            self.workers[name] = serv_worker

            self.state[name] = None

    def subscribe(self, channels: List[str], websocket):
        """Subscribe to a list of channels."""
        subscribed = []

        for chan in channels:
            try:
                self.subscribers[chan].append(websocket.client_id)
            except KeyError:
                pass

        return subscribed

    def unsub_all(self, websocket):
        """Unsubscribe a websocket from all known channels."""
        unsub = []

        for chan, subs in self.subscribers.items():
            log.info(f'Unsubscribing {websocket.client_id} from {chan}')
            try:
                subs.remove(websocket.client_id)
                unsub.append(chan)
            except ValueError:
                pass

        log.info(f'unsubscribed {websocket.client_id} from {unsub}')
        return unsub