import json
import tornado.web
import asyncio
import asyncpg
import logging
import tornado.concurrent

logger = logging.getLogger('chat.' + __name__)


def asyncio_coroutine(func):
    func = asyncio.coroutine(func)
    def decorator(*args, **kwargs):
        future = tornado.concurrent.Future()

        def future_done(f):
            try:
                future.set_result(f.result())
            except Exception as e:
                future.set_exception(e)

        asyncio.async(func(*args, **kwargs)).add_done_callback(future_done)
        return future

    return decorator


class BaseHandler(tornado.web.RequestHandler):
    @asyncio.coroutine
    async def _get_engine(self):
        engine = await asyncpg.connect(user='m4bulmagd', database='chatdb', host='localhost', password='123')
        return engine

    @asyncio.coroutine
    async def select(self, sqlquery):
        conn = await self._get_engine()
        # with (yield from engine) as conn:
        data = await conn.fetch(sqlquery)

        return data

    @asyncio.coroutine
    async def insert(self, sqlquery):
        conn = await self._get_engine()
        #with (yield from engine) as conn:
        await conn.execute(sqlquery)


############################################################

class LoginHandler(BaseHandler):
    @asyncio_coroutine
    def get(self):
        db_messages = yield from self.select('''select * from "user"''')
        self.render("login.html")