import contextlib
from datetime import datetime
import logging
import os
import sqlite3


logger = logging.getLogger(__name__)


DATABASE_FILE = os.environ['DATABASE']

assert os.path.isfile(DATABASE_FILE)


@contextlib.contextmanager
def get_db():
    db = sqlite3.connect(DATABASE_FILE)
    try:
        yield db
    finally:
        db.close()


def get_name_and_replies(code):
    with get_db() as db:
        rows = db.execute(
            '''\
            WITH latest_reply AS (
                SELECT
                    adults, children
                FROM replies
                WHERE family_code = :code
                ORDER BY date DESC
                LIMIT 1
            )
            SELECT
                families.name,
                (SELECT adults FROM latest_reply) AS adults,
                (SELECT children FROM latest_reply) AS children
            FROM families
            WHERE families.code = :code
            LIMIT 1;
            ''',
            dict(code=code),
        )
        try:
            return next(rows)
        except StopIteration:
            raise ValueError("Invalid code")


def record_reply(code, adults, children):
    assert isinstance(adults, int)
    assert isinstance(children, int)
    assert 0 <= adults and 0 <= children
    assert adults > 0 or children == 0

    with get_db() as db:
        # Insert update
        cursor = db.cursor()
        date = datetime.utcnow()
        cursor.execute(
            '''\
            INSERT INTO replies(family_code, date, adults, children)
            VALUES(:code, :date, :adults, :children);
            ''',
            dict(code=code, date=date, adults=adults, children=children),
        )
        cursor.execute('COMMIT;')
        logger.info(
            "Recorded update for code=%r date=%r adults=%d children=%d",
            code,
            date,
            adults,
            children,
        )