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_people_and_replies(code):
    with get_db() as db:
        return list(db.execute(
            '''\
            SELECT
                persons.id, persons.name,
                (
                    SELECT rsvp FROM replies
                    WHERE
                        replies.person_id = persons.id
                        AND replies.date = (
                            SELECT MAX(date)
                            FROM replies
                            WHERE person_id = persons.id
                        )
                ) AS rsvp
            FROM
                persons
            WHERE
                persons.code = :code;
            ''',
            dict(code=code),
        ))


def record_reply(code, persons):
    assert isinstance(persons, dict)
    with get_db() as db:
        # Check the IDs of people match
        expected_people_ids = set(
            row[0]
            for row in db.execute(
                '''\
                SELECT
                    id
                FROM
                    persons
                WHERE
                    code = :code;
                ''',
                dict(code=code),
            )
        )
        if not expected_people_ids:
            logger.warning("Got reply with invalid code %r", code)
            raise ValueError("Invalid code")
        for person_id in persons.keys():
            if person_id not in expected_people_ids:
                logger.warning(
                    "Got invalid person id=%d for code %r",
                    person_id,
                    code,
                )
                raise ValueError("Invalid person")

        # Insert update
        cursor = db.cursor()
        date = datetime.utcnow()
        for person_id, rsvp in persons.items():
            if rsvp not in ('yes', 'no'):
                raise ValueError("Invalid rsvp %r", rsvp)
            cursor.execute(
                '''\
                INSERT INTO replies(person_id, date, rsvp)
                VALUES(:id, :date, :rsvp);
                ''',
                dict(id=person_id, date=date, rsvp=rsvp),
            )
        cursor.execute('COMMIT;')
        logger.info(
            "Recorded update for code=%r date=%r persons: %s",
            code,
            date,
            ' '.join('%d=%s' % p for p in sorted(persons.items())),
        )