from celery.utils.log import get_task_logger

from sqlalchemy import distinct
from sqlalchemy.sql import null, and_, func, not_, case
from sqlalchemy.dialects import postgresql
from sqlalchemy.dialects.postgresql import insert

from ogn_python.collect.celery import app
from ogn_python.model import Country, DeviceInfo, DeviceInfoOrigin, AircraftBeacon, ReceiverBeacon, Device, Receiver
from ogn_python.utils import get_ddb, get_flarmnet


logger = get_task_logger(__name__)


def compile_query(query):
    """Via http://nicolascadou.com/blog/2014/01/printing-actual-sqlalchemy-queries"""
    compiler = query.compile if not hasattr(query, 'statement') else query.statement.compile
    return compiler(dialect=postgresql.dialect())


def upsert(session, model, rows, update_cols):
    """Insert rows in model. On conflicting update columns if new value IS NOT NULL."""

    table = model.__table__

    stmt = insert(table).values(rows)

    on_conflict_stmt = stmt.on_conflict_do_update(
        index_elements=table.primary_key.columns,
        set_={k: case([(getattr(stmt.excluded, k) != null(), getattr(stmt.excluded, k))], else_=getattr(model, k)) for k in update_cols},
    )

    # print(compile_query(on_conflict_stmt))
    session.execute(on_conflict_stmt)


def update_device_infos(session, address_origin, path=None):
    if address_origin == DeviceInfoOrigin.flarmnet:
        device_infos = get_flarmnet(fln_file=path)
    else:
        device_infos = get_ddb(csv_file=path)

    session.query(DeviceInfo) \
        .filter(DeviceInfo.address_origin == address_origin) \
        .delete(synchronize_session='fetch')
    session.commit()

    for device_info in device_infos:
        device_info.address_origin = address_origin

    session.bulk_save_objects(device_infos)
    session.commit()

    return len(device_infos)


@app.task
def import_ddb(session=None):
    """Import registered devices from the DDB."""

    if session is None:
        session = app.session

    logger.info("Import registered devices fom the DDB...")
    counter = update_device_infos(session, DeviceInfoOrigin.ogn_ddb)
    logger.info("Imported {} devices.".format(counter))

    return "Imported {} devices.".format(counter)


@app.task
def add_missing_devices(session=None):
    """Add/update entries in devices table and update foreign keys in aircraft beacons."""

    if session is None:
        session = app.session

    # Create missing Device from AircraftBeacon
    available_devices = session.query(Device.address) \
        .subquery()

    missing_devices_query = session.query(distinct(AircraftBeacon.address)) \
        .filter(and_(AircraftBeacon.device_id == null(), not_(AircraftBeacon.address.like('00%')), AircraftBeacon.error_count == 0)) \
        .filter(~AircraftBeacon.address.in_(available_devices))

    ins = insert(Device).from_select([Device.address], missing_devices_query)
    res = session.execute(ins)
    insert_count = res.rowcount
    session.commit()

    # Update relations to aircraft beacons
    upd = session.query(AircraftBeacon) \
        .filter(AircraftBeacon.device_id == null()) \
        .filter(AircraftBeacon.address == Device.address) \
        .update({
            AircraftBeacon.device_id: Device.id},
            synchronize_session='fetch')

    session.commit()
    logger.info("Devices: {} inserted, {} updated".format(insert_count, add_missing_receivers))
    logger.info("Updated {} AircraftBeacons".format(upd))

    return "{} Devices inserted, {} Devices updated, {} AircraftBeacons updated" \
        .format(insert_count, add_missing_receivers, upd)


@app.task
def add_missing_receivers(session=None):
    """Add/add_missing_receivers entries in receiver table and update receivers foreign keys and distance in aircraft beacons and update foreign keys in receiver beacons."""

    if session is None:
        session = app.session

    # Create missing Receiver from ReceiverBeacon
    available_receivers = session.query(Receiver.name) \
        .subquery()

    missing_receiver_query = session.query(distinct(ReceiverBeacon.name)) \
        .filter(ReceiverBeacon.receiver_id == null()) \
        .filter(~ReceiverBeacon.name.in_(available_receivers))

    ins = insert(Receiver).from_select([Receiver.name], missing_receiver_query)
    res = session.execute(ins)
    insert_count = res.rowcount

    # Update relations to aircraft beacons
    update_aircraft_beacons = session.query(AircraftBeacon) \
        .filter(and_(AircraftBeacon.receiver_id == null(), AircraftBeacon.receiver_name == Receiver.name)) \
        .update({AircraftBeacon.receiver_id: Receiver.id,
                 AircraftBeacon.distance: func.ST_Distance_Sphere(AircraftBeacon.location_wkt, Receiver.location_wkt)},
                synchronize_session='fetch')

    # Update relations to receiver beacons
    update_receiver_beacons = session.query(ReceiverBeacon) \
        .filter(and_(ReceiverBeacon.receiver_id == null(), ReceiverBeacon.name == Receiver.name)) \
        .update({ReceiverBeacon.receiver_id: Receiver.id},
                synchronize_session='fetch')

    session.commit()

    logger.info("Receivers: {} inserted, {} updated.".format(insert_count, add_missing_receivers))
    logger.info("Updated relations: {} aircraft beacons, {} receiver beacons".format(update_aircraft_beacons, update_receiver_beacons))

    return "{} Receivers inserted, {} Receivers updated, {} AircraftBeacons updated, {} ReceiverBeacons updated" \
        .format(insert_count, add_missing_receivers, update_aircraft_beacons, update_receiver_beacons)


@app.task
def update_country_code(session=None):
    """Update country code in receivers table if None."""

    if session is None:
        session = app.session

    update_receivers = session.query(Receiver) \
        .filter(and_(Receiver.country_id == null(), Receiver.location_wkt != null(), func.st_within(Receiver.location_wkt, Country.geom))) \
        .update({Receiver.country_id: Country.gid},
                synchronize_session='fetch')

    session.commit()
    logger.info("Updated {} AircraftBeacons".format(update_receivers))

    return "Updated country for {} Receivers".format(update_receivers)