from project.models import EventReviewStatus, EventCategory, Event, EventDate, EventReference, EventPlace, Location, EventSuggestion
from project.dateutils import dates_from_recurrence_rule, today, date_add_time, date_set_end_of_day
from sqlalchemy import and_, or_, not_, func
from sqlalchemy.sql import extract
from dateutil.relativedelta import relativedelta

def upsert_event_category(category_name):
    result = EventCategory.query.filter_by(name = category_name).first()
    if result is None:
        result = EventCategory(name = category_name)
        db.session.add(result)

    return result

def fill_event_filter(event_filter, params):
    if params.keyword:
        like_keyword = '%' + params.keyword + '%'
        event_filter = and_(event_filter, or_(Event.name.ilike(like_keyword), Event.description.ilike(like_keyword), Event.tags.ilike(like_keyword)))

    if params.category_id:
        if type(params.category_id) is list:
            category_ids = params.category_id
        else:
            category_ids = [params.category_id]
        event_filter = and_(event_filter, Event.categories.any(EventCategory.id.in_(category_ids)))

    if params.organizer_id:
        event_filter = and_(event_filter, Event.organizer_id == params.organizer_id)

    if params.latitude and params.longitude and params.distance:
        point = 'POINT({} {})'.format(params.longitude, params.latitude)
        event_filter = and_(event_filter, func.ST_DistanceSphere(Location.coordinate, point) <= params.distance)

    return event_filter

def get_event_dates_query(params):
    event_filter = (1 == 1)
    date_filter = (EventDate.start >= today)

    event_filter = fill_event_filter(event_filter, params)

    if params.admin_unit_id:
        event_filter = and_(event_filter, or_(Event.admin_unit_id == params.admin_unit_id, Event.references.any(EventReference.admin_unit_id == params.admin_unit_id)))

    if params.date_from:
        date_filter = (EventDate.start >= params.date_from)

    if params.date_to:
        date_filter = and_(date_filter, EventDate.start < params.date_to)

    # PostgreSQL specific https://stackoverflow.com/a/25597632
    if params.weekday:
        if type(params.weekday) is list:
            weekdays = params.weekday
        else:
            weekdays = [params.weekday]
        date_filter = and_(date_filter, extract('dow', EventDate.start).in_(weekdays))

    return EventDate.query.join(Event).join(EventPlace, isouter=True).join(Location, isouter=True).filter(date_filter).filter(event_filter).order_by(EventDate.start)

def get_events_query(params):
    event_filter = (1 == 1)
    date_filter = (EventDate.start >= today)

    event_filter = fill_event_filter(event_filter, params)

    if params.admin_unit_id:
        event_filter = and_(event_filter, Event.admin_unit_id == params.admin_unit_id)

    if params.date_from:
        date_filter = (EventDate.start >= params.date_from)

    if params.date_to:
        date_filter = and_(date_filter, EventDate.start < params.date_to)

    event_filter = and_(event_filter, Event.dates.any(date_filter))
    return Event.query.join(EventPlace, isouter=True).join(Location, isouter=True).filter(event_filter).order_by(Event.start)

def update_event_dates_with_recurrence_rule(event, start, end):
    event.start = start
    event.end = end

    if end:
        time_difference = relativedelta(end, start)

    dates_to_add = list()
    dates_to_remove = list(event.dates)

    if event.recurrence_rule:
        rr_dates = dates_from_recurrence_rule(start, event.recurrence_rule)
    else:
        rr_dates = [start]

    for rr_date in rr_dates:
        rr_date_start = date_add_time(rr_date, start.hour, start.minute, start.second, rr_date.tzinfo)

        if end:
            rr_date_end = rr_date_start + time_difference
        else:
            rr_date_end = None

        existing_date = next((date for date in event.dates if date.start == rr_date_start and date.end == rr_date_end), None)
        if existing_date:
            dates_to_remove.remove(existing_date)
        else:
            new_date = EventDate(event_id = event.id, start=rr_date_start, end=rr_date_end)
            dates_to_add.append(new_date)

    event.dates = [date for date in event.dates if date not in dates_to_remove]
    event.dates.extend(dates_to_add)