"""Database queries."""

import typing
from sqlalchemy.orm.query import Query
from sqlalchemy.engine.cursor import CursorResult
from sqlalchemy import func

from . import database, model


def top_speakers() -> Query:
    """Find people who spoke at the most conferences."""
    q: Query = (
        database.session.query(model.Person, func.count())
        .join(model.ConferencePerson)
        .filter(model.Person.id != 1046)  # FOSDEM Staff
        .group_by(model.Person)
        .order_by(func.count().desc(), model.Person.name)
    )
    return q


def top_events() -> Query:
    """Most common titles of events."""
    q: Query = (
        database.session.query(model.Event.title, func.count())
        .group_by(model.Event.title)
        .order_by(func.count().desc())
        .having(func.count() > 3)
    )
    return q


def search_for_events(search_for: str) -> Query:
    """Search for events with by title."""
    q: Query = model.Event.query.filter(
        model.Event.title.ilike(f"%{search_for}%")
    ).order_by(model.Event.title)
    return q


def search_for_people(search_for: str) -> Query:
    """Search for people by name."""
    q: Query = model.Person.query.filter(
        model.Person.name.ilike(f"%{search_for}%")
    ).order_by(model.Person.name)
    return q


def speaker_counts() -> CursorResult:
    """Speaker/conference frequency distribution."""
    sql = """
select num, count(*)
from (select person_id, count(*) as num from conference_person group by person_id) a
group by num
order by num
"""

    return typing.cast(CursorResult, database.session.execute(sql))