from django.db.models import F, Q, QuerySet

from apps.players.models import Player, PlayerCareerEntry


def get_origin_career_entry(player: Player) -> PlayerCareerEntry | None:
    """Earliest meaningful career entry, ordered by start_date then season start date."""
    return (
        PlayerCareerEntry.objects.select_related("competition", "team", "season")
        .filter(player=player)
        .filter(Q(competition__isnull=False) | Q(team__isnull=False))
        .order_by(
            F("start_date").asc(nulls_last=True),
            F("season__start_date").asc(nulls_last=True),
            "id",
        )
        .first()
    )


def refresh_player_origin(player: Player, *, save: bool = True) -> bool:
    """Update origin fields from earliest meaningful career entry."""
    entry = get_origin_career_entry(player)
    origin_competition = entry.competition if entry else None
    origin_team = entry.team if entry else None

    changed = (
        player.origin_competition_id != (origin_competition.id if origin_competition else None)
        or player.origin_team_id != (origin_team.id if origin_team else None)
    )
    if changed:
        player.origin_competition = origin_competition
        player.origin_team = origin_team
        if save:
            player.save(update_fields=["origin_competition", "origin_team", "updated_at"])
    return changed


def refresh_player_origins(queryset: QuerySet[Player] | None = None) -> int:
    """Backfill/recompute origin fields for players in queryset."""
    players = queryset if queryset is not None else Player.objects.all()
    updated = 0
    for player in players.iterator():
        if refresh_player_origin(player):
            updated += 1
    return updated