"""Moteur unique de génération des échéances depuis les tâches de lot."""
from datetime import date, timedelta

from app_new.extensions import db
from app_new.core.models.planning import Meter, ScheduledTask
from app_new.core.models.maintenance import LotTask
from app_new.core.services.planning_service import PlanningService


def _targets(lot):
    result = []
    for root in lot.equipments.filter_by(is_deleted=False):
        if root.tracked_individually:
            result.extend([x for x in root.all_children if not x.is_group and not x.is_deleted])
        elif root.is_group and root.children.count():
            result.extend([x for x in root.children if not x.is_deleted])
        else:
            result.append(root)
    return list({item.id: item for item in result}.values())


def _working_day(candidate):
    for _ in range(370):
        if PlanningService.get_working_hours(candidate):
            return candidate
        candidate += timedelta(days=1)
    raise ValueError("Aucune journée travaillée disponible dans les 12 prochains mois.")


def generate_due_tasks(task: LotTask, event=None, today=None):
    """Génère les échéances sans doublon et retourne les objets créés."""
    today = today or date.today()
    if not task.is_active:
        return []
    if task.trigger_type in ("event", "weather") and task.trigger_event != event:
        return []
    if task.trigger_type == "season":
        start, end = task.season_start_month or 1, task.season_end_month or 12
        inside = start <= today.month <= end if start <= end else today.month >= start or today.month <= end
        if not inside:
            return []
    created = []
    for equipment in _targets(task.lot):
        if task.trigger_type == "meter":
            meter = Meter.query.filter_by(equipment_id=equipment.id, is_active=True).order_by(Meter.current_value.desc()).first()
            if not meter or task.meter_threshold is None or meter.current_value < task.meter_threshold:
                continue
        existing = ScheduledTask.query.filter_by(lot_task_id=task.id, equipment_id=equipment.id, status="planned").first()
        if existing:
            continue
        due = _working_day(today + timedelta(days=max(task.advance_days or 0, 0)))
        item = ScheduledTask(lot_task_id=task.id, equipment_id=equipment.id,
                             room_id=equipment.effective_room.id if equipment.effective_room else None,
                             scheduled_date=due, estimated_duration=task.effective_duration(), status="planned")
        db.session.add(item)
        created.append(item)
    db.session.commit()
    return created