"""Import duty schedule: delete range, insert duties/unavailable/vacation. Accepts session."""

from datetime import date, timedelta

from sqlalchemy.orm import Session

from duty_teller.db.repository import (
    get_or_create_user_by_full_name,
    delete_duties_in_range,
    insert_duty,
)
from duty_teller.importers.duty_schedule import DutyScheduleResult
from duty_teller.utils.dates import day_start_iso, day_end_iso, duty_to_iso


def _consecutive_date_ranges(dates: list[date]) -> list[tuple[date, date]]:
    """Sort dates and merge consecutive ones into (first, last) ranges. Empty list -> []."""
    if not dates:
        return []
    sorted_dates = sorted(set(dates))
    ranges: list[tuple[date, date]] = []
    start_d = end_d = sorted_dates[0]
    for d in sorted_dates[1:]:
        if (d - end_d).days == 1:
            end_d = d
        else:
            ranges.append((start_d, end_d))
            start_d = end_d = d
    ranges.append((start_d, end_d))
    return ranges


def run_import(
    session: Session,
    result: DutyScheduleResult,
    hour_utc: int,
    minute_utc: int,
) -> tuple[int, int, int, int]:
    """Run import: delete range per user, insert duty/unavailable/vacation. Returns (num_users, num_duty, num_unavailable, num_vacation)."""
    from_date_str = result.start_date.isoformat()
    to_date_str = result.end_date.isoformat()
    num_duty = num_unavailable = num_vacation = 0
    for entry in result.entries:
        user = get_or_create_user_by_full_name(session, entry.full_name)
        delete_duties_in_range(session, user.id, from_date_str, to_date_str)
        for d in entry.duty_dates:
            start_at = duty_to_iso(d, hour_utc, minute_utc)
            d_next = d + timedelta(days=1)
            end_at = duty_to_iso(d_next, hour_utc, minute_utc)
            insert_duty(session, user.id, start_at, end_at, event_type="duty")
            num_duty += 1
        for d in entry.unavailable_dates:
            insert_duty(
                session,
                user.id,
                day_start_iso(d),
                day_end_iso(d),
                event_type="unavailable",
            )
            num_unavailable += 1
        for start_d, end_d in _consecutive_date_ranges(entry.vacation_dates):
            insert_duty(
                session,
                user.id,
                day_start_iso(start_d),
                day_end_iso(end_d),
                event_type="vacation",
            )
            num_vacation += 1
    return (len(result.entries), num_duty, num_unavailable, num_vacation)