"""Working-hours helpers.

Working hours are stored per tenant as:
    {"mon": [["09:00", "13:00"], ["14:00", "18:00"]], ..., "sun": []}
Multiple intervals per day model lunch breaks. Missing/empty day = closed.
All computations happen in the tenant's timezone.
"""

from __future__ import annotations

from datetime import date, datetime, time, timedelta
from zoneinfo import ZoneInfo

WEEKDAY_KEYS = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]

# Bosnian day names (Latin) for UI / agent context
DAY_NAMES_BS = {
    "mon": "ponedjeljak",
    "tue": "utorak",
    "wed": "srijeda",
    "thu": "četvrtak",
    "fri": "petak",
    "sat": "subota",
    "sun": "nedjelja",
}

DEFAULT_WORKING_HOURS: dict[str, list[list[str]]] = {
    "mon": [["09:00", "18:00"]],
    "tue": [["09:00", "18:00"]],
    "wed": [["09:00", "18:00"]],
    "thu": [["09:00", "18:00"]],
    "fri": [["09:00", "18:00"]],
    "sat": [["09:00", "14:00"]],
    "sun": [],
}


def _parse_hhmm(s: str) -> time:
    h, m = s.split(":")
    return time(int(h), int(m))


def day_intervals(
    working_hours: dict, day: date, tz: ZoneInfo
) -> list[tuple[datetime, datetime]]:
    """Open intervals for a calendar day as tz-aware datetimes."""
    key = WEEKDAY_KEYS[day.weekday()]
    out = []
    for start_s, end_s in working_hours.get(key, []):
        start = datetime.combine(day, _parse_hhmm(start_s), tzinfo=tz)
        end = datetime.combine(day, _parse_hhmm(end_s), tzinfo=tz)
        if end > start:
            out.append((start, end))
    return out


def is_open_at(working_hours: dict, at: datetime, tz: ZoneInfo) -> bool:
    at = at.astimezone(tz)
    return any(s <= at < e for s, e in day_intervals(working_hours, at.date(), tz))


def hours_summary_bs(working_hours: dict) -> str:
    """Human-readable Bosnian working-hours summary for prompts/emails."""
    parts = []
    for key in WEEKDAY_KEYS:
        intervals = working_hours.get(key, [])
        if not intervals:
            parts.append(f"{DAY_NAMES_BS[key]}: zatvoreno")
        else:
            spans = ", ".join(f"{a}–{b}" for a, b in intervals)
            parts.append(f"{DAY_NAMES_BS[key]}: {spans}")
    return "; ".join(parts)


def iter_days(start: date, end: date):
    d = start
    while d <= end:
        yield d
        d += timedelta(days=1)