"""Generate the .ics attachment (METHOD:REQUEST) for the first-choice slot (§9.1).

The .ics is a convenience so Gmail offers "Add to calendar" — the owner can move
and rearrange the event before saving. Gogo never writes to the owner's calendar.
"""

from __future__ import annotations

from datetime import datetime

from icalendar import Calendar, Event, vCalAddress, vText

from gogo.config import get_settings


def build_ics(
    *,
    uid: str,
    start: datetime,
    end: datetime,
    summary: str,
    description: str,
    organizer_email: str = "noreply@gogotelefon.ba",
) -> bytes:
    cal = Calendar()
    cal.add("prodid", "-//Gogo Telefon//gogotelefon.ba//BS")
    cal.add("version", "2.0")
    cal.add("method", "REQUEST")

    ev = Event()
    ev.add("uid", f"{uid}@gogotelefon.ba")
    ev.add("dtstart", start)
    ev.add("dtend", end)
    ev.add("summary", summary)
    ev.add("description", description)
    ev.add("status", "TENTATIVE")
    organizer = vCalAddress(f"MAILTO:{organizer_email}")
    organizer.params["cn"] = vText("Gogo Telefon")
    ev["organizer"] = organizer
    ev.add("url", get_settings().base_url)
    cal.add_component(ev)
    return cal.to_ical()