import { Room } from 'matrix-js-sdk';
import { StateEvent } from '../../types/matrix/room';

// MSC1763 — per-room message retention (`m.room.retention`). `max_lifetime` is a
// duration in milliseconds after which a message is considered expired.
export type RetentionContent = {
  max_lifetime?: number;
};

const DAY_MS = 24 * 60 * 60 * 1000;

// Floor to avoid foot-guns (an admin fat-fingering a tiny value nuking a room).
export const RETENTION_MIN_MS = 10 * 60 * 1000;

export type RetentionPreset = { label: string; ms: number };
export const RETENTION_PRESETS: RetentionPreset[] = [
  { label: 'Off', ms: 0 },
  { label: '1 Day', ms: DAY_MS },
  { label: '1 Week', ms: 7 * DAY_MS },
  { label: '1 Month', ms: 30 * DAY_MS },
];

/** The room's active retention window in ms, or `undefined` when unset/disabled. */
export const getRoomRetentionMs = (room: Room): number | undefined => {
  const event = room.currentState.getStateEvents(StateEvent.RoomRetention, '');
  const ms = event?.getContent<RetentionContent>()?.max_lifetime;
  return typeof ms === 'number' && ms > 0 ? ms : undefined;
};

/** True when an event at `tsMs` has passed the `maxLifetimeMs` retention window. */
export const isExpired = (tsMs: number, maxLifetimeMs: number, nowMs: number): boolean =>
  maxLifetimeMs > 0 && nowMs - tsMs > maxLifetimeMs;