log.ts

import type { ActivityEvent, ActivityEventInput } from './types';

type AppendListener = (event: ActivityEvent) => void;

type LogState = {
  events: ActivityEvent[];
  seq: number;
  listeners: Set<AppendListener>;
};

const GLOBAL_KEY = Symbol.for('super.activity.events.log');

type GlobalWithLog = typeof globalThis & { [GLOBAL_KEY]?: LogState };

function getState(): LogState {
  const g = globalThis as GlobalWithLog;
  let existing = g[GLOBAL_KEY];
  if (!existing) {
    existing = { events: [], seq: 0, listeners: new Set() };
    g[GLOBAL_KEY] = existing;
  }
  return existing;
}

export function appendEvent(input: ActivityEventInput): ActivityEvent {
  const state = getState();
  state.seq += 1;
  const at = input.at ?? new Date().toISOString();
  const event = { ...input, seq: state.seq, at } as ActivityEvent;
  state.events.push(event);
  for (const listener of state.listeners) {
    listener(event);
  }
  return event;
}

export function onAppend(listener: AppendListener): () => void {
  const state = getState();
  state.listeners.add(listener);
  return () => {
    state.listeners.delete(listener);
  };
}

export function getAllEvents(): readonly ActivityEvent[] {
  return getState().events;
}

export function getEventsSince(sinceSeq: number): ActivityEvent[] {
  return getState().events.filter((event) => event.seq > sinceSeq);
}

export function getEventsForOffer(offerId: string): ActivityEvent[] {
  return getState().events.filter((event) => event.offer_id === offerId);
}

export function getLatestSeq(): number {
  return getState().seq;
}

export function __resetActivityEventLog(): void {
  const state = getState();
  state.events = [];
  state.seq = 0;
}