/**
 * earth-now.co
 * Author:  Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * File:    apps/api/src/pollers/open-notify.ts
 * Purpose: Open Notify poller (1 h) for humans_in_space — extremely failure-tolerant, fixture value stays as fallback
 */

import { buildStaticRtModel } from "@earth-now/models";
import { type ModelStore, displayHintsOf } from "../store.js";
import { type PollerHandle, NOOP_POLLER, fetchJson, pollersEnabled } from "./poller.js";

const METRIC_ID = "humans_in_space";
const SOURCE_ID = "open_notify";
const ASTROS_URL = "http://api.open-notify.org/astros.json";
// The API is known to be flaky: only flag the metric stale after repeated failures.
const MAX_CONSECUTIVE_FAILURES = 3;

export const OPEN_NOTIFY_POLL_INTERVAL_MS = 60 * 60_000;

async function pollOnce(store: ModelStore): Promise<void> {
  const data = await fetchJson(ASTROS_URL);
  const count = (data as { number?: unknown }).number;
  if (typeof count !== "number" || !Number.isInteger(count) || count < 0 || count > 100) {
    throw new Error("astros.json malformed or implausible 'number' field");
  }
  const entry = store.registry.byId.get(METRIC_ID);
  if (!entry) throw new Error(`registry has no '${METRIC_ID}' entry`);
  const nowIso = new Date().toISOString();
  store.updateRtModel(
    METRIC_ID,
    buildStaticRtModel(
      {
        metricId: METRIC_ID,
        sourceId: SOURCE_ID,
        observedAt: nowIso,
        displayHints: displayHintsOf(entry),
      },
      { value: count, at: nowIso },
    ),
  );
}

export function startOpenNotifyPoller(
  store: ModelStore,
  intervalMs: number = OPEN_NOTIFY_POLL_INTERVAL_MS,
): PollerHandle {
  if (!pollersEnabled()) return NOOP_POLLER;
  let consecutiveFailures = 0;
  const tick = (): void => {
    void pollOnce(store)
      .then(() => {
        consecutiveFailures = 0;
      })
      .catch((err: unknown) => {
        consecutiveFailures += 1;
        if (consecutiveFailures >= MAX_CONSECUTIVE_FAILURES) store.markStale(METRIC_ID);
        console.error(
          `[open-notify] poll failed ${consecutiveFailures}× (fixture/previous value keeps serving): ${String(err)}`,
        );
      });
  };
  tick();
  const timer = setInterval(tick, intervalMs);
  timer.unref();
  return { stop: () => clearInterval(timer) };
}