// home-assistant's events. The tool runtime imports this once the broker is bound. It watches the
// entities whose state changing is a real signal — a door opening, a lock turning, a switch
// flipping — and emits when one does.
//
// Emits (novox/hq ADR 0041/0042):
//   module.home-assistant.state.changed   — a watched entity's state value changed
//
// Bounded on purpose. Home Assistant has hundreds of entities and many (temperature, humidity,
// power draw) tick constantly; emitting every tick would be noise, not signal. So the watch is
// limited to actuator/contact domains where a change is an event a human would care about, and
// only the discrete `state` value is diffed — not the attribute bag. The set is overridable with
// MESH_HOMEASSISTANT_WATCH (comma-separated entity ids) for a node that wants a specific few.

import { emit } from "@novox/mesh-sdk/events";
import { HomeAssistantClient, type HAEntityState } from "./client.js";

const ha = HomeAssistantClient.fromEnv();

// Domains whose state changing is meaningful rather than a continuous reading.
const WATCH_DOMAINS = new Set(["binary_sensor", "lock", "cover", "switch", "input_boolean", "light", "alarm_control_panel"]);

// An explicit allowlist of entity ids, if the node set one; otherwise fall back to the domain filter.
const watchList = (process.env.MESH_HOMEASSISTANT_WATCH ?? "")
  .split(",")
  .map((s) => s.trim())
  .filter(Boolean);
const watchSet = watchList.length ? new Set(watchList) : null;

function isWatched(s: HAEntityState): boolean {
  if (watchSet) return watchSet.has(s.entity_id);
  return WATCH_DOMAINS.has(s.entity_id.split(".")[0] ?? "");
}

const nameOf = (s: HAEntityState): string | undefined =>
  typeof s.attributes.friendly_name === "string" ? s.attributes.friendly_name : undefined;

// Last seen state per watched entity. Primed silently on the first poll so a restart does not
// re-announce the current state of everything as a fresh change.
const lastState = new Map<string, string>();
let primed = false;

async function pollStates(): Promise<void> {
  const states = (await ha.getStates()).filter(isWatched);
  for (const s of states) {
    const prev = lastState.get(s.entity_id);
    if (primed && prev !== undefined && prev !== s.state) {
      await emit("state.changed", {
        entity: s.entity_id,
        name: nameOf(s),
        from: prev,
        to: s.state,
      });
    }
    lastState.set(s.entity_id, s.state);
  }
  primed = true;
}

const tick = (fn: () => Promise<void>, everyMs: number): void => {
  const run = (): void => void fn().catch((err) => console.error(`[home-assistant] ${err}`));
  setInterval(run, everyMs);
  run();
};
tick(pollStates, 15_000);

console.log("[home-assistant] watching entity states, emitting on change");