/*
Copyright 2026 Lotus Guild

SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
Please see LICENSE in the repository root for full details.
*/

import { type IWidgetApiRequest } from "matrix-widget-api";
import { logger } from "matrix-js-sdk/lib/logger";

import { type MediaDevices } from "../state/MediaDevices";
import { widget } from "../widget";
import { LotusWidgetActions } from "./lotusActions";
import { lotusSendToHost } from "./lotusWidget";

/**
 * [Gitea #119] Let the host switch the audio output device (headset ↔
 * speakers) from its own call bar: `io.lotus.set_audio_output { deviceId }`
 * selects the output; the fork answers each change (and the initial state)
 * with `io.lotus.audio_output_state { deviceId, available: [{id,label}] }`.
 * No effect unless the host sends the action. Returns a teardown function.
 */
export function startLotusAudioOutput(mediaDevices: MediaDevices): () => void {
  const w = widget;
  if (!w) return () => undefined;

  const handler = (ev: CustomEvent<IWidgetApiRequest>): void => {
    w.api.transport.reply(ev.detail, {});
    const data = ev.detail.data as { deviceId?: string } | undefined;
    if (typeof data?.deviceId !== "string") return;
    logger.debug(`[lotus] set_audio_output: ${data.deviceId}`);
    mediaDevices.audioOutput.select(data.deviceId);
  };
  w.lazyActions.on(LotusWidgetActions.SetAudioOutput, handler);

  const sub = mediaDevices.audioOutput.selected$.subscribe((selected) => {
    lotusSendToHost(LotusWidgetActions.AudioOutputState, {
      deviceId: selected?.id ?? null,
    });
  });

  return () => {
    sub.unsubscribe();
    w.lazyActions.off(LotusWidgetActions.SetAudioOutput, handler);
  };
}