// Plays announcements generated by the server's local Piper voice. Any failure - Piper not
// installed, generation too slow, network hiccup - falls back to the browser's own voice,
// so an announcement is never lost and never holds up timing.
const PIPER_TIMEOUT_MS = 2500;
let current = null;

export function stopPiperSpeech() {
  if (!current) return;
  current.cancelled = true;
  current.controller.abort();
  if (current.audio) current.audio.pause();
  if (current.url) URL.revokeObjectURL(current.url);
  current = null;
}

export function isPiperSpeaking() {
  return Boolean(current);
}

// Returns true when the line was accepted (it will play via Piper or the fallback).
export function speakWithPiper(text, { language, voice = "", rate, volume = 1, interrupt, onEnd, onError, fallback }) {
  if (current && !interrupt) return false;
  stopPiperSpeech();
  const job = { cancelled: false, controller: new AbortController(), audio: null, url: "" };
  current = job;
  const finish = (callback) => {
    if (job.url) URL.revokeObjectURL(job.url);
    if (current === job) current = null;
    callback?.();
  };
  const timer = setTimeout(() => job.controller.abort(), PIPER_TIMEOUT_MS);
  fetch("/api/tts/speech", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ text, language, voice, rate }),
    signal: job.controller.signal,
  })
    .then((response) => {
      if (!response.ok) throw new Error(`tts ${response.status}`);
      return response.blob();
    })
    .then((blob) => {
      clearTimeout(timer);
      if (job.cancelled) return;
      job.url = URL.createObjectURL(blob);
      job.audio = new Audio(job.url);
      job.audio.volume = Math.max(0, Math.min(1, Number(volume)));
      job.audio.onended = () => finish(onEnd);
      job.audio.onerror = () => finish(onError);
      return job.audio.play();
    })
    .catch(() => {
      clearTimeout(timer);
      if (job.cancelled) return;
      finish(() => {
        if (!fallback?.()) onError?.();
      });
    });
  return true;
}