// Alarma corta generada con Web Audio (sin ficheros). Dos pitidos rápidos.
let ctx: AudioContext | null = null;

export function playAlarm() {
  try {
    const Ctor = window.AudioContext || (window as unknown as { webkitAudioContext: typeof AudioContext }).webkitAudioContext;
    ctx = ctx ?? new Ctor();
    if (ctx.state === "suspended") void ctx.resume();
    const now = ctx.currentTime;
    for (let i = 0; i < 2; i++) {
      const osc = ctx.createOscillator();
      const gain = ctx.createGain();
      osc.type = "square";
      osc.frequency.value = 880;
      const t = now + i * 0.18;
      gain.gain.setValueAtTime(0.0001, t);
      gain.gain.exponentialRampToValueAtTime(0.25, t + 0.01);
      gain.gain.exponentialRampToValueAtTime(0.0001, t + 0.15);
      osc.connect(gain);
      gain.connect(ctx.destination);
      osc.start(t);
      osc.stop(t + 0.16);
    }
  } catch {
    // sin audio disponible: ignoramos
  }
}

// Parsea "mm", "mm:ss" o "m.5" a segundos. Devuelve null si no es válido.
export function parseTime(input: string): number | null {
  const s = input.trim();
  if (!s) return null;
  if (s.includes(":")) {
    const [m, sec] = s.split(":");
    const mm = Number(m);
    const ss = Number(sec);
    if (!Number.isFinite(mm) || !Number.isFinite(ss) || ss < 0 || ss >= 60) return null;
    const total = Math.round(mm * 60 + ss);
    return total > 0 ? total : null;
  }
  const mins = Number(s);
  if (!Number.isFinite(mins) || mins <= 0) return null;
  return Math.round(mins * 60);
}