// utils/windowArgs.js
//
// Shared `--window` parsing for /wanstatus and /voicediag.

export function pickWindowArg(args) {
  return pickFlagValue(args, '--window');
}

function pickFlagValue(args, flag) {
  const prefix = `${flag.toLowerCase()}=`;
  for (let i = 0; i < args.length; i += 1) {
    const a = String(args[i] || '').toLowerCase();
    if (a.startsWith(prefix)) return String(args[i]).slice(prefix.length);
    if (a === flag.toLowerCase() && i + 1 < args.length) return args[i + 1];
  }
  return null;
}

/**
 * Parse a window shorthand (`15m`, `1h`, `24h`, `1d`, `1440`) into
 * minutes. Returns null on unrecognised input so the caller can
 * decide whether to surface a friendly error or fall back to the
 * env default.
 */
export function parseWindowMinutes(raw) {
  if (raw === null || raw === undefined || raw === '') return undefined;
  const s = String(raw).trim().toLowerCase();
  if (/^\d+$/.test(s)) return Math.max(1, parseInt(s, 10));
  const m = s.match(/^(\d+)\s*(m|min|mins|h|hr|hrs|hour|hours|d|day|days)$/);
  if (!m) return null;
  const n = parseInt(m[1], 10);
  const unit = m[2];
  if (['m', 'min', 'mins'].includes(unit)) return n;
  if (['h', 'hr', 'hrs', 'hour', 'hours'].includes(unit)) return n * 60;
  if (['d', 'day', 'days'].includes(unit)) return n * 60 * 24;
  return null;
}