export function parseSrt(data: string) {
  const lines = data.split(/\r?\n/);
  const result = [];
  const re = new RegExp(
    "(\\d{2}:\\d{2}:\\d{2},\\d{3})\\s*-->\\s*(\\d{2}:\\d{2}:\\d{2},\\d{3})",
  );
  let i = 0;
  while (i < lines.length) {
    if (!lines[i].trim()) {
      i++;
      continue;
    }
    i++;
    if (i >= lines.length) break;
    const timeMatch = lines[i].match(re);
    if (!timeMatch) {
      i++;
      continue;
    }
    const start = toSeconds(timeMatch[1]);
    const end = toSeconds(timeMatch[2]);
    i++;
    let text = "";
    while (i < lines.length && lines[i].trim()) {
      text += lines[i] + "\n";
      i++;
    }
    result.push({ start, end, text: text.trim() });
    i++;
  }
  return result;
}

export function getNearistIndex(
  srt: { start: number; end: number; text: string }[],
  ct: number,
) {
  for (let i = 0; i < srt.length; i++) {
    const s = srt[i];
    const l = ct - s.start >= 0;
    const r = ct - s.end >= 0;
    if (!(l || r)) return i - 1;
    if (l && !r) return i;
  }
}

export function getIndex(
  srt: { start: number; end: number; text: string }[],
  ct: number,
) {
  for (let i = 0; i < srt.length; i++) {
    if (ct >= srt[i].start && ct <= srt[i].end) {
      return i;
    }
  }
  return null;
}

export function getSubtitle(
  srt: { start: number; end: number; text: string }[],
  currentTime: number,
) {
  return (
    srt.find((sub) => currentTime >= sub.start && currentTime <= sub.end) ||
    null
  );
}

function toSeconds(timeStr: string): number {
  const [h, m, s] = timeStr.replace(",", ".").split(":");
  return parseFloat(
    (parseInt(h) * 3600 + parseInt(m) * 60 + parseFloat(s)).toFixed(3),
  );
}