export const parseVttTime = (raw: string): number => {
  const parts = raw.trim().split(':')
  if (parts.length < 2) return 0
  const secPart = parts.pop()!
  const minPart = parts.pop()!
  const hourPart = parts.pop() ?? '0'
  return (Number(hourPart) * 3600) + (Number(minPart) * 60) + Number(secPart.replace(',', '.'))
}

export const parseVttCue = (line: string, lines: string[], i: number) => {
  if (!line.includes('-->')) return null
  const [startRaw, endRaw] = line.split('-->')
  const payload: string[] = []
  let j = i + 1
  while (j < lines.length && lines[j].trim() !== '') {
    payload.push(lines[j]); j++
  }
  const text = payload.join('\n').replace(/<[^>]+>/g, '').trim()
  if (!text) return null
  return { start: parseVttTime(startRaw), end: parseVttTime(endRaw), text }
}

export const parseVtt = (text: string) => {
  const lines = text.replace(/\r/g, '').split('\n')
  const cues = []
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i].trim()
    if (!line) continue
    if (i + 1 < lines.length && !line.includes('-->') && lines[i + 1].includes('-->')) {
      const cue = parseVttCue(lines[i + 1].trim(), lines, i + 1)
      if (cue) cues.push(cue); i++
    } else if (line.includes('-->')) {
      const cue = parseVttCue(line, lines, i)
      if (cue) cues.push(cue)
    }
  }
  return cues
}