/**
 * Eingabe/Ausgabe geplanter Trainingsdauer (Minuten intern, Anzeige z. B. 1,5 h).
 */

export function parseDurationInput(raw) {
  if (raw === '' || raw == null) return null
  const s = String(raw).trim().toLowerCase().replace(/\s+/g, '')
  if (!s) return null

  const hMatch = s.match(/^(\d+(?:[.,]\d+)?)\s*h(?:\s*(\d{1,2}))?$/)
  if (hMatch) {
    const h = parseFloat(hMatch[1].replace(',', '.'))
    const extraMin = hMatch[2] ? parseInt(hMatch[2], 10) : 0
    if (!Number.isFinite(h) || h < 0) return null
    const total = Math.round(h * 60) + (Number.isFinite(extraMin) ? extraMin : 0)
    return total > 0 ? total : null
  }

  if (/^\d+(?:[.,]\d+)?$/.test(s)) {
    const n = parseFloat(s.replace(',', '.'))
    if (!Number.isFinite(n) || n <= 0) return null
    if (s.includes(',') || s.includes('.') || n < 8) {
      return Math.round(n * 60)
    }
    return Math.round(n)
  }

  const minMatch = s.match(/^(\d+)\s*min?$/)
  if (minMatch) {
    const m = parseInt(minMatch[1], 10)
    return Number.isFinite(m) && m > 0 ? m : null
  }

  return null
}

export function formatDurationDisplay(minutes, { empty = '—' } = {}) {
  if (minutes == null || minutes === '') return empty
  const m = Number(minutes)
  if (!Number.isFinite(m) || m <= 0) return empty
  if (m % 60 === 0) return `${m / 60} h`
  if (m >= 60) {
    const h = Math.floor(m / 60)
    const rest = m % 60
    return `${h} h ${rest} Min`
  }
  return `${m} Min`
}

/** Formularfeld: Minuten → Anzeige-String (z. B. 90 → "1,5") */
export function minutesToDurationFieldValue(minutes) {
  if (minutes == null || minutes === '') return ''
  const m = Number(minutes)
  if (!Number.isFinite(m) || m <= 0) return ''
  if (m % 60 === 0) return String(m / 60)
  if (m >= 60) {
    const h = m / 60
    return Number.isInteger(h) ? String(h) : String(Math.round(h * 10) / 10).replace('.', ',')
  }
  return String(m)
}

export function sumExercisePlannedMinutes(sections) {
  let sum = 0
  for (const sec of sections || []) {
    for (const it of sec.items || []) {
      if (it.item_type !== 'exercise') continue
      const n = parseDurationInput(it.planned_duration_min)
      if (n != null) sum += n
    }
  }
  return sum
}

export function sumSectionPlannedMinutes(sections) {
  let sum = 0
  for (const sec of sections || []) {
    const n = parseDurationInput(sec.planned_duration_min)
    if (n != null) sum += n
  }
  return sum
}

/**
 * Anzeige für Session-Dauer (ein Slot oder Min/Max über mehrere Sessions).
 * @param {number|null|undefined} minMinutes
 * @param {number|null|undefined} maxMinutes
 */
export function formatSessionDurationRange(minMinutes, maxMinutes, { empty = '—' } = {}) {
  const lo = minMinutes != null && minMinutes !== '' ? Number(minMinutes) : null
  const hi = maxMinutes != null && maxMinutes !== '' ? Number(maxMinutes) : null
  if (lo != null && Number.isFinite(lo) && lo > 0) {
    if (hi != null && Number.isFinite(hi) && hi > 0 && hi !== lo) {
      return `${formatDurationDisplay(lo, { empty: '' })} – ${formatDurationDisplay(hi, { empty: '' })}`
    }
    return formatDurationDisplay(lo, { empty })
  }
  if (hi != null && Number.isFinite(hi) && hi > 0) {
    return formatDurationDisplay(hi, { empty })
  }
  return empty
}