const TRACK_PAD = 4

const roundPosition = (value) => Math.round(value * 10) / 10

const getBadgePositions = (badges) => {
  const defs = Array.isArray(badges) ? badges : []
  if (defs.length === 0) return []
  if (defs.length === 1) return [TRACK_PAD]
  const segmentWidth = (100 - TRACK_PAD * 2) / (defs.length - 1)
  return defs.map((_, index) => roundPosition(TRACK_PAD + index * segmentWidth))
}

const getBadgeProgress = (badges, totalDays) => {
  const defs = Array.isArray(badges) ? badges : []
  if (defs.length === 0) return 0

  const days = Math.max(0, Number(totalDays) || 0)
  if (days < defs[0].days) return 0
  if (defs.length === 1 || days >= defs[defs.length - 1].days) return 100

  const positions = getBadgePositions(defs)
  let index = 0
  while (index < defs.length - 1 && days >= defs[index + 1].days) index++

  const ratio = (days - defs[index].days) / (defs[index + 1].days - defs[index].days)
  return roundPosition(positions[index] + ratio * (positions[index + 1] - positions[index]))
}

const getBadgeSegments = (badges, totalDays) => {
  const defs = Array.isArray(badges) ? badges : []
  const positions = getBadgePositions(defs)
  const days = Math.max(0, Number(totalDays) || 0)

  return defs.slice(0, -1).map((badge, index) => {
    const nextBadge = defs[index + 1]
    const segmentDays = nextBadge.days - badge.days
    const progress = days <= badge.days
      ? 0
      : days >= nextBadge.days
        ? 100
        : roundPosition((days - badge.days) / segmentDays * 100)

    return {
      left: positions[index],
      width: roundPosition(positions[index + 1] - positions[index]),
      progress
    }
  })
}

const getBadgeDisplayLabel = (badge, unlocked) => {
  if (!badge) return ''
  return unlocked && badge.name ? badge.name : `${badge.days}天`
}

const getBadgeCelebration = (previous, unlockedDays) => {
  const unlocked = Array.isArray(unlockedDays) ? unlockedDays : []
  if (!Array.isArray(previous)) return { newly: [], seen: Array.from(new Set(unlocked)) }

  const previousSet = new Set(previous)
  const newly = unlocked.filter(days => !previousSet.has(days))
  return { newly, seen: Array.from(new Set(previous.concat(unlocked))) }
}

module.exports = {
  getBadgeProgress,
  getBadgePositions,
  getBadgeSegments,
  getBadgeDisplayLabel,
  getBadgeCelebration
}