/** Generic display formatters shared across slices. */
export function formatBytes(value: number | null | undefined): string {
  if (value === null || value === undefined || !Number.isFinite(value)) return '—'
  const units = ['B', 'KB', 'MB', 'GB', 'TB']
  let size = value
  let unit = 0
  while (size >= 1024 && unit < units.length - 1) {
    size /= 1024
    unit += 1
  }
  return `${unit === 0 ? size : size.toFixed(1)} ${units[unit]}`
}

export function shortSha(sha: string | null | undefined, len = 7): string {
  return sha ? sha.slice(0, len) : '—'
}

export function fmtTime(value: string | number | null | undefined): string {
  if (value === null || value === undefined) return '—'
  if (typeof value === 'number') return new Date(value * 1000).toLocaleString('zh-CN', { hour12: false })
  // Rust's time crate emits `… +00:00:00` (seconds in the offset), which
  // Date cannot parse — fold it back to `+00:00` before constructing.
  const iso = value.replace(/([+-]\d{2}):(\d{2}):(\d{2})$/, '$1:$2')
  const date = new Date(iso)
  return Number.isNaN(date.getTime()) ? value : date.toLocaleString('zh-CN', { hour12: false })
}

/** Compact Chinese relative stamp ("19 天前") for commit rows. Accepts a unix
 * second value (the API's `author_time`) or a date string. */
export function fmtRelative(value: number | string | null | undefined): string {
  const epoch =
    typeof value === 'number'
      ? value
      : value
        ? Math.floor(new Date(value.replace(/([+-]\d{2}):(\d{2}):(\d{2})$/, '$1:$2')).getTime() / 1000)
        : Number.NaN
  if (!Number.isFinite(epoch)) return '—'
  const delta = Math.floor(Date.now() / 1000) - epoch
  // Future-dated commits (clock skew, rebased author time) read as "just now".
  if (delta < 60) return '刚刚'
  const minutes = Math.floor(delta / 60)
  if (minutes < 60) return `${minutes} 分钟前`
  const hours = Math.floor(minutes / 60)
  if (hours < 24) return `${hours} 小时前`
  const days = Math.floor(hours / 24)
  if (days < 31) return `${days} 天前`
  const months = Math.floor(days / 30)
  if (months < 12) return `${months} 个月前`
  return `${Math.floor(days / 365)} 年前`
}