/**
 * 截断文本，超过最大长度追加省略号
 * @param {string} text
 * @param {number} [maxLen=80]
 * @returns {string}
 */
export function truncate(text, maxLen = 80) {
  if (!text) return ''
  const s = String(text)
  return s.length > maxLen ? `${s.slice(0, maxLen)}…` : s
}

/**
 * 格式化字节数为人类可读大小
 * @param {number|null|undefined} bytes
 * @returns {string}
 */
export function formatSize(bytes) {
  if (bytes == null || bytes === '') return '-'
  const n = Number(bytes)
  if (Number.isNaN(n)) return '-'
  if (n < 1024) return `${n} B`
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`
  return `${(n / 1024 / 1024).toFixed(1)} MB`
}

/**
 * 安全拼接类名
 * @param  {...(string | false | null | undefined)} args
 * @returns {string}
 */
export function classnames(...args) {
  return args.filter(Boolean).join(' ')
}

/**
 * 防抖
 * @param {Function} fn
 * @param {number} [wait=300]
 * @returns {Function}
 */
export function debounce(fn, wait = 300) {
  let timer = null
  return function debounced(...args) {
    if (timer) {
      clearTimeout(timer)
    }
    timer = setTimeout(() => {
      fn.apply(this, args)
    }, wait)
  }
}