/**
 * 格式化工具函数
 */

// 相对时间映射
const RELATIVE = (diff) => {
  if (diff < 60000) return '刚刚'
  if (diff < 3600000) return `${Math.floor(diff / 60000)} 分钟前`
  if (diff < 86400000) return `${Math.floor(diff / 3600000)} 小时前`
  return `${Math.floor(diff / 86400000)} 天前`
}

/**
 * 格式化日期 (MMDDHHMM)
 * @param {string|Date} date - 日期
 * @param {string} format - 格式 ('short', 'long', 'relative')
 */
export const formatDate = (date, format = 'short') => {
  if (!date) return '未知时间'
  const d = new Date(date)
  if (isNaN(d.getTime())) return '无效日期'
  if (format === 'relative') return RELATIVE(new Date() - d)
  
  const pad = (n) => String(n).padStart(2, '0')
  return `${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}`
}

/**
 * 格式化数字
 * @param {number} num - 数字
 * @param {Object} options - 配置
 */
export const formatNumber = (num, options = {}) => {
  if (typeof num !== 'number') return num
  const { decimals = 0, thousands = true, suffix = '' } = options
  return new Intl.NumberFormat('zh-CN', {
    minimumFractionDigits: decimals,
    maximumFractionDigits: decimals,
    useGrouping: thousands
  }).format(num) + suffix
}

/**
 * 截断文本
 */
export const truncate = (text, maxLength = 50, suffix = '...') =>
  !text || text.length <= maxLength ? text : text.slice(0, maxLength - suffix.length) + suffix

/**
 * 格式化文件大小
 */
export const formatFileSize = (bytes) => {
  if (!bytes) return '0 B'
  const k = 1024, sizes = ['B', 'KB', 'MB', 'GB', 'TB']
  const i = Math.floor(Math.log(bytes) / Math.log(k))
  return `${(bytes / Math.pow(k, i)).toFixed(2)} ${sizes[i]}`
}

/**
 * 首字母大写
 */
export const capitalize = (str) => str ? str.replace(/^./, c => c.toUpperCase()) : ''

/**
 * 格式化令牌数
 */
export const formatTokens = (tokens) =>
  tokens >= 1e6 ? `${(tokens / 1e6).toFixed(1)}M`
  : tokens >= 1e3 ? `${(tokens / 1e3).toFixed(1)}K`
  : String(tokens)