/** 格式化日期为 YYYY-MM-DD */
export function formatDate(date?: string | Date): string {
  const d = date ? new Date(date) : new Date()
  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`
}

/** 格式化日期为 YYYY-MM */
export function formatMonth(date?: string | Date): string {
  const d = date ? new Date(date) : new Date()
  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}`
}

/** 获取相对时间描述 */
export function timeAgo(dateStr: string): string {
  if (!dateStr) return ''
  const diff = Math.floor((Date.now() - new Date(dateStr).getTime()) / 1000)
  if (diff < 60) return '刚刚'
  if (diff < 3600) return `${Math.floor(diff / 60)}分钟前`
  if (diff < 86400) return `${Math.floor(diff / 3600)}小时前`
  if (diff < 2592000) return `${Math.floor(diff / 86400)}天前`
  return formatDate(dateStr)
}

/** 打卡分类 */
export const CHECKIN_CATEGORY = {
  study: { label: '学习成长', icon: '📚', color: '#4CC9F0' },
  health: { label: '健康生活', icon: '❤️', color: '#06D6A0' },
  habit: { label: '习惯自律', icon: '🔄', color: '#7209B7' },
  hobby: { label: '兴趣爱好', icon: '⭐', color: '#F72585' },
  goal: { label: '目标任务', icon: '🎯', color: '#FF6B35' },
} as const

export type CheckinCategory = keyof typeof CHECKIN_CATEGORY

export function getCategoryLabel(cat: string): string {
  return CHECKIN_CATEGORY[cat as CheckinCategory]?.label || cat
}

/** 打卡周期 */
export const CYCLE_LABEL: Record<string, string> = {
  daily: '每日',
  weekly: '每周',
  every_other_day: '隔日',
  custom: '自定义',
}

export function getCycleLabel(cycle: string): string {
  return CYCLE_LABEL[cycle] || cycle
}

/** 隐私级别 */
export function getPrivacyLabel(level: number): string {
  const map: Record<number, string> = { 1: '公开', 2: '仅好友可见', 3: '仅自己可见' }
  return map[level] || '未知'
}

/** 积分格式化（带 + 号） */
export function formatPoints(p: number | undefined | null): string {
  if (p === undefined || p === null) return '--'
  return p > 0 ? `+${p}` : String(p)
}

/** 截断字符串 */
export function truncate(str: string, len = 20): string {
  return str.length > len ? str.slice(0, len) + '...' : str
}

/** ID 缩写 */
export function shortId(id: string): string {
  return id.length > 8 ? id.slice(0, 8) + '...' : id
}