export function formatAmount(fen: number): string {
  const yuan = (fen / 100).toFixed(2)
  return '¥ ' + yuan.replace(/\B(?=(\d{3})+(?!\d))/g, ',')
}

export function formatDate(date: string | Date): string {
  if (!date) return ''

  // 处理 Date 对象或 ISO 字符串
  let d: Date
  if (date instanceof Date) {
    d = date
  } else if (typeof date === 'string') {
    // 处理 YYYY-MM-DD 格式
    if (/^\d{4}-\d{2}-\d{2}$/.test(date)) {
      const parts = date.split('-').map(Number)
      d = new Date(parts[0], parts[1] - 1, parts[2])
    } else {
      // 处理 ISO 字符串或其他格式
      d = new Date(date)
    }
  } else {
    return ''
  }

  // 检查日期是否有效
  if (isNaN(d.getTime())) return ''

  const now = new Date()
  // Reset time portion for accurate day diff
  const today = new Date(now.getFullYear(), now.getMonth(), now.getDate())
  const target = new Date(d.getFullYear(), d.getMonth(), d.getDate())
  const diff = Math.floor((today.getTime() - target.getTime()) / 86400000)

  if (diff === 0) return '今天'
  if (diff === 1) return '昨天'
  if (diff === 2) return '前天'

  // 跨年显示年份
  const isCurrentYear = d.getFullYear() === now.getFullYear()
  return isCurrentYear
    ? `${d.getMonth() + 1}月${d.getDate()}日`
    : `${d.getFullYear()}年${d.getMonth() + 1}月${d.getDate()}日`
}

export function formatMonth(date: string): string {
  const [year, month] = date.split('-')
  return `${year}年${parseInt(month)}月`
}

/** 获取当前月份（UTC+8 时区，与服务端保持一致） */
export function getCurrentMonth(): string {
  const d = new Date()
  const offset = 8 * 60 * 60 * 1000
  const local = new Date(d.getTime() + offset)
  return local.toISOString().slice(0, 7)
}

export function formatAmountRaw(fen: number): string {
  const yuan = (fen / 100).toFixed(2)
  return yuan.replace(/\B(?=(\d{3})+(?!\d))/g, ',')
}