import dayjs from 'dayjs'

export function formatPostTime(input?: dayjs.ConfigType): string {
  if (!input)
    return ''

  const time = dayjs(input)
  if (!time.isValid())
    return ''

  const now = dayjs()

  const diffSeconds = now.diff(time, 'second')
  if (diffSeconds < 0) {
    // 未来时间兜底
    return time.format('YYYY年MM月DD日')
  }

  // 1 分钟内
  if (diffSeconds < 60) {
    return '刚刚'
  }

  const diffMinutes = now.diff(time, 'minute')
  if (diffMinutes < 60) {
    return `${diffMinutes}分钟前`
  }

  const diffHours = now.diff(time, 'hour')
  if (diffHours < 24) {
    return `${diffHours}小时前`
  }

  const diffDays = now.diff(time, 'day')
  if (diffDays < 14) {
    return `${diffDays}天前`
  }

  // 本年
  if (time.year() === now.year()) {
    return time.format('MM月DD日')
  }

  // 非本年
  return time.format('YYYY年MM月DD日')
}

export function formatCommentTime(input?: dayjs.ConfigType): string {
  if (!input)
    return ''

  const time = dayjs(input)
  if (!time.isValid())
    return ''

  const now = dayjs()
  const diffSeconds = now.diff(time, 'second')

  // 未来时间兜底
  if (diffSeconds < 0) {
    return time.format('YYYY-MM-DD HH:mm')
  }

  // 1 分钟内
  if (diffSeconds < 60) {
    return '刚刚'
  }

  const diffMinutes = now.diff(time, 'minute')
  if (diffMinutes < 60) {
    return `${diffMinutes}分钟前`
  }

  const diffHours = now.diff(time, 'hour')
  if (diffHours < 24) {
    return `${diffHours}小时前`
  }

  const diffDays = now.diff(time, 'day')
  if (diffDays < 7) {
    return `${diffDays}天前`
  }

  // 本年
  if (time.year() === now.year()) {
    return time.format('MM-DD HH:mm')
  }

  // 非本年
  return time.format('YYYY-MM-DD HH:mm')
}

type DateFormat
  = | 'YYYY'
    | 'MM'
    | 'DD'
    | 'YYYY-MM'
    | 'YYYY-MM-DD'
    | 'YYYY-MM-DD HH:mm'
    | 'YYYY-MM-DD HH:mm:ss'
    | 'YYYY年MM月DD日'

export function formatDate(
  input?: dayjs.ConfigType,
  format: DateFormat = 'YYYY-MM-DD',
): string {
  if (!input)
    return ''

  const date = dayjs(input)
  if (!date.isValid())
    return ''

  return date.format(format)
}

/**
 * 格式化聊天时间
 * @param timestamp - 毫秒级时间戳
 * @param mode - 显示模式：'list' 为列表，'chat' 为聊天记录
 * @returns 格式化后的时间字符串
 */
export function formatImTime(timestamp: number | null | undefined, mode: 'list' | 'chat' = 'list'): string {
  if (!timestamp)
    return ''

  const now = new Date()
  const date = new Date(timestamp)

  const hour = String(date.getHours()).padStart(2, '0')
  const minute = String(date.getMinutes()).padStart(2, '0')
  const weekDays = ['周日', '周一', '周二', '周三', '周四', '周五', '周六']

  // 去除时分秒的日期
  const nowMidnight = new Date(now.getFullYear(), now.getMonth(), now.getDate())
  const dateMidnight = new Date(date.getFullYear(), date.getMonth(), date.getDate())
  const diffDays = Math.floor((nowMidnight.getTime() - dateMidnight.getTime()) / (1000 * 3600 * 24))

  // 1️⃣ 当天
  if (diffDays === 0)
    return `${hour}:${minute}`

  // 2️⃣ 昨天
  if (diffDays === 1)
    return `昨天 ${hour}:${minute}`

  // 3️⃣ 一周内（周一到周日）
  const weekStart = new Date(nowMidnight.getTime() - ((now.getDay() || 7) - 1) * 24 * 3600 * 1000)
  if (dateMidnight >= weekStart) {
    return mode === 'chat'
      ? `${weekDays[date.getDay()]} ${hour}:${minute}`
      : weekDays[date.getDay()]
  }

  // 4️⃣ 本年或跨年（聊天记录模式：统一显示 YYYY/MM/DD HH:mm）
  const ymd = `${date.getFullYear()}/${String(date.getMonth() + 1).padStart(2, '0')}/${String(date.getDate()).padStart(2, '0')}`

  if (mode === 'chat')
    return `${ymd} ${hour}:${minute}`

  // 列表模式区分本年/跨年
  if (date.getFullYear() === now.getFullYear())
    return `${String(date.getMonth() + 1).padStart(2, '0')}/${String(date.getDate()).padStart(2, '0')}`

  return ymd
}