/** 前端工具函数 */
import { i18n } from '@/i18n'

function tt(key: string, params?: Record<string, unknown>): string {
  return i18n.global.t(key, params ?? {})
}

export function formatBytes(bytes: number | null | undefined): string {
  if (bytes === null || bytes === undefined || Number.isNaN(bytes)) return '-'
  if (bytes < 1024) return `${bytes} B`
  const units = ['KB', 'MB', 'GB', 'TB']
  let v = bytes
  let i = -1
  do {
    v /= 1024
    i++
  } while (v >= 1024 && i < units.length - 1)
  return `${v.toFixed(v >= 100 ? 0 : 1)} ${units[i]}`
}

export function formatDateTime(iso: string | null | undefined): string {
  if (!iso) return '-'
  const d = new Date(iso)
  if (Number.isNaN(d.getTime())) return String(iso)
  const p = (n: number) => `${n}`.padStart(2, '0')
  return `${d.getFullYear()}-${p(d.getMonth() + 1)}-${p(d.getDate())} ${p(d.getHours())}:${p(d.getMinutes())}:${p(d.getSeconds())}`
}

/** 剩余有效期的人类描述 */
export function formatRemaining(expiredAt: string | null | undefined): string {
  if (!expiredAt) return tt('time.forever')
  const t = new Date(expiredAt).getTime()
  if (Number.isNaN(t)) return tt('time.forever')
  const diff = t - Date.now()
  if (diff <= 0) return tt('time.expired')
  const m = Math.floor(diff / 60_000)
  if (m < 1) return tt('time.lessThanMinute')
  if (m < 60) return tt('time.minutes', { n: m })
  const h = Math.floor(m / 60)
  if (h < 24) return tt('time.hoursMinutes', { h, m: m % 60 })
  const d = Math.floor(h / 24)
  return tt('time.daysHours', { d, h: h % 24 })
}

export function formatDuration(ms: number | null | undefined): string {
  if (ms === null || ms === undefined) return '-'
  if (ms < 1000) return `${ms} ms`
  return `${(ms / 1000).toFixed(2)} s`
}

/** 过期样式选项（对齐参考实现的 expireStyle 配置；label 用 i18n 键名，展示时经 expireStyleLabel 翻译） */
export const EXPIRE_STYLES: { value: string; label: string }[] = [
  { value: 'day', label: 'day' },
  { value: 'hour', label: 'hour' },
  { value: 'minute', label: 'minute' },
  { value: 'count', label: 'count' },
  { value: 'forever', label: 'forever' },
]

/** 过期样式翻译（未知样式原样返回） */
export function expireStyleLabel(style: string): string {
  const known = EXPIRE_STYLES.find((s) => s.value === style)
  if (known) return tt(`expireStyle.${known.value}`)
  return style
}

/** 简单防抖 */
export function debounce<T extends (...args: never[]) => void>(fn: T, wait: number): (...args: Parameters<T>) => void {
  let timer: ReturnType<typeof setTimeout> | null = null
  return (...args: Parameters<T>) => {
    if (timer) clearTimeout(timer)
    timer = setTimeout(() => fn(...args), wait)
  }
}

/** 从 Content-Disposition 提取文件名（支持 RFC 5987 filename*=UTF-8''） */
export function filenameFromDisposition(header: string | null): string | null {
  if (!header) return null
  const star = /filename\*=(?:UTF-8'')?([^;]+)/i.exec(header)
  if (star) {
    try {
      return decodeURIComponent(star[1].replace(/["']/g, '').trim())
    } catch {
      /* fallthrough */
    }
  }
  const plain = /filename="?([^";]+)"?/i.exec(header)
  return plain ? plain[1] : null
}

/** 触发浏览器下载 Blob */
export function downloadBlob(blob: Blob, filename: string): void {
  const url = URL.createObjectURL(blob)
  const a = document.createElement('a')
  a.href = url
  a.download = filename
  document.body.appendChild(a)
  a.click()
  a.remove()
  setTimeout(() => URL.revokeObjectURL(url), 5_000)
}

export async function copyText(text: string): Promise<boolean> {
  try {
    await navigator.clipboard.writeText(text)
    return true
  } catch {
    // 兼容非安全上下文（http 部署）
    try {
      const ta = document.createElement('textarea')
      ta.value = text
      ta.style.position = 'fixed'
      ta.style.opacity = '0'
      document.body.appendChild(ta)
      ta.select()
      const ok = document.execCommand('copy')
      ta.remove()
      return ok
    } catch {
      return false
    }
  }
}

/** 计算 SHA-256（hex），用于分片上传 file_hash */
export async function sha256Hex(data: ArrayBuffer): Promise<string> {
  const digest = await crypto.subtle.digest('SHA-256', data)
  return Array.from(new Uint8Array(digest))
    .map((b) => b.toString(16).padStart(2, '0'))
    .join('')
}

/** 宽松取值：对象上第一个存在的键（用于兼容 camelCase/snake_case 响应） */
export function pick<T = unknown>(obj: Record<string, unknown>, keys: string[]): T | undefined {
  for (const k of keys) {
    if (obj && typeof obj === 'object' && k in obj && obj[k] !== undefined && obj[k] !== null) {
      return obj[k] as T
    }
  }
  return undefined
}