import request from '@/utils/request'

const signedUrlCache = new Map()

/**
 * 判断是否为腾讯云COS私有存储预签名地址
 */
export function isCosUrl(url) {
  if (!url || typeof url !== 'string') {
    return false
  }
  return url.includes('.myqcloud.com/') || url.includes('.cos.')
}

/**
 * 去除URL里预签名query参数，返回原始文件地址
 */
export function stripSignedParams(url) {
  if (!url) {
    return url
  }
  const index = url.indexOf('?')
  return index > 0 ? url.substring(0, index) : url
}

/**
 * 转换存储地址为可访问链接，私有文件自动获取预签名地址
 */
export function resolveAccessUrl(url) {
  const storedUrl = stripSignedParams(url)
  if (!storedUrl || !isCosUrl(storedUrl)) {
    return Promise.resolve(url)
  }
  if (signedUrlCache.has(storedUrl)) {
    return Promise.resolve(signedUrlCache.get(storedUrl))
  }
  return request({
    url: '/common/getSignedUrl',
    method: 'get',
    params: { url: storedUrl }
  }).then(res => {
    const accessUrl = (res.accessUrl || res.url || storedUrl)
    signedUrlCache.set(storedUrl, accessUrl)
    return accessUrl
  }).catch(() => storedUrl)
}

/**
 * 批量转换COS文件访问URL
 */
export function resolveAccessUrls(urls) {
  if (!urls || !urls.length) {
    return Promise.resolve([])
  }
  return Promise.all(urls.map(url => resolveAccessUrl(url)))
}