import { CNDHOST } from './../app.config'
const ensureTrailingSlash = (s: string) => (s.endsWith('/') ? s : s + '/')

/**
 * 从 CDN 地址中提取 key（例如返回 material/xxx.mp4）
 * @param input 完整URL，如 https://cdn.roasmax.cn/material/xxx.mp4?x=y
 * @param cdnHost 可选，默认使用 https://cdn.roasmax.cn/
 */
export const extractCdnKey = (input: string, cdnHost = CNDHOST): string | null => {
  if (!input) return null

  const base = ensureTrailingSlash(cdnHost)

  // 简单前缀匹配（最快）
  if (input?.startsWith(base)) {
    const rest = input.slice(base.length)
    return rest.split(/[?#]/)[0].replace(/^\/+/, '')
  }

  // URL 解析兜底
  try {
    const u = new URL(input)
    const b = new URL(base)
    if (u.origin === b.origin) {
      return u.pathname.replace(/^\/+/, '')
    }
    return null
  } catch {
    // 不是URL，直接返回 null
    return null
  }
}

/** 判断是否为指定 CDN 的地址 */
export const isFromCdn = (input: string, cdnHost = CNDHOST): boolean => {
  if (!input) return false
  try {
    const u = new URL(input)
    const b = new URL(ensureTrailingSlash(cdnHost))
    return u.origin === b.origin
  } catch {
    return input.startsWith(ensureTrailingSlash(cdnHost))
  }
}

/**
 * 将 key 拼接为完整 CDN URL。若传入已是完整URL则直接返回规范化结果
 * @param keyOrUrl 资源 key 或 完整 URL
 * @param cdnHost CDN 根域名
 */
export const buildCdnUrl = (keyOrUrl: string, cdnHost = CNDHOST): string | null => {
  if (!keyOrUrl) return null
  const base = ensureTrailingSlash(cdnHost)

  // 已是该 CDN 的完整 URL，返回去除查询/哈希后的规范化结果
  if (isFromCdn(keyOrUrl, cdnHost)) {
    try {
      const u = new URL(keyOrUrl)
      return `${u.origin}${u.pathname}`
    } catch {
      return keyOrUrl
    }
  }

  // 传入为其他域的URL或纯key，提取路径作为key再拼接
  const pathOrKey = (() => {
    try {
      const u = new URL(keyOrUrl)
      return u.pathname
    } catch {
      return keyOrUrl
    }
  })()

  const cleaned = pathOrKey.split(/[?#]/)[0].replace(/^\/+/, '')
  return base + cleaned
}