export const standardHeaderKeys = ['content-type', 'cache-control', 'content-disposition', 'content-encoding', 'content-language', 'expires'];

export type StandardHeaders = {
  ContentType?: string;
  CacheControl?: string;
  ContentDisposition?: string;
  ContentEncoding?: string;
  ContentLanguage?: string;
  Expires?: Date;
};

/**
 * 从元数据中提取标准头部和自定义元数据
 * @param metaData 原始元数据
 * @returns 标准头部和自定义元数据
 */
export function extractStandardHeaders(metaData: Record<string, string>): {
  standardHeaders: StandardHeaders;
  customMetadata: Record<string, string>;
} {
  const standardHeaders: StandardHeaders = {};
  const customMetadata: Record<string, string> = {};

  for (const [key, value] of Object.entries(metaData)) {
    const lowerKey = key.toLowerCase();
    if (lowerKey === 'content-type') {
      standardHeaders.ContentType = value;
    } else if (lowerKey === 'cache-control') {
      standardHeaders.CacheControl = value;
    } else if (lowerKey === 'content-disposition') {
      standardHeaders.ContentDisposition = value;
    } else if (lowerKey === 'content-encoding') {
      standardHeaders.ContentEncoding = value;
    } else if (lowerKey === 'content-language') {
      standardHeaders.ContentLanguage = value;
    } else if (lowerKey === 'expires') {
      standardHeaders.Expires = new Date(value);
    } else {
      customMetadata[key] = value;
    }
  }

  return { standardHeaders, customMetadata };
}