/**
 * Host 所有的易失 Artifact 内容缓存。
 *
 * 它只保存已经通过 ArtifactState 接纳的宿主字节；内容不写入 Conversation Store，
 * Agent 只能引用不透明 local_ref，不能直接填充或读取缓存。
 *
 * Host-owned volatile bytes for Artifact metadata already accepted by
 * ArtifactState. This cache has no network, persistence, DOM or protocol
 * dependency: an Agent can name an opaque ref but cannot populate or read it.
 */
export class ArtifactContentCache {
  private readonly blobs = new Map<string, Blob>();

  public put(localRef: string, content: Blob): boolean {
    if (!opaqueRef(localRef) || content.size > 512 * 1024 * 1024) return false;
    this.blobs.set(localRef, content);
    return true;
  }

  public get(localRef: string): Blob | undefined { return this.blobs.get(localRef); }
  public has(localRef: string | undefined): boolean { return Boolean(localRef && this.blobs.has(localRef)); }
  public clear(): void { this.blobs.clear(); }
}

function opaqueRef(value: string): boolean {
  return /^[A-Za-z0-9_.:-]{1,128}$/.test(value) && !/[\\/]/.test(value);
}