import { Annotation } from "@langchain/langgraph";
import { Document } from "@langchain/core/documents";
import { reduceDocs } from "../shared/state.js";

/**
 * Represents the state for document indexing and retrieval.
 *
 * This interface defines the structure of the index state, which includes
 * the documents to be indexed and the retriever used for searching
 * these documents.
 */
export const IndexStateAnnotation = Annotation.Root({
  /**
   * A list of documents that the agent can index.
   */
  docs: Annotation<
    Document[],
    Document[] | { [key: string]: any }[] | string[] | string | "delete"
  >({
    default: () => [],
    reducer: reduceDocs,
  }),
});

export type IndexStateType = typeof IndexStateAnnotation.State;