import { Collection, ObjectId as MongoObjectId } from "mongodb";
import { getDb, ObjectId } from "../index";
import {
  KNOWLEDGE_DOCUMENTS_COLLECTION,
  KNOWLEDGE_DOCUMENT_READY_PROJECTION,
  KNOWLEDGE_DOCUMENT_STATUSES,
} from "./knowledgeDocuments.constants";
import type {
  CreateKnowledgeDocumentInput,
  KnowledgeDocument,
  KnowledgeDocumentDoc,
  KnowledgeDocumentReadyProjection,
  UpdateKnowledgeDocumentInput,
} from "./knowledgeDocuments.types";

export const getKnowledgeDocumentsCollection =
  (): Collection<KnowledgeDocument> => {
    return getDb().collection<KnowledgeDocument>(
      KNOWLEDGE_DOCUMENTS_COLLECTION,
    );
  };

export const createKnowledgeDocument = async (
  input: CreateKnowledgeDocumentInput,
): Promise<MongoObjectId> => {
  const now = new Date();
  const { status, progressPercent, _id, ...rest } = input;
  const { insertedId } = await getKnowledgeDocumentsCollection().insertOne({
    ...(_id ? { _id } : {}),
    ...rest,
    status: status ?? KNOWLEDGE_DOCUMENT_STATUSES.UPLOADING,
    progressPercent: progressPercent ?? 0,
    createdAt: now,
    updatedAt: now,
  });
  return insertedId;
};

export const getKnowledgeDocumentById = async (
  id: string,
): Promise<KnowledgeDocumentDoc | null> => {
  return getKnowledgeDocumentsCollection().findOne({ _id: new ObjectId(id) });
};

export const listKnowledgeDocumentsByClientId = async (
  clientId: string,
): Promise<KnowledgeDocumentDoc[]> => {
  return getKnowledgeDocumentsCollection()
    .find({ clientId })
    .sort({ createdAt: -1 })
    .toArray();
};

export const listReadyKnowledgeDocumentIdsByClientId = async (
  clientId: string,
): Promise<string[]> => {
  const docs = await getKnowledgeDocumentsCollection()
    .find(
      { clientId, status: KNOWLEDGE_DOCUMENT_STATUSES.READY },
      { projection: { _id: 1 } },
    )
    .sort({ createdAt: -1 })
    .toArray();
  return docs.map((doc) => doc._id.toString());
};

export const listReadyKnowledgeDocumentsByClientId = async (
  clientId: string,
): Promise<KnowledgeDocumentReadyProjection[]> => {
  return getKnowledgeDocumentsCollection()
    .find(
      { clientId, status: KNOWLEDGE_DOCUMENT_STATUSES.READY },
      { projection: KNOWLEDGE_DOCUMENT_READY_PROJECTION },
    )
    .sort({ createdAt: -1 })
    .toArray() as Promise<KnowledgeDocumentReadyProjection[]>;
};

export const updateKnowledgeDocument = async (
  id: string,
  updates: UpdateKnowledgeDocumentInput,
): Promise<KnowledgeDocumentDoc | null> => {
  return getKnowledgeDocumentsCollection().findOneAndUpdate(
    { _id: new ObjectId(id) },
    { $set: { ...updates, updatedAt: new Date() } },
    { returnDocument: "after" },
  );
};

export const deleteKnowledgeDocument = async (id: string): Promise<boolean> => {
  const result = await getKnowledgeDocumentsCollection().deleteOne({
    _id: new ObjectId(id),
  });
  return result.deletedCount === 1;
};