import { useCallback, useRef, useState } from 'react';
import { CollectionService, MilvusService } from '@/http';
import { WS_EVENTS, WS_EVENTS_TYPE, LOADING_STATE } from '@server/utils/Const';
import { checkIndexing, checkLoading } from '@server/utils/Shared';
import type {
  IndexCreateParam,
  IndexManageParam,
} from '@/pages/databases/collections/schema/Types';
import type { CollectionObject, CollectionFullObject } from '@server/types';

export function useCollectionsManagement(database: string) {
  const [collections, setCollections] = useState<CollectionObject[]>([]);
  const [loading, setLoading] = useState(true);
  const requestIdRef = useRef(0);

  const detectLoadingIndexing = useCallback(
    (collections: CollectionObject[]) => {
      const LoadingOrBuildingCollections = collections.filter(v => {
        const isLoading = checkLoading(v);
        const isBuildingIndex = checkIndexing(v);
        return isLoading || isBuildingIndex;
      });
      if (LoadingOrBuildingCollections.length > 0) {
        MilvusService.triggerCron({
          name: WS_EVENTS.COLLECTION_UPDATE,
          type: WS_EVENTS_TYPE.START,
          payload: {
            database,
            collections: LoadingOrBuildingCollections.map(
              c => c.collection_name
            ),
          },
        });
      }
    },
    [database]
  );

  const updateCollections = useCallback(
    (props: { collections: CollectionFullObject[]; database?: string }) => {
      const { collections: updated = [], database: remote } = props;
      if (
        remote !== database &&
        database !== undefined &&
        remote !== undefined
      ) {
        return;
      }
      detectLoadingIndexing(updated);
      setCollections(prev => {
        const prevMap = new Map(prev.map(c => [c.id, c]));
        updated.forEach(c => {
          prevMap.set(c.id, c);
        });
        return Array.from(prevMap.values());
      });
    },
    [database, detectLoadingIndexing]
  );

  const fetchCollections = async () => {
    const currentRequestId = ++requestIdRef.current;
    try {
      setLoading(true);
      setCollections([]);
      const res = await CollectionService.getAllCollections();
      if (currentRequestId === requestIdRef.current) {
        detectLoadingIndexing(res);
        setCollections(res);
        setLoading(false);
      }
    } catch (error) {
      if (currentRequestId === requestIdRef.current) {
        setLoading(false);
      }
      throw error;
    }
  };

  const fetchCollection = async (name: string) => {
    const res = await CollectionService.getCollection(name);
    updateCollections({ collections: [res] });
    return res;
  };

  const _fetchCollections = useCallback(
    async (collectionNames: string[]) => {
      const res = await CollectionService.getCollections({
        db_name: database,
        collections: collectionNames,
      });
      updateCollections({ collections: res });
    },
    [database, updateCollections]
  );

  const refreshCollectionsDebounceMapRef = useRef<
    Map<
      string,
      { timer: NodeJS.Timeout | null; names: string[]; pending: Set<string> }
    >
  >(new Map());

  const batchRefreshCollections = useCallback(
    (collectionNames: string[], key: string = 'default') => {
      let ref = refreshCollectionsDebounceMapRef.current.get(key);
      if (!ref) {
        ref = { timer: null, names: [], pending: new Set() };
        refreshCollectionsDebounceMapRef.current.set(key, ref);
      }
      const filteredCollectionNames = collectionNames.filter(name => {
        const collection = collections.find(v => v.collection_name === name);
        return collection && !collection.schema && !ref!.pending.has(name);
      });
      ref.names = filteredCollectionNames;
      if (ref.timer) {
        clearTimeout(ref.timer);
      }
      function getRandomBatchSize() {
        const weights = [2, 2, 2, 3, 3, 3, 4, 4, 5];
        return weights[Math.floor(Math.random() * weights.length)];
      }
      ref.timer = setTimeout(async () => {
        if (ref!.names.length === 0) return;
        try {
          while (ref!.names.length > 0) {
            const batchSize = getRandomBatchSize();
            let batch = ref!.names.slice(0, batchSize);
            batch = batch.filter(name => {
              const collection = collections.find(
                v => v.collection_name === name
              );
              return collection && !collection.schema;
            });
            batch.forEach(name => ref!.pending.add(name));
            await _fetchCollections(batch);
            batch.forEach(name => ref!.pending.delete(name));
            ref!.names = ref!.names.slice(batch.length);
          }
        } catch (error) {
          console.error('Failed to refresh collections:', error);
        }
        ref!.names = [];
        ref!.timer = null;
      }, 200);
    },
    [collections, _fetchCollections]
  );

  const createCollection = async (data: any) => {
    const newCollection = await CollectionService.createCollection(data);
    const newCollections = collections.concat(newCollection).sort((a, b) => {
      if (a.loadedPercentage === b.loadedPercentage && a.schema && b.schema) {
        if (a.schema.hasVectorIndex === b.schema.hasVectorIndex) {
          return b.createdTime - a.createdTime;
        }
        return a.schema.hasVectorIndex ? -1 : 1;
      }
      return (b.loadedPercentage || 0) - (a.loadedPercentage || 0);
    });
    setCollections(newCollections);
    return newCollection;
  };

  const loadCollection = async (name: string, param?: any) => {
    const res = await CollectionService.loadCollection(name, param);
    const collection = collections.find(
      v => v.collection_name === name
    ) as CollectionFullObject;
    if (collection) {
      collection.loadedPercentage = 0;
      collection.loaded = false;
      collection.status = LOADING_STATE.LOADING;
    }
    updateCollections({ collections: [collection] });
    return res;
  };

  const releaseCollection = async (name: string) => {
    return await CollectionService.releaseCollection(name);
  };

  const renameCollection = async (name: string, newName: string) => {
    const newCollection = await CollectionService.renameCollection(name, {
      new_collection_name: newName,
    });
    updateCollections({ collections: [newCollection] });
    return newCollection;
  };

  const duplicateCollection = async (name: string, newName: string) => {
    const newCollection = await CollectionService.duplicateCollection(name, {
      new_collection_name: newName,
    });
    setCollections(prev => [...prev, newCollection]);
    return newCollection;
  };

  const dropCollection = async (name: string) => {
    const dropped = await CollectionService.dropCollection(name);
    if (dropped.error_code === 'Success') {
      setCollections(prev => prev.filter(v => v.collection_name !== name));
    }
    return dropped;
  };

  const createIndex = async (param: IndexCreateParam) => {
    const newCollection = await CollectionService.createIndex(param);
    updateCollections({ collections: [newCollection] });
    return newCollection;
  };

  const dropIndex = async (params: IndexManageParam) => {
    const { data } = await CollectionService.dropIndex(params);
    updateCollections({ collections: [data] });
    return data;
  };

  const createAlias = async (collectionName: string, alias: string) => {
    const newCollection = await CollectionService.createAlias(collectionName, {
      alias,
    });
    updateCollections({ collections: [newCollection] });
    return newCollection;
  };

  const dropAlias = async (collectionName: string, alias: string) => {
    const { data } = await CollectionService.dropAlias(collectionName, {
      alias,
    });
    updateCollections({ collections: [data] });
    return data;
  };

  const setCollectionProperty = async (
    collectionName: string,
    key: string,
    value: any
  ) => {
    const newCollection = await CollectionService.setProperty(collectionName, {
      [key]: value,
    });
    updateCollections({ collections: [newCollection] });
    return newCollection;
  };

  return {
    collections,
    setCollections,
    loading,
    fetchCollections,
    fetchCollection,
    batchRefreshCollections,
    createCollection,
    loadCollection,
    releaseCollection,
    renameCollection,
    duplicateCollection,
    dropCollection,
    createIndex,
    dropIndex,
    createAlias,
    dropAlias,
    setCollectionProperty,
    updateCollections,
  };
}