/**
 * useYjsBinding – React hook that ties YjsDocument, WebSocketProvider,
 * and AwarenessManager together for real-time collaboration.
 */
import { useEffect, useRef, useState, useCallback } from 'react';
import * as Y from 'yjs';
import { YjsDocument } from './YjsDocument';
import { WebSocketProvider, type ConnectionStatus } from './WebSocketProvider';
import { AwarenessManager, type UserCursor, type UserSelection } from './AwarenessManager';
import type { CADElement, CADLayer, BlockDefinition } from '../types/cad.types';
import type { ElementGroup } from '../tools/modification/GroupTool';
import type { BackgroundConfig } from '../services/backgroundService';

export interface UseYjsBindingOptions {
  docName: string;
  wsUrl?: string;
  userId: string;
  userName: string;
  userColor: string;
  enabled?: boolean;
  token?: string;
}

export interface UseYjsBindingResult {
  yjsDoc: YjsDocument | null;
  provider: WebSocketProvider | null;
  awareness: AwarenessManager | null;
  status: ConnectionStatus;
  elements: CADElement[];
  layers: CADLayer[];
  blocks: BlockDefinition[];
  groups: ElementGroup[];
  bgConfigs: BackgroundConfig[];
  cursors: UserCursor[];
  selections: UserSelection[];
  setElement: (el: CADElement) => void;
  deleteElement: (id: string) => void;
  setLayer: (layer: CADLayer) => void;
  deleteLayer: (id: string) => void;
  setBlock: (block: BlockDefinition) => void;
  deleteBlock: (id: string) => void;
  setGroup: (group: ElementGroup) => void;
  deleteGroup: (id: string) => void;
  setBgConfig: (id: string, config: BackgroundConfig) => void;
  deleteBgConfig: (id: string) => void;
  loadFromState: (state: {
    elements: CADElement[];
    layers: CADLayer[];
    blocks: BlockDefinition[];
    groups?: ElementGroup[];
    bgConfigs?: BackgroundConfig[];
  }) => void;
  setCursor: (x: number, y: number) => void;
  hideCursor: () => void;
  setSelection: (elementIds: string[]) => void;
  clearSelection: () => void;
}

const DEFAULT_WS_URL = `wss://${window.location.host}`;

export function useYjsBinding(opts: UseYjsBindingOptions): UseYjsBindingResult {
  const { docName, wsUrl = DEFAULT_WS_URL, userId, userName, userColor, enabled = true, token } = opts;

  // Refs for stable values that don't need to trigger effect re-runs
  const wsUrlRef = useRef(wsUrl);
  wsUrlRef.current = wsUrl;
  const enabledRef = useRef(enabled);
  enabledRef.current = enabled;

  const yjsDocRef = useRef<YjsDocument | null>(null);
  const providerRef = useRef<WebSocketProvider | null>(null);
  const awarenessRef = useRef<AwarenessManager | null>(null);
  const unbindRef = useRef<(() => void) | null>(null);

  const [status, setStatus] = useState<ConnectionStatus>('disconnected');
  const [elements, setElements] = useState<CADElement[]>([]);
  const [layers, setLayers] = useState<CADLayer[]>([]);
  const [blocks, setBlocks] = useState<BlockDefinition[]>([]);
  const [groups, setGroups] = useState<ElementGroup[]>([]);
  const [bgConfigs, setBgConfigs] = useState<BackgroundConfig[]>([]);
  const [cursors, setCursors] = useState<UserCursor[]>([]);
  const [selections, setSelections] = useState<UserSelection[]>([]);

  // Initialize Yjs document, provider, and awareness
  useEffect(() => {
    const currentWsUrl = wsUrlRef.current;
    const currentEnabled = enabledRef.current;
    if (!currentEnabled || !docName) return;

    const doc = new YjsDocument();
    yjsDocRef.current = doc;

    const awareness = new AwarenessManager(doc, userId);
    awarenessRef.current = awareness;

    const provider = new WebSocketProvider({
      url: currentWsUrl,
      docName,
      yjsDoc: doc,
      awareness,
      onStatusChange: (s) => setStatus(s),
    });
    providerRef.current = provider;

    // Sync local state from Y.Doc on changes
    const syncState = () => {
      setElements(doc.getElements());
      setLayers(doc.getLayers());
      setBlocks(doc.getBlocks());
      setGroups(doc.getGroups());
      setBgConfigs(doc.getBgConfigs());
      setCursors(awareness.getAllCursors());
      setSelections(awareness.getAllSelections());
    };

    const unbindDoc = doc.onChange(syncState);
    const unbindAwareness = awareness.onChange(syncState);

    // Dedicated observers for groups and bgConfig maps
    const groupsMap = doc.data.groups;
    const bgConfigMap = doc.data.bgConfig;

    const groupsObserver = () => {
      setGroups(Array.from(groupsMap.values()));
    };
    const bgConfigObserver = () => {
      setBgConfigs(Array.from(bgConfigMap.values()));
    };

    groupsMap.observe(groupsObserver);
    bgConfigMap.observe(bgConfigObserver);

    // Forward local updates to server
    const unbindLocal = provider.bindLocalUpdates();
    // Forward local awareness updates to server
    const unbindAwarenessUpdates = provider.bindAwarenessUpdates();

    // Connect
    provider.connect(token);
    syncState();

    // Cleanup
    return () => {
      groupsMap.unobserve(groupsObserver);
      bgConfigMap.unobserve(bgConfigObserver);
      unbindDoc();
      unbindAwareness();
      unbindLocal();
      unbindAwarenessUpdates();
      awareness.removeSelf();
      awareness.destroy();
      provider.disconnect();
      doc.destroy();
      yjsDocRef.current = null;
      providerRef.current = null;
      awarenessRef.current = null;
    };
  }, [docName, userId, token]);

  // Mutators
  const setElement = useCallback((el: CADElement) => {
    yjsDocRef.current?.setElement(el);
  }, []);

  const deleteElement = useCallback((id: string) => {
    yjsDocRef.current?.deleteElement(id);
  }, []);

  const setLayer = useCallback((layer: CADLayer) => {
    yjsDocRef.current?.setLayer(layer);
  }, []);

  const deleteLayer = useCallback((id: string) => {
    yjsDocRef.current?.deleteLayer(id);
  }, []);

  const setBlock = useCallback((block: BlockDefinition) => {
    yjsDocRef.current?.setBlock(block);
  }, []);

  const deleteBlock = useCallback((id: string) => {
    yjsDocRef.current?.deleteBlock(id);
  }, []);

  const setGroup = useCallback((group: ElementGroup) => {
    yjsDocRef.current?.setGroup(group);
  }, []);

  const deleteGroup = useCallback((id: string) => {
    yjsDocRef.current?.deleteGroup(id);
  }, []);

  const setBgConfig = useCallback((id: string, config: BackgroundConfig) => {
    yjsDocRef.current?.setBgConfig(id, config);
  }, []);

  const deleteBgConfig = useCallback((id: string) => {
    yjsDocRef.current?.deleteBgConfig(id);
  }, []);

  const loadFromState = useCallback((state: {
    elements: CADElement[];
    layers: CADLayer[];
    blocks: BlockDefinition[];
    groups?: ElementGroup[];
    bgConfigs?: BackgroundConfig[];
  }) => {
    yjsDocRef.current?.loadFromState(state);
  }, []);

  const setCursor = useCallback((x: number, y: number) => {
    awarenessRef.current?.setCursor(x, y, userName, userColor);
  }, [userName, userColor]);

  const hideCursor = useCallback(() => {
    awarenessRef.current?.hideCursor();
  }, []);

  const setSelection = useCallback((elementIds: string[]) => {
    awarenessRef.current?.setSelection(elementIds);
  }, []);

  const clearSelection = useCallback(() => {
    awarenessRef.current?.clearSelection();
  }, []);

  return {
    yjsDoc: yjsDocRef.current,
    provider: providerRef.current,
    awareness: awarenessRef.current,
    status,
    elements,
    layers,
    blocks,
    groups,
    bgConfigs,
    cursors,
    selections,
    setElement,
    deleteElement,
    setLayer,
    deleteLayer,
    setBlock,
    deleteBlock,
    setGroup,
    deleteGroup,
    setBgConfig,
    deleteBgConfig,
    loadFromState,
    setCursor,
    hideCursor,
    setSelection,
    clearSelection,
  };
}