import { useState, useLayoutEffect, useCallback, useEffect, useRef, type ReactNode } from 'react';
import { useLocation } from 'react-router-dom';
import { NavigationMemoryContext } from './navigationMemoryContext';

export function NavigationMemoryProvider({ children }: { children: ReactNode }) {
  const location = useLocation();
  const { pathname, search } = location;

  const [mainContentPath, setMainContentPath] = useState(pathname);
  const [mainContentSearch, setMainContentSearch] = useState(search);
  const [scrollPositions, setScrollPositions] = useState<Record<string, number>>({});
  const [pageStates, setPageStates] = useState<Record<string, any>>({});

  const setScrollPosition = useCallback((path: string, pos: number) => {
    setScrollPositions((prev) => {
      if (prev[path] === pos) return prev;
      return { ...prev, [path]: pos };
    });
  }, []);

  const clearScrollPosition = useCallback((path: string) => {
    setScrollPositions((prev) => {
      if (!(path in prev)) return prev;
      const next = { ...prev };
      delete next[path];
      return next;
    });
  }, []);

  const setPageState = useCallback((path: string, newStateOrUpdater: any) => {
    setPageStates((prev) => {
      const oldState = prev[path];
      const newState = typeof newStateOrUpdater === 'function'
        ? newStateOrUpdater(oldState)
        : newStateOrUpdater;
      if (oldState === newState) return prev;
      return { ...prev, [path]: newState };
    });
  }, []);

  const updateMainContent = useCallback((path: string, s: string) => {
    setMainContentPath(path);
    setMainContentSearch(s);
  }, []);

  useLayoutEffect(() => {
    const isPostUrl = pathname.startsWith('/post/');
    const isProfileUrl = pathname.match(/^\/profile\/[^/]+$/);

    if (!isPostUrl && !isProfileUrl) {
      // eslint-disable-next-line react-hooks/set-state-in-effect
      updateMainContent(pathname, search);
    }
  }, [pathname, search, updateMainContent]);

  const lastKnownScrollRef = useRef<Record<string, number>>({});

  useEffect(() => {
    const handleScroll = () => {
      lastKnownScrollRef.current[pathname + search] = window.scrollY;
      setScrollPosition(pathname + search, window.scrollY);
    };

    window.addEventListener('scroll', handleScroll, { passive: true });
    return () => {
      window.removeEventListener('scroll', handleScroll);
      const currentScroll = window.scrollY;
      const lastKnown = lastKnownScrollRef.current[pathname + search];
      if (lastKnown === undefined || Math.abs(currentScroll - lastKnown) < 5) {
        setScrollPosition(pathname + search, currentScroll);
      }
    };
  }, [pathname, search, setScrollPosition]);

  return (
    <NavigationMemoryContext.Provider value={{
      mainContentPath,
      mainContentSearch,
      scrollPositions,
      setScrollPosition,
      clearScrollPosition,
      pageStates,
      setPageState
    }}>
      {children}
    </NavigationMemoryContext.Provider>
  );
}