import { useEffect, useMemo, useRef, useState } from 'react';
import { useUIStore } from '@/stores/uiStore';

interface PhotoFrameProps {
  intervalMs?: number;
  transitionMs?: number;
}

function shuffle<T>(arr: T[]): T[] {
  const out = arr.slice();
  for (let i = out.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [out[i], out[j]] = [out[j], out[i]];
  }
  return out;
}

function useClock() {
  const [now, setNow] = useState(() => new Date());
  useEffect(() => {
    const id = setInterval(() => setNow(new Date()), 10_000);
    return () => clearInterval(id);
  }, []);
  return now;
}

export function PhotoFrame({ intervalMs = 15_000, transitionMs = 1_200 }: PhotoFrameProps) {
  const setIdle = useUIStore((s) => s.setIdle);
  const [files, setFiles] = useState<string[]>([]);
  const [index, setIndex] = useState(0);
  const [currentUrl, setCurrentUrl] = useState<string | null>(null);
  const [prevUrl, setPrevUrl] = useState<string | null>(null);
  const [empty, setEmpty] = useState(false);
  const [emptyDir, setEmptyDir] = useState('');
  const mountedRef = useRef(true);

  useEffect(() => {
    mountedRef.current = true;
    return () => {
      mountedRef.current = false;
    };
  }, []);

  useEffect(() => {
    const load = async () => {
      const api = window.electronAPI;
      if (!api?.photos) {
        setEmpty(true);
        return;
      }
      const list = await api.photos.list();
      const dir = await api.photos.getDir();
      if (!mountedRef.current) return;
      if (!list.length) {
        setEmpty(true);
        setEmptyDir(dir);
        return;
      }
      setFiles(shuffle(list));
      setEmpty(false);
    };
    load();
    // Re-scan every 10 min in case photos are added while idle
    const id = setInterval(load, 10 * 60_000);
    return () => clearInterval(id);
  }, []);

  useEffect(() => {
    if (!files.length) return;
    const id = setInterval(() => {
      setIndex((i) => (i + 1) % files.length);
    }, intervalMs);
    return () => clearInterval(id);
  }, [files.length, intervalMs]);

  // Resolve file:// URLs via IPC when the index changes
  useEffect(() => {
    if (!files.length) return;
    const api = window.electronAPI;
    if (!api?.photos?.getUrl) return;
    let cancelled = false;
    (async () => {
      const url = await api.photos.getUrl(files[index]);
      if (cancelled || !mountedRef.current) return;
      setPrevUrl(currentUrl);
      setCurrentUrl(url);
    })();
    return () => {
      cancelled = true;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [index, files]);

  const handleExit = () => setIdle(false);

  const now = useClock();
  const timeStr = useMemo(
    () =>
      now.toLocaleTimeString(undefined, {
        hour: 'numeric',
        minute: '2-digit',
      }),
    [now],
  );
  const dateStr = useMemo(
    () =>
      now.toLocaleDateString(undefined, {
        weekday: 'long',
        month: 'long',
        day: 'numeric',
      }),
    [now],
  );

  const currentSrc = currentUrl;
  const prevSrc = prevUrl;

  return (
    <div
      className="fixed inset-0 z-[60] bg-black flex items-center justify-center overflow-hidden animate-fade-in"
      onClick={handleExit}
      onTouchStart={handleExit}
    >
      {empty ? (
        <div className="text-center text-white/80 px-8">
          <div className="text-6xl font-light mb-6">{timeStr}</div>
          <div className="text-2xl mb-10 capitalize">{dateStr}</div>
          <div className="text-lg opacity-60">
            No photos found{emptyDir ? ` in ${emptyDir}` : ''}.
          </div>
          <div className="text-sm opacity-40 mt-2">Touch anywhere to exit</div>
        </div>
      ) : (
        <>
          {prevSrc && (
            <img
              key={`prev-${prevSrc}`}
              src={prevSrc}
              alt=""
              className="absolute inset-0 w-full h-full object-contain animate-ken-burns"
              style={{ opacity: 1 }}
            />
          )}
          {currentSrc && (
            <img
              key={`cur-${index}`}
              src={currentSrc}
              alt=""
              className="absolute inset-0 w-full h-full object-contain animate-ken-burns"
              style={{
                opacity: 0,
                animation: `photo-fade-in ${transitionMs}ms ease-out forwards, ken-burns 20s ease-in-out infinite alternate`,
              }}
            />
          )}
          {/* Lower-right clock + date overlay */}
          <div className="pointer-events-none absolute bottom-8 right-10 text-right text-white leading-tight"
               style={{ textShadow: '0 2px 12px rgba(0,0,0,0.9), 0 0 4px rgba(0,0,0,0.7)' }}>
            <div className="text-6xl md:text-7xl font-light tracking-tight">{timeStr}</div>
            <div className="text-xl md:text-2xl mt-1 capitalize font-light">{dateStr}</div>
          </div>
          <style>{`
            @keyframes photo-fade-in {
              from { opacity: 0; }
              to { opacity: 1; }
            }
          `}</style>
        </>
      )}
    </div>
  );
}