import { useCallback, useEffect, useState } from "react";
import { useParams } from "react-router-dom";
import { getPhotoWallPresent, type PhotoWallPresentData } from "../lib/api";

const POLL_MS = 4000;

export function PhotoWallPresentPage() {
  const { presentToken } = useParams<{ presentToken: string }>();
  const [data, setData] = useState<PhotoWallPresentData | null>(null);
  const [err, setErr] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);

  const refresh = useCallback(async () => {
    if (!presentToken) return;
    try {
      const next = await getPhotoWallPresent(presentToken);
      setData(next);
      setErr(null);
    } catch (e) {
      setErr(e instanceof Error ? e.message : "Photo wall not available");
      setData(null);
    } finally {
      setLoading(false);
    }
  }, [presentToken]);

  useEffect(() => {
    void refresh();
    const id = window.setInterval(() => void refresh(), POLL_MS);
    return () => window.clearInterval(id);
  }, [refresh]);

  if (loading) {
    return (
      <div className="eb-gradient-auth flex min-h-dvh items-center justify-center text-white/80">
        Loading wall…
      </div>
    );
  }

  if (!data) {
    return (
      <div className="eb-gradient-auth flex min-h-dvh flex-col items-center justify-center gap-2 px-6 text-center text-white">
        <p className="text-lg font-semibold">Photo wall unavailable</p>
        <p className="text-sm text-white/80">{err}</p>
      </div>
    );
  }

  const cols = Math.max(1, Math.min(12, data.photosPerRow || 4));
  const maxW = data.maxPhotoWidth || 320;
  const maxH = data.maxPhotoHeight || 320;
  const gap = data.gapPx ?? 8;
  const showNames = Boolean(data.showUploaderNameOnWall);
  const frameEnabled = Boolean(data.frameEnabled);
  const frameW = data.frameCanvasWidth || 1080;
  const frameH = data.frameCanvasHeight || 1080;
  const aspectRatio = frameEnabled ? `${frameW} / ${frameH}` : `${maxW} / ${maxH}`;

  return (
    <div className="eb-gradient-auth min-h-dvh text-white">
      <div className="px-4 pb-3 pt-4 text-center card-bg rounded-lg shadow-sm max-w-[400px] mx-auto mb-3">
        <p className="text-xs uppercase tracking-[0.2em] text-[var(--theme-card-text-color)]/70">Photo Wall</p>
        <h1 className="text-xl font-semibold sm:text-2xl text-[var(--theme-card-text-color)]">{data.eventName}</h1>
      </div>

      {data.photos.length === 0 ? (
        <div className="flex min-h-[60dvh] items-center justify-center px-6 text-center text-white/80">
          Waiting for photos…
        </div>
      ) : (
        <div
          className="mx-auto w-full max-w-[100vw] px-3 pb-6"
          style={{
            display: "grid",
            gridTemplateColumns: `repeat(${cols}, minmax(0, 1fr))`,
            gap: `${gap}px`,
            justifyItems: "center",
            alignItems: "start",
          }}
        >
          {data.photos.map((p) => (
            <div
              key={p._id}
              className="flex w-full flex-col items-center"
              style={{ maxWidth: maxW }}
            >
              <img
                src={p.url}
                alt=""
                className="w-full rounded-md object-cover shadow-lg"
                style={{
                  maxWidth: maxW,
                  maxHeight: maxH,
                  aspectRatio,
                  objectFit: "cover",
                }}
              />
              {showNames && p.displayName ? (
                <p
                  className="mt- w-full truncate text-center text-xs font-medium text-[var(--theme-card-text-color)]/90 bg-[var(--theme-card-color)] rounded-md p-1 sm:text-sm"
                  title={p.displayName}
                >
                  {p.displayName}
                </p>
              ) : null}
            </div>
          ))}
        </div>
      )}
    </div>
  );
}