"use client";

import { useEffect, useState, type RefObject } from "react";
import {
  blankingInsets,
  findAspectPreset,
  isFullFrame,
  letterboxRect,
  type BlankingMode,
} from "@/lib/aspect-overlays";

interface AspectOverlayProps {
  /** Preset id, or "off" — anything unknown draws nothing. */
  presetId: string;
  mode: BlankingMode;
  videoRef: RefObject<HTMLVideoElement | null>;
}

/**
 * Delivery blanking drawn over the video. Purely visual: it never touches the
 * video element, sits under the annotation canvas, and passes every pointer
 * event through so click-to-play still works underneath it.
 */
export function AspectOverlay({ presetId, mode, videoRef }: AspectOverlayProps) {
  const preset = findAspectPreset(presetId);
  const [box, setBox] = useState<{
    top: number;
    bottom: number;
    left: number;
    right: number;
    rect: { left: number; top: number; width: number; height: number };
  } | null>(null);

  useEffect(() => {
    const video = videoRef.current;
    if (!video || !preset) {
      setBox(null);
      return;
    }

    const measure = () => {
      const rect = letterboxRect(
        video.clientWidth,
        video.clientHeight,
        video.videoWidth,
        video.videoHeight
      );
      // Before metadata lands videoWidth is 0 and there is nothing to measure.
      if (!rect) {
        setBox(null);
        return;
      }
      const insets = blankingInsets(rect, preset.ratio);
      setBox(isFullFrame(insets) ? null : { ...insets, rect });
    };

    measure();

    // The picture rect moves on layout changes (panel resize, fullscreen) and
    // on metadata, which is when intrinsic dimensions first exist.
    const observer = new ResizeObserver(measure);
    observer.observe(video);
    video.addEventListener("loadedmetadata", measure);

    return () => {
      observer.disconnect();
      video.removeEventListener("loadedmetadata", measure);
    };
  }, [preset, videoRef]);

  if (!preset || !box) return null;

  const { rect } = box;
  const barClass =
    mode === "solid"
      ? "absolute bg-black"
      : "absolute bg-black/60 ring-1 ring-inset ring-white/25";

  // Each bar is positioned against the picture rect, not the element box, so
  // blanking lands on the image itself whatever shape the player is.
  const horizontal = box.top > 0;

  return (
    // No z-index: the annotation canvas is also absolutely positioned and comes
    // later in the DOM, so it stays on top and marks drawn over a blanked area
    // remain visible.
    <div
      className="pointer-events-none absolute inset-0"
      aria-hidden="true"
      data-testid="aspect-overlay"
    >
      {horizontal ? (
        <>
          <div
            className={barClass}
            style={{ left: rect.left, top: rect.top, width: rect.width, height: box.top }}
          />
          <div
            className={barClass}
            style={{
              left: rect.left,
              top: rect.top + rect.height - box.bottom,
              width: rect.width,
              height: box.bottom,
            }}
          />
        </>
      ) : (
        <>
          <div
            className={barClass}
            style={{ left: rect.left, top: rect.top, width: box.left, height: rect.height }}
          />
          <div
            className={barClass}
            style={{
              left: rect.left + rect.width - box.right,
              top: rect.top,
              width: box.right,
              height: rect.height,
            }}
          />
        </>
      )}

      <div className="absolute bottom-3 right-3 rounded bg-black/70 px-2 py-1 font-mono text-[11px] text-zinc-300">
        {preset.label}
      </div>
    </div>
  );
}