import { useLingui } from "@lingui/react/macro";
import { buttonVariants } from "@rakazo/ui-web";
import { Download } from "lucide-react";
import type { RefObject } from "react";
import { useEffect, useRef, useState } from "react";
import { artifactUrl } from "../../lib/artifact-url";

export type MediaPlayerProps = {
  artifactId: string;
  kind: "video" | "audio";
  name: string;
  posterArtifactId?: string;
  width?: number;
  height?: number;
};

const MAX_VIDEO_WIDTH = 420;
const MAX_VIDEO_HEIGHT = 480;

/** Plays a video or audio artifact in place; loads nothing until it is near the viewport. */
export function MediaPlayer({
  artifactId,
  kind,
  name,
  posterArtifactId,
  width,
  height,
}: MediaPlayerProps) {
  const container = useRef<HTMLDivElement>(null);
  const near = useNearViewport(container);
  const [failed, setFailed] = useState(false);
  const [frame, setFrame] = useState<{ width: number; height: number } | null>(null);
  const src = near ? artifactUrl(artifactId) : undefined;

  if (failed) return <MediaFallback artifactId={artifactId} name={name} />;

  if (kind === "audio") {
    return (
      <div ref={container} className="w-72 max-w-full" data-testid="media-audio">
        {/* biome-ignore lint/a11y/useMediaCaption: user media has no caption track. */}
        <audio
          src={src}
          controls
          preload="metadata"
          aria-label={name}
          className="w-full"
          onError={() => setFailed(true)}
        />
      </div>
    );
  }

  // Uploads carry no dimensions; size the frame from the file once its metadata loads.
  const box = videoBox(width ?? frame?.width, height ?? frame?.height);
  return (
    <div
      ref={container}
      className="max-w-full overflow-hidden rounded-[20px] bg-muted"
      style={{ width: box.width, aspectRatio: `${box.width} / ${box.height}` }}
      data-testid="media-video"
    >
      {/* biome-ignore lint/a11y/useMediaCaption: user media has no caption track. */}
      <video
        src={src}
        poster={near && posterArtifactId ? artifactUrl(posterArtifactId) : undefined}
        controls
        playsInline
        preload="metadata"
        aria-label={name}
        className="block size-full object-contain"
        onError={() => setFailed(true)}
        onLoadedMetadata={(event) => {
          const { videoWidth, videoHeight } = event.currentTarget;
          if (videoWidth > 0 && videoHeight > 0) {
            setFrame({ width: videoWidth, height: videoHeight });
          }
        }}
      />
    </div>
  );
}

/** Fits the frame into the chat column, defaulting to 16:9 until the size is known. */
function videoBox(width?: number, height?: number) {
  const w = width && width > 0 ? width : 16;
  const h = height && height > 0 ? height : 9;
  const scale = Math.min(MAX_VIDEO_WIDTH / w, MAX_VIDEO_HEIGHT / h);
  return { width: Math.round(w * scale), height: Math.round(h * scale) };
}

function MediaFallback({ artifactId, name }: { artifactId: string; name: string }) {
  const { t } = useLingui();
  return (
    <div className="flex max-w-full items-center gap-2 rounded-[20px] border border-border bg-muted py-2 ps-4 pe-2 text-ui-body text-muted-foreground">
      <span className="min-w-0 truncate">{name}</span>
      <a
        href={artifactUrl(artifactId, { download: true })}
        download={name}
        aria-label={t`Download ${name}`}
        title={t`Download ${name}`}
        className={buttonVariants({ variant: "ghost", size: "icon-sm" })}
      >
        <Download />
      </a>
    </div>
  );
}

function useNearViewport(ref: RefObject<HTMLElement | null>) {
  const [near, setNear] = useState(false);
  useEffect(() => {
    const element = ref.current;
    if (!element || typeof IntersectionObserver === "undefined") {
      setNear(true);
      return;
    }
    const observer = new IntersectionObserver(
      (entries) => {
        if (entries.some((entry) => entry.isIntersecting)) {
          setNear(true);
          observer.disconnect();
        }
      },
      { rootMargin: "320px" },
    );
    observer.observe(element);
    return () => observer.disconnect();
  }, [ref]);
  return near;
}