import type { Edl } from "@rakazo/contracts";
import { cn } from "@rakazo/ui-web";
import { useCallback, useEffect, useImperativeHandle, useRef, useState } from "react";
import { assetFileUrl, useMediaObjectUrl } from "./media-files";
import { clipLengthMs, clipOutputStartMs, edlDurationMs, locateOutputTime } from "./timeline";

export interface PlayerHandle {
  /** Jump to an output timestamp in ms. */
  seek(ms: number): void;
}

/** What the source player currently shows, in source coordinates. */
export interface SourceFrame {
  outputMs: number;
  clipId: string;
  assetId: string;
  sourceMs: number;
}

/** Plays a finished render. Reports the playhead in output ms. */
export function RenderVideo({
  src,
  poster,
  handleRef,
  onTime,
  className,
  label,
}: {
  src: string | null;
  poster?: string | null;
  handleRef?: React.Ref<PlayerHandle>;
  onTime?: (ms: number) => void;
  className?: string;
  label: string;
}) {
  const video = useRef<HTMLVideoElement>(null);
  const pending = useRef<number | null>(null);
  useImperativeHandle(handleRef, () => ({
    seek(ms) {
      const element = video.current;
      if (!element || element.readyState < 1) {
        pending.current = ms;
        return;
      }
      element.currentTime = ms / 1000;
      onTime?.(ms);
    },
  }));
  return (
    // biome-ignore lint/a11y/useMediaCaption: renders carry burned-in or sidecar captions.
    <video
      ref={video}
      aria-label={label}
      className={cn("aspect-video w-full rounded-lg bg-muted object-contain", className)}
      controls
      playsInline
      preload="metadata"
      poster={poster ?? undefined}
      src={src ?? undefined}
      onLoadedMetadata={(event) => {
        if (pending.current === null) return;
        event.currentTarget.currentTime = pending.current / 1000;
        pending.current = null;
      }}
      onTimeUpdate={(event) => onTime?.(Math.round(event.currentTarget.currentTime * 1000))}
    />
  );
}

/**
 * Plays a plan's timeline from the source proxies (the unredacted "before"
 * view, and the only view of a render the gate blocked). Clips play in order;
 * gaps and the intro show nothing.
 */
export function SourcePlayer({
  edl,
  handleRef,
  onFrame,
  label,
  children,
}: {
  edl: Edl;
  handleRef?: React.Ref<PlayerHandle>;
  onFrame?: (frame: SourceFrame | null) => void;
  label: string;
  /** Overlays positioned over the video frame (masks, mark prompts). */
  children?: React.ReactNode;
}) {
  const [outputMs, setOutputMs] = useState(() => clipOutputStartMs(edl, firstClip(edl)));
  const located = locateOutputTime(edl, outputMs);
  const assetId = located?.clip.assetId ?? null;
  const src = useMediaObjectUrl(assetId ? assetFileUrl(assetId, "proxy") : null);
  const video = useRef<HTMLVideoElement>(null);
  const playing = useRef(false);
  const [ratio, setRatio] = useState(16 / 9);

  const report = useCallback(
    (ms: number) => {
      const at = locateOutputTime(edl, ms);
      onFrame?.(
        at
          ? { outputMs: ms, clipId: at.clip.id, assetId: at.clip.assetId, sourceMs: at.sourceMs }
          : null,
      );
    },
    [edl, onFrame],
  );

  const seek = useCallback(
    (ms: number) => {
      const clamped = Math.max(0, Math.min(ms, edlDurationMs(edl)));
      setOutputMs(clamped);
      const at = locateOutputTime(edl, clamped);
      const element = video.current;
      if (at && element && at.clip.assetId === assetId && element.readyState >= 1) {
        element.currentTime = at.sourceMs / 1000;
      }
      report(clamped);
    },
    [edl, assetId, report],
  );
  useImperativeHandle(handleRef, () => ({ seek }), [seek]);

  // A new clip's proxy loaded: start at the mapped source time.
  const onLoaded = (element: HTMLVideoElement) => {
    if (element.videoWidth > 0 && element.videoHeight > 0) {
      setRatio(element.videoWidth / element.videoHeight);
    }
    if (located) element.currentTime = located.sourceMs / 1000;
    if (playing.current) void element.play().catch(() => undefined);
  };

  const onTimeUpdate = (element: HTMLVideoElement) => {
    if (!located) return;
    const { clip } = located;
    const sourceMs = element.currentTime * 1000;
    const clipEnd = clipOutputStartMs(edl, clip) + clipLengthMs(clip);
    if (sourceMs >= clip.outMs) {
      const next = nextClipStart(edl, clipEnd);
      if (next === null) {
        element.pause();
        playing.current = false;
        return;
      }
      setOutputMs(next);
      report(next);
      return;
    }
    const ms = clipOutputStartMs(edl, clip) + Math.round((sourceMs - clip.inMs) / clip.speed);
    setOutputMs(ms);
    report(ms);
  };

  // Report once per plan; playback reports through onTimeUpdate.
  useEffect(() => {
    report(outputMs);
  }, [edl]);

  return (
    <div className="relative aspect-video w-full overflow-hidden rounded-lg bg-muted">
      {/* biome-ignore lint/a11y/useMediaCaption: source footage has no caption track. */}
      <video
        ref={video}
        aria-label={label}
        className="absolute inset-0 h-full w-full object-contain"
        controls
        playsInline
        preload="auto"
        src={src ?? undefined}
        onLoadedMetadata={(event) => onLoaded(event.currentTarget)}
        onPlay={() => {
          playing.current = true;
        }}
        onPause={() => {
          playing.current = false;
        }}
        onTimeUpdate={(event) => onTimeUpdate(event.currentTarget)}
      />
      {children ? (
        // Children get the displayed frame, so normalized boxes map onto the picture.
        <div className="pointer-events-none absolute inset-0 flex items-center justify-center">
          <div
            data-frame
            className="relative"
            style={{
              aspectRatio: ratio,
              ...(ratio >= 16 / 9 ? { width: "100%" } : { height: "100%" }),
            }}
          >
            {children}
          </div>
        </div>
      ) : null}
    </div>
  );
}

function firstClip(edl: Edl) {
  return [...edl.tracks.video].sort((a, b) => a.atMs - b.atMs)[0] ?? edl.tracks.video[0]!;
}

/** Output start of the first clip beginning at or after `ms`, or null. */
function nextClipStart(edl: Edl, ms: number): number | null {
  let best: number | null = null;
  for (const clip of edl.tracks.video) {
    const start = clipOutputStartMs(edl, clip);
    if (start >= ms && (best === null || start < best)) best = start;
  }
  return best;
}