"use client";

import {
  useRef,
  useEffect,
  useState,
  useCallback,
  useMemo,
  forwardRef,
  useImperativeHandle,
} from "react";
import { useReviewStore } from "@/hooks/use-review-player";
import { AnnotationCanvas } from "@/components/annotations/AnnotationCanvas";
import { AnnotationTools } from "@/components/annotations/AnnotationTools";
import { AspectOverlay } from "./AspectOverlay";
import { FrameTimeline } from "./FrameTimeline";
import { PlaybackControls } from "./PlaybackControls";
import { HandleOverlay } from "./HandleOverlay";
import { useZoomPan } from "@/hooks/use-zoom-pan";
import { Minus, Plus } from "lucide-react";
import { timeToFrame, frameToTime, durationToFrameCount } from "@/lib/frame-utils";
import { cn } from "@/lib/utils";
import { computeEditRange, frameRegion, type VersionHandles } from "@/lib/handles";
import type { CommentWithReplies } from "@/types";

export interface ReviewPlayerRef {
  seekToFrame: (frame: number) => void;
  play: () => void;
  pause: () => void;
}

interface ReviewPlayerProps {
  videoUrl: string;
  versionId: string;
  fps?: number;
  comments?: CommentWithReplies[];
  annotations?: unknown[];
  className?: string;
  onAddComment?: (frameNumber: number, timestamp: number) => void;
  onAnnotationSaved?: (frameNumber: number) => void;
  /** Override the default server action used to persist annotations (e.g. for client-token routes) */
  saveAnnotationFn?: (data: { versionId: string; frameNumber: number; drawingData: unknown; color: string }) => Promise<void>;
  /** Override the default server action used to create the companion comment */
  addCommentFn?: (data: { versionId: string; frameNumber: number; timestamp: number; text: string }) => Promise<void>;
  /** The version's handle metadata — frames past the cut get flagged. */
  handles?: VersionHandles | null;
  /** Start with playback kept to the edit (the client portal's default). */
  defaultEditRangeOnly?: boolean;
  /** High quality source (full res, high bitrate); enables the quality switch. */
  hqVideoUrl?: string | null;
}

export type PlaybackQuality = "standard" | "high";
const QUALITY_KEY = "review:quality";

export const ReviewPlayer = forwardRef<ReviewPlayerRef, ReviewPlayerProps>(
  function ReviewPlayer(
    {
      videoUrl,
      versionId,
      fps = 24,
      comments = [],
      annotations,
      className,
      onAddComment,
      onAnnotationSaved,
      saveAnnotationFn,
      addCommentFn,
      handles,
      defaultEditRangeOnly = false,
      hqVideoUrl,
    },
    ref
  ) {
    // Stabilise the annotations reference so AnnotationCanvas's sync effect
    // only fires when the actual content changes, not on every parent re-render.
    const stableAnnotations = useMemo(() => annotations ?? [], [annotations]);
    const videoRef = useRef<HTMLVideoElement>(null);
    const containerRef = useRef<HTMLDivElement>(null);
    const stageRef = useRef<HTMLDivElement>(null);
    const zoomLayerRef = useRef<HTMLDivElement>(null);
    const reverseIntervalRef = useRef<ReturnType<typeof setInterval> | null>(null);
    const openedAtCut = useRef(false);

    // ── Quality ──────────────────────────────────────────────────────────────
    // Standard is the review MP4; High is the full-res, high-bitrate encode of
    // the delivery MOV. The choice is a per-browser preference, read after
    // mount so the server render and the first client render agree.
    const [quality, setQuality] = useState<PlaybackQuality>("standard");
    const [switchingQuality, setSwitchingQuality] = useState(false);
    // Where to pick up once the other source has loaded.
    const resumeRef = useRef<{ time: number; playing: boolean } | null>(null);
    useEffect(() => {
      try {
        if (localStorage.getItem(QUALITY_KEY) === "high") setQuality("high");
      } catch {
        // storage blocked — Standard it is
      }
    }, []);
    const activeSrc = quality === "high" && hqVideoUrl ? hqVideoUrl : videoUrl;

    const changeQuality = useCallback(
      (next: PlaybackQuality) => {
        if (next === quality) return;
        const video = videoRef.current;
        if (video && video.readyState > 0 && hqVideoUrl) {
          resumeRef.current = { time: video.currentTime, playing: !video.paused };
          setSwitchingQuality(true);
        }
        setQuality(next);
        try {
          localStorage.setItem(QUALITY_KEY, next);
        } catch {
          // preference just isn't remembered
        }
      },
      [quality, hqVideoUrl]
    );
    const [isReversing, setIsReversing] = useState(false);

    const {
      isPlaying,
      currentFrame,
      isAnnotating,
      showAnnotations,
      aspectPresetId,
      blankingMode,
      setPlaying,
      setCurrentFrame,
      setCurrentTime,
      setDuration,
      setFps,
      setTotalFrames,
      totalFrames,
      editRange,
      editRangeOnly,
      setEditRange,
      setEditRangeOnly,
    } = useReviewStore();

    // ── Handles ──────────────────────────────────────────────────────────────
    // Where the cut sits in this media. Recomputed from primitives so a parent
    // re-render with a fresh `handles` object does not churn the store.
    const handleHead = handles?.handleHead ?? null;
    const handleTail = handles?.handleTail ?? null;
    const pictureStartFrame = handles?.pictureStartFrame ?? null;
    const handleFrameCount = handles?.frameCount ?? null;
    useEffect(() => {
      setEditRange(
        computeEditRange(
          { handleHead, handleTail, pictureStartFrame, frameCount: handleFrameCount },
          totalFrames
        )
      );
    }, [handleHead, handleTail, pictureStartFrame, handleFrameCount, totalFrames, setEditRange]);
    useEffect(() => () => setEditRange(null), [setEditRange]);

    useEffect(() => {
      setEditRangeOnly(defaultEditRangeOnly);
    }, [defaultEditRangeOnly, setEditRangeOnly]);

    // Read inside event handlers / intervals without re-binding them.
    const keepToEdit = useRef<{ range: typeof editRange; on: boolean }>({ range: null, on: false });
    keepToEdit.current = { range: editRange, on: editRangeOnly && !!editRange };

    const zoom = useZoomPan(stageRef, zoomLayerRef, {
      gesturesEnabled: !isAnnotating,
    });
    const { reset: resetZoom, zoomBy } = zoom;

    // Initialize player config from props
    useEffect(() => {
      setFps(fps);
    }, [fps, setFps]);

    // Reset playback state when the source changes so the timeline and
    // timecode don't briefly show the previous clip's values while the new
    // video is loading its metadata.
    useEffect(() => {
      setCurrentFrame(0);
      setCurrentTime(0);
      setDuration(0);
      setTotalFrames(0);
      resetZoom();
      openedAtCut.current = false;
      resumeRef.current = null;
      setSwitchingQuality(false);
    }, [videoUrl, setCurrentFrame, setCurrentTime, setDuration, setTotalFrames, resetZoom]);

    // ── Playback state sync ──────────────────────────────────────────────────
    const handleTimeUpdate = useCallback(() => {
      const video = videoRef.current;
      if (!video) return;
      const frame = timeToFrame(video.currentTime, fps);
      setCurrentFrame(frame);
      setCurrentTime(video.currentTime);
    }, [fps, setCurrentFrame, setCurrentTime]);

    const handleLoadedMetadata = useCallback(() => {
      const video = videoRef.current;
      if (!video) return;
      const frames = durationToFrameCount(video.duration, fps);
      setDuration(video.duration);
      setTotalFrames(frames);
      // A new source starts at 1x; keep the speed the reviewer chose.
      video.playbackRate = useReviewStore.getState().playbackRate;
      // Quality switch: carry on from the same frame, playing or not.
      const resume = resumeRef.current;
      resumeRef.current = null;
      if (resume) {
        video.currentTime = resume.time;
        if (resume.playing) video.play().catch(() => {});
      }
    }, [fps, setDuration, setTotalFrames]);

    // High quality failed to load (pruned, or a network hiccup): fall back to
    // Standard rather than leave a black player. Not remembered as a choice.
    const handleVideoError = useCallback(() => {
      if (quality !== "high" || !hqVideoUrl) return;
      setQuality("standard");
    }, [quality, hqVideoUrl]);

    /**
     * Play — when keeping to the edit, from the cut in-point if the playhead
     * is outside the cut (slate, a handle, or parked on the last cut frame).
     */
    const startPlayback = useCallback(() => {
      const video = videoRef.current;
      if (!video) return;
      const { range, on } = keepToEdit.current;
      if (on && range) {
        const frame = timeToFrame(video.currentTime, fps);
        if (frame < range.cutIn || frame >= range.tailStart - 1) {
          video.currentTime = frameToTime(range.cutIn, fps);
        }
      }
      // A pause() or power-saving pause before playback starts rejects this;
      // that's expected, not an error.
      video.play().catch(() => {});
    }, [fps]);

    // Keeping to the edit: stop on the last frame of the cut rather than
    // playing into the tail handle. Checked every animation frame — the
    // video's own timeupdate only fires ~4x a second.
    useEffect(() => {
      if (!isPlaying || !editRangeOnly || !editRange) return;
      const lastCutFrame = editRange.tailStart - 1;
      let raf = 0;
      const tick = () => {
        const video = videoRef.current;
        if (!video || video.paused) return;
        if (timeToFrame(video.currentTime, fps) >= editRange.tailStart) {
          video.pause();
          video.currentTime = frameToTime(lastCutFrame, fps);
          return;
        }
        raf = requestAnimationFrame(tick);
      };
      raf = requestAnimationFrame(tick);
      return () => cancelAnimationFrame(raf);
    }, [isPlaying, editRangeOnly, editRange, fps]);

    // Keeping to the edit: open on the first frame of the cut rather than on
    // the slate. Once per video, so it never moves the playhead afterwards.
    useEffect(() => {
      const video = videoRef.current;
      if (!video || openedAtCut.current || !editRangeOnly || !editRange) return;
      openedAtCut.current = true;
      if (video.paused && timeToFrame(video.currentTime, fps) < editRange.cutIn) {
        video.currentTime = frameToTime(editRange.cutIn, fps);
      }
    }, [editRange, editRangeOnly, fps]);

    const handlePlay = useCallback(() => setPlaying(true), [setPlaying]);
    const handlePause = useCallback(() => setPlaying(false), [setPlaying]);

    // ── Exposed ref API ──────────────────────────────────────────────────────
    useImperativeHandle(ref, () => ({
      seekToFrame: (frame: number) => {
        const video = videoRef.current;
        if (!video) return;
        video.currentTime = frameToTime(frame, fps);
        if (!video.paused) video.pause();
      },
      play: () => startPlayback(),
      pause: () => videoRef.current?.pause(),
    }));

    // ── Frame step functions ─────────────────────────────────────────────────
    const stepFrame = useCallback(
      (delta: number) => {
        const video = videoRef.current;
        if (!video) return;
        video.pause();
        stopReverse();
        const newTime = Math.max(0, Math.min(video.duration, video.currentTime + delta / fps));
        video.currentTime = newTime;
      },
      [fps]
    );

    const stopReverse = useCallback(() => {
      if (reverseIntervalRef.current) {
        clearInterval(reverseIntervalRef.current);
        reverseIntervalRef.current = null;
      }
      setIsReversing(false);
    }, []);

    const startReverse = useCallback(() => {
      const video = videoRef.current;
      if (!video) return;
      video.pause();
      setIsReversing(true);
      reverseIntervalRef.current = setInterval(() => {
        // Keeping to the edit, reverse stops at the cut in-point.
        const { range, on } = keepToEdit.current;
        const floor = on && range ? frameToTime(range.cutIn, fps) : 0;
        if (!videoRef.current || videoRef.current.currentTime <= floor) {
          stopReverse();
          return;
        }
        videoRef.current.currentTime = Math.max(floor, videoRef.current.currentTime - 1 / fps);
      }, 1000 / fps);
    }, [fps, stopReverse]);

    const togglePlayback = useCallback(() => {
      const video = videoRef.current;
      if (!video) return;
      stopReverse();
      if (video.paused) {
        startPlayback();
      } else {
        video.pause();
      }
    }, [stopReverse, startPlayback]);

    // ── Keyboard shortcuts (JKL + arrows + space + F) ───────────────────────
    useEffect(() => {
      const handleKeyDown = (e: KeyboardEvent) => {
        const target = e.target as HTMLElement;
        if (
          target.tagName === "INPUT" ||
          target.tagName === "TEXTAREA" ||
          target.isContentEditable
        )
          return;

        switch (e.key.toLowerCase()) {
          case "j":
            e.preventDefault();
            if (isReversing) {
              stopReverse();
            } else {
              startReverse();
            }
            break;
          case "k":
            e.preventDefault();
            if (isReversing) {
              stopReverse();
            } else {
              togglePlayback();
            }
            break;
          case "l":
            e.preventDefault();
            stopReverse();
            if (videoRef.current?.paused) startPlayback();
            break;
          case "arrowleft":
            e.preventDefault();
            stepFrame(-1);
            break;
          case "arrowright":
            e.preventDefault();
            stepFrame(1);
            break;
          case " ":
            e.preventDefault();
            stopReverse();
            togglePlayback();
            break;
          case "f":
            e.preventDefault();
            toggleFullscreen();
            break;
          case "=":
          case "+":
            e.preventDefault();
            zoomBy(1.25);
            break;
          case "-":
          case "_":
            e.preventDefault();
            zoomBy(0.8);
            break;
          case "0":
            e.preventDefault();
            resetZoom();
            break;
        }
      };

      window.addEventListener("keydown", handleKeyDown);
      return () => window.removeEventListener("keydown", handleKeyDown);
    }, [isReversing, stepFrame, startReverse, stopReverse, togglePlayback, startPlayback, zoomBy, resetZoom]);

    // Stop a running reverse only on unmount. This used to live in the
    // cleanup above, which re-runs whenever isReversing changes — so starting
    // reverse immediately stopped it, and J never did anything.
    useEffect(() => stopReverse, [stopReverse]);

    // ── Fullscreen ───────────────────────────────────────────────────────────
    const toggleFullscreen = () => {
      const el = containerRef.current;
      if (!el) return;
      if (!document.fullscreenElement) {
        el.requestFullscreen().catch(() => {});
      } else {
        document.exitFullscreen();
      }
    };

    const handleSeek = useCallback(
      (frame: number) => {
        const video = videoRef.current;
        if (!video) return;
        stopReverse();
        video.currentTime = frameToTime(frame, fps);
        video.pause();
      },
      [fps, stopReverse]
    );

    const handleAddComment = useCallback(() => {
      const video = videoRef.current;
      if (!video) return;
      video.pause();
      onAddComment?.(currentFrame, video.currentTime);
    }, [currentFrame, onAddComment]);

    return (
      <div
        ref={containerRef}
        className={cn(
          "review-player-container flex flex-col bg-black select-none h-full",
          className
        )}
      >
        {/* Video — tap anywhere to play/pause (pointer-events pass through canvas when not annotating).
            Wheel / pinch zooms, drag pans when zoomed; a drag never counts as a tap. */}
        <div
          ref={stageRef}
          className="relative flex-1 min-h-0 overflow-hidden"
          style={zoom.stageStyle}
          {...zoom.stageHandlers}
          onClick={
            !isAnnotating
              ? () => {
                  if (!zoom.consumeDrag()) togglePlayback();
                }
              : undefined
          }
        >
          {/* Zoomed as one layer so blanking and annotations stay pinned to the
              picture — annotation coords are normalised from the canvas's
              transformed bounding rect, so drawing while zoomed lands correctly. */}
          <div
            ref={zoomLayerRef}
            className="absolute inset-0 origin-top-left will-change-transform"
          >
          <video
            ref={videoRef}
            src={activeSrc}
            className="block w-full h-full object-contain"
            onTimeUpdate={handleTimeUpdate}
            onLoadedMetadata={handleLoadedMetadata}
            onPlay={handlePlay}
            onPause={handlePause}
            onCanPlay={() => setSwitchingQuality(false)}
            onError={handleVideoError}
            preload="metadata"
            playsInline
          />

          {/* Delivery blanking — under the annotation canvas, so a reviewer
              can still draw over a blanked area if they need to */}
          <AspectOverlay
            presetId={aspectPresetId}
            mode={blankingMode}
            videoRef={videoRef}
          />

          {/* Annotation canvas overlay */}
          <AnnotationCanvas
            versionId={versionId}
            videoRef={videoRef}
            frameNumber={currentFrame}
            fps={fps}
            isAnnotating={isAnnotating && !isPlaying}
            showAnnotations={showAnnotations}
            existingAnnotations={stableAnnotations}
            onAnnotationSaved={onAnnotationSaved}
            saveAnnotationFn={saveAnnotationFn as any}
            addCommentFn={addCommentFn}
          />
          </div>

          {/* Handle flag — drawn over the player, never into the media */}
          <HandleOverlay region={frameRegion(editRange, currentFrame)} />

          {/* Zoom badge — only while zoomed */}
          {zoom.zoomed && (
            <div
              className="absolute top-3 right-3 flex items-center gap-0.5 rounded bg-black/70 p-0.5 text-xs text-white"
              onClick={(e) => e.stopPropagation()}
              onPointerDown={(e) => e.stopPropagation()}
            >
              <button
                type="button"
                className="rounded p-1.5 hover:bg-white/15"
                onClick={() => zoomBy(0.8)}
                aria-label="Zoom out"
              >
                <Minus className="h-3.5 w-3.5" />
              </button>
              <span className="w-10 text-center font-mono tabular-nums">
                {Math.round(zoom.scale * 100)}%
              </span>
              <button
                type="button"
                className="rounded p-1.5 hover:bg-white/15"
                onClick={() => zoomBy(1.25)}
                aria-label="Zoom in"
              >
                <Plus className="h-3.5 w-3.5" />
              </button>
              <button
                type="button"
                className="rounded px-2 py-1 hover:bg-white/15"
                onClick={resetZoom}
              >
                Fit
              </button>
            </div>
          )}

          {switchingQuality && (
            <div className="pointer-events-none absolute bottom-3 left-3 rounded bg-black/70 px-2 py-1 text-xs text-white">
              Loading {quality === "high" ? "high" : "standard"} quality…
            </div>
          )}

          {/* JKL hint overlay — shown briefly when reversing */}
          {isReversing && (
            <div className="absolute top-3 left-3 rounded bg-black/60 px-2 py-1 text-xs font-mono text-white">
              ◄◄ REVERSE
            </div>
          )}
        </div>

        {/* Annotation Tools (visible when annotation mode is active) */}
        <AnnotationTools />

        {/* Frame Timeline */}
        <FrameTimeline
          fps={fps}
          comments={comments}
          annotations={annotations as { frameNumber: number }[]}
          videoRef={videoRef}
          onSeek={handleSeek}
        />

        {/* Playback Controls */}
        <PlaybackControls
          videoRef={videoRef}
          fps={fps}
          isReversing={isReversing}
          onStepBackward={() => stepFrame(-1)}
          onStepForward={() => stepFrame(1)}
          onReverse={isReversing ? stopReverse : startReverse}
          onTogglePlay={togglePlayback}
          onToggleFullscreen={toggleFullscreen}
          onAddComment={handleAddComment}
          quality={hqVideoUrl ? quality : null}
          onQualityChange={changeQuality}
        />
      </div>
    );
  }
);