pargar/frontend/src/components/video-player.tsx

"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import Link from "next/link";
import {
  ChevronDown,
  Gauge,
  Lock,
  Maximize,
  Minimize,
  Pause,
  Play,
  Rewind,
  Volume1,
  Volume2,
  VolumeX,
} from "lucide-react";
import { motion, AnimatePresence } from "framer-motion";
import type Hls from "hls.js";
import { api, http, toUserError } from "@/lib/api";
import type { Lesson, LessonProgress } from "@/lib/types";
import { Skeleton } from "@/components/ui/skeleton";
import { Progress } from "@/components/ui/progress";
import { Button } from "@/components/ui/button";
import { toast } from "@/components/providers";
import { cn } from "@/lib/utils";

// ─── Constants ────────────────────────────────────────────────────────────────
const INTERVAL_MS = 10_000;
const SEEK_FORWARD_SLACK = 0.35;
const CONTINUOUS_PLAY_MAX_DT = 3;
const ALLOWED_SPEEDS = [0.5, 0.75, 1, 1.25, 1.5, 2] as const;
type Speed = (typeof ALLOWED_SPEEDS)[number];
const MAX_RETRY_DELAY_MS = 30_000;
const DOUBLE_TAP_MS = 300;
const DOUBLE_TAP_SLOP = 60;

// ─── localStorage helpers ─────────────────────────────────────────────────────
function readStorage<T>(key: string, fallback: T, guard: (v: unknown) => v is T): T {
  try {
    const raw = localStorage.getItem(key);
    if (raw === null) return fallback;
    const parsed: unknown = JSON.parse(raw);
    return guard(parsed) ? parsed : fallback;
  } catch { return fallback; }
}
function writeStorage(key: string, value: unknown) {
  try { localStorage.setItem(key, JSON.stringify(value)); } catch { /* ignore */ }
}

const isNumber = (v: unknown): v is number => typeof v === "number" && Number.isFinite(v);

// ─── Main Component ───────────────────────────────────────────────────────────
export function VideoPlayer({
  lessonId,
  videoUrl,
  duration,
  completionThresholdPct,
  initialProgress,
}: {
  lessonId: number;
  videoUrl: string;
  duration: number;
  completionThresholdPct: number;
  initialProgress?: LessonProgress | null;
}) {
  // ── Refs ────────────────────────────────────────────────────────────────────
  const videoRef = useRef<HTMLVideoElement>(null);
  const containerRef = useRef<HTMLDivElement>(null);
  const hlsRef = useRef<Hls | null>(null);

  const lockedSrcRef = useRef(videoUrl);
  const resumeAppliedRef = useRef(false);
  const accRef = useRef(0);
  const lastTimeRef = useRef(0);
  const maxTrustedPosRef = useRef(0);
  const seekToastAtRef = useRef(0);
  const seqRef = useRef(0);
  const programmaticSeekRef = useRef(false);
  const refreshingSrcRef = useRef(false);
  const retryCountRef = useRef(0);
  const retryTimerRef = useRef<number | null>(null);
  const userSpeedRef = useRef<Speed>(1);
  const sendHeartbeatRef = useRef<(pos: number, delta: number) => Promise<void>>(async () => undefined);

  // Double-tap detection
  const lastTapRef = useRef<{ time: number; x: number } | null>(null);
  const tapTimeoutRef = useRef<number | null>(null);

  // ── Persisted prefs ─────────────────────────────────────────────────────────
  const [volume, setVolume] = useState(() => readStorage("pargar:volume", 1, isNumber));
  const [speed, setSpeed] = useState<Speed>(() => {
    const s = readStorage("pargar:speed", 1, isNumber);
    return (ALLOWED_SPEEDS as readonly number[]).includes(s) ? s as Speed : 1;
  });

  // ── Playback state ──────────────────────────────────────────────────────────
  const [playing, setPlaying] = useState(false);
  const [muted, setMuted] = useState(false);
  const [position, setPosition] = useState(0);
  const [bufferedEnd, setBufferedEnd] = useState(0);
  const [hoverTime, setHoverTime] = useState<number | null>(null);
  const [hoverX, setHoverX] = useState(0);
  const [watchedPct, setWatchedPct] = useState(initialProgress?.watchedPct ?? 0);
  const [quizUnlocked, setQuizUnlocked] = useState(!!initialProgress?.quizUnlocked);
  const [quizUnlockedNow, setQuizUnlockedNow] = useState(false);
  const [loading, setLoading] = useState(true);
  const [buffering, setBuffering] = useState(false);
  const [loadError, setLoadError] = useState<string | null>(null);
  const [uiIdle, setUiIdle] = useState(false);
  const [mediaDuration, setMediaDuration] = useState(duration);
  const [fullscreen, setFullscreen] = useState(false);
  const [theaterMode, setTheaterMode] = useState(false);
  const [seekIndicator, setSeekIndicator] = useState<"back" | null>(null);

  const hideTimer = useRef<number | null>(null);

  // ── Utilities ───────────────────────────────────────────────────────────────
  const warnSeekBlocked = useCallback(() => {
    const now = Date.now();
    if (now - seekToastAtRef.current < 2500) return;
    seekToastAtRef.current = now;
    toast.error("پرش سریع و نمایش شناور مجاز نیست");
  }, []);

  const flushAcc = useCallback(() => {
    const v = videoRef.current;
    if (!v) return;
    const delta = accRef.current;
    accRef.current = 0;
    if (delta < 0.05) return;
    void sendHeartbeatRef.current(v.currentTime, delta);
  }, []);

  const seekProgrammatic = useCallback((to: number) => {
    const v = videoRef.current;
    if (!v) return;
    programmaticSeekRef.current = true;
    v.currentTime = Math.max(0, to);
    lastTimeRef.current = v.currentTime;
    setPosition(v.currentTime);
    window.setTimeout(() => { programmaticSeekRef.current = false; }, 120);
  }, []);

  const fmt = (s: number) => {
    const m = Math.floor(s / 60);
    const sec = Math.floor(s % 60);
    return `${m}:${sec.toString().padStart(2, "0")}`;
  };

  const poke = useCallback(() => {
    setUiIdle(false);
    if (hideTimer.current) window.clearTimeout(hideTimer.current);
    const v = videoRef.current;
    if (v && !v.paused && !v.ended) {
      hideTimer.current = window.setTimeout(() => setUiIdle(true), 2600);
    }
  }, []);

  const skipBack = useCallback(() => {
    const v = videoRef.current;
    if (!v) return;
    flushAcc();
    seekProgrammatic(Math.max(0, v.currentTime - 10));
    poke();
  }, [flushAcc, seekProgrammatic, poke]);

  const toggle = useCallback(() => {
    const v = videoRef.current;
    if (!v) return;
    if (v.paused) void v.play().catch(() => toast.error("پخش ویدیو ممکن نشد"));
    else v.pause();
  }, []);

  const toggleFullscreen = useCallback(() => {
    const el = containerRef.current;
    if (!el) return;
    if (!document.fullscreenElement) {
      void el.requestFullscreen().catch(() => undefined);
    } else {
      void document.exitFullscreen().catch(() => undefined);
    }
  }, []);

  const changeSpeed = useCallback((s: Speed) => {
    userSpeedRef.current = s;
    setSpeed(s);
    writeStorage("pargar:speed", s);
    const v = videoRef.current;
    if (v) v.playbackRate = s;
  }, []);

  const cycleSpeed = useCallback(() => {
    const idx = ALLOWED_SPEEDS.indexOf(userSpeedRef.current);
    const next = ALLOWED_SPEEDS[(idx + 1) % ALLOWED_SPEEDS.length];
    changeSpeed(next);
  }, [changeSpeed]);


  // ── HLS init ────────────────────────────────────────────────────────────────
  useEffect(() => {
    const v = videoRef.current;
    if (!v) return;
    const src = lockedSrcRef.current;
    const isHLS = src.includes(".m3u8");

    if (isHLS) {
      let cancelled = false;
      import("hls.js").then(({ default: HlsClass }) => {
        if (cancelled) return;
        if (HlsClass.isSupported()) {
          const hls = new HlsClass({
            maxBufferLength: 45,
            maxMaxBufferLength: 60,
            startLevel: -1,
            autoStartLoad: true,
          });
          hls.loadSource(src);
          hls.attachMedia(v);
          hlsRef.current = hls;
        } else if (v.canPlayType("application/vnd.apple.mpegurl")) {
          // Safari native HLS
          v.src = src;
        }
      });
      return () => {
        cancelled = true;
        hlsRef.current?.destroy();
        hlsRef.current = null;
      };
    } else {
      v.src = src;
    }
  }, [lessonId]);

  // ── Resume position ─────────────────────────────────────────────────────────
  useEffect(() => {
    let cancelled = false;
    resumeAppliedRef.current = false;
    (async () => {
      try {
        const { position: p, lastSeq } = await api<{ position: number; lastSeq?: number }>(
          `/api/lessons/${lessonId}/resume`
        );
        if (typeof lastSeq === "number" && lastSeq > seqRef.current) seqRef.current = lastSeq;
        if (cancelled || resumeAppliedRef.current || !(p > 1)) return;
        const apply = () => {
          const v = videoRef.current;
          if (!v || resumeAppliedRef.current) return;
          if (v.currentTime >= 1) { resumeAppliedRef.current = true; return; }
          const dur = Number.isFinite(v.duration) && v.duration > 0 ? v.duration : duration;
          if (p < dur - 2) {
            programmaticSeekRef.current = true;
            v.currentTime = p;
            setPosition(p);
            lastTimeRef.current = p;
            maxTrustedPosRef.current = Math.max(maxTrustedPosRef.current, p);
            window.setTimeout(() => { programmaticSeekRef.current = false; }, 120);
          }
          resumeAppliedRef.current = true;
        };
        if (videoRef.current) {
          if (videoRef.current.readyState >= 1) apply();
          else videoRef.current.addEventListener("loadedmetadata", apply, { once: true });
        }
      } catch { /* ignore */ }
    })();
    return () => { cancelled = true; };
  }, [lessonId, duration]);

  useEffect(() => {
    if (initialProgress?.lastPosition && initialProgress.lastPosition > 0) {
      maxTrustedPosRef.current = Math.max(maxTrustedPosRef.current, initialProgress.lastPosition);
    }
  }, [initialProgress?.lastPosition]);

  // ── Heartbeat ───────────────────────────────────────────────────────────────
  const sendHeartbeat = useCallback(async (pos: number, delta: number) => {
    seqRef.current += 1;
    try {
      const res = await api<{ watchedPct: number; quizUnlocked: boolean; quizUnlockedNow: boolean }>(
        `/api/lessons/${lessonId}/heartbeat`,
        { method: "POST", body: { position: pos, delta, seq: seqRef.current } }
      );
      setWatchedPct(res.watchedPct);
      if (res.quizUnlocked) setQuizUnlocked(true);
      if (res.quizUnlockedNow) {
        setQuizUnlockedNow(true);
        toast.success("آزمون باز شد! می‌توانید آموخته‌هایتان را محک بزنید.");
      }
    } catch (e) {
      const msg = (e as Error)?.message ?? "";
      if (msg.includes("locked") || msg.includes("قفل")) { toast.error(msg); return; }
      toast.error(toUserError(e, "همگام‌سازی تماشا قطع شد — اتصال را بررسی کنید"));
    }
  }, [lessonId]);

  useEffect(() => { sendHeartbeatRef.current = sendHeartbeat; }, [sendHeartbeat]);

  // ── Anti-cheat: rate cap, forward-seek block, PiP block ────────────────────
  useEffect(() => {
    const v = videoRef.current;
    if (!v) return;

    v.disablePictureInPicture = true;
    v.disableRemotePlayback = true;

    const capRate = () => {
      const target = userSpeedRef.current;
      if (Math.abs(v.playbackRate - target) > 0.01) {
        v.playbackRate = target;
        if (v.playbackRate > 2.01) warnSeekBlocked();
      }
    };

    const snapForwardSeek = () => {
      if (programmaticSeekRef.current) return false;
      const max = maxTrustedPosRef.current;
      if (v.currentTime > max + SEEK_FORWARD_SLACK) {
        programmaticSeekRef.current = true;
        v.currentTime = max;
        lastTimeRef.current = max;
        setPosition(max);
        window.setTimeout(() => { programmaticSeekRef.current = false; }, 120);
        warnSeekBlocked();
        return true;
      }
      return false;
    };

    const onTimeUpdate = () => {
      capRate();
      if (snapForwardSeek()) return;
      const dt = v.currentTime - lastTimeRef.current;
      // Accumulate content-time delta (backend credits content coverage)
      if (dt > 0 && dt < CONTINUOUS_PLAY_MAX_DT) {
        accRef.current += dt;
        if (v.currentTime > maxTrustedPosRef.current) maxTrustedPosRef.current = v.currentTime;
      }
      lastTimeRef.current = v.currentTime;
      setPosition(v.currentTime);
      if (v.buffered.length > 0) setBufferedEnd(v.buffered.end(v.buffered.length - 1));
    };

    const onEnded = () => {
      setPlaying(false);
      const delta = accRef.current; accRef.current = 0;
      void sendHeartbeatRef.current(v.currentTime, delta);
    };

    const blockPiP = () => {
      void (async () => {
        try { if (document.pictureInPictureElement === v) await document.exitPictureInPicture(); }
        catch { /* ignore */ }
        v.pause(); warnSeekBlocked();
      })();
    };

    v.addEventListener("timeupdate", onTimeUpdate);
    v.addEventListener("ended", onEnded);
    v.addEventListener("seeking", snapForwardSeek);
    v.addEventListener("seeked", snapForwardSeek);
    v.addEventListener("ratechange", capRate);
    v.addEventListener("enterpictureinpicture", blockPiP);
    return () => {
      v.removeEventListener("timeupdate", onTimeUpdate);
      v.removeEventListener("ended", onEnded);
      v.removeEventListener("seeking", snapForwardSeek);
      v.removeEventListener("seeked", snapForwardSeek);
      v.removeEventListener("ratechange", capRate);
      v.removeEventListener("enterpictureinpicture", blockPiP);
    };
  }, [lessonId, warnSeekBlocked]);

  // ── Periodic heartbeats + visibility flush ──────────────────────────────────
  useEffect(() => {
    const v = videoRef.current;
    if (!v) return;
    const sendPending = (opts?: { evenIfPaused?: boolean }) => {
      const delta = accRef.current;
      if (delta < 0.05) return;
      if (!opts?.evenIfPaused && (v.paused || v.ended)) return;
      accRef.current = 0;
      void sendHeartbeatRef.current(v.currentTime, delta);
    };
    const iv = window.setInterval(() => sendPending(), INTERVAL_MS);
    const flush = () => sendPending({ evenIfPaused: true });
    const onPause = () => sendPending({ evenIfPaused: true });
    const vis = () => {
      if (document.hidden) { sendPending({ evenIfPaused: true }); if (!v.paused) v.pause(); }
      if (document.pictureInPictureElement === v) { void document.exitPictureInPicture().catch(() => undefined); v.pause(); }
    };
    v.addEventListener("pause", onPause);
    document.addEventListener("visibilitychange", vis);
    window.addEventListener("beforeunload", flush);
    window.addEventListener("pagehide", flush);
    return () => {
      window.clearInterval(iv);
      v.removeEventListener("pause", onPause);
      document.removeEventListener("visibilitychange", vis);
      window.removeEventListener("beforeunload", flush);
      window.removeEventListener("pagehide", flush);
      flush();
    };
  }, [lessonId]);

  // ── Volume / mute sync ──────────────────────────────────────────────────────
  useEffect(() => {
    const v = videoRef.current;
    if (!v) return;
    v.volume = volume;
    v.muted = muted || volume === 0;
    writeStorage("pargar:volume", volume);
  }, [volume, muted]);

  // ── Apply speed on mount and change ────────────────────────────────────────
  useEffect(() => {
    const v = videoRef.current;
    if (v) { v.playbackRate = speed; userSpeedRef.current = speed; }
  }, [speed]);

  // ── Fullscreen change listener ──────────────────────────────────────────────
  useEffect(() => {
    const onFsChange = () => setFullscreen(!!document.fullscreenElement);
    document.addEventListener("fullscreenchange", onFsChange);
    return () => document.removeEventListener("fullscreenchange", onFsChange);
  }, []);

  // ── Keyboard shortcuts ──────────────────────────────────────────────────────
  useEffect(() => {
    const onKey = (e: KeyboardEvent) => {
      const active = document.activeElement;
      if (active && (active.tagName === "INPUT" || active.tagName === "TEXTAREA" || active.tagName === "SELECT")) return;
      const v = videoRef.current;
      if (!v) return;

      switch (e.code) {
        case "Space": case "KeyK": e.preventDefault(); toggle(); poke(); break;
        case "KeyJ": case "ArrowLeft":
          e.preventDefault(); skipBack(); setSeekIndicator("back");
          setTimeout(() => setSeekIndicator(null), 700);
          break;
        case "KeyL": case "ArrowRight":
          e.preventDefault(); warnSeekBlocked(); break;
        case "ArrowUp":
          e.preventDefault(); setVolume((vol) => Math.min(1, Math.round((vol + 0.1) * 10) / 10)); poke(); break;
        case "ArrowDown":
          e.preventDefault(); setVolume((vol) => Math.max(0, Math.round((vol - 0.1) * 10) / 10)); poke(); break;
        case "KeyM": e.preventDefault(); setMuted((m) => !m); poke(); break;
        case "KeyF": e.preventDefault(); toggleFullscreen(); break;
      }
    };
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, [toggle, skipBack, warnSeekBlocked, poke, toggleFullscreen]);

  // ── Cleanup timers ──────────────────────────────────────────────────────────
  useEffect(() => {
    return () => {
      if (retryTimerRef.current) window.clearTimeout(retryTimerRef.current);
      if (tapTimeoutRef.current) window.clearTimeout(tapTimeoutRef.current);
      if (hideTimer.current) window.clearTimeout(hideTimer.current);
    };
  }, []);

  // ── Refresh signed URL (error recovery) ────────────────────────────────────
  const scheduleRetry = useCallback(() => {
    if (retryTimerRef.current) return;
    retryCountRef.current += 1;
    const delay = Math.min(1000 * 2 ** (retryCountRef.current - 1), MAX_RETRY_DELAY_MS);
    retryTimerRef.current = window.setTimeout(() => {
      retryTimerRef.current = null;
      void refreshSignedUrl();
    }, delay);
  }, []); // eslint-disable-line react-hooks/exhaustive-deps

  const refreshSignedUrl = useCallback(async () => {
    if (refreshingSrcRef.current) return;
    refreshingSrcRef.current = true;
    try {
      const data = await http.get<{ lesson: Lesson; videoUrl: string; progress: LessonProgress | null }>(
        `/api/lessons/${lessonId}`
      );
      if (!data.videoUrl) { setLoadError("ویدیوی این درس در دسترس نیست."); return; }
      lockedSrcRef.current = data.videoUrl;
      const v = videoRef.current;
      if (v) {
        const keep = v.currentTime;
        const wasPlaying = !v.paused;
        if (hlsRef.current) {
          hlsRef.current.loadSource(data.videoUrl);
        } else {
          v.src = data.videoUrl;
          v.load();
        }
        const restore = () => {
          if (keep > 0) {
            programmaticSeekRef.current = true;
            v.currentTime = keep; lastTimeRef.current = keep;
            window.setTimeout(() => { programmaticSeekRef.current = false; }, 120);
          }
          if (wasPlaying) void v.play().catch(() => undefined);
        };
        v.addEventListener("loadedmetadata", restore, { once: true });
      }
      if (data.progress) { setWatchedPct(data.progress.watchedPct); if (data.progress.quizUnlocked) setQuizUnlocked(true); }
      setLoadError(null); setLoading(true); retryCountRef.current = 0;
    } catch { setLoadError("بارگذاری مجدد ویدیو ممکن نشد. دوباره تلاش کنید."); }
    finally { refreshingSrcRef.current = false; }
  }, [lessonId]);

  // ── Double-tap detection ────────────────────────────────────────────────────
  const handlePointerDown = useCallback((e: React.PointerEvent) => {
    poke();
    if (e.pointerType !== "touch") return; // only touch triggers double-tap

    const rect = containerRef.current?.getBoundingClientRect();
    if (!rect) return;
    const x = e.clientX - rect.left;
    const now = Date.now();
    const lastTap = lastTapRef.current;

    if (lastTap && now - lastTap.time < DOUBLE_TAP_MS && Math.abs(x - lastTap.x) < DOUBLE_TAP_SLOP) {
      lastTapRef.current = null;
      if (tapTimeoutRef.current) { window.clearTimeout(tapTimeoutRef.current); tapTimeoutRef.current = null; }
      // Double-tap: left half = seek back, right half = blocked
      if (x < rect.width / 2) {
        skipBack();
        setSeekIndicator("back");
        setTimeout(() => setSeekIndicator(null), 700);
      } else {
        warnSeekBlocked();
      }
    } else {
      lastTapRef.current = { time: now, x };
      if (tapTimeoutRef.current) window.clearTimeout(tapTimeoutRef.current);
      tapTimeoutRef.current = window.setTimeout(() => {
        lastTapRef.current = null;
        tapTimeoutRef.current = null;
        // Single tap: toggle play on mobile
        toggle();
      }, DOUBLE_TAP_MS);
    }
  }, [poke, skipBack, warnSeekBlocked, toggle]);

  // ── Progress bar hover ──────────────────────────────────────────────────────
  const onProgressHover = (e: React.MouseEvent<HTMLDivElement>) => {
    const rect = e.currentTarget.getBoundingClientRect();
    const frac = Math.max(0, Math.min(1, (e.clientX - rect.left) / rect.width));
    setHoverTime(frac * mediaDuration);
    setHoverX((e.clientX - rect.left));
  };

  // ── Derived values ──────────────────────────────────────────────────────────
  const pct = mediaDuration > 0 ? Math.min(100, (position / mediaDuration) * 100) : 0;
  const bufferedPct = mediaDuration > 0 ? Math.min(100, (bufferedEnd / mediaDuration) * 100) : 0;
  const VolumeIcon = muted || volume === 0 ? VolumeX : volume < 0.5 ? Volume1 : Volume2;

  return (
    <div
      className={cn(
        "space-y-4",
        // Theater mode: on mobile remove page padding; on sm+ break out to full-bleed
        theaterMode && "max-sm:-mx-4 max-sm:w-[calc(100%+2rem)] sm:relative sm:left-1/2 sm:right-1/2 sm:-mx-[50vw] sm:w-screen",
      )}
    >
      {/* ── Player container ─── */}
      <div
        ref={containerRef}
        className={cn(
          "group relative overflow-hidden bg-black shadow-soft",
          theaterMode
            ? "rounded-none border-y border-border"
            : "rounded-xl border border-border",
        )}
        onMouseMove={poke}
        onPointerDown={handlePointerDown}
      >
        {/* Video element */}
        <video
          ref={videoRef}
          className="relative z-10 aspect-video w-full"
          controls={false}
          controlsList="nodownload noplaybackrate noremoteplayback nofullscreen"
          disablePictureInPicture
          playsInline
          preload="metadata"
          draggable={false}
          onDragStart={(e) => e.preventDefault()}
          onContextMenu={(e) => e.preventDefault()}
          onPlay={() => {
            const el = videoRef.current;
            if (el) el.playbackRate = userSpeedRef.current;
            setLoadError(null); setPlaying(true); poke();
          }}
          onPause={() => { setPlaying(false); poke(); }}
          onWaiting={() => setBuffering(true)}
          onPlaying={() => { setLoading(false); setBuffering(false); retryCountRef.current = 0; }}
          onCanPlay={() => { setLoading(false); setBuffering(false); }}
          onLoadedMetadata={() => {
            const el = videoRef.current;
            if (el && Number.isFinite(el.duration) && el.duration > 0) setMediaDuration(el.duration);
          }}
          onError={() => {
            setLoading(false); setBuffering(false);
            setLoadError(`پخش ویدیو قطع شد. تلاش مجدد ${retryCountRef.current > 0 ? `(${retryCountRef.current})` : ""}…`);
            scheduleRetry();
          }}
          muted={muted || volume === 0}
        />

        {/* Loading spinner */}
        {(loading || buffering) && !loadError && (
          <div className="absolute inset-0 z-30 flex items-center justify-center bg-black/50">
            <Skeleton className="h-16 w-16 rounded-full" />
          </div>
        )}

        {/* Error overlay */}
        {loadError && (
          <div className="absolute inset-0 z-30 flex flex-col items-center justify-center gap-3 bg-black/85 px-6 text-center">
            <p className="text-sm font-bold text-white">{loadError}</p>
            <Button type="button" variant="secondary" onClick={() => {
              if (retryTimerRef.current) { window.clearTimeout(retryTimerRef.current); retryTimerRef.current = null; }
              void refreshSignedUrl();
            }}>تلاش دوباره</Button>
          </div>
        )}

        {/* Center play button (idle, non-playing) */}
        <div className="pointer-events-none absolute inset-0 z-20 flex items-center justify-center">
          <AnimatePresence>
            {!playing && !buffering && !loading && !loadError && (
              <motion.button
                key="play-btn"
                type="button"
                initial={{ scale: 0.8, opacity: 0 }}
                animate={{ scale: 1, opacity: 1 }}
                exit={{ scale: 0.8, opacity: 0 }}
                onClick={toggle}
                className="pointer-events-auto flex h-16 w-16 items-center justify-center rounded-full bg-primary text-primary-foreground shadow-lg transition-opacity hover:opacity-90"
                aria-label="پخش"
              >
                <Play className="ms-1 h-8 w-8 fill-white" />
              </motion.button>
            )}
          </AnimatePresence>
        </div>

        {/* Seek indicator (rewind feedback — physical right side) */}
        <AnimatePresence>
          {seekIndicator && (
            <motion.div
              key="seek-indicator"
              initial={{ opacity: 0, scale: 0.7 }}
              animate={{ opacity: 1, scale: 1 }}
              exit={{ opacity: 0, scale: 0.7 }}
              className="pointer-events-none absolute right-8 top-1/2 z-30 flex -translate-y-1/2 flex-col items-center gap-1"
            >
              <div className="flex h-12 w-12 items-center justify-center rounded-full bg-white/20 backdrop-blur-sm">
                <Rewind className="h-6 w-6 text-white" />
              </div>
              <span className="text-xs font-bold text-white drop-shadow">۱۰ ثانیه</span>
            </motion.div>
          )}
        </AnimatePresence>

        {/* Controls overlay */}
        <div
          className={cn(
            "absolute inset-x-0 bottom-0 z-20 bg-gradient-to-t from-black/90 via-black/50 to-transparent pb-[env(safe-area-inset-bottom,0px)] transition-opacity duration-300",
            uiIdle ? "pointer-events-none opacity-0" : "opacity-100",
          )}
        >
          {/* Status bar */}
          <div className="mb-2 flex items-center gap-1 px-4 pt-4 text-[11px] font-medium text-white/90">
            <span className="rounded bg-white/10 px-2 py-0.5">تماشای تاییدشده</span>
            <Lock className="h-3 w-3 opacity-60" />
            <span className="opacity-80">پرش سریع غیرفعال است</span>
            <span className="ms-auto tabular-nums">{fmt(position)} / {fmt(mediaDuration)}</span>
          </div>

          {/* Timeline — unified dir="ltr" coordinate space */}
          <div
            dir="ltr"
            className="relative mx-4 cursor-pointer py-2"
            onMouseMove={onProgressHover}
            onMouseLeave={() => setHoverTime(null)}
          >
            {/* Hover timestamp tooltip */}
            {hoverTime !== null && (
              <div
                className="pointer-events-none absolute -top-6 z-10 rounded bg-black/80 px-1.5 py-0.5 text-[11px] font-bold text-white"
                style={{ left: `${hoverX}px`, transform: "translateX(-50%)" }}
              >
                {fmt(hoverTime)}
              </div>
            )}
            {/* Track layers stacked bottom-to-top: base → buffer → progress → thumb */}
            <div className="relative h-2 overflow-hidden rounded-full bg-white/10">
              {/* Buffer layer */}
              <div
                className="absolute left-0 top-0 h-full rounded-full bg-white/25 transition-[width] duration-300"
                style={{ width: `${bufferedPct}%` }}
              />
              {/* Play progress layer */}
              <div
                className="absolute left-0 top-0 h-full rounded-full bg-primary transition-[width] duration-150"
                style={{ width: `${pct}%` }}
              />
            </div>
            {/* Playhead thumb — positioned outside overflow:hidden, same dir="ltr" space */}
            <div
              className="pointer-events-none absolute top-1/2 h-4 w-4 -translate-y-1/2 rounded-full bg-white shadow-md transition-[left] duration-150"
              style={{ left: `calc(${pct}% - 8px)` }}
            />
          </div>

          {/* Bottom control row — dir="ltr" for physical left→right placement */}
          <div dir="ltr" className="mt-1 flex items-center justify-between gap-1 px-4 pb-3">
            {/* Left group: playback controls + volume + speed */}
            <div className="flex items-center gap-1">
              {/* Play/Pause */}
              <button type="button" onClick={toggle} className="flex min-h-[44px] min-w-[44px] items-center justify-center rounded-full bg-white/10 p-2.5 text-white transition hover:bg-white/20" aria-label="پخش / توقف (Space)">
                {playing ? <Pause className="h-5 w-5" /> : <Play className="h-5 w-5" />}
              </button>

              {/* Rewind 10s */}
              <button type="button" onClick={() => { skipBack(); setSeekIndicator("back"); setTimeout(() => setSeekIndicator(null), 700); }} className="flex min-h-[44px] min-w-[44px] items-center justify-center rounded-full bg-white/10 p-2.5 text-white transition hover:bg-white/20" aria-label="بازگشت ۱۰ ثانیه (J)" title="۱۰ ثانیه عقب (J/←)">
                <Rewind className="h-5 w-5" />
              </button>

              {/* Volume */}
              <button type="button" onClick={() => setMuted((m) => !m)} className="flex min-h-[44px] min-w-[44px] items-center justify-center rounded-full bg-white/10 p-2.5 text-white transition hover:bg-white/20" aria-label="قطع صدا (M)" title="قطع/وصل صدا (M)">
                <VolumeIcon className="h-5 w-5" />
              </button>
              <input type="range" min={0} max={1} step={0.05} value={muted ? 0 : volume} onChange={(e) => { const v = parseFloat(e.target.value); setVolume(v); if (v > 0 && muted) setMuted(false); }} className="hidden h-1 w-16 cursor-pointer accent-white opacity-80 hover:opacity-100 sm:block" aria-label="میزان صدا" />

              {/* Speed pill */}
              <button
                type="button"
                onClick={cycleSpeed}
                title={`سرعت پخش: ${speed}× — کلیک برای تغییر`}
                className="inline-flex min-h-[44px] items-center gap-1 rounded-full bg-white/10 px-2.5 py-2 text-xs font-bold text-white transition hover:bg-white/20"
              >
                <Gauge className="h-4 w-4" />
                <span>{speed}×</span>
              </button>
            </div>

            {/* Right group: watched%, theater, fullscreen */}
            <div className="flex items-center gap-1">
              <span className="hidden text-xs text-white/70 sm:inline">{Math.round(watchedPct)}٪</span>

              {/* Theater mode */}
              <button type="button" onClick={() => setTheaterMode((t) => !t)} className="hidden min-h-[44px] min-w-[44px] items-center justify-center rounded-full bg-white/10 p-2.5 text-white transition hover:bg-white/20 sm:flex" title="حالت تئاتر">
                <ChevronDown className={cn("h-5 w-5 transition-transform", theaterMode && "rotate-180")} />
              </button>

              {/* Fullscreen */}
              <button type="button" onClick={toggleFullscreen} className="flex min-h-[44px] min-w-[44px] items-center justify-center rounded-full bg-white/10 p-2.5 text-white transition hover:bg-white/20" aria-label="تمام‌صفحه (F)" title="تمام‌صفحه (F)">
                {fullscreen ? <Minimize className="h-5 w-5" /> : <Maximize className="h-5 w-5" />}
              </button>
            </div>
          </div>
        </div>

        {/* Quiz unlock CTA */}
        <AnimatePresence>
          {quizUnlockedNow && (
            <motion.div
              key="quiz-cta"
              initial={{ y: 40, opacity: 0 }}
              animate={{ y: 0, opacity: 1 }}
              className="absolute end-4 top-4 z-30"
            >
              <Button asChild variant="gradient" size="lg">
                <Link href={`/quiz/${lessonId}`}>شروع آزمون</Link>
              </Button>
            </motion.div>
          )}
        </AnimatePresence>
      </div>

      {/* ── Progress strip below player ─── */}
      <div className={cn(
        "flex flex-wrap items-center justify-between gap-4 rounded-xl border border-border bg-card p-4",
        theaterMode && "mx-auto max-w-5xl px-6",
      )}>
        <div className="min-w-0 flex-1">
          <p className="text-sm font-medium">پیشرفت تماشای تاییدشده</p>
          <p className="text-xs text-muted-foreground">
            ضربان‌های ارسالی هر {INTERVAL_MS / 1000} ثانیه، زمان واقعی تماشا را تایید می‌کنند. رسیدن به آستانه{" "}
            {completionThresholdPct}٪ آزمون را باز می‌کند.
          </p>
        </div>
        <div className="w-40 shrink-0">
          <Progress value={watchedPct} gradient smooth />
          <p className="mt-1 text-right text-xs text-muted-foreground">{Math.round(watchedPct)}٪</p>
        </div>
        {quizUnlocked ? (
          <Button asChild variant="gradient">
            <Link href={`/quiz/${lessonId}`}>شروع آزمون</Link>
          </Button>
        ) : (
          <Button disabled variant="outline">
            <Lock className="h-4 w-4" /> آزمون قفل است
          </Button>
        )}
      </div>
    </div>
  );
}