import { useRef, useState, useCallback, useEffect } from "react";
import { Camera, CameraOff, Aperture, X } from "lucide-react";

export default function CameraPanel({ onCapture, previewUrl, onReset }) {
  const videoRef = useRef(null);
  const canvasRef = useRef(null);
  const streamRef = useRef(null);
  const [isCameraOn, setIsCameraOn] = useState(false);
  const [cameraError, setCameraError] = useState("");
  const [isVideoReady, setIsVideoReady] = useState(false);

  // Cleanup saat unmount
  useEffect(() => {
    return () => {
      stopCamera();
    };
  }, []);

  // Assign stream ke video element setelah state berubah dan element ter-render
  useEffect(() => {
    if (isCameraOn && videoRef.current && streamRef.current) {
      const video = videoRef.current;
      video.srcObject = streamRef.current;

      video.onloadedmetadata = () => {
        video.play()
          .then(() => setIsVideoReady(true))
          .catch((err) => console.error("Video play error:", err));
      };
    }
  }, [isCameraOn]);

  async function startCamera() {
    setCameraError("");
    setIsVideoReady(false);
    try {
      const stream = await navigator.mediaDevices.getUserMedia({
        video: {
          facingMode: "environment",
          width: { ideal: 1280 },
          height: { ideal: 720 },
        },
      });
      streamRef.current = stream;

      // Set state dulu agar video element di-render,
      // lalu useEffect di atas akan assign stream
      setIsCameraOn(true);
    } catch (err) {
      console.error("Camera error:", err);
      if (err.name === "NotAllowedError") {
        setCameraError("Izin kamera ditolak. Aktifkan izin kamera pada browser.");
      } else if (err.name === "NotFoundError") {
        setCameraError("Kamera tidak ditemukan pada perangkat ini.");
      } else {
        setCameraError("Gagal mengaktifkan kamera. Coba lagi.");
      }
    }
  }

  function stopCamera() {
    if (streamRef.current) {
      streamRef.current.getTracks().forEach((track) => track.stop());
      streamRef.current = null;
    }
    if (videoRef.current) {
      videoRef.current.srcObject = null;
    }
    setIsCameraOn(false);
    setIsVideoReady(false);
  }

  const captureImage = useCallback(() => {
    if (!videoRef.current || !canvasRef.current) return;

    const video = videoRef.current;
    const canvas = canvasRef.current;

    canvas.width = video.videoWidth;
    canvas.height = video.videoHeight;

    const ctx = canvas.getContext("2d");
    ctx.drawImage(video, 0, 0);

    canvas.toBlob(
      (blob) => {
        if (blob) {
          const file = new File([blob], `capture_${Date.now()}.jpg`, {
            type: "image/jpeg",
          });
          onCapture(file);
          stopCamera();
        }
      },
      "image/jpeg",
      0.9
    );
  }, [onCapture]);

  return (
    <div className="space-y-4">
      {cameraError && (
        <div className="bg-red-50 border border-red-200 rounded-lg px-4 py-3 text-sm text-red-700">
          {cameraError}
        </div>
      )}

      {previewUrl ? (
        <div className="relative">
          <img
            src={previewUrl}
            alt="Captured"
            className="w-full rounded-xl border border-slate-200 object-contain max-h-72"
          />
          <button
            onClick={() => {
              onReset();
            }}
            className="absolute top-2 right-2 bg-red-500 hover:bg-red-600 text-white rounded-full p-1.5 shadow-md transition-colors cursor-pointer"
          >
            <X className="w-4 h-4" />
          </button>
        </div>
      ) : isCameraOn ? (
        <div className="relative rounded-xl overflow-hidden border border-slate-200 bg-slate-900">
          {/* Loading indicator sebelum video ready */}
          {!isVideoReady && (
            <div className="absolute inset-0 flex items-center justify-center z-10">
              <div className="text-center">
                <div className="w-8 h-8 border-3 border-white border-t-transparent rounded-full animate-spin mx-auto mb-2"></div>
                <p className="text-xs text-white/70">Memuat kamera...</p>
              </div>
            </div>
          )}

          <video
            ref={videoRef}
            autoPlay
            playsInline
            muted
            className="w-full object-cover"
            style={{ minHeight: "280px", maxHeight: "400px" }}
          />

          {isVideoReady && (
            <div className="absolute bottom-3 left-0 right-0 flex justify-center gap-3">
              <button
                onClick={captureImage}
                className="bg-white hover:bg-slate-100 text-slate-800 rounded-full p-3 shadow-lg transition-colors cursor-pointer"
                title="Ambil Gambar"
              >
                <Aperture className="w-6 h-6" />
              </button>
              <button
                onClick={stopCamera}
                className="bg-red-500 hover:bg-red-600 text-white rounded-full p-3 shadow-lg transition-colors cursor-pointer"
                title="Matikan Kamera"
              >
                <CameraOff className="w-6 h-6" />
              </button>
            </div>
          )}
        </div>
      ) : (
        <div className="border-2 border-dashed border-slate-300 rounded-xl p-8 md:p-12 text-center">
          <Camera className="w-10 h-10 text-slate-400 mx-auto mb-3" />
          <p className="text-sm text-slate-600 mb-4">
            Gunakan kamera untuk mengambil gambar kendaraan
          </p>
          <button
            onClick={startCamera}
            className="inline-flex items-center gap-2 bg-blue-600 hover:bg-blue-700 text-white text-sm font-medium px-5 py-2.5 rounded-lg transition-colors cursor-pointer"
          >
            <Camera className="w-4 h-4" />
            Aktifkan Kamera
          </button>
        </div>
      )}

      <canvas ref={canvasRef} className="hidden" />
    </div>
  );
}