import 'dart:async';
import 'dart:math' as math;
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:flutter_compass/flutter_compass.dart';
import 'package:get/get.dart';
import 'package:sensors_plus/sensors_plus.dart';
import '../models/angle_unit.dart';
import '../services/camera_sensor_calibration_service.dart';

/// ============================================================================
/// [OpticalRangefinderController] - متحكم منظومة قياس المدى البصري وحساسات الكاميرا
/// ============================================================================
/// English:
/// GetX Controller managing live optical stadiametric rangefinding, camera pinch-to-zoom,
/// sensor intrinsics calibration, inclination pitch, and directional compass heading (الاتجاه).
///
/// العربية:
/// متحكم GetX لإدارة قياس المسافة البصري عبر الكاميرا والتقريب والتبعيد بدون GPS،
/// مع متابعة زوايا الميل والاتجاه المغناطيسي وفحص مستشعر الجهاز.
/// ============================================================================
class OpticalRangefinderController extends GetxController {
  CameraController? cameraController;

  // ── Observables / الحالات التفاعلية ──────────────────────────────────────
  final RxBool isCameraReady = false.obs;
  final RxDouble currentZoom = 1.0.obs;
  final RxDouble minZoom = 1.0.obs;
  final RxDouble maxZoom = 8.0.obs;

  /// زاوية الاتجاه بالدرجات (0 - 360) — مصطلح "الاتجاه"
  final RxDouble headingDeg = 0.0.obs;

  /// زاوية الميل الرأسي بالدرجات (-90 إلى +90)
  final RxDouble pitchDeg = 0.0.obs;

  /// زاوية الميل الجانبي (Roll)
  final RxDouble rollDeg = 0.0.obs;

  /// الهدف التكتيكي المختار
  final Rx<TargetPreset> selectedTarget = CameraSensorCalibrationService.standardTargets[0].obs;
  final RxDouble customHeight = 2.0.obs;
  final RxBool isCustomTarget = false.obs;

  /// ارتفاع شبكة التصويب بالبكسل / نسبة الشاشة (0.05 إلى 0.8)
  final RxDouble reticuleHeightRatio = 0.15.obs;

  /// المسافة المحسوبة بالأمتار
  final RxDouble calculatedDistanceMeters = 0.0.obs;
  final RxDouble errorMarginMeters = 0.0.obs;

  /// معلومات المستشعر الحالية
  final Rx<CameraSensorProfile> sensorProfile = CameraSensorCalibrationService.currentProfile.obs;

  // Stream Subscriptions
  StreamSubscription? _compassSub;
  StreamSubscription? _accelerometerSub;

  double _screenHeight = 800.0;

  @override
  void onInit() {
    super.onInit();
    initSensors();
    initCamera();
  }

  @override
  void onClose() {
    _compassSub?.cancel();
    _accelerometerSub?.cancel();
    cameraController?.dispose();
    super.onClose();
  }

  /// تهيئة مستشعرات الاتجاه والميل
  void initSensors() {
    // 1. Compass for Direction / الاتجاه
    _compassSub = FlutterCompass.events?.listen((event) {
      if (event.heading != null) {
        headingDeg.value = (event.heading! + 360.0) % 360.0;
      }
    });

    // 2. Accelerometer for Pitch & Roll Inclination
    _accelerometerSub = accelerometerEventStream().listen((event) {
      // Calculate Pitch angle from gravity vector
      final gX = event.x;
      final gY = event.y;
      final gZ = event.z;

      final pitch = math.atan2(-gY, math.sqrt(gX * gX + gZ * gZ)) * (180.0 / math.pi);
      final roll = math.atan2(gX, gZ) * (180.0 / math.pi);

      pitchDeg.value = pitch;
      rollDeg.value = roll;
    });
  }

  /// تهيئة الكاميرا وفحص المستشعر
  Future<void> initCamera() async {
    try {
      final cameras = await availableCameras();
      if (cameras.isEmpty) return;

      final backCamera = cameras.firstWhere(
        (c) => c.lensDirection == CameraLensDirection.back,
        orElse: () => cameras.first,
      );

      cameraController = CameraController(
        backCamera,
        ResolutionPreset.high,
        enableAudio: false,
      );

      await cameraController!.initialize();

      // Get Zoom limits
      minZoom.value = await cameraController!.getMinZoomLevel();
      maxZoom.value = math.min(10.0, await cameraController!.getMaxZoomLevel());
      currentZoom.value = minZoom.value;

      // Inspect & Calibrate sensor parameters
      final previewSize = cameraController!.value.previewSize ?? const Size(1920, 1080);
      sensorProfile.value = CameraSensorCalibrationService.inspectSensor(
        backCamera,
        Size(previewSize.width, previewSize.height),
      );

      isCameraReady.value = true;
      recalculateDistance();
    } catch (e) {
      debugPrint('Optical Rangefinder Camera Error: $e');
    }
  }

  /// تحديث ارتفاع الشاشة الفعلي عند الرسم
  void updateScreenDimensions(Size size) {
    if (size.height > 0 && size.height != _screenHeight) {
      _screenHeight = size.height;
      recalculateDistance();
    }
  }

  /// تغيير مستوى التقريب (Pinch or Slider)
  Future<void> setZoom(double newZoom) async {
    final clamped = newZoom.clamp(minZoom.value, maxZoom.value);
    currentZoom.value = clamped;
    try {
      await cameraController?.setZoomLevel(clamped);
    } catch (_) {}
    recalculateDistance();
  }

  /// تعديل حجم مؤشر التصويب (Pinch / Drag Reticule)
  void setReticuleHeightRatio(double newRatio) {
    reticuleHeightRatio.value = newRatio.clamp(0.02, 0.75);
    recalculateDistance();
  }

  /// اختيار هدف تكتيكي جاهز
  void selectTarget(TargetPreset preset) {
    selectedTarget.value = preset;
    isCustomTarget.value = false;
    recalculateDistance();
  }

  /// تعيين ارتفاع مخصص للهدف
  void setCustomTargetHeight(double heightMeters) {
    customHeight.value = heightMeters.clamp(0.2, 500.0);
    isCustomTarget.value = true;
    recalculateDistance();
  }

  /// إعادة احتساب المسافة بناءً على المعادلة البصرية
  void recalculateDistance() {
    final targetH = isCustomTarget.value
        ? customHeight.value
        : selectedTarget.value.heightMeters;

    final reticulePx = reticuleHeightRatio.value * _screenHeight;

    final dist = CameraSensorCalibrationService.calculateStadiametricDistance(
      targetRealHeightMeters: targetH,
      reticulePixelHeight: reticulePx,
      screenHeightPixels: _screenHeight,
      zoomMultiplier: currentZoom.value,
    );

    calculatedDistanceMeters.value = dist;
    errorMarginMeters.value = CameraSensorCalibrationService.estimateErrorMarginMeters(
      dist,
      currentZoom.value,
    );
  }

  /// تنسيق قيمة الاتجاه بحسب نظام الزوايا المعتمد
  String formatHeading(AngleUnit unit) {
    return unit.formatHeading(headingDeg.value);
  }

  /// تنسيق نص المسافة (متر / كم)
  String formatDistance() {
    final dist = calculatedDistanceMeters.value;
    final err = errorMarginMeters.value;
    if (dist >= 1000.0) {
      final km = dist / 1000.0;
      final errKm = err / 1000.0;
      return '${km.toStringAsFixed(2)} كم (±${(errKm * 1000).toInt()}م)';
    }
    return '${dist.toStringAsFixed(0)} م (±${err.toStringAsFixed(0)}م)';
  }
}