import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:mobile_scanner_example/picklist/classes/detect_collision.dart';
import 'package:mobile_scanner_example/picklist/widgets/crosshair.dart';
import 'package:mobile_scanner_example/picklist/widgets/draw_detected_barcodes.dart';
import 'package:mobile_scanner_example/scanner_error_widget.dart';

class BarcodeScannerPicklist extends StatefulWidget {
  const BarcodeScannerPicklist({super.key});

  @override
  State<BarcodeScannerPicklist> createState() => _BarcodeScannerPicklistState();
}

class _BarcodeScannerPicklistState extends State<BarcodeScannerPicklist>
    with WidgetsBindingObserver {
  final _mobileScannerController = MobileScannerController(autoStart: false);
  StreamSubscription<Object?>? _barcodesSubscription;

  final _scannerDisabled = ValueNotifier(false);

  late final Offset _crosshair;

  bool barcodeDetected = false;

  @override
  void didChangeDependencies() {
    _crosshair = MediaQuery.sizeOf(context).center(Offset.zero);
    super.didChangeDependencies();
  }

  @override
  void initState() {
    SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);
    WidgetsBinding.instance.addObserver(this);
    _barcodesSubscription = _mobileScannerController.barcodes.listen(
      _handleBarcodes,
    );
    super.initState();
    unawaited(_mobileScannerController.start());
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (!_mobileScannerController.value.isInitialized) {
      return;
    }

    switch (state) {
      case AppLifecycleState.detached:
      case AppLifecycleState.hidden:
      case AppLifecycleState.paused:
        return;
      case AppLifecycleState.resumed:
        _barcodesSubscription =
            _mobileScannerController.barcodes.listen(_handleBarcodes);

        unawaited(_mobileScannerController.start());
      case AppLifecycleState.inactive:
        unawaited(_barcodesSubscription?.cancel());
        _barcodesSubscription = null;
        unawaited(_mobileScannerController.stop());
    }
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    unawaited(_barcodesSubscription?.cancel());
    _barcodesSubscription = null;
    super.dispose();
    _mobileScannerController.dispose();
  }

  void _handleBarcodes(BarcodeCapture barcodes) {
    if (_scannerDisabled.value) {
      return;
    }

    for (final barcode in barcodes.barcodes) {
      if (isOffsetInsideShape(
        _crosshair,
        barcode.corners,
      )) {
        if (!barcodeDetected) {
          barcodeDetected = true;
          Navigator.of(context).pop(barcode);
        }
        return;
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    const boxFit = BoxFit.contain;
    return PopScope(
      onPopInvokedWithResult: (didPop, result) {
        if (didPop) {
          SystemChrome.setPreferredOrientations([...DeviceOrientation.values]);
        }
      },
      child: Scaffold(
        appBar: AppBar(title: const Text('Picklist scanner')),
        backgroundColor: Colors.black,
        body: StreamBuilder(
          stream: _mobileScannerController.barcodes,
          builder: (context, snapshot) {
            final barcodes = snapshot.data;
            if (barcodes == null) {
              debugPrint('ISNULL');
            }
            return Listener(
              behavior: HitTestBehavior.opaque,
              onPointerDown: (_) => _scannerDisabled.value = true,
              onPointerUp: (_) => _scannerDisabled.value = false,
              onPointerCancel: (_) => _scannerDisabled.value = false,
              child: Stack(
                fit: StackFit.expand,
                children: [
                  MobileScanner(
                    controller: _mobileScannerController,
                    errorBuilder: (context, error, child) {
                      return ScannerErrorWidget(error: error);
                    },
                    fit: boxFit,
                  ),
                  ...drawDetectedBarcodes(
                    barcodes: barcodes?.barcodes,
                    cameraPreviewSize: _mobileScannerController.value.size,
                    fit: boxFit,
                  ),
                  ValueListenableBuilder(
                    valueListenable: _scannerDisabled,
                    builder: (context, value, child) {
                      return Crosshair(
                        scannerDisabled: value,
                      );
                    },
                  ),
                ],
              ),
            );
          },
        )
        // body:  Stack(
        //   fit: StackFit.expand,
        //   children: [
        //     MobileScanner(
        //       controller: _mobileScannerController,
        //       errorBuilder: (context, error, child) {
        //         return ScannerErrorWidget(error: error);
        //       },
        //       fit: boxFit,
        //     ),
        //     ...drawDetectedBarcodes(
        //       controller: _mobileScannerController,
        //       cameraPreviewSize: _mobileScannerController.value.size,
        //       fit: boxFit,
        //     ),
        //     ...drawDetectedBarcodes(
        //       controller: _mobileScannerController,
        //       cameraPreviewSize: _mobileScannerController.value.size,
        //       fit: boxFit,
        //     ),
        //     //   barcodes: _mobileScannerController. value. _barcodes.value,
        //     //   cameraPreviewSize: _mobileScannerController.value.size,
        //     //   fit: boxFit,
        //     // ),
        //     CustomPaint(
        //       painter: BarcodeOverlay(
        //         barcodeCorners: [
        //           const Offset(0, 0),
        //           const Offset(50, 0),
        //           const Offset(50, 50),
        //           const Offset(0, 50)
        //         ],
        //         barcodeSize: Size(50, 50),
        //         boxFit: boxFit,
        //         cameraPreviewSize: _mobileScannerController.value.size,
        //       ),
        //     ),
        //     Crosshair(
        //       crosshairRectangle: _crosshairRectangle,
        //       scannerDisabled: _scannerDisabled.value,
        //     ),
        //   ],
        // ),
        ,
      ),
    );
  }
}