import 'dart:io';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
// import 'package:qr_code_scanner/qr_code_scanner.dart';
import 'package:flutter_qrcode_scanner/flutter_qrcode_scanner.dart';

class QRCodeScanner extends StatefulWidget {
  const QRCodeScanner({
    Key key,
  }) : super(key: key);

  @override
  State<StatefulWidget> createState() => _QRCodeScannerState();
}

class _QRCodeScannerState extends State<QRCodeScanner> {
  var result;
  String resultingCode = "";
  QRViewController controller;
  final GlobalKey qrKey = GlobalKey(debugLabel: 'QR');

  // In order to get hot reload to work we need to pause the camera if the platform
  // is android, or resume the camera if the platform is iOS.
  @override
  void reassemble() {
    super.reassemble();
    if (Platform.isAndroid) {
      controller.pauseCamera();
    }
    controller.resumeCamera();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          _buildQrView(context),
          Container(
            margin: EdgeInsets.only(
                top: (MediaQuery.of(context).size.height) -
                    (MediaQuery.of(context).size.height * 0.935),
                left: 10),
            child: Material(
              elevation: 5,
              color: Color.fromRGBO(0, 0, 0, 0.4),
              borderRadius: BorderRadius.only(
                bottomLeft: Radius.circular(25),
                bottomRight: Radius.circular(25),
                topLeft: Radius.circular(25),
                topRight: Radius.circular(25),
              ),
              child: ClipRRect(
                borderRadius: BorderRadius.circular(25.0),
                child: IconButton(
                  icon: Icon(
                    Icons.arrow_back_ios,
                    size: 20,
                  ),
                  color: Colors.white,
                  onPressed: () => Navigator.pop(context),
                ),
              ),
            ),
          ),
          Align(
            alignment: Alignment.bottomCenter,
            child: Container(
              margin: EdgeInsets.only(
                bottom: MediaQuery.of(context).size.height * 0.18,
              ),
              child: Text(
                "Scan QR Code from vender to redeem",
                style: TextStyle(
                  color: Colors.grey,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildQrView(BuildContext context) {
    // For this example we check how width or tall the device is and change the scanArea and overlay accordingly.
    var scanArea = (MediaQuery.of(context).size.width < 400 ||
            MediaQuery.of(context).size.height < 400)
        ? 150.0
        : 300.0;
    // To ensure the Scanner view is properly sizes after rotation
    // we need to listen for Flutter SizeChanged notification and update controller
    return QRView(
      key: qrKey,
      onQRViewCreated: _onQRViewCreated,
      overlay: QrScannerOverlayShape(
          borderColor: Colors.red,
          borderRadius: 10,
          borderLength: 30,
          borderWidth: 10,
          cutOutSize: scanArea),
    );
  }

  void _onQRViewCreated(QRViewController controller) {
    setState(() {
      this.controller = controller;
    });
    controller.scannedDataStream.listen((scanData) {
      setState(() {
        resultingCode = scanData;
      });
      if (resultingCode.isNotEmpty) {
        this.controller.dispose();
        Navigator.pop(context, resultingCode);
      }
    });
  }

  @override
  void dispose() {
    controller?.dispose();
    super.dispose();
  }
}